1.
Gene family
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A gene family is a set of several similar genes, formed by duplication of a single original gene, and generally with similar biochemical functions. One such family are the genes for human hemoglobin subunits, the ten genes are in two clusters on different chromosomes, called the α-globin and β-globin loci. These two gene clusters are thought to have arisen as a result of a gene being duplicated approximately 500 million years ago. Genes are categorized into families based on shared nucleotide or protein sequences, phylogenetic techniques can be used as a more rigorous test. The positions of exons within the sequence can be used to infer common ancestry. If the genes of a gene family encode proteins, the protein family is often used in an analogous manner to gene family. The expansion or contraction of gene families along a lineage can be due to chance. To distinguish between two cases is often difficult in practice. Recent work uses a combination of models and algorithmic techniques to detect gene families that are under the effect of natural selection. The HUGO Gene Nomenclature Committee creates nomenclature schemes using a symbol for members of a gene family. For example, for the family, PRDX is the root symbol, and the family members are PRDX1, PRDX2, PRDX3, PRDX4, PRDX5. One level of organization is the grouping of genes into several gene families. Gene families are groups of related genes that share a common ancestor, members of gene families may be paralogs or orthologs. Gene paralogs are genes with similar sequences from within the species while gene orthologs are genes with similar sequences in different species. Gene families are highly variable in size, sequence diversity, depending on the diversity and functions of the genes within the family, families can be classified as a multigene families or superfamilies. Multigene families typically consist of members with similar sequences and functions, individual genes in the family may be arranged close together on the same chromosome or dispersed throughout the genome on different chromosomes. Due to the similarity of their sequences and their overlapping functions, in some instances, gene members have identical sequences. Such families allow for massive amounts of product to be expressed in a short time as needed
2.
Protein family
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A protein family is a group of evolutionarily-related proteins. In many cases a protein family has a gene family. The term protein family should not be confused with family as it is used in taxonomy, proteins in a family descend from a common ancestor and typically have similar three-dimensional structures, functions, and significant sequence similarity. The most important of these is sequence similarity since it is the strictest indicator of homology, there is a fairly well developed framework for evaluating the significance of similarity between a group of sequences using sequence alignment methods. Families are sometimes grouped together into larger clades called superfamilies based on structural and mechanistic similarity, currently, over 60,000 protein families have been defined, although ambiguity in the definition of protein family leads different researchers to wildly varying numbers. Other terms such as class, group, clan and sub-family have been coined over the years. A common usage is that superfamilies contain families which contain sub-families, hence a superfamily, such as the PA clan of proteases, has far lower sequence conservation than one of the families it contains, the C04 family. It is unlikely that an exact definition will be agreed and to it is up to the reader to discern exactly how these terms are being used in a particular context, since that time, it was found that many proteins comprise multiple independent structural and functional units or domains. Due to evolutionary shuffling, different domains in a protein have evolved independently and this has led, in recent years, to a focus on families of protein domains. A number of resources are devoted to identifying and cataloging such domains. Regions of each protein have differing functional constraints, for example, the active site of an enzyme requires certain amino acid residues to be precisely oriented in three dimensions. On the other hand, a protein–protein binding interface may consist of a surface with constraints on the hydrophobicity or polarity of the amino acid residues. These blocks are most commonly referred to as motifs, although other terms are used. Again, a number of online resources are devoted to identifying and cataloging protein motifs. According to current consensus, protein families arise in two ways, firstly, the separation of a parent species into two genetically isolated descendent species allows a gene/protein to independently accumulate variations in these two lineages. This results in a family of proteins, usually with conserved sequence motifs. Secondly, a gene duplication may create a copy of a gene. Because the original gene is able to perform its function
3.
Life
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Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguous and may or may not define viruses, viroids, biology is the primary science concerned with the study of life, although many other sciences are involved. The definition of life is controversial, the current definition is that organisms maintain homeostasis, are composed of cells, undergo metabolism, can grow, adapt to their environment, respond to stimuli, and reproduce. However, many other definitions have been proposed, and there are some borderline cases. Modern definitions are more complex, with input from a diversity of scientific disciplines, biophysicists have proposed many definitions based on chemical systems, there are also some living systems theories, such as the Gaia hypothesis, the idea that the Earth itself is alive. Another theory is that life is the property of systems, and yet another is elaborated in complex systems biology. Abiogenesis describes the process of life arising from non-living matter. Properties common to all organisms include the need for certain chemical elements to sustain biochemical functions. Life on Earth first appeared as early as 4.28 billion years ago, soon after ocean formation 4.41 billion years ago, Earths current life may have descended from an RNA world, although RNA-based life may not have been the first. The mechanism by which began on Earth is unknown, though many hypotheses have been formulated and are often based on the Miller–Urey experiment. The earliest known forms are microfossils of bacteria. In July 2016, scientists reported identifying a set of 355 genes believed to be present in the last universal ancestor of all living organisms. Since its primordial beginnings, life on Earth has changed its environment on a time scale. To survive in most ecosystems, life must often adapt to a range of conditions. Some microorganisms, called extremophiles, thrive in physically or geochemically extreme environments that are detrimental to most other life on Earth, Aristotle was the first person to classify organisms. Later, Carl Linnaeus introduced his system of nomenclature for the classification of species. Eventually new groups and categories of life were discovered, such as cells and microorganisms, cells are sometimes considered the smallest units and building blocks of life. There are two kinds of cells, prokaryotic and eukaryotic, both of which consist of cytoplasm enclosed within a membrane and contain many such as proteins
4.
