1.
Taxonomy (biology)
–
Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
Taxonomy (biology)
–
Title page of
Systema Naturae, Leiden, 1735
Taxonomy (biology)
–
Evolution of the
vertebrates at class level, width of spindles indicating number of families. Spindle diagrams are typical for
Evolutionary taxonomy
Taxonomy (biology)
–
The same relationship, expressed as a
cladogram typical for
cladistics
Taxonomy (biology)
–
Type specimen for
Nepenthes smilesii, a tropical
pitcher plant.
2.
Eukaryote
–
A eukaryote is any organism whose cells contain a nucleus and other organelles enclosed within membranes. Eukaryotes belong to the taxon Eukarya or Eukaryota, the presence of a nucleus gives eukaryotes their name, which comes from the Greek εὖ and κάρυον. Eukaryotic cells also contain other membrane-bound organelles such as mitochondria and the Golgi apparatus, in addition, plants and algae contain chloroplasts. Eukaryotic organisms may be unicellular or multicellular, only eukaryotes form multicellular organisms consisting of many kinds of tissue made up of different cell types. Eukaryotes can reproduce asexually through mitosis and sexually through meiosis and gamete fusion. In mitosis, one cell divides to produce two identical cells. In meiosis, DNA replication is followed by two rounds of division to produce four daughter cells each with half the number of chromosomes as the original parent cell. These act as sex cells resulting from genetic recombination during meiosis, the domain Eukaryota appears to be monophyletic, and so makes up one of the three domains of life. The two other domains, Bacteria and Archaea, are prokaryotes and have none of the above features, eukaryotes represent a tiny minority of all living things. However, due to their larger size, eukaryotes collective worldwide biomass is estimated at about equal to that of prokaryotes. Eukaryotes first developed approximately 1. 6–2.1 billion years ago, in 1905 and 1910, the Russian biologist Konstantin Mereschkowsky argued three things about the origin of nucleated cells. Firstly, plastids were reduced cyanobacteria in a symbiosis with a non-photosynthetic host, secondly, the host had earlier in evolution formed by symbiosis between an amoeba-like host and a bacteria-like cell that formed the nucleus. Thirdly, plants inherited photosynthesis from cyanobacteria, the split between the prokaryotes and eukaryotes was introduced in the 1960s. The concept of the eukaryote has been attributed to the French biologist Edouard Chatton, the terms prokaryote and eukaryote were more definitively reintroduced by the Canadian microbiologist Roger Stanier and the Dutch-American microbiologist C. B. van Niel in 1962. In his 1938 work Titres et Travaux Scientifiques, Chatton had proposed the two terms, calling the bacteria prokaryotes and organisms with nuclei in their cells eukaryotes. However he mentioned this in one paragraph, and the idea was effectively ignored until Chattons statement was rediscovered by Stanier. In 1967, Lynn Margulis provided microbiological evidence for endosymbiosis as the origin of chloroplasts and mitochondria in cells in her paper. In the 1970s, Carl Woese explored microbial phylogenetics, studying variations in 16S ribosomal RNA and this helped to uncover the origin of the eukaryotes and the symbiogenesis of two important eukaryote organelles, mitochondria and chloroplasts
Eukaryote
–
Had'n
Eukaryote
–
Longitudinal section through the flagellum of
Chlamydomonas reinhardtii
3.
Fungus
–
A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from the other eukaryotic life kingdoms of plants, a characteristic that places fungi in a different kingdom from plants, bacteria and some protists, is chitin in their cell walls. Similar to animals, fungi are heterotrophs, they acquire their food by absorbing dissolved molecules, growth is their means of mobility, except for spores, which may travel through the air or water. Fungi are the principal decomposers in ecological systems and this fungal group is distinct from the structurally similar myxomycetes and oomycetes. The discipline of biology devoted to the study of fungi is known as mycology, in the past, mycology was regarded as a branch of botany, although it is now known fungi are genetically more closely related to animals than to plants. Abundant worldwide, most fungi are inconspicuous because of the size of their structures. Fungi include symbionts of plants, animals, or other fungi and they may become noticeable when fruiting, either as mushrooms or as molds. Fungi perform a role in the decomposition of organic matter and have fundamental roles in nutrient cycling. Since the 1940s, fungi have been used for the production of antibiotics, Fungi are also used as biological pesticides to control weeds, plant diseases and insect pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, the fruiting structures of a few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies. Fungi can break down manufactured materials and buildings, and become significant pathogens of humans, losses of crops due to fungal diseases or food spoilage can have a large impact on human food supplies and local economies. The fungus kingdom encompasses a diversity of taxa with varied ecologies, life cycle strategies. However, little is known of the biodiversity of Kingdom Fungi. Advances in molecular genetics have opened the way for DNA analysis to be incorporated into taxonomy, phylogenetic studies published in the last decade have helped reshape the classification within Kingdom Fungi, which is divided into one subkingdom, seven phyla, and ten subphyla. The English word fungus is directly adopted from the Latin fungus, used in the writings of Horace, a group of all the fungi present in a particular area or geographic region is known as mycobiota, e. g. the mycobiota of Ireland. Like plants, fungi grow in soil and, in the case of mushrooms, form conspicuous fruit bodies. The fungi are now considered a kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago. Fungi have membrane-bound cytoplasmic organelles such as mitochondria, sterol-containing membranes and they have a characteristic range of soluble carbohydrates and storage compounds, including sugar alcohols, disaccharides, and polysaccharides
Fungus
Fungus
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Omphalotus nidiformis, a bioluminescent mushroom
Fungus
–
Bracket fungi on a tree stump
Fungus
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Two types of edible fungi
4.
Ascomycota
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Ascomycota is a division or phylum of the kingdom Fungi that, together with the Basidiomycota, form the subkingdom Dikarya. Its members are known as the sac fungi or ascomycetes. They are the largest phylum of Fungi, with over 64,000 species, the defining feature of this fungal group is the ascus, a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of the Ascomycota are asexual, meaning that they do not have a sexual cycle, the ascomycetes are a monophyletic group, i. e. it contains all descendants of one common ancestor. Familiar examples of sac fungi include morels, truffles, brewers yeast and bakers yeast, dead mans fingers, the fungal symbionts in the majority of lichens such as Cladonia belong to the Ascomycota. There are many plant-pathogenic ascomycetes, including apple scab, rice blast, the fungi, black knot. Several species of ascomycetes are biological model organisms in laboratory research, most famously, Neurospora crassa, several species of yeasts, and Aspergillus species are used in many genetics and cell biology studies. Penicillium species on cheeses and those producing antibiotics for treating infectious diseases are examples of taxa that belong to the Ascomycota. They are fungi which produce microscopic spores inside special, elongated cells or sacs, known as asci, Asexual reproduction, Asexual reproduction is the dominant form of propagation in the Ascomycota, and is responsible for the rapid spread of these fungi into new areas. Asexual reproduction of ascomycetes is very diverse from both structural and functional points of view, the most important and general is production of conidia, but chlamydospores are also frequently produced. Furthermore, Ascomycota also reproduce asexually through budding, 1) Conidia formation, Asexual reproduction may occur through vegetative reproductive spores, the conidia. Asexual, non-motile haploid spore of a fungus, which is named after the Greek word for dust, conia and they are typically formed at the ends of specialized hyphae, the conidiophores. Depending on the species they may be dispersed by wind or water, conidiophores may simply branch off from the mycelia or they may be formed in fruiting bodies. The hypha that creates the sporing tip can be similar to the normal hyphal tip. The most common differentiation is the formation of a bottle shaped cell called a phialide, as all of these asexual structures are not single hyphae. In some groups, the conidiophores are aggregated to form a thick structure, in the order Moniliales, all of them are single hyphae with the exception of the aggregations, termed as coremia or synnema. These produce structures rather like corn-stokes, with many conidia being produced in a mass from the aggregated conidiophores, the diverse conidia and conidiophores sometimes develop in asexual sporocarps with different characteristics. Some species of Ascomycetes form their structures within plant tissue, either as parasite or saprophytes and these fungi have evolved more complex asexual sporing structures, probably influenced by the cultural conditions of plant tissue as a substrate
Ascomycota
–
Ascomycota
Ascomycota
–
A member of the
Cordyceps genus which is parasitic on arthropods. Note the elongated ascocarps. Species unknown, perhaps Cordyceps ignota.
Ascomycota
–
The "candlesnuff fungus",
Xylaria hypoxylon
Ascomycota
–
The ascocarp of a
morel contains numerous apothecia.
5.
Pro parte
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For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies. This name is no longer in use, it is now a synonym of the current scientific name which is Picea abies, unlike synonyms in other contexts, in taxonomy a synonym is not interchangeable with the name of which it is a synonym. In taxonomy, synonyms are not equals, but have a different status, for any taxon with a particular circumscription, position, and rank, only one scientific name is considered to be the correct one at any given time. A synonym cannot exist in isolation, it is always an alternative to a different scientific name, given that the correct name of a taxon depends on the taxonomic viewpoint used a name that is one taxonomists synonym may be another taxonomists correct name. Synonyms may arise whenever the same taxon is described and named more than once, independently. They may also arise when existing taxa are changed, as when two taxa are joined to one, a species is moved to a different genus. To the general user of scientific names, in such as agriculture, horticulture, ecology, general science. A synonym is a name that was used as the correct scientific name but which has been displaced by another scientific name. Thus Oxford Dictionaries Online defines the term as a name which has the same application as another. In handbooks and general texts, it is useful to have mentioned as such after the current scientific name. Synonyms used in this way may not always meet the strict definitions of the synonym in the formal rules of nomenclature which govern scientific names. Changes of scientific name have two causes, they may be taxonomic or nomenclatural, a name change may be caused by changes in the circumscription, position or rank of a taxon, representing a change in taxonomic, scientific insight. A name change may be due to purely nomenclatural reasons, that is, based on the rules of nomenclature, the earliest such name is called the senior synonym, while the later name is the junior synonym. One basic principle of zoological nomenclature is that the earliest correctly published name, synonyms are important because if the earliest name cannot be used, then the next available junior synonym must be used for the taxon. Objective synonyms refer to taxa with the type and same rank. For example, John Edward Gray published the name Antilocapra anteflexa in 1855 for a species of pronghorn, however, it is now commonly accepted that his specimen was an unusual individual of the species Antilocapra americana published by George Ord in 1815. Ords name thus takes precedence, with Antilocapra anteflexa being a subjective synonym. Objective synonyms are common at the level of genera, because for various reasons two genera may contain the type species, these are objective synonyms
Pro parte
–
The
Latin Caudata and
Greek Urodela both mean "tailed" and have been used as a scientific name at the rank of order for the
salamanders (as opposed to the tail-less
frogs). Thus they are synonyms.
Pro parte
–
The common dandelion
Taraxacum officinale sensu lato is an extremely widespread group of
apomictic lineages, and some scientists apply the "biological species concept" to divide it into many distinct species; other scientists regard all the names for those independent species as synonyms.
6.
Taphrinomycotina
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The Taphrinomycotina are one of three subdivisions constituting the Ascomycota and is more or less synonymous with the slightly older invalid name Archiascomycetes. Recent molecular studies suggest that the group is monophyletic and basal to the rest of the Ascomycota, the Schizosaccharomycetes are yeasts that reproduce by fission rather than budding, unlike most other yeasts, many of which are in the subdivision Saccharomycotina. The Taphrinomycetes are dimorphic plant parasites with both a yeast state and a state in infected plants. They characteristically infect leaves, catkins, and branches, not roots, the Neolectomycetes are species in a single genus, Neolecta, which are the only members of the subdivision that form fruiting bodies, and which specifically grow out of root tips. They may have a yeast state, the Pneumocystidomycetes also encompasses only one genus, Pneumocystis, one of which causes Pneumocystis pneumonia in humans. All species infect mammalian lungs and are yeasts, none has ascogenous hyphae giving rise to the asci. The Oregon Coalition of Interdisciplinary Databases, Archiascomycetes, Early Diverging Ascomycetes
Taphrinomycotina
–
Taphrinomycotina
7.
Basidiomycota
–
Basidiomycota is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya within the kingdom Fungi. Basidiomycota are filamentous fungi composed of hyphae and reproduce sexually via the formation of specialized club-shaped end cells called basidia that normally bear external meiospores and these specialized spores are called basidiospores. However, some Basidiomycota reproduce asexually in addition or exclusively, the most recent classification adopted by a coalition of 67 mycologists recognizes three subphyla and two other class level taxa outside of these, among the Basidiomycota. As now classified, the join and also cut across various obsolete taxonomic groups previously commonly used to describe Basidiomycota. According to a 2008 estimate, Basidiomycota comprise three subphyla 16 classes,52 orders,177 families,1,589 genera, and 31,515 species, the terms basidiomycetes and ascomycetes are frequently used loosely to refer to Basidiomycota and Ascomycota. They are often abbreviated to basidios and ascos as mycological slang, the Agaricomycotina include what had previously been called the Hymenomycetes, the Gasteromycetes, as well as most of the jelly fungi. The three classes in the Agaricomycotina are the Agaricomycetes, the Dacrymycetes, and the Tremellomycetes, the class Wallemiomycetes is not yet placed in a subdivision, but recent genomic evidence suggests that it is a sister group of Agaricomycotina. The Ustilaginomycotina are most of the former smut fungi and the Exobasidiales, the classes of the Ustilaginomycotina are the Exobasidiomycetes, the Entorrhizomycetes, and the Ustilaginomycetes. Typically haploid Basidiomycota mycelia fuse via plasmogamy and then the compatible nuclei migrate into each others mycelia, karyogamy is delayed, so that the compatible nuclei remain in pairs, called a dikaryon. The hyphae are said to be dikaryotic. Conversely, the mycelia are called monokaryons. Often, the mycelium is more vigorous than the individual monokaryotic mycelia. The dikaryons can be long-lived, lasting years, decades, or centuries, the monokaryons are neither male nor female. They have either a bipolar or a mating system. However, there are variations of these genes in the population. It is as if there were multiple sexes, meiosis follows shortly with the production of 4 haploid nuclei that migrate into 4 external, usually apical basidiospores. Typically the basidiospores are ballistic, hence they are also called ballistospores. In most species, the basidiospores disperse and each can start a new haploid mycelium, basidia are microscopic but they are often produced on or in multicelled large fructifications called basidiocarps or basidiomes, or fruitbodies), variously called mushrooms, puffballs, etc
Basidiomycota
–
Basidiomycota
8.
Agaricomycotina
–
The subdivision Agaricomycotina, also known as the hymenomycetes, is one of three taxa of the fungal division Basidiomycota. Species in the Agaricomycotina that are not Agaricomycetes include the jelly fungi, certain yeasts, ear fungi, and others, a higher-level phylogenetic classification of the Fungi. Cryptogamic Botany, Vol. I, Algae and Fungi, 2nd Ed. McGraw Hill Book Co, data related to Agaricomycotina at Wikispecies Media related to Agaricomycotina at Wikimedia Commons Tree of Life Agaricomycotina Hymenomycetes at the Tree of Life Web Project
Agaricomycotina
–
Agaricomycotina
9.
Pucciniomycotina
–
Pucciniomycotina is a subdivision of fungus within the division Basidiomycota. The subdivision contains 9 classes,20 orders, and 37 families, over 8400 species of Pucciniomycotina have been described - more than 8% of all described fungi. The group was known as Urediniomycetes until 2006, when it was elevated from a class to a subdivision and named after the largest order in the group, Puccinales. Pucciniomycotina have a range of ecologies as insect parasites, mycoparasites. Many Pucciniomycotina are rust fungi and are placed in the order Puccinales that contains roughly 7800 species, some members of the group are of economical importance as a pathogen on a wide range of commercial plants, e. g. wheat. Pucciniomycotina is a cosmopolite and exists all over the world, there is a high morphological diversity in the Pucciniomycontina. The sporulating forms range from macrobasidiocarp to single-celled yeasts, the presence of simple septal pores unites Pucciniomycotina and distinguishes it from the sister groups. The predominance of mannose in the walls is also a uniting feature of the group. Some members are known from their anamorphs, and asexual stages predominate in most. A striking characteristic of Puccinomycotina is the developmental pattern. Rust Fungi or plant pathogenic members in Puccinales have the most complex life cycles known in the fungal kingdom, studies have shown that Puccinales also has one the largest genomes in the fungi kingdom, and that genome size expansion may be common. This explains the complex life cycles within the group, an overview of the higher level classification of Pucciniomycotina based on combined analyses of nuclear large and small subunit rDNA sequences. Mycologia, Band 98,2006, S. 896-905, robert Bauer, Dominik Begerow, José Paulo Sampaio, Michael Weiβ, Franz Oberwinkler, The simple-septate basidiomycetes, a synopsis. Mycological Progress, Band 5,2006, S. 41-66, ISSN 1617-416X, tree of Life Pucciniomycotina http, //website. nbm-mnb. ca/mycologywebpages/NaturalHistoryOfFungi/PucciniomycotinaDiscussion. html http, //tolweb. org/Pucciniomycotina/20528
Pucciniomycotina
–
Pucciniomycotina
10.
Unicellular organism
–
A unicellular organism, also known as a single-celled organism, is an organism that consists of only one cell, unlike a multicellular organism that consists of more than one cell. Historically, simple unicellular organisms have been referred to as monads, though this term is used more specifically to describe organisms of the genus Monas. The main groups of organisms are bacteria, archaea, protozoa, unicellular algae. Unicellular organisms fall into two categories, prokaryotic organisms and eukaryotic organisms. Unicellular organisms are thought to be the oldest form of life, prokaryotes, most Protista, and some fungi are unicellular. Although some of these live in colonies, they dont exhibit specialization. These organisms live together, and each cell in the colony is the same, however, each individual cell must carry out all life processes to survive. In contrast, even the simplest multicellular organisms have cells that depend on each other to survive, most multicellular organisms have a unicellular life-cycle stage. Gametes, for example, are reproductive unicells for multicellular organisms, additionally, multicellularity appears to have evolved independently many times in the history of life. Some organisms are partially uni- and multicellular, like Dictyostelium discoideum, additionally, unicellular organisms can be multinucleate, like Myxogastria and Plasmodium. Candidatus Magnetoglobus multicellular, related to Deltaproteobacteria, is a multicellular prokaryote and it is neither unicellular, nor a colony. Primitive cells, often referred to as protocells, are the precursors to todays unicellular organisms, the RNA world hypothesis assumes that RNA molecules could form in abiotic conditions, which would require nucleic acids and ribose to be present. Theoretical and experimental findings show that nucleic acids and sugars could have been synthesized in early prebiotic conditions, compartmentalization was necessary for chemical reactions to be more likely as well as to differentiate reactions with the external environment. For example, an early RNA replicator ribozyme may have replicated other replicator ribozymes of different RNA sequences if not kept separate, when amphiphiles like lipids are placed in water, the hydrophobic tails aggregate to form micelles and vesicles, with the hydrophilic ends facing outwards. Primitive cells likely used self-assembling fatty-acid vesicles to separate chemical reactions, because of their simplicity and ability to self-assemble in water, its likely that these simple membranes predated other forms of early biological molecules. Prokaryotes lack membrane-bound organelles, such as mitochondria or a nucleus, instead, most prokaryotes have an irregular region that contains DNA, known as the nucleoid. Most prokaryotes have a single, circular chromosome, which is in contrast to eukaryotes, nutritionally, prokaryotes have the ability to utilize a wide range of organic and inorganic material for use in metabolism, including sulfur, cellulose, ammonia, or nitrite. Prokaryotes as a whole are ubiquitous in the environment and exist in extreme environments as well, bacteria are one of the world’s oldest forms of life, and are found virtually everywhere in nature
Unicellular organism
–
Valonia ventricosa, a species of
algae with a diameter that ranges typically from 1 to 4 centimetres (0.39 to 1.57 in) is among the largest unicellular species
11.
Microorganism
–
A microorganism or microbe is a microscopic organism, which may be single-celled or multicellular. The study of microorganisms is called microbiology, a subject that began with the discovery of microorganisms in 1674 by Antonie van Leeuwenhoek, microorganisms are very diverse and include all bacteria, archaea and most protozoa. This group also contains some fungi, algae, and some such as rotifers. Many macroscopic animals and plants have microscopic juvenile stages, some microbiologists classify viruses and viroids as microorganisms, but others consider these as nonliving. In July 2016, scientists identified a set of 355 genes from the last universal ancestor of all life, including microorganisms. Microorganisms, under certain test conditions, have observed to thrive in the vacuum of outer space. Microorganisms likely far outweigh all other living things combined, the mass of prokaryote microorganisms including the bacteria and archaea may be as much as 0.8 trillion tons of carbon, out of the total biomass of between 1 and 4 trillion tons. Microorganisms appear to thrive in the Mariana Trench, the deepest spot in the Earths oceans, in August 2014, scientists confirmed the existence of microorganisms living 800 m below the ice of Antarctica. According to one researcher, You can find microbes everywhere — theyre extremely adaptable to conditions, microorganisms are crucial to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a part of the nitrogen cycle. Microorganisms are also exploited in biotechnology, both in food and beverage preparation, and in modern technologies based on genetic engineering. A small proportion of microorganisms are pathogenic, causing disease and even death in plants, Robert Hooke coined the term cell after viewing plant cells under his microscope. Antonie Van Leeuwenhoek was one of the first people to observe microorganisms in 1673, later, in the 19th century, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In 1876 Robert Koch discovered that microorganisms cause diseases, single-celled microorganisms were the first forms of life to develop on Earth, approximately 3–4 billion years ago. Further evolution was slow, and for about 3 billion years in the Precambrian eon, so, for most of the history of life on Earth, the only forms of life were microorganisms. Bacteria, algae and fungi have been identified in amber that is 220 million years old, microorganisms tend to have a relatively fast rate of evolution. Most microorganisms can reproduce rapidly, and bacteria are able to freely exchange genes through conjugation, transformation and transduction. This rapid evolution is important in medicine, as it has led to the development of multidrug resistant pathogenic bacteria, superbugs, the possible existence of microorganisms was discussed for many centuries before their discovery in the 17th century
Microorganism
–
A cluster of
Escherichia coli bacteria magnified 10,000 times
Microorganism
–
Antonie van Leeuwenhoek, the first
microbiologist and the first to observe microorganisms using a
microscope
Microorganism
–
Lazzaro Spallanzani showed that boiling a broth stopped it from decaying
Microorganism
–
Louis Pasteur showed that Spallanzani's findings held even if air could enter through a filter that kept particles out
12.
Kingdom (biology)
–
In biology, kingdom is the second highest taxonomic rank below domain. Kingdoms are divided into groups called phyla. Traditionally, textbooks from the United States used a system of six kingdoms while textbooks in Great Britain, India, Australia, Latin America and other countries used five kingdoms. Later two further main ranks were introduced, making the kingdom, phylum or division, class, order, family, genus. In the 1960s a rank was introduced above kingdom, namely domain, prefixes can be added so subkingdom and infrakingdom are the two ranks immediately below kingdom. Superkingdom may be considered as an equivalent of domain or empire or as an independent rank between kingdom and domain or subdomain, in some classification systems the additional rank branch can be inserted between subkingdom and infrakingdom. Taxonomic ranks, including kingdoms, were to be groups of organisms with a common ancestor, based on such RNA studies, Carl Woese thought life could be divided into three large divisions and referred to them as the three primary kingdom model or urkingdom model. In 1990, the domain was proposed for the highest rank. This term represents a synonym for the category of dominion, introduced by Moore in 1974, unlike Moore, Whoese et al. did not suggest a Latin term for this category, which represents a further argument supporting the accurately introduced term dominion. It was also found that the eukaryotes are more related to the Archaea than they are to the Eubacteria. Although the primacy of the Eubacteria-Archaea divide has been questioned, it has been upheld by subsequent research, there is no consensus on how many kingdoms exist in the classification scheme proposed by Woese. In 2004, a article by Simpson and Roger noted that the Protista were a grab-bag for all eukaryotes that are not animals. On this basis, the diagram opposite showed the real kingdoms of the eukaryotes, a classification which followed this approach was produced in 2005 for the International Society of Protistologists, by a committee which worked in collaboration with specialists from many societies. It divided the eukaryotes into the same six supergroups, the published classification deliberately did not use formal taxonomic ranks, including that of kingdom. In this system the multicellular animals are descended from the same ancestor as both the unicellular choanoflagellates and the fungi which form the Opisthokonta, Plants are thought to be more distantly related to animals and fungi. Beyond this, there does not appear to be a consensus, rogozin et al. in 2009 noted that The deep phylogeny of eukaryotes is an extremely difficult and controversial problem. The classification of living things into animals and plants is an ancient one, aristotle classified animal species in his History of Animals, while his pupil Theophrastus wrote a parallel work, the Historia Plantarum, on plants. Carl Linnaeus laid the foundations for biological nomenclature, now regulated by the Nomenclature Codes
Kingdom (biology)
13.
Species
–
In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
Species
–
John Ray
Species
–
Carl Linnaeus believed in the fixity of species.
14.
Multicellular organism
–
Multicellular organisms are organisms that consist of more than one cell, in contrast to unicellular organisms. Multicellular organisms arise in different ways, for example by cell division or by aggregation of many single cells. Colonial organisms are the result of identical individuals joining together to form a colony. Multicellularity has evolved independently at least 46 times, including in some prokaryotes, like cyanobacteria, myxobacteria, actinomycetes, however, complex multicellular organisms evolved only in six eukaryotic groups, animals, fungi, brown algae, red algae, green algae, and land plants. It evolved repeatedly for Chloroplastida, once or twice for animals, once for brown algae, the first evidence of multicellularity is from cyanobacteria-like organisms that lived 3–3.5 billion years ago. To reproduce, true multicellular organisms must solve the problem of regenerating a whole organism from germ cells, animals have evolved a considerable diversity of cell types in a multicellular body, compared with 10–20 in plants and fungi. Loss of multicellularity occurred in some groups, fungi are predominantly multicellular, though early diverging lineages are largely unicellular and there have been numerous reversions to unicellularity across fungi. It may also have occurred in some red algae, but it is possible that they are primitively unicellular), loss of multicellularity is also considered probable in some green algae. In other groups, generally parasites, a reduction of multicellularity occurred, multicellular organisms, especially long-living animals, face the challenge of cancer, which occurs when cells fail to regulate their growth within the normal program of development. Changes in tissue morphology can be observed during this process, cancer in animals has often been described as a loss of multicellularity. There is a discussion about the possibility of existence of cancer in other organisms or even in protozoa. For example, plant galls have been characterized as tumors but some argue that plants do not develop cancer. In some multicellular groups, which are called Weismannists, a separation between a sterile somatic cell line and a cell line evolved. However, Weismannist development is relatively rare, as part of species have the capacity for somatic embryogenesis. One hypothesis for the origin of multicellularity is that a group of function-specific cells aggregated into a mass called a grex. This is essentially what slime molds do, another hypothesis is that a primitive cell underwent nucleus division, thereby becoming a coenocyte. A membrane would then form around each nucleus, thereby resulting in a group of connected cells in one organism and this is what plant and animal embryos do as well as colonial choanoflagellates. Because the first multicellular organisms were simple, soft organisms lacking bone, shell or other body parts
Multicellular organism
–
In this image, a
wild-type Caenorhabditis elegans is stained to highlight the nuclei of its cells.