Domain (biology)
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In biological taxonomy, a domain is the highest taxonomic rank of organisms in the three-domain system of taxonomy designed by Carl Woese, an American microbiologist and biophysicist. According to the Woese system, introduced in 1990, the tree of life consists of three domains, Archaea, Bacteria, and Eukarya, the first two are all prokaryotic microorganisms, or single-celled organisms whose cells have no nucleus. All life that has a nucleus and membrane-bound organelles, and multicellular organisms, is included in the Eukarya, stefan Luketa in 2012 proposed the five-domain system of life with both cellular and non-cellular organisms. The term domain is proposed by Woese et al. in his three-domain system and this term represents a synonym for the category of dominion, introduced by Moore in 1974. However, only S. Luketa uses the term dominion, each of these three domains of life recognized by biologists today contain unique rRNA. This fact in itself forms the basis of the three-domain system, Archaea are prokaryotic cells, typically characterized by membrane lipids that are branched hydrocarbon chains attached to glycerol by ether linkages. The presence of ether linkages in Archaea adds to their ability to withstand extreme temperatures and highly acidic conditions. Halophiles, organisms that thrive in salty environments, and hyperthermophiles. Archaea evolved many cell sizes, but all are relatively small and their size ranges from 0.1 to 15 μ diameter and up to 200 μ long. They are about the size of bacteria or similar to the size of a mitochondrion in a eukaryotic cell, members of the genus Thermoplasma are the smallest of the archaea. Even though bacteria are prokaryotic cells just like Archaea, their membranes are made of unbranched fatty acid chains attached to glycerol by ester linkages, cyanobacteria and mycoplasmas are two examples of bacteria. They characteristically do not have ether linkages like Archaea, and they are grouped into a different category—and hence a different domain. There is a deal of diversity in this domain. Members of the domain Eukarya have membrane-bound organelles and are represented by four kingdoms, Plantae, Protista, Animalia, none of the three systems currently include non-cellular life. As of 2011 there is talk about Nucleocytoplasmic large DNA viruses possibly being a branch domain of life. Stefan Luketa in 2012 proposed a system, adding Prionobiota and Virusobiota to the traditional three domains. Alternative classifications of life so far proposed include, The two-empire system or superdomain system, the eocyte hypothesis, first proposed by James A. Lake et al. in 1984, which posits two domains
5.
Kingdom (biology)
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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
6.
Phylum
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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
7.
Class (biology)
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In biological classification, class is, a taxonomic rank. Other well-known ranks in descending order of size are life, domain, kingdom, phylum, order, family, genus, as for the other well-known ranks, there is the option of an immediately lower rank, indicated by the prefix sub-, subclass. A taxonomic unit, a taxon, in that rank, in that case the plural is classes The composition of each class is determined by a taxonomist. Often there is no agreement, with different taxonomists taking different positions. There are no rules that a taxonomist needs to follow in describing a class. For example, dogs are assigned to the phylum Chordata, in the class Mammalia. In botany, classes are now rarely discussed, for some clades, a number of alternative classifications are used. In the first edition of his Systema Naturae, carl Linnaeus divided all three of his kingdoms of Nature into classes. The class was considered the highest level of the hierarchy until George Cuviers embranchements. Cladistics List of animal classes Phylogenetics Systematics Taxonomy
8.
Order (biology)
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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
9.
Family (biology)
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In biological classification, family is one of the eight major taxonomic ranks, it is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks above the rank of genus. In vernacular usage, a family may be named one of its common members, for example, walnuts and hickory trees belong to the family Juglandaceae. What does or does not belong to a family—or whether a family should be recognized at all—are proposed and determined by practicing taxonomists. There are no rules for describing or recognizing a family. Taxonomists often take different positions about descriptions of taxa, and there may be no broad consensus across the community for some time. Some described taxa are accepted broadly and quickly, but others only rarely, if at all, the naming of families is codified by various international codes. In zoological nomenclature, the names of animals end with the suffix -idae. The concept of rank at time was not yet settled, and in the preface to the Prodromus Magnol spoke of uniting his families into larger genera. Carolus Linnaeus used the word familia in his Philosophia botanica to denote groups of plants, trees, herbs, ferns, palms. He used this term only in the section of the book. In zoology, the family as an intermediate between order and genus was introduced by Pierre André Latreille in his Précis des caractères génériques des insectes. He used families in some but not in all his orders of insects, families can be used for evolutionary, palaeontological and generic studies because they are more stable than lower taxonomic levels such as genera and species
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Genus
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A genus is a taxonomic rank used in the biological classification of living and fossil organisms in biology. In the hierarchy of classification, genus comes above species. In binomial nomenclature, the name forms the first part of the binomial species name for each species within the genus. Felis catus and Felis silvestris are two species within the genus Felis, Felis is a genus within the family Felidae. The composition of a genus is determined by a taxonomist, the standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. Moreover, genera should be composed of units of the same kind as other genera. The term comes from the Latin genus, a noun form cognate with gignere, linnaeus popularized its use in his 1753 Species Plantarum, but the French botanist Joseph Pitton de Tournefort is considered the founder of the modern concept of genera. The scientific name of a genus may be called the name or generic epithet. It plays a role in binomial nomenclature, the system of naming organisms. The rules for the names of organisms are laid down in the Nomenclature Codes. The standard way of scientifically describing species and other lower-ranked taxa is by binomial nomenclature, the generic name forms its first half. For example, the gray wolfs binomial name is Canis lupus, with Canis being the name shared by the wolfs close relatives. The specific name is written in lower-case and may be followed by names in zoology or a variety of infraspecific names in botany. Especially with these names, when the generic name is known from context. Because animals are typically only grouped within subspecies, it is written as a trinomen with a third name. Dog breeds, meanwhile, are not scientifically distinguished, there are several divisions of plant species and therefore their infraspecific names generally include contractions explaining the relation. For example, the genus Hibiscus includes hundreds of other species apart from the Rose of Sharon or common garden hibiscus, Rose of Sharon doesnt have subspecies but has cultivars that carry desired traits, such as the bright white H. syriaca Diana. Hawaiian hibiscus, meanwhile, includes several separate species, since not all botanists agree on the divisions or names between species, it is common to specify the source of the name using author abbreviations
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Species
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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
12.
Taxonomic rank
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In biological classification, rank is the relative level of a group of organisms in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, order, class, phylum, kingdom, domain, a given rank subsumes under it less general categories, that is, more specific descriptions of life forms. Above it, each rank is classified within more general categories of organisms, the rank of any species and the description of its genus is basic, which means that to identify a particular organism, it is usually not necessary to specify ranks other than these first two. Consider a particular species, the red fox Vulpes vulpes, its next rank, as one group of the class Mammalia, all of the above are classified among those with backbones in the Chordata phylum rank, and with them among all the animals in the Animalia kingdom rank. Finally, all of the above will find their earliest relatives somewhere in their domain rank Eukarya, today, nomenclature is regulated by the nomenclature codes. There are seven main ranks, kingdom, phylum or division, class, order, family, genus. In addition, the domain is now used as one of the fundamental ranks. Also, this represents a synonym for the category of dominion. Unlike Moore, Whoese et al. did not suggest a Latin term for this category, a taxon is usually assigned a rank when it is given its formal name. The basic ranks are species and genus, when an organism is given a species name it is assigned to a genus, and the genus name is part of the species name. The species name is called a binomial, that is. For example, the name for the human species is Homo sapiens. This is usually italicized in print and underlined when italics are not available, in this case, Homo is the generic name and it is capitalized, sapiens indicates the species and it is not capitalized. There are definitions of the taxonomic ranks in the International Code of Zoological Nomenclature, superfamily, family, subfamily, tribe, subtribe, genus, subgenus. The International Code of Zoological Nomenclature divides names into family-group names, genus-group names, in the genus group and species group no further ranks are allowed. At higher ranks a lower level may be denoted by adding the prefix infra, meaning lower, a taxon above the rank of species has a scientific name in one part. A species has a composed of two parts, generic name + specific name, for example Canis lupus. A subspecies has a composed of three parts, generic name + specific name + subspecific name, for example Canis lupus familiaris
13.