Multicellular organism
15.
Pseudohyphae
–
A hypha is a long, branching filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the mode of vegetative growth. Yeasts are unicellular fungi that do not grow as hyphae, a hypha consists of one or more cells surrounded by a tubular cell wall. In most fungi, hyphae are divided into cells by internal cross-walls called septa, septa are usually perforated by pores large enough for ribosomes, mitochondria and sometimes nuclei to flow between cells. The major structural polymer in fungal cell walls is typically chitin, in contrast to plants, some fungi have aseptate hyphae, meaning their hyphae are not partitioned by septa. Hyphae have a diameter of 4-6 µm. During tip growth, cell walls are extended by the assembly and polymerization of cell wall components. The spitzenkörper is an intracellular organelle associated with tip growth and it is composed of an aggregation of membrane-bound vesicles containing cell wall components. The spitzenkörper is part of the system of fungi, holding and releasing vesicles it receives from the Golgi apparatus. These vesicles travel to the membrane via the cytoskeleton and release their contents outside the cell by the process of exocytosis. Vesicle membranes contribute to growth of the membrane while their contents form new cell wall. As a hypha extends, septa may be formed behind the tip to partition each hypha into individual cells. Hyphae can branch through the bifurcation of a tip, or by the emergence of a new tip from an established hypha. The direction of growth can be controlled by environmental stimuli. Hyphae can sense reproductive units from some distance, and grow towards them, hyphae can weave through a permeable surface to penetrate it. Hyphae may be modified in different ways to serve specific functions. Some parasitic fungi form haustoria that function in absorption within the host cells, the arbuscules of mutualistic mycorrhizal fungi serve a similar function in nutrient exchange, so are important in assisting nutrient and water absorption by plants. Hyphae are found enveloping the gonidia in lichens, making up a part of their structure
Pseudohyphae
–
Hyphae of
Penicillium
Pseudohyphae
–
Aspergillus niger
16.
Diameter
–
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle, both definitions are also valid for the diameter of a sphere. In more modern usage, the length of a diameter is called the diameter. In this sense one speaks of the rather than a diameter, because all diameters of a circle or sphere have the same length. Both quantities can be calculated efficiently using rotating calipers, for a curve of constant width such as the Reuleaux triangle, the width and diameter are the same because all such pairs of parallel tangent lines have the same distance. For an ellipse, the terminology is different. A diameter of an ellipse is any chord passing through the midpoint of the ellipse, for example, conjugate diameters have the property that a tangent line to the ellipse at the endpoint of one of them is parallel to the other one. The longest diameter is called the major axis, the word diameter is derived from Greek διάμετρος, diameter of a circle, from διά, across, through and μέτρον, measure. It is often abbreviated DIA, dia, d, or ⌀, the definitions given above are only valid for circles, spheres and convex shapes. However, they are cases of a more general definition that is valid for any kind of n-dimensional convex or non-convex object. The diameter of a subset of a space is the least upper bound of the set of all distances between pairs of points in the subset. So, if A is the subset, the diameter is sup, if the distance function d is viewed here as having codomain R, this implies that the diameter of the empty set equals −∞. Some authors prefer to treat the empty set as a case, assigning it a diameter equal to 0. For any solid object or set of scattered points in n-dimensional Euclidean space, in medical parlance concerning a lesion or in geology concerning a rock, the diameter of an object is the supremum of the set of all distances between pairs of points in the object. In differential geometry, the diameter is an important global Riemannian invariant, the symbol or variable for diameter, ⌀, is similar in size and design to ø, the Latin small letter o with stroke. In Unicode it is defined as U+2300 ⌀ Diameter sign, on an Apple Macintosh, the diameter symbol can be entered via the character palette, where it can be found in the Technical Symbols category. The character will not display correctly, however, since many fonts do not include it. In many situations the letter ø is a substitute, which in Unicode is U+00F8 ø
Diameter
–
Circle with
circumference (C) in black, diameter (D) in cyan, radius (R) in red, and centre or origin (O) in magenta.
17.
Asexual reproduction
–
Asexual reproduction is the primary form of reproduction for single-celled organisms such as the Archaea and bacteria. Many plants and fungi reproduce asexually as well, a complete lack of sexual reproduction is relatively rare among multicellular organisms, particularly animals. It is not entirely understood why the ability to reproduce sexually is so common among them, developmental constraints may underlie why few animals have relinquished sexual reproduction completely in their life-cycles. An important form of fission is binary fission, in binary fission, the parent/adult organism is replaced by two daughter organisms, because it literally divides in two. Only prokaryotes reproduce asexually through binary fission, eukaryotes may reproduce in a functionally similar manner by mitosis, most of these are also capable of sexual reproduction. Another type of fission is multiple fission, multiple fission at the cellular level occurs in many protists, e. g. sporozoans and algae. The nucleus of the parent cell divides several times by mitosis, the cytoplasm then separates, creating multiple daughter cells. In apicomplexans, multiple fission, or schizogony, is manifested either as merogony, sporogony or gametogony, merogony results in merozoites, which are multiple daughter cells, that originate within the same cell membrane, sporogony results in sporozoites, and gametogony results in microgametes. Some cells split via budding, resulting in a mother and daughter cell, the offspring organism is smaller than the parent. Budding is also known on a level, an animal example is the hydra. The buds grow into fully matured individuals which break away from the parent organism. Internal budding is a process of reproduction, favoured by parasites such as Toxoplasma gondii. It involves a process in which two or more daughter cells are produced inside a mother cell, which is then consumed by the offspring prior to their separation. Also, budding is present in some worm like Taenia or Echinococci, vegetative propagation is a type of asexual reproduction found in plants where new individuals are formed without the production of seeds or spores by meiosis or syngamy. Examples of vegetative reproduction include the formation of miniaturized plants called plantlets on specialized leaves, other plants reproduce by forming bulbs or tubers. Some plants produce adventitious shoots and may form a colony, where all the individuals are clones. Many multicellular organisms form spores during their life cycle in a process called sporogenesis. Exceptions are animals and some protists, who undergo meiosis immediately followed by fertilization, plants and many algae on the other hand undergo sporic meiosis where meiosis leads to the formation of haploid spores rather than gametes
Asexual reproduction
–
Asexual reproduction in
liverworts: a
caducous phylloid germinating
Asexual reproduction
–
Closeup of a
Bryophyllum daigremontianum
18.
Mitosis
–
In cell biology, mitosis is a part of the cell cycle when replicated chromosomes are separated into two new nuclei. Mitosis and cytokinesis together define the phase of an animal cell cycle—the division of the mother cell into two daughter cells genetically identical to each other. The process of mitosis is divided into stages corresponding to the completion of one set of activities and these stages are prophase, prometaphase, metaphase, anaphase, and telophase. During mitosis, the chromosomes, which have already duplicated, condense, the result is two genetically identical daughter nuclei. The rest of the cell may then continue to divide by cytokinesis to produce two daughter cells, producing three or more daughter cells instead of normal two is a mitotic error called tripolar mitosis or multipolar mitosis. Other errors during mitosis can induce apoptosis or cause mutations, certain types of cancer can arise from such mutations. Mitosis occurs only in eukaryotic cells, prokaryotic cells, which lack a nucleus, divide by a different process called binary fission. Most animal cells undergo a change, known as mitotic cell rounding. Most human cells are produced by cell division. Important exceptions include the gametes – sperm and egg cells – which are produced by meiosis, german zoologist Otto Bütschli might have claimed the discovery of the process presently known as mitosis, a term coined by Walther Flemming in 1882. Mitosis was discovered in frog, rabbit, and cat cornea cells in 1873, the term is derived from the Greek word μίτος mitos warp thread. The primary result of mitosis and cytokinesis is the transfer of a parent cells genome into two daughter cells, the genome is composed of a number of chromosomes—complexes of tightly coiled DNA that contain genetic information vital for proper cell function. Because each resultant daughter cell should be identical to the parent cell. This occurs during the S phase of interphase, chromosome duplication results in two identical sister chromatids bound together by cohesin proteins at the centromere. When mitosis begins, the chromosomes condense and become visible, in some eukaryotes, for example animals, the nuclear envelope, which segregates the DNA from the cytoplasm, disintegrates into small vesicles. The nucleolus, which makes ribosomes in the cell, also disappears, microtubules project from opposite ends of the cell, attach to the centromeres, and align the chromosomes centrally within the cell. The microtubules then contract to pull the chromatids of each chromosome apart. Sister chromatids at this point are called daughter chromosomes, as the cell elongates, corresponding daughter chromosomes are pulled toward opposite ends of the cell and condense maximally in late anaphase
Mitosis
–
Onion (
Allium) cells in different phases of the cell cycle enlarged 800 diameters. a. non-dividing cells b. nuclei preparing for division (spireme-stage) c. dividing cells showing mitotic figures e. pair of daughter-cells shortly after division
Mitosis
–
Mitosis in an
animal cell.
Mitosis
Mitosis
19.
Budding
–
Budding is a form of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. The new organism remains attached as it grows, separating from the parent organism only when it is mature, since the reproduction is asexual, the newly created organism is a clone and is genetically identical to the parent organism. Organisms such as hydra use regenerative cells for reproduction in the process of budding, in hydra, a bud develops as an outgrowth due to repeated cell division at one specific site. These buds develop into tiny individuals and, when mature, detach from the parent body. Internal budding or endodyogeny is a process of reproduction, favoured by parasites such as Toxoplasma gondii. It involves a process in which two daughter cells are produced inside a mother cell, which is then consumed by the offspring prior to their separation. Endopolygeny is the division into several organisms at once by internal budding, some cells divide asymmetrically by budding, for example Saccharomyces cerevisiae, the yeast species used in baking and brewing. This process results in a cell and a smaller daughter cell. Cryo-electron tomography recently revealed that mitochondria in cells divide by budding, in some multicellular animals, offspring may develop as outgrowths of the mother. Animals that reproduce by budding include corals, some sponges, some acoel flatworms, colonies of some bee species have also exhibited budding behavior, such as Apis dorsata. Although budding behavior is rare in this bee species, it has been observed when a group of workers leave the natal nest and construct a new nest usually near the natal one. In virology, budding is a form of viral shedding by which enveloped viruses acquire their external envelope from the host cell membrane, in agriculture and horticulture, budding refers to grafting the bud of one plant onto another
Budding
–
Saccharomyces cerevisiae reproducing by budding
Budding
–
Hydra with two buds
20.
Mold
–
A mold or mould is a fungus that grows in the form of multicellular filaments called hyphae. In contrast, fungi that can adopt a single-celled growth habit are called yeasts, molds are a large and taxonomically diverse number of fungal species in which the growth of hyphae results in discoloration and a fuzzy appearance, especially on food. The network of these tubular branching hyphae, called a mycelium, is considered a single organism, the hyphae are generally transparent, so the mycelium appears like very fine, fluffy white threads over the surface. Cross-walls may delimit connected compartments along the hyphae, each containing one or multiple, the dusty texture of many molds is caused by profuse production of asexual spores formed by differentiation at the ends of hyphae. The mode of formation and shape of spores is traditionally used to classify molds. Many of these spores are colored, making the much more obvious to the human eye at this stage in its life-cycle. Molds are considered to be microbes and do not form a taxonomic or phylogenetic grouping. In the past, most molds were classified within the Deuteromycota, molds cause biodegradation of natural materials, which can be unwanted when it becomes food spoilage or damage to property. They also play important roles in biotechnology and food science in the production of foods, beverages, antibiotics, pharmaceuticals. There are thousands of species of molds, which have diverse life-styles including saprotrophs, mesophiles, psychrophiles and thermophiles. They all require moisture for growth and some live in aquatic environments, like all fungi, molds derive energy not through photosynthesis but from the organic matter on which they live, utilising heterotrophy. Typically, molds secrete hydrolytic enzymes, mainly from the hyphal tips and these enzymes degrade complex biopolymers such as starch, cellulose and lignin into simpler substances which can be absorbed by the hyphae. In this way molds play a role in causing decomposition of organic material. Many molds also synthesise mycotoxins and siderophores which, together with lytic enzymes, molds can also grow on stored food for animals and humans, making the food unpalatable or toxic and are thus a major source of food losses and illness. Many strategies for food preservation are to prevent or slow growth as well as growth of other microbes. Molds reproduce by producing large numbers of spores, which may contain a single nucleus or be multinucleate. Mold spores can be asexual or sexual, many species can produce both types, other mold spores have slimy sheaths and are more suited to water dispersal. Mold spores are spherical or ovoid single cells, but can be multicellular
Mold
–
Mold growing on a
clementine
Mold
–
Mold growth covering a decaying
peach. The frames were taken approximately 12 hours apart over a period of six days.
Mold
–
Spinellus fusiger growing on the mushroom
Mycena haematopus
Mold
–
Moldy tomatoes
21.
Hypha
–
A hypha is a long, branching filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the mode of vegetative growth. Yeasts are unicellular fungi that do not grow as hyphae, a hypha consists of one or more cells surrounded by a tubular cell wall. In most fungi, hyphae are divided into cells by internal cross-walls called septa, septa are usually perforated by pores large enough for ribosomes, mitochondria and sometimes nuclei to flow between cells. The major structural polymer in fungal cell walls is typically chitin, in contrast to plants, some fungi have aseptate hyphae, meaning their hyphae are not partitioned by septa. Hyphae have a diameter of 4-6 µm. During tip growth, cell walls are extended by the assembly and polymerization of cell wall components. The spitzenkörper is an intracellular organelle associated with tip growth and it is composed of an aggregation of membrane-bound vesicles containing cell wall components. The spitzenkörper is part of the system of fungi, holding and releasing vesicles it receives from the Golgi apparatus. These vesicles travel to the membrane via the cytoskeleton and release their contents outside the cell by the process of exocytosis. Vesicle membranes contribute to growth of the membrane while their contents form new cell wall. As a hypha extends, septa may be formed behind the tip to partition each hypha into individual cells. Hyphae can branch through the bifurcation of a tip, or by the emergence of a new tip from an established hypha. The direction of growth can be controlled by environmental stimuli. Hyphae can sense reproductive units from some distance, and grow towards them, hyphae can weave through a permeable surface to penetrate it. Hyphae may be modified in different ways to serve specific functions. Some parasitic fungi form haustoria that function in absorption within the host cells, the arbuscules of mutualistic mycorrhizal fungi serve a similar function in nutrient exchange, so are important in assisting nutrient and water absorption by plants. Hyphae are found enveloping the gonidia in lichens, making up a part of their structure
Hypha
–
Hyphae of
Penicillium
Hypha
–
Aspergillus niger
22.
Fermentation (food)
–
Fermentation in food processing is the process of converting carbohydrates to alcohol or organic acids using microorganisms—yeasts or bacteria—under anaerobic conditions. Fermentation usually implies that the action of microorganisms is desired, the science of fermentation is known as zymology or zymurgy. The term fermentation sometimes refers specifically to the conversion of sugars into ethanol, producing alcoholic drinks such as wine, beer. However, similar processes take place in the leavening of bread, other widely consumed fermented foods include vinegar, olives, and cheese. More localised foods prepared by fermentation may also be based on beans, grain, vegetables, fruit, honey, dairy products, fish, meat, since ancient times, humans have exploited the fermentation process. Seven-thousand-year-old jars containing the remains of wine, now on display at the University of Pennsylvania, were excavated in the Zagros Mountains in Iran. There is strong evidence that people were fermenting alcoholic drinks in Babylon c.3000 BC, ancient Egypt c.3150 BC, pre-Hispanic Mexico c.2000 BC, the French chemist Louis Pasteur founded zymology, when in 1856 he connected yeast to fermentation. When studying the fermentation of sugar to alcohol by yeast, Pasteur concluded that the fermentation was catalyzed by a force, called ferments. The ferments were thought to only within living organisms. Alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells, nevertheless, it was known that yeast extracts can ferment sugar even in the absence of living yeast cells. In 1907 he received the Nobel Prize in Chemistry for his research, one year earlier, in 1906, ethanol fermentation studies led to the early discovery of NAD+. Food fermentation is the conversion of sugars and other carbohydrates into alcohol or preservative organic acids, all three products have found human uses. The production of carbon dioxide is used to leaven bread, the production of organic acids is exploited to preserve and flavor vegetables and dairy products. It has more cases of botulism than any state in the United States of America. The World Health Organization has classified pickled foods as possibly carcinogenic, other research found that fermented food contains a carcinogenic by-product, ethyl carbamate. A2009 review of the studies conducted across Asia concluded that regularly eating pickled vegetables roughly doubles a persons risk for esophageal squamous cell carcinoma. Science aid, Fermentation - Process and uses of fermentation Fermented cereals, a global perspective - FAO1999
Fermentation (food)
–
Beer fermenting at a
brewery
Fermentation (food)
–
Beer and bread, two major uses of fermentation in food
Fermentation (food)
–
Nattō, a Japanese fermented
soybean food
Fermentation (food)
–
Batter made from rice and lentil (Vigna mungo) prepared and fermented for baking
idlis and
dosas
23.
Saccharomyces cerevisiae
–
Saccharomyces cerevisiae is a species of yeast. It has been instrumental to winemaking, baking, and brewing since ancient times and it is believed to have been originally isolated from the skin of grapes. It is one of the most intensively studied model organisms in molecular and cell biology. It is the microorganism behind the most common type of fermentation, S. cerevisiae cells are round to ovoid, 5–10 μm in diameter. It reproduces by a process known as budding. Many proteins important in biology were first discovered by studying their homologs in yeast, these proteins include cell cycle proteins, signaling proteins. S. cerevisiae is currently the only yeast cell known to have Berkeley bodies present, antibodies against S. cerevisiae are found in 60–70% of patients with Crohns disease and 10–15% of patients with ulcerative colitis. Saccharomyces derives from Latinized Greek and means sugar-mold or sugar-fungus, saccharo being the combining form sugar, cerevisiae comes from Latin and means of beer. Refinements in microbiology following the work of Louis Pasteur led to more advanced methods of culturing pure strains, in 1879, Great Britain introduced specialized growing vats for the production of S. The company created yeast that would rise twice as fast, cutting down on baking time, lesaffre would later create instant yeast in the 1970s, which has gained considerable use and market share at the expense of both fresh and dry yeast in their various applications. In nature, yeast cells are primarily on ripe fruits such as grapes. Since S. cerevisiae is not airborne, it requires a vector to move, queens of social wasps overwintering as adults can harbor yeast cells from autumn to spring and transmit them to their progeny. The intestine of Polistes dominula, a wasp, hosts S. cerevisiae strains as well as S. cerevisiae × S. paradoxus hybrids. The optimum temperature for growth of S. cerevisiae is 30–35 °C, two forms of yeast cells can survive and grow, haploid and diploid. The haploid cells undergo a simple lifecycle of mitosis and growth and this is the asexual form of the fungus. The diploid cells undergo a simple lifecycle of mitosis and growth. The rate at which the cell cycle progresses often differs substantially between haploid and diploid cells. Under conditions of stress, diploid cells can undergo sporulation, entering meiosis and producing four haploid spores and this is the sexual form of the fungus
Saccharomyces cerevisiae
–
Saccharomyces cerevisiae
Saccharomyces cerevisiae
–
Yeast colonies on an agar plate.
Saccharomyces cerevisiae
–
Saccharomyces cerevisiae Numbered ticks are 10 micrometers apart.
Saccharomyces cerevisiae
–
Types
24.
Carbohydrate
–
A carbohydrate is a biological molecule consisting of carbon, hydrogen and oxygen atoms, usually with a hydrogen–oxygen atom ratio of 2,1, in other words, with the empirical formula Cmn. This formula holds true for monosaccharides, some exceptions exist, for example, deoxyribose, a sugar component of DNA, has the empirical formula C5H10O4. Carbohydrates are technically hydrates of carbon, structurally it is accurate to view them as polyhydroxy aldehydes and ketones. The term is most common in biochemistry, where it is a synonym of saccharide, a group that includes sugars, starch, the saccharides are divided into four chemical groups, monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Monosaccharides and disaccharides, the smallest carbohydrates, are referred to as sugars. The word saccharide comes from the Greek word σάκχαρον, meaning sugar, while the scientific nomenclature of carbohydrates is complex, the names of the monosaccharides and disaccharides very often end in the suffix -ose. For example, grape sugar is the glucose, cane sugar is the disaccharide sucrose. Carbohydrates perform numerous roles in living organisms, polysaccharides serve for the storage of energy and as structural components. The 5-carbon monosaccharide ribose is an important component of coenzymes and the backbone of the genetic molecule known as RNA, the related deoxyribose is a component of DNA. Saccharides and their derivatives include many other important biomolecules that play key roles in the system, fertilization, preventing pathogenesis, blood clotting. In food science and in informal contexts, the term carbohydrate often means any food that is particularly rich in the complex carbohydrate starch or simple carbohydrates. Often in lists of information, such as the USDA National Nutrient Database, the term carbohydrate is used for everything other than water, protein, fat, ash. This will include chemical compounds such as acetic or lactic acid, carbohydrates are found in wide variety of foods. The important sources are cereals, potatoes, sugarcane, fruits, table sugar, bread, milk, starch and sugar are the important carbohydrates in our diet. Starch is abundant in potatoes, maize, rice and other cereals, sugar appears in our diet mainly as sucrose which is added to drinks and many prepared foods such as jam, biscuits and cakes. Glucose and fructose are found naturally in fruits and some vegetables. Glycogen is carbohydrate found in the liver and muscles, cellulose in the cell wall of all plant tissue is a carbohydrate. It is important in our diet as fibre which helps to maintain a healthy digestive system, formerly the name carbohydrate was used in chemistry for any compound with the formula Cm n
Carbohydrate
–
Grain products: rich sources of carbohydrates
Carbohydrate
25.
Ethanol
–
Ethanol, also called alcohol, ethyl alcohol, and drinking alcohol, is the principal type of alcohol found in alcoholic beverages. It is a volatile, flammable, colorless liquid with a characteristic odor. Its chemical formula is C 2H 6O, which can be written also as CH 3-CH 2-OH or C 2H 5-OH, ethanol is mostly produced by the fermentation of sugars by yeasts, or by petrochemical processes. It is a psychoactive drug, causing a characteristic intoxication. It is widely used as a solvent, as fuel, and as a feedstock for synthesis of other chemicals, the eth- prefix and the qualifier ethyl in ethyl alcohol originally come from the name ethyl assigned in 1834 to the group C 2H 5- by Justus Liebig. He coined the word from the German name Aether of the compound C 2H 5-O-C 2H5, according to the Oxford English Dictionary, Ethyl is a contraction of the Ancient Greek αἰθήρ and the Greek word ύλη. The name ethanol was coined as a result of a resolution that was adopted at the International Conference on Chemical Nomenclature that was held in April 1892 in Geneva, Switzerland. The term alcohol now refers to a class of substances in chemistry nomenclature. The Oxford English Dictionary claims that it is a loan from Arabic al-kuḥl, a powdered ore of antimony used since aniquity as a cosmetic. The use of alcohol for ethanol is modern, first recorded 1753, the systematic use in chemistry dates to 1850. Ethanol is used in medical wipes and most common antibacterial hand sanitizer gels as an antiseptic, ethanol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacteria and fungi, and many viruses. However, ethanol is ineffective against bacterial spores, ethanol may be administered as an antidote to methanol and ethylene glycol poisoning. Ethanol, often in high concentrations, is used to dissolve many water-insoluble medications, as a central nervous system depressant, ethanol is one of the most commonly consumed psychoactive drugs. The amount of ethanol in the body is typically quantified by blood alcohol content, small doses of ethanol, in general, produce euphoria and relaxation, people experiencing these symptoms tend to become talkative and less inhibited, and may exhibit poor judgment. Ethanol is commonly consumed as a drug, especially while socializing. The largest single use of ethanol is as a fuel and fuel additive. Brazil in particular relies heavily upon the use of ethanol as an engine fuel, gasoline sold in Brazil contains at least 25% anhydrous ethanol. Hydrous ethanol can be used as fuel in more than 90% of new gasoline fueled cars sold in the country, Brazilian ethanol is produced from sugar cane and noted for high carbon sequestration
Ethanol
–
USP grade ethanol for laboratory use.
Ethanol
–
Ethanol pump station in
São Paulo, Brazil
Ethanol
–
A
Ford Taurus fueled by ethanol in
New York City
Ethanol
–
USPS truck running on
E85 in
Minnesota
26.
Baking
–
Baking is a method of cooking food that uses prolonged dry heat, normally in an oven, but also in hot ashes, or on hot stones. The most common baked item is bread but many types of foods are baked. Heat is gradually transferred from the surface of cakes, cookies, as heat travels through it transforms batters and doughs into baked goods with a firm dry crust and a softer centre. Baking can be combined with grilling to produce a hybrid barbecue variant by using both methods simultaneously, or one after the other, Baking is related to barbecuing because the concept of the masonry oven is similar to that of a smoke pit. Because of historical social and familial roles, baking has traditionally performed at home by women for domestic consumption and by men in bakeries. When production was industrialized, baking was automated by machines in large factories, the art of baking remains a fundamental skill and is important for nutrition, as baked goods, especially breads, are a common but important food, both from an economic and cultural point of view. A person who prepares baked goods as a profession is called a baker, all types of food can be baked, but some require special care and protection from direct heat. Various techniques have developed to provide this protection. In addition to bread, baking is used to prepare cakes, pastries, pies, tarts, quiches, cookies, scones, crackers, pretzels, and more. Larger cuts prepared without stuffing or coating are often roasted. Roasting, however, is suitable for finer cuts of meat. One of these is the known as en croûte, which protects the food from direct heat. Meat, poultry, game, fish or vegetables can be prepared by baking en croûte, the en croûte method also allows meat to be baked by burying it in the embers of a fire – a favourite method of cooking venison. In this case, the casing is made from a paste of flour. Salt can also be used to make a protective crust that is not eaten, another method of protecting food from the heat while it is baking, is to cook it en papillote. In this method, the food is covered by baking paper to protect it while it is being baked, the cooked parcel of food is sometimes served unopened, allowing diners to discover the contents for themselves which adds an element of surprise. Eggs can also be used in baking to produce savoury or sweet dishes, in combination with dairy products especially cheese, they are often prepared as a dessert. For example, although a baked custard can be made using starch, baked custards, such as crème caramel, are among the items that need protection from an ovens direct heat, and the bain-marie method serves this purpose
Baking
–
Bedouins making and baking bread
Baking
–
Anders Zorn - Bread baking (1889)
Baking
–
A
Palestinian woman baking
markook bread on
tava or Saj oven in
Artas,
Bethlehem
Baking
–
A
terracotta baking mould for
pastry or
bread, representing goats and a lion attacking a cow. Early 2nd millennium BC, Royal palace at
Mari, Syria
27.