Walnut
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A walnut is the nut of any tree of the genus Juglans, particularly the Persian or English walnut, Juglans regia. Technically a walnut is the seed of a drupe or drupaceous nut and it is used for food after being processed while green for pickled walnuts or after full ripening for its nutmeat. Nutmeat of the black walnut from the Juglans nigra is less commercially available. The walnut is nutrient-dense with protein and essential fatty acids, walnuts are rounded, single-seeded stone fruits of the walnut tree commonly used for the meat after fully ripening. Following full ripening, the removal of the husk reveals the wrinkly walnut shell, during the ripening process, the husk will become brittle and the shell hard. The shell encloses the kernel or meat, which is made up of two halves separated by a partition. The seed kernels – commonly available as shelled walnuts – are enclosed in a seed coat which contains antioxidants. The antioxidants protect the seed from atmospheric oxygen, thereby preventing rancidity. Walnuts are late to grow leaves, typically not until more than halfway through the spring and they secrete chemicals into the soil to prevent competing vegetation from growing. Because of this, flowers or vegetable gardens should not be planted close to them, the two most common major species of walnuts are grown for their seeds – the Persian or English walnut and the black walnut. The English walnut originated in Persia, and the black walnut is native to eastern North America, the black walnut is of high flavor, but due to its hard shell and poor hulling characteristics it is not grown commercially for nut production. Numerous walnut cultivars have been developed commercially, which are nearly all hybrids of the English walnut, other species include J. californica, the California black walnut, J. cinerea, and J. major, the Arizona walnut. In 2013, worldwide production of walnuts was 3.458 million tonnes, other major producers were, Iran, United States, Turkey and Ukraine. The average worldwide walnut yield was about 3.5 tonnes per hectare in 2013, eastern European countries had the highest yield, with Slovenia and Romania each harvesting about 22 tonnes per hectare. The United States is the worlds largest exporter of walnuts, followed by Turkey, the Central Valley of California produces 99 percent of United States commercial English walnuts. Walnuts, like tree nuts, must be processed and stored properly. Poor storage makes walnuts susceptible to insect and fungal mold infestations, a mold-infested walnut batch should be entirely discarded. The ideal temperature for longest possible storage of walnuts is in the −3 to 0 °C and low humidity – for industrial and home storage
14.
Hickory
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Hickory is a type of tree, comprising the genus Carya. The genus includes 17–19 species of trees with pinnately compound leaves. Five or six species are native to China, Indochina, and India, as many as 12 are native to the United States, four are found in Mexico, Hickory flowers are small, yellow-green catkins produced in spring. The fruit is a globose or oval nut, 2–5 cm long and 1. 5–3 cm diameter, enclosed in a four-valved husk, which splits open at maturity. The nut shell is thick and bony in most species, and thin in a few, notably the pecan, beaked hickory is a species formerly classified as Carya sinensis, but now adjudged in the monotypic genus Annamocarya. In the APG system, genus Carya has been moved to the Fagales order. Sinocarya – Asian hickories Carya dabieshanensis M. C, liu – Dabie Shan hickory Carya cathayensis Sarg. Carya – typical hickories Carya floridana Sarg, – Scrub hickory Carya glabra Sweet – Pignut hickory, pignut, sweet pignut, coast pignut hickory, smoothbark hickory, swamp hickory, broom hickory Carya myristiciformis Nutt. – Nutmeg hickory, swamp hickory, bitter water hickory Carya ovalis Sarg, – Sand hickory Carya texana Buckley – Black hickory Carya tomentosa Nutt. – Mockernut hickory †Carya washingtonensis - Manchester Extinct Miocene Carya sect, apocarya – pecans Carya aquatica Nutt. – Bitter pecan or water hickory Carya cordiformis K. Koch – Bitternut hickory Carya illinoinensis K. Koch – Pecan Carya palmeri W. E, manning – Mexican hickory Hickory is used as a food plant by the larvae of some Lepidoptera species. Phylloxeridae are related to aphids and have a complex life cycle. Eggs hatch in spring and the galls quickly form around the developing insects. Phylloxera galls may damage weakened or stressed hickories, but are generally harmless, the pecan gall curculio is a true weevil species also found feeding on galls of the hickory leaf stem gall phylloxera. The banded hickory borer is also found on hickories, some fruits are borderline and difficult to categorize. Hickory nuts and walnuts in the Juglandaceae family grow within an outer husk, tryma is a specialized term for such nut-like drupes. Hickory wood is hard, stiff, dense and shock resistant. Paddles are often made from hickory, Hickory is replacing ash as the wood of choice for Scottish shinty sticks
15.
Juglandaceae
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The Juglandaceae are a family, known as the walnut family, of trees, or sometimes shrubs, in the order Fagales. Various members of family are native to the Americas, Eurasia. Members of the family have large, aromatic leaves that are usually alternate. The leaves are compound or ternate, and usually 20–100 cm long. The trees are wind-pollinated, and the flowers are arranged in catkins. The nine or ten genera in the family have a total of ca 50 species, and include the commercially important nut-producing trees walnut, pecan, the Persian walnut, Juglans regia, is one of the major nut crops of the world. Walnut, hickory, and gaulin are also valuable timber trees, the known living genera are grouped into subfamilies, tribes, and subtribes as follows, Subfamily Rhoipteleoideae Reveal Rhoiptelea Diels & Hand. -Mazz. 1932 Subfamily Engelhardioideae Iljinskaya 1990 Alfaroa Standl,1856 Subfamily Juglandoideae Eaton 1836 Tribe Platycaryeae Nakai 1933 Platycarya Siebold & Zucc. Stone & P. S. Manos 2001 Carya Nutt, hickory nuts and walnuts grow within an outer husk, these fruits are sometimes considered to be drupes or drupaceous nuts, rather than true botanical nuts. Tryma is a term for such nut-like drupes. These odd nuts fall into two different types, in the genus, it is a pseudodrupe and in the hickory genus
16.
Botanical nomenclature
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Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy, plant taxonomy is concerned with grouping and classifying plants, botanical nomenclature then provides names for the results of this process. The starting point for botanical nomenclature is Linnaeus Species Plantarum of 1753. Botanical nomenclature is governed by the International Code of Nomenclature for algae, fungi, and plants, fossil plants are also covered by the code of nomenclature. Botanical nomenclature has a history, going back beyond the period when Latin was the scientific language throughout Europe, to Theophrastus, Dioscorides. Many of these works have come down to us in Latin translations, the principal Latin writer on botany was Pliny the Elder. From Mediaeval times, Latin became the scientific language in Europe. Most written plant knowledge was the property of monks, particularly Benedictine, and it would require the invention of the printing press to make such information more widely available. Leonhart Fuchs, a German physician and botanist is often considered the originator of Latin names for the increasing number of plants known to science. For instance he coined the name Digitalis in his De Historia Stirpium Commentarii Insignes, a key event was Linnaeus’ adoption of binomial names for plant species in his Species Plantarum. In the nineteenth century it became clear that there was a need for rules to govern scientific nomenclature. These were published in more sophisticated editions. For plants, key dates are 1867 and 1906, the most recent is the Melbourne Code, adopted in 2011. Another development was the insight into the delimitation of the concept of plant, gradually more and more groups of organisms are being recognised as being independent of plants. Nevertheless, the names of most of these organisms are governed by the. Some protists that do not fit easily into either plant or animal categories are treated under either or both of the ICN and the ICZN, a separate Code was adopted to govern the nomenclature of Bacteria, the International Code of Nomenclature of Bacteria. Botanical nomenclature is closely linked to plant taxonomy, and botanical nomenclature serves plant taxonomy, Botanical nomenclature is merely the body of rules prescribing which name applies to that taxon and if a new name may be coined. Plant taxonomy is a science, a science that determines what constitutes a particular taxon
17.
Asteraceae
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Asteraceae or Compositae is a very large and widespread family of flowering plants. The family currently has 32,913 accepted species names, in 1,911 genera and 13 subfamilies, in terms of numbers of species, the Asteraceae are rivaled only by the Orchidaceae. Many members have composite flowers in the form of flower heads surrounded by involucral bracts, when viewed from a distance, each capitulum may have the appearance of being a single flower. The name Asteraceae comes from the type genus Aster, from the Greek ἀστήρ, meaning star, Compositae is an older but still valid name which refers to the fact that the family is one of the few angiosperm ones to have composite flowers. Most members of Asteraceae are herbaceous, but a significant number are also shrubs, vines, the family has a worldwide distribution, from the polar regions to the tropics, colonizing a wide variety of habitats. It is most common in the arid and semiarid regions of subtropical, the Asteraceae may represent as much as 10% of autochthonous flora in many regions of the world. Asteraceae is an important family, providing products such as cooking oils, lettuce, sunflower seeds, artichokes, sweetening agents, coffee substitutes. Several genera are of importance, including pot marigold, Calendula officinalis, Echinacea, various daisies, fleabane, chrysanthemums, dahlias, zinnias. Asteraceae are important in medicine, including Grindelia, yarrow. A number of species are considered invasive, including, most notably in North America, dandelion, the name Asteraceae comes to international scientific vocabulary from New Latin, from Aster, the type genus, + -aceae, a standardized suffix for plant family names in modern taxonomy. The genus name comes from the Classical Latin word aster, star, Compositae, an older but still valid name, means composite and refers to the characteristic inflorescence, a special type of pseudanthium found in only a few other angiosperm families. The study of family is known as synantherology. The vernacular name daisy, widely applied to members of family, is derived from its Old English name, dægesege, from dæges eage. This is because the open at dawn and close at dusk. Composite flowers have a distribution, and are found everywhere except Antarctica. They are especially numerous in tropical and subtropical regions, Compositae were first described in 1792 by the German botanist Paul Dietrich Giseke. Traditionally, two subfamilies were recognised, Asteroideae and Cichorioideae, the latter has been shown to be extensively paraphyletic, and has now been divided into 12 subfamilies, but the former still stands. The phylogenetic tree presented below is based on Panero & Funk updated in 2014, the diamond denotes a very poorly supported node, the dot a poorly supported node
18.
Poaceae
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Poaceae or Gramineae is a large and nearly ubiquitous family of monocotyledonous flowering plants known as grasses. Poaceae includes the cereal grasses, bamboos and the grasses of natural grassland and cultivated lawns, Grasses have stems that are hollow except at the nodes and narrow alternate leaves borne in two ranks. The lower part of each leaf encloses the stem, forming a leaf-sheath, with ca 780 genera and around 12,000 species, Poaceae are the fifth-largest plant family, following the Asteraceae, Orchidaceae, Fabaceae and Rubiaceae. Grasslands such as savannah and prairie grasses are dominant are estimated to constitute 40. 5% of the land area of the Earth, excluding Greenland. Grasses are also an important part of the vegetation in many habitats, including wetlands, forests. Though commonly called grasses, seagrasses, rushes, and sedges fall outside this family, the rushes and sedges are related to the Poaceae, being members of the order Poales, but the seagrasses are members of order Alismatales. The name Poaceae was given by John Hendley Barnhart in 1895, based on the tribe Poeae described in 1814 by Robert Brown, the term is derived from the Ancient Greek πόα. Grasses include some of the most versatile plant life-forms, a cladogram shows subfamilies and approximate species numbers in brackets, Before 2005, fossil findings indicated that grasses evolved around 55 million years ago. Recent findings of grass-like phytoliths in Cretaceous dinosaur coprolites have pushed this back to 66 million years ago. In 2011, revised dating of the origins of the rice tribe Oryzeae suggested a date as early as 107 to 129 Mya, a multituberculate mammal with grass-eating adaptations seems to suggest that grasses were already around at 120 mya. This separation occurred within the short time span of about 4 million years. Grass leaves are always alternate and distichous, and have parallel veins. Each leaf is differentiated into a lower sheath hugging the stem, the leaf blades of many grasses are hardened with silica phytoliths, which discourage grazing animals, some, such as sword grass, are sharp enough to cut human skin. A membranous appendage or fringe of hairs called the ligule lies at the junction between sheath and blade, preventing water or insects from penetrating into the sheath, flowers of Poaceae are characteristically arranged in spikelets, each having one or more florets. The spikelets are further grouped into panicles or spikes, the part of the spikelet that bears the florets is called the rachilla. A spikelet consists of two bracts at the base, called glumes, followed by one or more florets, a floret consists of the flower surrounded by two bracts, one external—the lemma—and one internal—the palea. The flowers are usually hermaphroditic—maize being an important exception—and anemophilous or wind-pollinated, the perianth is reduced to two scales, called lodicules, that expand and contract to spread the lemma and palea, these are generally interpreted to be modified sepals. This complex structure can be seen in the image on the right, the fruit of grasses is a caryopsis, in which the seed coat is fused to the fruit wall
19.