Model organism
–
Model organisms are in vivo models and are widely used to research human disease when human experimentation would be unfeasible or unethical. This strategy is made possible by the descent of all living organisms. Studying model organisms can be informative, but care must be taken when extrapolating from one organism to another, in researching human disease, model organisms allow for better understanding the disease process without the added risk of harming an actual human. The species chosen will usually meet a determined taxonomic equivalency to humans, although biological activity in a model organism does not ensure an effect in humans, many drugs, treatments and cures for human diseases are developed in part with the guidance of animal models. There are three types of disease models, homologous, isomorphic and predictive. Homologous animals have the same causes, symptoms and treatment options as would humans who have the same disease, isomorphic animals share the same symptoms and treatments. Predictive models are similar to a human disease in only a couple of aspects. The use of animals in research dates back to ancient Greece, with Aristotle, research using animal models has been central to most of the achievements of modern medicine. It has contributed most of the knowledge in fields such as human physiology and biochemistry. For example, the results have included the near-eradication of polio and the development of organ transplantation, from 1910 to 1927, Thomas Hunt Morgans work with the fruit fly Drosophila melanogaster identified chromosomes as the vector of inheritance for genes. Drosophila became one of the first, and for some time the most widely used, model organisms, D. melanogaster remains one of the most widely used eukaryotic model organisms. The mouse has since been used extensively as an organism and is associated with many important biological discoveries of the 20th. In the late 19th century, Emil von Behring isolated the diphtheria toxin and he went on to develop an antitoxin against diphtheria in animals and then in humans, which resulted in the modern methods of immunization and largely ended diphtheria as a threatening disease. The diphtheria antitoxin is famously commemorated in the Iditarod race, which is modeled after the delivery of antitoxin in the 1925 serum run to Nome. The success of animal studies in producing the diphtheria antitoxin has also attributed as a cause for the decline of the early 20th-century opposition to animal research in the United States. This led to the 1922 discovery of insulin and its use in treating diabetes, modern general anaesthetics, such as halothane and related compounds, were also developed through studies on model organisms, and are necessary for modern, complex surgical operations. In the 1940s, Jonas Salk used rhesus monkey studies to isolate the most virulent forms of the polio virus, the vaccine, which was made publicly available in 1955, reduced the incidence of polio 15-fold in the United States over the following five years. It has been estimated that developing and producing the vaccines required the use of 100,000 rhesus monkeys, models are those organisms with a wealth of biological data that make them attractive to study as examples for other species and/or natural phenomena that are more difficult to study directly
Model organism
–
Escherichia coli is a
Gram-negative prokaryotic model organism
Model organism
–
Drosophila melanogaster, one of the most famous subjects for
genetics experiments
Model organism
–
Saccharomyces cerevisiae, one of the most intensively studied
eukaryotic model organisms in
molecular and
cell biology
Model organism
–
Electron microphotograph of
tobacco mosaic virus (TMV) particles
28.
Cell biology
–
Cell biology is a branch of biology that studies the different structures and functions of the cell and focuses mainly on the idea of the cell as the basic unit of life. This is done both on a microscopic and molecular level as it encompasses prokaryotic cells and eukaryotic cells, knowing the components of cells and how cells work is fundamental to all biological sciences, it is also essential for research in bio-medical fields such as cancer, and other diseases. Research in cell biology is closely related to genetics, biochemistry, molecular biology, immunology, and developmental biology. The study of the cell is done on a level, however, most of the processes within the cell are made up of a mixture of small organic molecules, inorganic ions, hormones. Approximately 75-85% of the volume is due to water making it an indispensable solvent as a result of its polarity. These molecules within the cell, which operate as substrates, provide an environment for the cell to carry out metabolic reactions. The cell shape varies among the different types of organisms, and are then classified into two categories, eukaryotes and prokaryotes. Cell biology focuses more on the study of cells, and their signalling pathways. This environment of the cell is made up of hydrophilic and hydrophobic regions which allows for the exchange of the above-mentioned molecules and ions. The hydrophilic regions of the cell are mainly on the inside and outside of the cell, the cell membrane consists of lipids and proteins which accounts for its hydrophobicity as a result of being non-polar substances. Therefore, in order for these molecules to participate in reactions, within the cell and they accomplish this process of gaining access to the cell via, osmotic pressure, diffusion, concentration gradients, and membrane channels. Inside of the cell are extensive internal sub-cellular membrane-bounded compartments called organelles, cytoplasm - contents of the main fluid-filled space inside cells, chemical reactions also happen in this jelly-like substance. Nuclear Architecture is important for dictating nuclear function, vacuole - contain cell sap or other storage material. Vesicle - small membrane-bounded spheres inside cells which transport substances, the growth process of the cell does not refer to the size of the cell, but instead the density of the number of cells present in the organism at a given time. Cell growth pertains to the increase in the number of cells present in an organism as it grows and develops, Cells are the foundation of all organisms, they are the fundamental unit of life. The growth and development of the cell are essential for the maintenance of the host, for this process the cell goes through the steps of the cell cycle and development which involves cell growth, DNA replication, cell division, regeneration, specialization, and cell death. The cell cycle is divided into four phases, G1, S, G2. The G phases – which is the growth phase - makes up approximately 95% of the cycle
Cell biology
–
Understanding cells in terms of their
molecular components.
Cell biology
–
Endothelial cells under the microscope. Nuclei are stained blue with DAPI, microtubles are marked green by an antibody and actin filaments are labelled red with phalloidin.
Cell biology
–
Electron micrograph.
Cell biology
–
Czech anatomist Jan Evangelista Purkyně is best known for his 1837 discovery of
Purkinje cells.
29.
Eukaryotic
–
A eukaryote is any organism whose cells contain a nucleus and other organelles enclosed within membranes. Eukaryotes belong to the taxon Eukarya or Eukaryota, the presence of a nucleus gives eukaryotes their name, which comes from the Greek εὖ and κάρυον. Eukaryotic cells also contain other membrane-bound organelles such as mitochondria and the Golgi apparatus, in addition, plants and algae contain chloroplasts. Eukaryotic organisms may be unicellular or multicellular, only eukaryotes form multicellular organisms consisting of many kinds of tissue made up of different cell types. Eukaryotes can reproduce asexually through mitosis and sexually through meiosis and gamete fusion. In mitosis, one cell divides to produce two identical cells. In meiosis, DNA replication is followed by two rounds of division to produce four daughter cells each with half the number of chromosomes as the original parent cell. These act as sex cells resulting from genetic recombination during meiosis, the domain Eukaryota appears to be monophyletic, and so makes up one of the three domains of life. The two other domains, Bacteria and Archaea, are prokaryotes and have none of the above features, eukaryotes represent a tiny minority of all living things. However, due to their larger size, eukaryotes collective worldwide biomass is estimated at about equal to that of prokaryotes. Eukaryotes first developed approximately 1. 6–2.1 billion years ago, in 1905 and 1910, the Russian biologist Konstantin Mereschkowsky argued three things about the origin of nucleated cells. Firstly, plastids were reduced cyanobacteria in a symbiosis with a non-photosynthetic host, secondly, the host had earlier in evolution formed by symbiosis between an amoeba-like host and a bacteria-like cell that formed the nucleus. Thirdly, plants inherited photosynthesis from cyanobacteria, the split between the prokaryotes and eukaryotes was introduced in the 1960s. The concept of the eukaryote has been attributed to the French biologist Edouard Chatton, the terms prokaryote and eukaryote were more definitively reintroduced by the Canadian microbiologist Roger Stanier and the Dutch-American microbiologist C. B. van Niel in 1962. In his 1938 work Titres et Travaux Scientifiques, Chatton had proposed the two terms, calling the bacteria prokaryotes and organisms with nuclei in their cells eukaryotes. However he mentioned this in one paragraph, and the idea was effectively ignored until Chattons statement was rediscovered by Stanier. In 1967, Lynn Margulis provided microbiological evidence for endosymbiosis as the origin of chloroplasts and mitochondria in cells in her paper. In the 1970s, Carl Woese explored microbial phylogenetics, studying variations in 16S ribosomal RNA and this helped to uncover the origin of the eukaryotes and the symbiogenesis of two important eukaryote organelles, mitochondria and chloroplasts
Eukaryotic
–
Had'n
Eukaryotic
–
Longitudinal section through the flagellum of
Chlamydomonas reinhardtii
30.
Candida albicans
–
Candida albicans is a dimorphic fungus that grows both as yeast and filamentous cells and one of the few species of the Candida genus that cause the infection candidiasis in humans. C. albicans is responsible for 50–90% of all cases of candidiasis in humans, systemic fungal infections including those by C. albicans have emerged as important causes of morbidity and mortality in immunocompromised patients. C. albicans biofilms may form on the surface of implantable medical devices, in addition, hospital-acquired infections by C. albicans have become a cause of major health concerns. About 85-95% of vaginal infections cases are responsible for office visits every year. C. albicans is a member of human gut flora and is detectable in the gastrointestinal tract in 40% of healthy adults. It is usually a commensal organism, but can become pathogenic in immunocompetent individuals under a variety of conditions, overgrowth of the fungus results in candidiasis. Candidiasis is often observed in immunocompromised individuals, including HIV-infected patients and it commonly occurs on mucous membranes in the mouth or vagina, but may affect a number of other regions. For example, higher prevalence of colonization of C. albicans was reported in individuals with tongue piercing. To infect host tissue, the usual unicellular yeast-like form of C. albicans reacts to environmental cues and switches into an invasive, multicellular filamentous form, in addition, an overgrowth infection is considered superinfection, usually applied when an infection become opportunistic and very resistant to antifungals. It then becomes suppressed by antibiotics, the infection is prolonged when the original sensitive strain is replaced by the antibiotic-resistant strain. One of the most important features of the C and these karyotypic alterations lead to changes in the phenotype, which is an adaptation strategy of this fungus. These mechanisms will be understood with the complete analysis of the C. albicans genome. An unusual feature of the Candida genus is that in many of its species the CUG codon and this is an unusual example of a departure from the standard genetic code, and most such departures are in start codons or, for eukaryotes, mitochondrial genetic codes. This alteration may, in environments, help these Candida species by inducing a permanent stress response. The genome of C. albicans is highly dynamic, and this variability has been used advantageously for molecular epidemiological studies, the genome sequence has allowed for identifying the presence of a parasexual cycle in C. albicans. This study of the evolution of reproduction in six Candida species found recent losses in components of the major meiotic crossover-formation pathway. The authors suggested that if Candida species undergo meiosis it is with reduced machinery, or different machinery, in another evolutionary study, introduction of partial CUG identity redefinition into Saccharomyces cerevisiae clones caused a stress response that negatively affected sexual reproduction. This CUG identity redefinition, occurring in ancestors of Candida species, was thought to lock these species into a diploid or polyploid state with possible blockage of sexual reproduction, although often referred to as dimorphic, C. albicans is in fact polyphenic
Candida albicans
–
Candida albicans
Candida albicans
–
Candida albicans growing on
Sabouraud agar
Candida albicans
–
Round, white-phase and elongated, opaque-phase Candida albicans cells: the scale bar is 5 µm.
Candida albicans
31.
Microbial fuel cell
–
A microbial fuel cell, or biological fuel cell, is a bio-electrochemical system that drives an electric current by using bacteria and mimicking bacterial interactions found in nature. MFCs can be grouped into two categories, mediated and unmediated. The first MFCs, demonstrated in the early 20th century, used a mediator, in the 21st century MFCs started to find a commercial use in wastewater treatment. The idea of using microbes to produce electricity was conceived in the twentieth century. M. C. Potter initiated the subject in 1911, Potter managed to generate electricity from Escherichia coli, but the work received little coverage. In 1931, Branet Cohen created microbial half fuel cells that, a study by DelDuca et al. used hydrogen produced by the fermentation of glucose by Clostridium butyricum as the reactant at the anode of a hydrogen and air fuel cell. Though the cell functioned, it was owing to the unstable nature of hydrogen production by the micro-organisms. This issue was resolved by Suzuki et al. in 1976, in the late 1970s little was understood about how microbial fuel cells functioned. The idea was studied by Robin M. Allen and later by H. Peter Bennetto, people saw the fuel cell as a possible method for the generation of electricity for developing countries. Bennettos work, starting in the early 1980s, helped build an understanding of how fuel cells operate, in May 2007, the University of Queensland, Australia completed a prototype MFC as a cooperative effort with Fosters Brewing. The prototype, a 10 L design, converted brewery wastewater into carbon dioxide, clean water, the group had plans to create a pilot-scale model for an upcoming international bio-energy conference. A microbial fuel cell is a device that converts energy to electrical energy by the action of microorganisms. These electrochemical cells are constructed using either a bioanode and/or a biocathode, most MFCs contain a membrane to separate the compartments of the anode and the cathode. The electrons produced during oxidation are transferred directly to an electrode or, the electron flux is moved to the cathode. The charge balance of the system is compensated by ionic movement inside the cell, most MFCs use an organic electron donor that is oxidised to produce CO2, protons and electrons. Other electron donors have been reported, such as sulphur compounds or hydrogen, the cathode reaction uses a variety of electron acceptors that includes the reduction of oxygen as the most studied process. However, other electron acceptors have been studied, including metal recovery by reduction, water to hydrogen, nitrate reduction, MFCs are attractive for power generation applications that require only low power, but where replacing batteries may be impractical, such as wireless sensor networks. Virtually any organic material could be used to feed the fuel cell, MFCs are a clean and efficient method of energy production
Microbial fuel cell
–
A plant microbial fuel cell (PMFC)
32.