Pierre Magnol
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Pierre Magnol was a French botanist. He was born in the city of Montpellier, where he lived and worked for most of his life and he became Professor of Botany and Director of the Royal Botanic Garden of Montpellier and held a seat in the Académie Royale des Sciences de Paris for a short while. He was one of the innovators who devised the scheme of classification. He was the first to publish the concept of plant families as they are understood today, pierre Magnol was born into a family of apothecaries. His father Claude ran a pharmacy as did his grandfather Jean Magnol, pierres mother was from a family of physicians. Pierres older brother Cesar succeeded his father in the pharmacy, pierre, being one of the younger children, had more freedom to choose his own profession, and wanted to become a physician. He had become devoted to history and especially botany at an early stage in his life. In Magnols days, the study of botany and medicine were inseparable, thus he enrolled as a student in medicine at the University of Montpellier on May 19,1655. Montpellier is an old city, and in Magnols days it had already been an important commercial and educational centre for several ages and its medical school attracted students from all over Europe. So it was in one of the intellectual and botanical capitals that Magnol took his education and he got his doctors degree on January 11,1659. After receiving his degree, his once again shifted to botany. Montpellier was a bastion of Protestantism and Magnol was raised in the tradition of Calvinism. At that time, Roman Catholicism was the state church, but since the Edict of Nantes, Protestants officially had religious freedom. The edict did not end religious persecution and discrimination, in his life, Magnol was several times denied a position because of religious discrimination. With the revocation of the Edict of Nantes in 1685, Magnol renounced Protestantism, in December 1663 Magnol received the honorary title brevet de médecine royal through mediation of Antoine Vallot, an influential physician of the king. No means of his financial stability are mentioned but it is suggested that he was practicing medicine and had an out of that. From 1659 on he devoted much of his time to the study of botany and made trips through the Languedoc. In 1664 there was a vacancy for Demonstrator of plants in Montpellier and he was denied the appointment because of religious discrimination
20.
Carl Linnaeus
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Carl Linnaeus, also known after his ennoblement as Carl von Linné, was a Swedish botanist, physician, and zoologist, who formalised the modern system of naming organisms called binomial nomenclature. He is known by the father of modern taxonomy. Many of his writings were in Latin, and his name is rendered in Latin as Carolus Linnæus, Linnaeus was born in the countryside of Småland, in southern Sweden. He received most of his education at Uppsala University. He lived abroad between 1735 and 1738, where he studied and also published a first edition of his Systema Naturae in the Netherlands and he then returned to Sweden, where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on journeys through Sweden to find and classify plants. In the 1750s and 1760s, he continued to collect and classify animals, plants, and minerals, at the time of his death, he was one of the most acclaimed scientists in Europe. The philosopher Jean-Jacques Rousseau sent him the message, Tell him I know no man on earth. The German writer Johann Wolfgang von Goethe wrote, With the exception of Shakespeare and Spinoza, Swedish author August Strindberg wrote, Linnaeus was in reality a poet who happened to become a naturalist. Among other compliments, Linnaeus has been called Princeps botanicorum, The Pliny of the North and he is also considered as one of the founders of modern ecology. In botany, the abbreviation used to indicate Linnaeus as the authority for species names is L. In older publications, sometimes the abbreviation Linn. is found, Linnæus was born in the village of Råshult in Småland, Sweden, on 23 May 1707. He was the first child of Nicolaus Ingemarsson and Christina Brodersonia and his siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus, and Emerentia Linnæa. One of a line of peasants and priests, Nils was an amateur botanist, a Lutheran minister. Christina was the daughter of the rector of Stenbrohult, Samuel Brodersonius, a year after Linnæus birth, his grandfather Samuel Brodersonius died, and his father Nils became the rector of Stenbrohult. The family moved into the rectory from the curates house, even in his early years, Linnæus seemed to have a liking for plants, flowers in particular. Whenever he was upset, he was given a flower, which calmed him. Nils spent much time in his garden and often showed flowers to Linnaeus, soon Linnæus was given his own patch of earth where he could grow plants
21.
Tree
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In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. Trees are not a group but include a variety of plant species that have independently evolved a woody trunk. In looser senses, the palms, the tree ferns, bananas. Trees tend to be long-lived, some reaching several thousand years old, the tallest known tree, a coast redwood named Hyperion, stands 115.6 m high. Trees have been in existence for 370 million years and it is estimated that there are just over 3 trillion mature trees in the world. A tree typically has many secondary branches supported clear of the ground by the trunk and this trunk typically contains woody tissue for strength, and vascular tissue to carry materials from one part of the tree to another. For most trees it is surrounded by a layer of bark which serves as a protective barrier, below the ground, the roots branch and spread out widely, they serve to anchor the tree and extract moisture and nutrients from the soil. Above ground, the divide into smaller branches and shoots. The shoots typically bear leaves, which light energy and convert it into sugars by photosynthesis, providing the food for the trees growth. Flowers and fruit may also be present, but some trees, such as conifers, instead have pollen cones and seed cones, others, such as tree ferns, trees play a significant role in reducing erosion and moderating the climate. They remove carbon dioxide from the atmosphere and store large quantities of carbon in their tissues, trees and forests provide a habitat for many species of animals and plants. Tropical rainforests are one of the most biodiverse habitats in the world, trees provide shade and shelter, timber for construction, fuel for cooking and heating, and fruit for food as well as having many other uses. In parts of the world, forests are shrinking as trees are cleared to increase the amount of available for agriculture. Because of their longevity and usefulness, trees have always revered, with sacred groves in various cultures. Although tree is a term of common parlance, there is no universally recognised precise definition of what a tree is, either botanically or in common language. In its broadest sense, a tree is any plant with the form of an elongated stem, or trunk. Trees are also defined by height, with smaller plants from 0.5 to 10 m being called shrubs
22.