Biofuel
–
Biofuels can be derived directly from plants, or indirectly from agricultural, commercial, domestic, and/or industrial wastes. Renewable biofuels generally involve contemporary carbon fixation, such as those that occur in plants or microalgae through the process of photosynthesis, other renewable biofuels are made through the use or conversion of biomass. This biomass can be converted to convenient energy-containing substances in three different ways, thermal conversion, chemical conversion, and biochemical conversion and this biomass conversion can result in fuel in solid, liquid, or gas form. This new biomass can also be used directly for biofuels, bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as corn, sugarcane, or sweet sorghum. Cellulosic biomass, derived from sources, such as trees and grasses, is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, bioethanol is widely used in the USA and in Brazil. Current plant design does not provide for converting the portion of plant raw materials to fuel components by fermentation. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe, in 2010, worldwide biofuel production reached 105 billion liters, up 17% from 2009, and biofuels provided 2. 7% of the worlds fuels for road transport. Global ethanol fuel production reached 86 billion liters in 2010, with the United States and Brazil as the top producers. The worlds largest biodiesel producer is the European Union, accounting for 53% of all production in 2010. As of 2011, mandates for blending biofuels exist in 31 countries at the national level, the International Energy Agency has a goal for biofuels to meet more than a quarter of world demand for transportation fuels by 2050 to reduce dependence on petroleum and coal. The production of biofuels also led into an automotive industry. There are various social, economic, environmental and technical issues relating to production and use. Most transportation fuels are liquids, because vehicles usually require high energy density and this occurs naturally in liquids and solids. High energy density can also be provided by a combustion engine. The fuels that are easiest to burn cleanly are typically liquids, thus, liquids meet the requirements of being both energy-dense and clean-burning. In addition, liquids can be pumped, which means handling is easily mechanized, first-generation or conventional biofuels are made from sugar, starch, or vegetable oil. Biobutanol is often claimed to provide a replacement for gasoline
Biofuel
–
A bus fueled by
biodiesel
Biofuel
–
Information on pump regarding
ethanol fuel blend up to 10%,
California
Biofuel
–
Neat ethanol on the left (A),
gasoline on the right (G) at a
filling station in
Brazil
Biofuel
–
Walmart 's truck fleet logs millions of miles each year, and the company planned to double the fleet's efficiency between 2005 and 2015. This truck is one of 15 based at Walmart's
Buckeye, Arizona distribution center that was converted to run on a biofuel made from reclaimed cooking grease produced during food preparation at Walmart stores.
33.
Phylogenetics
–
In biology, phylogenetics /ˌfaɪloʊdʒəˈnɛtɪks, -lə-/ is the study of the evolutionary history and relationships among individuals or groups of organisms. These relationships are discovered through phylogenetic inference methods that evaluate observed heritable traits, the result of these analyses is a phylogeny – a diagrammatic hypothesis about the history of the evolutionary relationships of a group of organisms. The tips of a tree can be living organisms or fossils. Phylogenetic analyses have become central to understanding biodiversity, evolution, ecology, taxonomy is the classification, identification and naming of organisms. It is usually richly informed by phylogenetics, but remains a methodologically and logically distinct discipline, usual methods of phylogenetic inference involve computational approaches implementing the optimality criteria and methods of parsimony, maximum likelihood, and MCMC-based Bayesian inference. All these depend upon an implicit or explicit mathematical model describing the evolution of characters observed, prior to 1990, phylogenetic inferences were generally presented as narrative scenarios. Such methods are often ambiguous and lack explicit criteria for evaluating alternative hypotheses, the term phylogeny derives from the German Phylogenie, introduced by Haeckel in 1866, and the Darwinian approach to classification became known as the phyletic approach. During the late 19th century, Ernst Haeckels recapitulation theory, or biogenetic fundamental law, was widely accepted, but this theory has long been rejected. O. See, Huerta-Cepas, Jaime, Dopazo, Joaquín, Gabaldón, ETE, A python Environment for Tree Exploration. PhylomeDB, A public database hosting thousands of gene phylogenies ranging many different species, See, Huerta-Cepas, J. Capella-Gutierrez, S. Pryszcz, L. P. Denisov, I. Kormes, D. Marcet-Houben, M. Gabaldón, T. PhylomeDB v3.0, An expanding repository of genome-wide collections of trees, alignments, lents, N. H. Cifuentes, O. E. Carpi, A. Teaching the Process of Molecular Phylogeny and Systematics, A Multi-Part Inquiry-Based Exercise
Phylogenetics
–
Red algae
Phylogenetics
–
Diagrammatic representation of the
divergence of modern
taxonomic groups from their
common ancestor
34.
Synonym
–
A synonym is a word or phrase that means exactly or nearly the same as another word or phrase in the same language. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy, the word comes from Ancient Greek sýn and ónoma. An example of synonyms are the words begin, start, commence, words can be synonymous when meant in certain senses, even if they are not synonymous in all of their senses. For example, if one talks about a time or an extended time, long. Some academics call the former type cognitive synonyms to distinguish them from the latter type, some lexicographers claim that no synonyms have exactly the same meaning because etymology, orthography, phonic qualities, ambiguous meanings, usage, etc. make them unique. Different words that are similar in meaning usually differ for a reason, feline is more formal than cat, long and extended are only synonyms in one usage, synonyms are also a source of euphemisms. In the figurative sense, two words are said to be synonymous if they have the same connotation. a widespread impression that. Metonymy can sometimes be a form of synonymy, as when, for example, thus a metonym is a type of synonym, and the word metonym is a hyponym of the word synonym. The analysis of synonymy, polysemy, hyponymy, and hypernymy is inherent to taxonomy and it has applications in pedagogy and machine learning, because they rely on word-sense disambiguation and schema. Synonyms can be any part of speech, as long as both words belong to the part of speech. Such like, he expired means the same as he died, in English, many synonyms emerged in the Middle Ages, after the Norman conquest of England. While Englands new ruling class spoke Norman French, the lower classes continued to speak Old English, thus, today we have synonyms like the Norman-derived people, liberty and archer, and the Saxon-derived folk, freedom and bowman. For more examples, see the list of Germanic and Latinate equivalents in English, the purpose of a thesaurus is to offer the user a listing of similar or related words, these are often, but not always, synonyms. The word poecilonym is a synonym of the word synonym. It is not entered in most major dictionaries and is a curiosity or piece of trivia for being a word because of its meta quality as a synonym of synonym. Antonyms are words with opposite or nearly opposite meanings, for example, hot ↔ cold, large ↔ small, thick ↔ thin, synonym ↔ antonym Hypernyms and hyponyms are words that refer to, respectively, a general category and a specific instance of that category. For example, vehicle is a hypernym of car, and car is a hyponym of vehicle, homophones are words that have the same pronunciation, but different meanings. For example, witch and which are homophones in most accents, homographs are words that have the same spelling, but have different pronunciations
Synonym
–
Synonym list in
cuneiform on a clay tablet,
Neo-Assyrian period. Ref: K.4375.
35.
Phylum
–
In biology, a phylum is a taxonomic rank below kingdom and above class. Traditionally, in botany the term division was used instead of phylum, although from 1993 the International Code of Nomenclature for algae, fungi, depending on definitions, the kingdom Animalia contains approximately 35 phyla, Plantae contains about 12, and Fungi contains around 7. Current research in phylogenetics is uncovering the relationships between phyla, which are contained in larger clades, like Ecdysozoa and Embryophyta, the definitions of zoological phyla have changed from their origins in the six Linnaean classes and the four embranchements of Georges Cuvier. Haeckel introduced the term phylum, based on the Greek word phylon, in plant taxonomy, Eichler classified plants into five groups, named divisions. Informally, phyla can be thought of as grouping organisms based on general specialization of body plan, the most important objective measure in the above definitions is the certain degree—how unrelated do organisms need to be to be members of different phyla. The minimal requirement is that all organisms in a phylum should be more closely related to one another than to any other group. So phyla can be merged or split if it becomes apparent that they are related to one another or not, a definition of a phylum based on body plan has been proposed by paleontologists Graham Budd and Sören Jensen. By Budd and Jensens definition, a phylum is defined by a set of shared by all its living representatives. This approach brings some small problems—for instance, ancestral characters common to most members of a phylum may have been lost by some members, also, this definition is based on an arbitrary point of time, the present. However, as it is based, it is easy to apply to the fossil record. A greater problem is that it relies on a decision about which groups of organisms should be considered as phyla. However, proving that a fossil belongs to the group of a phylum is difficult. Furthermore, organisms in the group of a phylum can possess the body plan of the phylum without all the characteristics necessary to fall within it. This weakens the idea that each of the phyla represents a body plan. A classification using this definition may be affected by the chance survival of rare groups. Representatives of many modern phyla did not appear until long after the Cambrian, the kingdom Plantae is defined in various ways by different biologists. All definitions include the living embryophytes, to which may be added the two green algae divisions, Chlorophyta and Charophyta, to form the clade Viridiplantae. The table below follows the influential Cavalier-Smith system in equating Plantae with Archaeplastida, a group containing Viridiplantae, the definition and classification of plants at the division level also varies from source to source, and has changed progressively in recent years
Phylum
–
The hierarchy of
biological classification 's eight major
taxonomic ranks. A
kingdom contains one or more phyla. Intermediate minor rankings are not shown.
36.
Order (biology)
–
In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, an immediately higher rank, superorder, may be added directly above order, while suborder would be a lower rank. A taxonomic unit, a taxon, in that rank, in that case the plural is orders. Example, The Juglans and Hickory trees belong to the family Juglandaceae, what does and does not belong to each order is determined by a taxonomist, as is whether a particular order should be recognized at all. Often there is no agreement, with different taxonomists each taking a different position. There are no rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognised only rarely, for some groups of organisms, consistent suffixes are used to denote that the rank is an order. The Latin suffix -formes meaning having the form of is used for the name of orders of birds and fishes. The suffix -ales is for the name of orders of plants, fungi, for some clades covered by the International Code of Zoological Nomenclature, a number of additional classifications are sometimes used, although not all of these are officially recognised. In their 1997 classification of mammals, McKenna and Bell used two levels between superorder and order, grandorder and mirorder. Michael Novacek inserted them at the same position, michael Benton inserted them between superorder and magnorder instead. This position was adopted by Systema Naturae 2000 and others, in botany, the ranks of subclass and suborder are secondary ranks pre-defined as respectively above and below the rank of order. Any number of further ranks can be used as long as they are clearly defined, the superorder rank is commonly used, with the ending -anae that was initiated by Armen Takhtajans publications from 1966 onwards. Carl Linnaeus was the first to apply it consistently to the division of all three kingdoms of nature in his Systema Naturae, for plants, Linnaeus orders in the Systema Naturae and the Species Plantarum were strictly artificial, introduced to subdivide the artificial classes into more comprehensible smaller groups. In French botanical publications, from Michel Adansons Familles naturelles des plantes and until the end of the 19th century, some of the plant families still retain the names of Linnaean natural orders or even the names of pre-Linnaean natural groups recognised by Linnaeus as orders in his natural classification. Such names are known as family names. In zoology, the Linnaean orders were used more consistently and that is, the orders in the zoology part of the Systema Naturae refer to natural groups. Some of his names are still in use
Order (biology)
–
Title page of the 1758 edition of Linnaeus's Systema Naturæ.
37.
History of wine
–
The earliest archaeological evidence of wine consumption yet found has been at sites in China, Georgia, Iran, and Greece. The oldest evidence of production has been found in Armenia. The altered consciousness produced by wine has been considered religious since its origin, the Greeks worshiped Dionysus or Bacchus and the Romans carried on his cult. Consumption of ritual wine was part of Jewish practice since Biblical times and, as part of the eucharist commemorating Jesuss Last Supper, Wine production and consumption increased, burgeoning from the 15th century onwards as part of European expansion. Despite the devastating 1887 phylloxera louse infestation, modern science and technology adapted and industrial wine production, the origins of wine predate written records, and modern archaeology is still uncertain about the details of the first cultivation of wild grapevines. It has been hypothesized that early humans climbed trees to pick berries, liked their sugary flavor, after a few days with fermentation setting in, juice at the bottom of any container would begin producing low-alcohol wine. According to this theory, things changed around 10. 000-8000 BC with the transition from a nomadic to a style of living. Wild grapes grow in Armenia, Georgia, Azerbaijan, the northern Levant, coastal and southeastern Turkey, the fermenting of strains of this wild Vitis vinifera subsp. Sylvestris would have become easier following the development of pottery during the later Neolithic, however, the earliest evidence so far discovered dates from millennia afterwards. The earliest archaeological evidence of wine production yet found has been at sites in China, Georgia, Iran, Greece, the Iranian jars contained a form of retsina, using turpentine pine resin to more effectively seal and preserve the wine. Production spread to sites in Greater Iran and Grecian Macedonia by c. 4500 BC. The Greek site is notable for the recovery at the site of the remnants of crushed grapes, the oldest-known winery was discovered in the Areni-1 cave in Vayots Dzor, Armenia. Dated to c. 4100 BC, the site contained a press, fermentation vats, jars. Archaeologists also found V. vinifera seeds and vines, commenting on the importance of the find, McGovern said, The fact that winemaking was already so well developed in 4000 BC suggests that the technology probably goes back much earlier. The seeds were from Vitis vinifera vinifera, a still used to make wine. The cave remains date to about 4000 BC -900 years before the earliest comparable wine remains and this is what CNN wrote, Forget France. It turns out, the birthplace of wine may be in a cave in Armenia. Wine found in Armenia is considered to be at least 6100 years old, the fame of Persian wine has been well known in Ancient times
History of wine
–
Wine boy at a Greek
symposium
History of wine
–
Georgian Kvevri ancient wine vessel
History of wine
–
Entrance to the Areni-1 cave in southern Armenia near the town of
Areni. The cave is the location of the
world's oldest known winery and where the world's oldest known
shoe has been found.