Herb
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In general use, herbs are any plants used for food, flavoring, medicine, or fragrances for their savory or aromatic properties. Culinary use typically distinguishes herbs from spices, Herbs refers to the leafy green or flowering parts of a plant, while spices are produced from other parts of the plant, including seeds, berries, bark, roots and fruits. In botanical English, the herb is also used as a synonym of herbaceous plant. Herbs have a variety of uses including culinary, medicinal, and in some cases, general usage of the term herb differs between culinary herbs and medicinal herbs. In medicinal or spiritual use any of the parts of the plant might be considered herbs, including leaves, roots, flowers, seeds, root bark, inner bark, resin and pericarp. The word herb is pronounced /ˈhɜːrb/ in the UK, but /ˈɜːrb/ is common among North American speakers, as far back as 5000 BCE, Sumerians used herbs in medicine. Ancient Egyptians used fennel, coriander and thyme around 1555 BCE, in ancient Greece, in 162 CE, a physician by the name of Galen was known for concocting complicated herbal remedies that contained up to 100 ingredients. Culinary herbs are distinguished from vegetables in that, like spices, they are used in small amounts, Herbs can be perennials such as thyme or lavender, biennials such as parsley, or annuals like basil. Perennial herbs can be such as rosemary, Rosmarinus officinalis, or trees such as bay laurel, Laurus nobilis – this contrasts with botanical herbs. Some plants are used as herbs and spices, such as dill weed and dill seed or coriander leaves and seeds. Also, there are some such as those in the mint family that are used for both culinary and medicinal purposes. Some plants contain phytochemicals that have effects on the body, there may be some effects when consumed in the small levels that typify culinary spicing, and some herbs are toxic in larger quantities. For instance, some types of herbal extract, such as the extract of St. Johns-wort or of kava can be used for purposes to relieve depression. However, large amounts of these herbs may lead to toxic overload that may involve complications, some of a serious nature, Herbs have long been used as the basis of traditional Chinese herbal medicine, with usage dating as far back as the first century CE and far before. In India, the Ayurveda medicinal system is based on herbs, medicinal use of herbs in Western cultures has its roots in the Hippocratic elemental healing system, based on a quaternary elemental healing metaphor. Famous herbalist of the Western tradition include Avicenna, Galen, Paracelsus, Culpepper, the indigenous peoples of Australia developed herbal medicine based on plants that were readily available to them. The isolation of the people meant the remedies developed were for far less serious diseases. Herbs such as mint, wattle and eucalyptus were used for coughs, diarrhea, fever
23.
Arecaceae
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The Arecaceae are a botanical family of perennial climbers, shrubs, acaules and trees commonly known as palm trees. They are flowering plants, a family in the monocot order Arecales, currently 181 genera with around 2600 species are known, most of them restricted to tropical, subtropical, and warm temperate climates. Most palms are distinguished by their large, compound, evergreen leaves, known as fronds, however, palms exhibit an enormous diversity in physical characteristics and inhabit nearly every type of habitat within their range, from rainforests to deserts. Palms are among the best known and most extensively cultivated plant families and they have been important to humans throughout much of history. Many common products and foods are derived from palms, and palms are widely used in landscaping, making them one of the most economically important plants. In many historical cultures, palms were symbols for such ideas as victory, peace, for inhabitants of cooler climates today, palms symbolize the tropics and vacations. Whether as shrubs, trees, or vines, palms have two methods of growth, solitary or clustered, the common representation is that of a solitary shoot ending in a crown of leaves. This monopodial character may be exhibited by prostrate, trunkless, some common palms restricted to solitary growth include Washingtonia and Roystonea. Palms may instead grow in sparse though dense clusters, the trunk develops an axillary bud at a leaf node, usually near the base, from which a new shoot emerges. The new shoot, in turn, produces an axillary bud, exclusively sympodial genera include many of the rattans, Guihaia, and Rhapis. Several palm genera have both solitary and clustering members, Palms which are usually solitary may grow in clusters, and vice versa. These aberrations suggest the habit operates on a single gene, Palms have large, evergreen leaves that are either palmately or pinnately compound and spirally arranged at the top of the stem. The leaves have a sheath at the base that usually splits open on one side at maturity. The inflorescence is a spadix or spike surrounded by one or more bracts or spathes that become woody at maturity, the flowers are generally small and white, radially symmetric, and can be either uni- or bisexual. The sepals and petals usually number three each, and may be distinct or joined at the base, the stamens generally number six, with filaments that may be separate, attached to each other, or attached to the pistil at the base. The fruit is usually a single-seeded drupe but some genera may contain two or more seeds in each fruit, like all monocots, palms do not have the ability to increase the width of a stem via the same kind of vascular cambium found in non-monocot woody plants. This explains the shape of the trunk that is often seen in palms. The Arecaceae are notable among monocots for their height and for the size of their seeds, leaves, Ceroxylon quindiuense, Colombias national tree, is the tallest monocot in the world, reaching up to 60 m tall
24.
Michel Adanson
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Michel Adanson was an 18th-century French botanist and naturalist, of Scottish descent. His family moved to Paris on 1730, after leaving the Collège Sainte-Barbe he was employed in the cabinets of R. A. F. Réaumur and Bernard de Jussieu, as well as in the Jardin des Plantes, Paris. He attended lectures at the Jardin du Roi and the Collège Royal in Paris from 1741 to 1746, at the end of 1748, funded by a director of the Compagnie des Indes, he left France on an exploring expedition to Senegal. He remained there for five years, collecting and describing numerous animals, after his return to Paris in 1754 he made use of a small portion of the materials he had collected in his Histoire naturelle du Senegal. He founded his classification of all organized beings on the consideration of each individual organ, as each organ gave birth to new relations, so he established a corresponding number of arbitrary arrangements. Those beings possessing the greatest number of organs were referred to one great division. In 1763 he published his Familles naturelles des plantes, in 1774 Adanson submitted to the consideration of the French Academy of Sciences an immense work, extending to all known beings and substances. He obstinately rejected this advice, and the work, at which he continued to labour, was never published. Adanson was a proponent of the inheritance of acquired characters. Historian of science Conway Zirkle has noted that Adanson was Lamarcks predecessor at the Jardin Royal, in an article for the Histoire and Memoires de lAcademie Royale des Sciences of 1769, Adanson used the term mutations to refer to small changes that could bring about new variations in individuals. Despite being described as a precursor of evolutionism by historians, Adanson rejected the concept of species, preferring to focus on individuals and he had been elected a member of the Academy of Sciences in 1759, and he latterly subsisted on a small pension it had conferred on him. Afterwards he was granted a sufficient to relieve his simple wants. Besides the books already mentioned he published papers on the ship-worm, the tree, the origin of the varieties of cultivated plants. Subsequently, the Hunt Institute republished his Familles des plantes in two volumes, under the editorship of G. H. M. Lawrence, in The Commodore, the seventeenth novel of Patrick OBrians Aubrey-Maturin series, Stephen Maturin makes reference to Adanson. He elaborates on Adansons botanical work in Senegal, the volume of his written output. Stephen Maturin, He was a very great naturalist, as zealous, prolific, I knew him in Paris when I was young, and admired him extremely, so did Cuvier. At that time he was kind to us. All this he showed to the Academy and it was much praised but never published
25.