History of wine
–
Mosaic depicting grapes and wine with Armenian inscription in Jerusalim
38.
History of beer
–
Chemical tests of ancient pottery jars reveal that beer was produced as far back as about 7,000 years ago in what is today Iran. This discovery reveals one of the earliest known uses of fermentation and is the earliest evidence of brewing to date, in Mesopotamia, the oldest evidence of beer is believed to be a 6, 000-year-old Sumerian tablet depicting people drinking a beverage through reed straws from a communal bowl. A 3900-year-old Sumerian poem honouring Ninkasi, the goddess of brewing, contains the oldest surviving beer recipe. In China, residue on pottery dating from between 5400 and 4900 years ago shows beer was brewed using barley and other grains, the invention of bread and beer has been argued to be responsible for humanitys ability to develop technology and build civilization. Beer may have known in Neolithic Europe as far back as 5,000 years ago. Women brewers dominated alcohol production on every occupied continent until commercialization and industrialization of brewing occurred, Beer produced before the Industrial Revolution continued to be made and sold on a domestic scale, although by the 7th century AD beer was also being produced and sold by European monasteries. During the Industrial Revolution, the production of beer moved from artisanal manufacture to industrial manufacture, the development of hydrometers and thermometers changed brewing by allowing the brewer more control of the process, and greater knowledge of the results. Today, the industry is a global business, consisting of several dominant multinational companies. More than 133 billion liters are sold per year—producing total global revenues of $294.5 billion in 2006, approximately 5000 years ago, workers in the city of Uruk were paid by their employers in beer. Ninkasi, you are the one who pours out the beer of the collector vat It is the onrush of Tigris. Beer is also mentioned in the Epic of Gilgamesh, in which the wild man Enkidu is given beer to drink and he ate until he was full, drank seven pitchers of beer, his heart grew light, his face glowed and he sang out with joy. These beers were often thick, more of a gruel than a beverage, though beer was drunk in Ancient Rome, it was replaced in popularity by wine. Tacitus wrote disparagingly of the beer brewed by the Germanic peoples of his day, thracians were also known to consume beer made from rye, even since the 5th century BC, as the ancient Greek logographer Hellanicus of Lesbos says. Their name for beer was brutos, or brytos, the Romans called their brew cerevisia, from the Celtic word for it. Beer was apparently enjoyed by some Roman legionaries, for instance, among the Vindolanda tablets, the cavalry decurion Masculus wrote a letter to prefect Flavius Cerialis inquiring about the exact instructions for his men for the following day. This included a polite request for beer to be sent to the garrison, Ancient Nubians had used beer as an antibiotic medicine. Mesopotamian brewing appears to have incorporated the usage of a twice-baked barley bread called bappir and it was discovered early that reusing the same container for fermenting the mash would produce more reliable results, brewers on the move carried their tubs with them. The Ebla tablets, discovered in 1974 in Ebla, Syria, early traces of beer and the brewing process have been found in ancient Babylonia as well
History of beer
–
Alulu beer receipt – This records a purchase of "best" beer from a brewer, c. 2050 BC from the
Sumerian city of
Umma in
ancient Iraq.
History of beer
–
A replica of ancient Egyptian beer, brewed from
emmer wheat by the
Courage brewery in 1996
History of beer
–
Achel trappist beer (Belgium) with glass
History of beer
–
The
Caledonian Brewery, founded in 1869,
Edinburgh, Scotland
39.
Old English language
–
Old English or Anglo-Saxon is the earliest historical form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlers probably in the mid 5th century, Old English developed from a set of Anglo-Frisian or North Sea Germanic dialects originally spoken by Germanic tribes traditionally known as the Angles, Saxons, and Jutes. As the Anglo-Saxons became dominant in England, their language replaced the languages of Roman Britain, Common Brittonic, a Celtic language, Old English had four main dialects, associated with particular Anglo-Saxon kingdoms, Mercian, Northumbrian, Kentish and West Saxon. It was West Saxon that formed the basis for the standard of the later Old English period, although the dominant forms of Middle. The speech of eastern and northern parts of England was subject to strong Old Norse influence due to Scandinavian rule, Old English is one of the West Germanic languages, and its closest relatives are Old Frisian and Old Saxon. Like other old Germanic languages, it is different from Modern English. Old English grammar is similar to that of modern German, nouns, adjectives, pronouns, and verbs have many inflectional endings and forms. The oldest Old English inscriptions were using a runic system. Old English was not static, and its usage covered a period of 700 years, from the Anglo-Saxon settlement of Britain in the 5th century to the late 11th century, some time after the Norman invasion. While indicating that the establishment of dates is a process, Albert Baugh dates Old English from 450 to 1150, a period of full inflections. Perhaps around 85 per cent of Old English words are no longer in use, Old English is a West Germanic language, developing out of Ingvaeonic dialects from the 5th century. It came to be spoken over most of the territory of the Anglo-Saxon kingdoms which became the Kingdom of England and this included most of present-day England, as well as part of what is now southeastern Scotland, which for several centuries belonged to the Anglo-Saxon kingdom of Northumbria. Other parts of the island – Wales and most of Scotland – continued to use Celtic languages, Norse was also widely spoken in the parts of England which fell under Danish law. Anglo-Saxon literacy developed after Christianisation in the late 7th century, the oldest surviving text of Old English literature is Cædmons Hymn, composed between 658 and 680. There is a corpus of runic inscriptions from the 5th to 7th centuries. The Old English Latin alphabet was introduced around the 9th century, with the unification of the Anglo-Saxon kingdoms by Alfred the Great in the later 9th century, the language of government and literature became standardised around the West Saxon dialect. In Old English, typical of the development of literature, poetry arose before prose, a later literary standard, dating from the later 10th century, arose under the influence of Bishop Æthelwold of Winchester, and was followed by such writers as the prolific Ælfric of Eynsham. This form of the language is known as the Winchester standard and it is considered to represent the classical form of Old English
Old English language
–
A detail of the first page of the
Beowulf manuscript, showing the words "ofer hron rade", i.e. "over the whale's road (=sea)". It is an example of an Old English stylistic device, the
kenning.
Old English language
–
"Her swutelað seo gecwydrædnes ðe" Old English inscription over the arch of the south porticus in the 10th-century
St Mary's parish church, Breamore, Hampshire
Old English language
–
The first page of the
Beowulf manuscript with its opening Hƿæt ƿē Gārde/na ingēar dagum þēod cyninga / þrym ge frunon... "Listen! We of the Spear-Danes from days of yore have heard of the glory of the folk-kings..."
40.
Proto Indo-European language
–
Proto-Indo-European is the linguistic reconstruction of the common ancestor of the Indo-European languages, the most widely spoken language family in the world. Far more work has gone into reconstructing PIE than any other proto-language and these methods supply all of the knowledge concerning PIE, since there is no written record of the language. PIE is estimated to have spoken as a single language around 3500 B. C. E. during the Neolithic Age. According to the prevailing Kurgan hypothesis, the homeland of the Proto-Indo-Europeans may have been in the Pontic–Caspian steppe of Eastern Europe. Work has also gone into reconstructing their culture and religion, PIE had a complex system of morphology that included inflectional suffixes as well as ablaut and accent. PIE nominals and pronouns had a system of declension. The PIE phonology, particles, numerals, and copula are also well-reconstructed, today, the most widely-spoken daughter languages of PIE are Spanish, English, Hindustani, Portuguese, Bengali, Russian, Punjabi, German, French, and Marathi. There is no evidence of PIE. It has been reconstructed from its present-day descendants using the comparative method, the comparative method is based on the Neogrammarian rule that the Indo-European sound laws are applied without exception. The method compares languages and applies the laws to find a common ancestor. For example, compare the pairs of words in Italian and English, piede and foot, padre and father, pesce and fish. Since there is a consistent correspondence of the consonants that is far too frequent to be coincidental. Although his name is associated with this observation, he was not the first to make it. In many ways Jones work was less accurate than his predecessors, as he erroneously included Egyptian, Japanese and Chinese in the Indo-European languages, while omitting Hindi. In 1818, Rasmus Christian Rask elaborated the set of correspondences to include other Indo-European languages, such as Sanskrit and Greek, and the full range of consonants involved. In 1816 Franz Bopp published On the System of Conjugation in Sanskrit in which he investigated a common origin of Sanskrit, Persian, Greek, Latin, and German. In 1833 he began publishing the Comparative Grammar of Sanskrit, Zend, Greek, Latin, Lithuanian, Old Slavic, Gothic, in 1822, Jacob Grimm formulated what is now known as Grimms law as a general rule in his Deutsche Grammatik. Grimm showed correlations between the Germanic and other Indo-European languages, and showed that sound change affects an entire language systematically, august Schleichers A Compendium of the Comparative Grammar of the Indo-European, Sanskrit, Greek and Latin Languages was an early attempt to reconstruct the proto-Indo-European language
Proto Indo-European language
–
Classification of Indo-European languages. Red: Extinct languages. White: categories or unattested proto-languages. Left half:
centum languages; right half:
satem languages
41.
Dutch (ethnic group)
–
The Dutch, occasionally referred to as Netherlanders—a term that is cognate to the Dutch word for Dutch people, Nederlanders—are a Germanic ethnic group native to the Netherlands. They share a culture and speak the Dutch language. The high degree of urbanization characteristic of Dutch society was attained at an early date. During the Republic the first series of large scale Dutch migrations outside of Europe took place, despite the small size of the Netherlands, the Dutch left behind a legacy in excess of their mere numbers. The traditional art and culture of the Dutch encompasses various forms of music, dances, architectural styles and clothing. Internationally, Dutch painters such as Rembrandt, Vermeer and Van Gogh are held in high regard, the dominant religion of the Dutch is Christianity, although in modern times the majority is no longer religious. Significant percentages of the Dutch are adherents of humanism, agnosticism, atheism or individual spirituality, as with all ethnic groups the ethnogenesis of the Dutch has been a lengthy and complex process. The text below hence focuses on the history of the Dutch ethnic group, for Dutch national history, for Dutch colonial history, see the article on the Dutch Empire. Following the end of the period in the West around 500, with large federations settling the decaying Roman Empire. In the Low Countries, this began when the Franks, themselves a union of multiple smaller tribes. Eventually, in 358, the Salian Franks, one of the three main subdivisions among the Frankish alliance settled the areas Southern lands as foederati, Roman allies in charge of border defense. On a political level, the Frankish warlords abandoned tribalism and founded a number of kingdoms, however, the population make-up of the Frankish Empire, or even early Frankish kingdoms such as Neustria and Austrasia, was not dominated by Franks. Though the Frankish leaders controlled most of Western Europe, the Franks themselves were confined to the Northwestern part of the Empire, the current Dutch-French language border has remained virtually identical ever since, and could be seen as marking the furthest pale of gallicization among the Franks. The medieval cities of the Low Countries, which experienced major growth during the 11th and 12th century, were instrumental in breaking down the already relatively loose local form of feudalism, as they became increasingly powerful, they used their economical strength to influence the politics of their nobility. While the cities were of political importance, they also formed catalysts for medieval Dutch culture. The various city guilds as well as the necessity of water boards in the Dutch delta and it is also around this time, that ethnonyms such as Diets and Nederlands emerge. This process marked a new episode in the development of the Dutch ethnic group, as now political unity started to emerge, consolidating the strengthened cultural, despite their linguistic and cultural unity, and economic similarities, there was still little sense of political unity among the Dutch people. However, the centralist policies of Burgundy in the 14th and 15th centuries, at first violently opposed by the cities of the Low Countries, had a profound impact and changed this
Dutch (ethnic group)
Dutch (ethnic group)
–
The conversion of the Frankish king
Clovis to Christianity would have great significance in helping shape the identity of the future Dutch people.
Dutch (ethnic group)
–
The
Act of Abjuration, signed on July 26, 1581, was the formal declaration of independence of the Dutch Low Countries.
Dutch (ethnic group)
–
A typical November scene in the Dutch town
Middelburg,
Netherlands
42.