Augustin Pyramus de Candolle
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Augustin Pyramus de Candolle also spelled Augustin Pyrame de Candolle was a Swiss botanist. René Louiche Desfontaines launched de Candolles botanical career by recommending him at an herbarium, within a couple of years de Candolle had established a new genus, and he went on to document hundreds of plant families and create a new natural plant classification system. Although de Candolles main focus was botany, he contributed to related fields such as phytogeography, agronomy, paleontology, medical botany. Candolle originated the idea of Natures war, which influenced Charles Darwin, de Candolle recognized that multiple species may develop similar characteristics that did not appear in a common evolutionary ancestor, this was later termed analogy. During his work with plants, de Candolle noticed that plant leaf movements follow a cycle in constant light. Though many scientists doubted de Candolles findings, experiments over a century later demonstrated that ″the internal biological clock″ indeed exists, Candolles descendants continued his work on plant classification. Alphonse de Candolle and Casimir Pyrame de Candolle contributed to the Prodromus Systematis Naturalis Regni Vegetabilis, Augustin Pyramus de Candolle was born on 4 February 1778 in Geneva, Switzerland, to Augustin de Candolle, a former official, and his wife, Louise Eléonore Brière. His family descended from one of the ancient families of Provence in France, at age seven de Candolle contracted of a severe case of hydrocephalus, which significantly affected his childhood. Candolles initiation to botany happened in 1794 thanks to Pierre Etienne Vaucher in Geneva and he spent then four years at the Geneva Academy, studying science and law according to his fathers wishes. In 1798, he moved to Paris after Geneva had been annexed to the French Republic and his botanical career began with the help of René Louiche Desfontaines, who recommended de Candolle for work in the herbarium of Charles Louis LHéritier de Brutelle during the summer of 1798. The position elevated de Candolles reputation and also led to valuable instruction from Desfontaines himself, the premise of de Candolles method is that taxa do not fall along a linear scale, they are discrete, not continuous. In 1804, de Candolle published his Essai sur les propriétés médicales des plantes and was granted a doctor of medicine degree by the faculty of Paris. In 1807 he was appointed professor of botany in the faculty of the University of Montpellier. While in Montpellier, de Candolle published his Théorie élémentaire de la botanique, which introduced a new classification system and the word taxonomy. Candolle moved back to Geneva in 1816 and in the year was invited by the government of the Canton of Geneva to fill the newly created chair of natural history. De Candolle spent the rest of his life in an attempt to elaborate and complete his natural system of botanical classification, de Candolle published initial work in his Regni vegetabillis systema naturale, but after two volumes he realized he could not complete the project on such a large scale. Consequently, he began his less extensive Prodromus Systematis Naturalis Regni Vegetabilis in 1824, however, he was able to finish only seven volumes, or two-thirds of the whole. Even so, he was able to characterize over one hundred families of plants, although de Candolles main focus was botany, throughout his career he also dabbled in fields related to botany, such as phytogeography, agronomy, paleontology, medical botany, and economic botany
26.
George Bentham
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George Bentham CMG FRS was an English botanist, characterised by Duane Isely as the premier systematic botanist of the nineteenth century. Bentham was born in Stoke, Plymouth, on 22 September 1800 and his father, Sir Samuel Bentham, a naval architect, was the only brother of Jeremy Bentham to survive into adulthood. George Bentham had neither a school nor a college education, and he also had a remarkable linguistic aptitude. By the age of seven he could speak French, German and Russian and they eventually settled in the neighbourhood of Montpellier where Sir Samuel purchased a large estate. George Bentham became attracted to botanical studies by applying to them his uncles logical methods, while studying at Angoulême he came across a copy of A. P. de Candolles Flore française, and he became interested in the analytical tables for identifying plants. He immediately proceeded to test their use on the first plant he saw, the result was successful and he continued to apply it to every plant he came across. A visit to London in 1823 brought him contact with the brilliant circle of English botanists. In 1826, at the invitation of his uncle, he agreed to act as his secretary, at the same time entering Lincolns Inn. He was called in due time and in 1832 held his first and last brief, however, his interest in botany never flagged and he was secretary of the Horticultural Society of London from 1829 to 1840. In 1832, Jeremy Bentham died, leaving his property to his nephew, having inherited his fathers estate the previous year, he was now in a position of modest independence, and able to pursue wholeheartedly his favourite studies. For a time these were divided between botany, jurisprudence and logic, in addition to editing his fathers professional papers, Bentham married Sarah Jones, daughter of Sir Harford Jones Brydges, on 11 April 1833, they did not have children. Bentham died at his London home of 30 years,25 Wilton Place, on 10 September 1884 and he was laid to rest in Brompton Cemetery. Benthams life spanned the Darwinian revolution and, moreover, his young colleague Joseph Dalton Hooker was Darwins closest friend, Bentham was until then an unquestioning adherent of the dogma of the constancy of species. We can no more set up a typical species than a typical individual, Bentham was awarded the Royal Medal of the Royal Society in 1859 and elected a Fellow in 1862. He served as president of the Linnean Society of London from 1861 to 1874 and he was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1866. He was appointed CMG in 1878 and his foreign awards included the Clarke Medal of the Royal Society of New South Wales in 1879. It is interesting to notice that in it Bentham adopted the principle from which he never deviated and this was followed by articles on various legal subjects, on codification, in which he disagreed with his uncle, on the laws affecting larceny and on the law of real property. But the most remarkable production of this period was the Outline of a new system of logic, in this the principle of the quantification of the predicate was first explicitly stated
27.