Anton van Leeuwenhoek
–
Antonie Philips van Leeuwenhoek was a Dutch businessman, scientist, and one of the notable representatives in the golden age of Dutch science and technology. A largely self-taught man in science, he is known as the Father of Microbiology. Van Leeuwenhoek is best known for his work in the field of microscopy. Raised in Delft, in the Dutch Republic, Van Leeuwenhoek worked as a draper in his youth and he made a name for himself in municipal politics, and eventually developed an interest in lensmaking. Using his handcrafted microscopes, he was the first to observe and describe microorganisms, most of the animalcules are now referred to as unicellular organisms, though he observed multicellular organisms in pond water. He was also the first to document microscopic observations of muscle fibers, bacteria, spermatozoa, Van Leeuwenhoek did not write any books, his discoveries came to light through correspondence with the Royal Society, which published his letters. Antonie van Leeuwenhoek was born in Delft, Dutch Republic, on 24 October 1632, on 4 November, he was baptized as Thonis. His father, Philips Antonisz van Leeuwenhoek, was a maker who died when Antonie was only five years old. His mother, Margaretha, came from a well-to-do brewers family, and remarried Jacob Jansz Molijn, Antonie had four older sisters, Margriet, Geertruyt, Neeltje, and Catharina. When he was ten years old his step-father died. He attended school in Warmond for a time before being sent to live in Benthuizen with his uncle. At the age of 16 he became an apprentice at a linen-drapers shop in Amsterdam owned by the Scot William Davidson. Van Leeuwenhoek left after six years, Van Leeuwenhoek married Barbara de Mey in July 1654, with whom he would have one surviving daughter, Maria. That same year he returned to Delft, where he would live and he opened a drapers shop, which he ran throughout the 1650s. His wife died in 1666, and in 1671, Van Leeuwenhoek remarried to Cornelia Swalmius with whom he had no children and his status in Delft had grown throughout the years. In 1660 he received a job as chamberlain for the Delft sheriffs assembly chamber in the City Hall. Van Leeuwenhoek was a contemporary of another famous Delft citizen, the painter Johannes Vermeer and it has been suggested that he is the man portrayed in two of Vermeers paintings of the late 1660s, The Astronomer and The Geographer. However, others argue that there appears to be little physical similarity, while running his drapers shop, Van Leeuwenhoek wanted to see the quality of the thread better than the then-current magnifying lenses available allowed
Anton van Leeuwenhoek
–
Portrait of Antonie van Leeuwenhoek (1632–1723) by
Jan Verkolje
Anton van Leeuwenhoek
–
William Davidson had appointed Van Leeuwenhoek in 1648 as his assistant. Van Leeuwenhoek left after six years. (Portrait by
Abraham van den Tempel, 1664)
Anton van Leeuwenhoek
–
The Geographer by
Johannes Vermeer.
Anton van Leeuwenhoek
–
Microscopic section through one-year-old
ash tree (Fraxinus) wood, drawing made by Van Leeuwenhoek.
43.
Microscopy
–
Microscopy is the technical field of using microscopes to view objects and areas of objects that cannot be seen with the naked eye. There are three branches of microscopy, optical, electron, and scanning probe microscopy. This process may be carried out by irradiation of the sample or by scanning of a fine beam over the sample. Scanning probe microscopy involves the interaction of a probe with the surface of the object of interest. The development of microscopy revolutionized biology, gave rise to the field of histology and so remains an essential technique in the life and physical sciences. Optical or light microscopy involves passing visible light transmitted through or reflected from the sample through a single or multiple lenses to allow a view of the sample. The resulting image can be detected directly by the eye, imaged on a plate or captured digitally. The single lens with its attachments, or the system of lenses and imaging equipment, along with the lighting equipment, sample stage and support. The most recent development is the microscope, which uses a CCD camera to focus on the exhibit of interest. The image is shown on a screen, so eye-pieces are unnecessary. Limitations of standard optical microscopy lie in three areas, This technique can only image dark or strongly refracting objects effectively, diffraction limits resolution to approximately 0.2 micrometres. This limits the practical limit to ~1500x. Out of focus light from points outside the focal plane reduces image clarity, live cells in particular generally lack sufficient contrast to be studied successfully, since the internal structures of the cell are colourless and transparent. The most common way to increase contrast is to stain the different structures with selective dyes, staining may also introduce artifacts, apparent structural details that are caused by the processing of the specimen and are thus not legitimate features of the specimen. In general, these make use of differences in the refractive index of cell structures. It is comparable to looking through a window, you dont see the glass. There is a difference, as glass is a material. The human eye is not sensitive to this difference in phase, in order to improve specimen contrast or highlight certain structures in a sample special techniques must be used
Microscopy
–
Scanning electron microscope image of
pollen
Microscopy
–
Stereo microscope
Microscopy
–
A
diatom under Rheinberg illumination
Microscopy
–
Phase-contrast
light micrograph of
hyaline cartilage showing
chondrocytes and
organelles,
lacunae and
extracellular matrix.
44.
Organism
–
In biology, an organism is any contiguous living system, such as an animal, plant, fungus, protist, archaeon, or bacterium. All known types of organisms are capable of some degree of response to stimuli, reproduction, growth and development and homeostasis. An organism consists of one or more cells, when it has one cell it is known as an organism. Most unicellular organisms are of microscopic scale and are thus described as microorganisms. Humans are multicellular organisms composed of trillions of cells grouped into specialized tissues. An organism may be either a prokaryote or a eukaryote, prokaryotes are represented by two separate domains—bacteria and archaea. Eukaryotic organisms are characterized by the presence of a cell nucleus. Fungi, animals and plants are examples of kingdoms of organisms within the eukaryotes, estimates on the number of Earths current species range from 10 million to 14 million, of which only about 1.2 million have been documented. More than 99% of all species, amounting to five billion species. In 2016, a set of 355 genes from the last universal ancestor of all living organisms living was identified. The term organism first appeared in the English language in 1703 and it is directly related to the term organization. There is a tradition of defining organisms as self-organizing beings. An organism may be defined as an assembly of molecules functioning as a more or less stable whole that exhibits the properties of life. Dictionary definitions can be broad, using such as any living structure, such as a plant, animal, fungus or bacterium, capable of growth. Many definitions exclude viruses and possible man-made non-organic life forms, as viruses are dependent on the machinery of a host cell for reproduction. A superorganism is an organism consisting of individuals working together as a single functional or social unit. There has been controversy about the best way to define the organism, several contributions are responses to the suggestion that the category of organism may well not be adequate in biology. Viruses are not typically considered to be organisms because they are incapable of autonomous reproduction and this controversy is problematic because some cellular organisms are also incapable of independent survival and live as obligatory intracellular parasites
Organism
–
These
Escherichia coli cells provide an example of a
prokaryotic microorganism.
Organism
–
A
polypore mushroom has a
parasitic relationship with its
host.
Organism
–
An
ericoid mycorrhizal fungus
Organism
45.
Theodor Schwann
–
Theodor Schwann was a German physiologist. His father was a goldsmith, later a printer, Schwann studied at the Jesuits College in Cologne, and then at Bonn, where he met physiologist Johannes Peter Müller. It was during the four years spent under the influence of Müller at Berlin that Schwanns most valuable work was done, Müller was at this time preparing his great book on physiology, and Schwann assisted him in the experimental work required. Schwann observed animal cells under the microscope, noting their different properties, Schwann found particular interest in the nervous and muscular tissues. He discovered the cells that envelope the nerve fibers, now called Schwann cells in his honor, Schwann discovered the striated muscle in the upper esophagus and initiated research into muscle contraction, since expanded upon greatly by Emil du Bois-Reymond and others. Müller directed Schwanns attention to the process of digestion, and in 1837 Schwann isolated an enzyme essential to digestion, Schwann became chair of anatomy at the Belgian Catholic University of Leuven in 1839. Here he produced little new work, the exception being a paper establishing the importance of bile in digestion. He nonetheless proved to be a dedicated and conscientious professor, in 1848, his compatriot Antoine Frédéric Spring convinced him to transfer to the University of Liège, also in Belgium. At Liège, he continued to follow the latest advances in anatomy and he became something of an inventor, working on numerous projects including a human respirator for environments where the surroundings are not breathable. In his later years, Schwann found growing interest in theological issues, three years after retiring, Schwann died in Cologne on 11 January 1882. In 1837, Matthias Jakob Schleiden viewed and stated that new plant cells formed from the nuclei of old plant cells, while dining that year with Schwann, the conversation turned on the nuclei of plant and animal cells. Schwann remembered seeing similar structures in the cells of the notochord and this became cell theory or cell doctrine. In the course of his verification of cell theory, Schwann proved the origin and development of the most highly differentiated tissues including nails, feathers. Schwann established a principle of embryology by observing that the ovum is a single cell that eventually develops into a complete organism. In 1857, pathologist Rudolf Virchow posed the maxim Omnis cellula e cellula—that every cell arises from another cell, by the 1860s, cell doctrine became the conventional view of the elementary anatomical composition of plants and animals. Schwanns theory and observations became the foundation of modern histology, Schwann was the first of Johannes Peter Müllers pupils to break with vitalism and work towards a physico-chemical explanation of life. Schwann also examined the question of spontaneous generation, which led to its eventual disconfirmation, embattled controversy ensued as eminent chemists alleged that Schwann was undoing scientific progress by reverting to vitalism. After publishing anonymous mockery in a journal of their own editorship, in retrospect, the germ theory of Pasteur, as well as its antiseptic applications by Lister, can be traced to Schwanns influence
Theodor Schwann
–
Theodor Schwann
46.
Louis Pasteur
–
Louis Pasteur was a French biologist, microbiologist and chemist renowned for his discoveries of the principles of vaccination, microbial fermentation and pasteurization. He is remembered for his breakthroughs in the causes and prevention of diseases. He reduced mortality from puerperal fever, and created the first vaccines for rabies and his medical discoveries provided direct support for the germ theory of disease and its application in clinical medicine. He is best known to the public for his invention of the technique of treating milk and wine to stop bacterial contamination. He is regarded as one of the three founders of bacteriology, together with Ferdinand Cohn and Robert Koch, and is popularly known as the father of microbiology. Pasteur was responsible for disproving the doctrine of spontaneous generation and he performed experiments that showed that without contamination, microorganisms could not develop. Under the auspices of the French Academy of Sciences, he demonstrated that in sterilized and sealed flasks nothing ever developed, although Pasteur was not the first to propose the germ theory, his experiments indicated its correctness and convinced most of Europe that it was true. Today, he is regarded as one of the fathers of germ theory. Pasteur also made significant discoveries in chemistry, most notably on the basis for the asymmetry of certain crystals. Early in his career, his investigation of tartaric acid resulted in the first resolution of what is now called optical isomers and his work led the way to the current understanding of a fundamental principle in the structure of organic compounds. He was the director of the Pasteur Institute, established in 1887, till his death, although Pasteur made groundbreaking experiments, his reputation became associated with various controversies. Historical reassessment of his notebook revealed that he practiced deception to overcome his rivals, Louis Pasteur was born on December 27,1822, in Dole, Jura, France, to a Catholic family of a poor tanner. He was the child of Jean-Joseph Pasteur and Jeanne-Etiennette Roqui. The family moved to Marnoz in 1826 and then to Arbois in 1827, Pasteur entered primary school in 1831. He was a student in his early years, and not particularly academic. He drew many pastels and portraits of his parents, friends, Pasteur attended secondary school at the Collège dArbois. In October 1838, he left for Paris to join the Pension Barbet, in 1839, he entered the Collège Royal de Besançon to study philosophy and earned his Bachelor of Letters degree in 1840. He was appointed a tutor at the Besançon college while continuing a degree course with special mathematics
Louis Pasteur
–
Photograph by
Nadar
Louis Pasteur
–
The house in which Pasteur was born,
Dole
Louis Pasteur
–
Pasteur in 1857
Louis Pasteur
–
Pasteur experimenting in his laboratory.
47.
Cell growth
–
The term cell growth is used in the contexts of biological cell development and cell division. When used in the context of cell division, it refers to growth of cell populations, when used in the context of cell development, the term refers to increase in cytoplasmic and organelle volume, as well as increase in genetic material following the replication during S phase. Cell populations go through a type of exponential growth called doubling. Thus, each generation of cells should be twice as numerous as the previous generation, however, the number of generations only gives a maximum figure as not all cells survive in each generation. Cell size is variable among organisms, with some algae such as Caulerpa taxifolia being a single cell several meters in length. Plant cells are larger than animal cells, and protists such as Paramecium can be 330 μm long. How these cells decide how big they should be before dividing is an open question, chemical gradients are known to be partly responsible, and it is hypothesized that mechanical stress detection by cytoskeletal structures is involved. Work on the topic generally requires an organism whose cell cycle is well-characterized, the relationship between cell size and cell division has been extensively studied in yeast. For some cells, there is a mechanism by which division is not initiated until a cell has reached a certain size. If the nutrient supply is restricted, and the rate of increase in size is slowed. Yeast cell-size mutants were isolated that begin cell division reaching a normal/regular size. Wee1 protein is a kinase that normally phosphorylates the Cdc2 cell cycle regulatory protein. Cdc2 drives entry into mitosis by phosphorylating a range of targets. This covalent modification of the structure of Cdc2 inhibits the enzymatic activity of Cdc2. Wee1 acts to keep Cdc2 inactive during early G2 when cells are still small, when cells have reached sufficient size during G2, the phosphatase Cdc25 removes the inhibitory phosphorylation, and thus activates Cdc2 to allow mitotic entry. A balance of Wee1 and Cdc25 activity with changes in size is coordinated by the mitotic entry control system. It has been shown in Wee1 mutants, cells with weakened Wee1 activity, thus, mitosis occurs before the yeast reach their normal size. This suggests that cell division may be regulated in part by dilution of Wee1 protein in cells as they grow larger, the protein kinase Cdr2 and the Cdr2-related kinase Cdr1 are localized to a band of cortical nodes in the middle of interphase cells
Cell growth
–
Cell growth
.svg)
. PMID 26447128. doi:10.1534/genetics.115.181503.