Joseph Dalton Hooker
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Sir Joseph Dalton Hooker OM GCSI CB PRS was one of the greatest British botanists and explorers of the 19th century. He was a founder of botany and Charles Darwins closest friend. For twenty years he served as director of the Royal Botanical Gardens, Kew, succeeding his father, William Jackson Hooker, Hooker was born in Halesworth, Suffolk, England. From age seven, Hooker attended his fathers lectures at Glasgow University, taking an early interest in plant distribution and he was educated at the Glasgow High School and went on to study medicine at Glasgow University, graduating M. D. in 1839. In 1851 he married Frances Harriet Henslow, daughter of Darwins mentor and they had four sons and three daughters, William Henslow Hooker Harriet Anne Hooker married William Turner Thiselton-Dyer Charles Paget Hooker Maria Elizabeth Hooker died aged 6. Brian Harvey Hodgson Hooker Reginald Hawthorn Hooker statistician Grace Ellen Hooker Frances Harriet Henslows contribution to his work included translating French botanical texts which Hooker edited. After his first wifes death in 1874, in 1876 he married Lady Hyacinth Jardine, daughter of William Samuel Symonds and they had two sons, Joseph Symonds Hooker Richard Symonds Hooker. Joseph Hooker died in his sleep at midnight at home, the Camp, Sunningdale in Berkshire, on 10 December 1911 after a short, the Dean and Chapter of Westminster Abbey offered a grave near Darwins in the nave but also insisted that Hooker be cremated before. His memorial tablet in the church, with a motif of five plants, was designed by Matilds Smith. Hookers first expedition, led by James Clark Ross, consisted of two ships, HMS Erebus and HMS Terror, it was the last major voyage of exploration made entirely under sail, Hooker was the youngest of the 128-man crew. He sailed on the Erebus and was assistant to Robert McCormick, the ships sailed on 30 September 1839. Before journeying to Antarctica they visited Madeira, Tenerife, Santiago and Quail Island in the Cape Verde archipelago, St Paul Rocks, Trinidade east of Brazil, St Helena, and the Cape of Good Hope. Hooker made plant collections at each location and while travelling drew these and specimens of algae, from the Cape they entered the southern ocean. Their first stop was the Crozet Islands where they set down on Possession Island to deliver coffee to sealers and they departed for the Kerguelen Islands where they would spend several days. The expedition spent some time in Hobart, Van Diemens Land, and then moved on to the Auckland Islands and Campbell Island, and onward to Antarctica to locate the South Magnetic Pole. After spending 5 months in the Antarctic they returned to resupply in Hobart, then went on to Sydney, and they left New Zealand to return to Antarctica. They made a landing at Cockburn Island and after leaving the Antarctic, stopped at the Cape, St Helena and Ascension Island. The ships arrived back in England on 4 September 1843, the voyage had been a success for Ross as it was the first to confirm the existence of the southern continent, in 1845, Hooker applied for the Chair of Botany at the University of Edinburgh
28.
Zoology
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The term is derived from Ancient Greek ζῷον, zōion, i. e. animal and λόγος, logos, i. e. knowledge, study. The history of zoology traces the study of the kingdom from ancient to modern times. This ancient work was developed in the Middle Ages by Muslim physicians. During the Renaissance and early period, zoological thought was revolutionized in Europe by a renewed interest in empiricism. Microscopy revealed the unknown world of microorganisms, laying the groundwork for cell theory. The growing importance of natural theology, partly a response to the rise of mechanical philosophy, over the 18th and 19th centuries, zoology became an increasingly professional scientific discipline. Naturalists began to reject essentialism and consider the importance of extinction, cell theory provided a new perspective on the fundamental basis of life. These developments, as well as the results from embryology and paleontology, were synthesized in Charles Darwins theory of evolution by natural selection. In 1859, Darwin placed the theory of evolution on a new footing, by his discovery of a process by which organic evolution can occur. Darwin gave new direction to morphology and physiology, by uniting them in a biological theory. The end of the 19th century saw the fall of spontaneous generation, cell biology studies the structural and physiological properties of cells, including their behavior, interactions, and environment. This is done on both the microscopic and molecular levels, for single-celled organisms such as bacteria as well as the cells in multicellular organisms such as humans. Understanding the structure and function of cells is fundamental to all of the biological sciences, the similarities and differences between cell types are particularly relevant to molecular biology. Anatomy considers the forms of macroscopic structures such as organs and organ systems and it focuses on how organs and organ systems work together in the bodies of humans and animals, in addition to how they work independently. Anatomy and cell biology are two studies that are related, and can be categorized under structural studies. Physiology studies the mechanical, physical, and biochemical processes of living organisms by attempting to understand how all of the function as a whole. The theme of structure to function is central to biology, for example, what is learned about the physiology of yeast cells can also apply to human cells. The field of animal physiology extends the tools and methods of physiology to non-human species
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Arthropod
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An arthropod is an invertebrate animal having an exoskeleton, a segmented body, and jointed appendages. Arthropods form the phylum Arthropoda, which includes the insects, arachnids, myriapods, arthropods are characterized by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages, the rigid cuticle inhibits growth, so arthropods replace it periodically by moulting. Their versatility has enabled them to become the most species-rich members of all guilds in most environments. They have over a million described species, making up more than 80% of all described living species, some of which. Arthropods range in size from the microscopic crustacean Stygotantulus up to the Japanese spider crab, arthropods primary internal cavity is a hemocoel, which accommodates their internal organs, and through which their haemolymph – analogue of blood – circulates, they have open circulatory systems. Like their exteriors, the organs of arthropods are generally built of repeated segments. Their nervous system is ladder-like, with paired ventral nerve cords running through all segments and their heads are formed by fusion of varying numbers of segments, and their brains are formed by fusion of the ganglia of these segments and encircle the esophagus. The respiratory and excretory systems of arthropods vary, depending as much on their environment as on the subphylum to which they belong, arthropods also have a wide range of chemical and mechanical sensors, mostly based on modifications of the many setae that project through their cuticles. Aquatic species use internal or external fertilization. Almost all arthropods lay eggs, but scorpions give birth to live young after the eggs have hatched inside the mother, arthropod hatchlings vary from miniature adults to grubs and caterpillars that lack jointed limbs and eventually undergo a total metamorphosis to produce the adult form. The level of care for hatchlings varies from nonexistent to the prolonged care provided by scorpions. The evolutionary ancestry of arthropods dates back to the Cambrian period, the group is generally regarded as monophyletic, and many analyses support the placement of arthropods with cycloneuralians in a superphylum Ecdysozoa. Overall however, the relationships of Metazoa are not yet well resolved. Likewise, the relationships between various groups are still actively debated. Arthropods contribute to the food supply both directly as food, and more importantly indirectly as pollinators of crops. Some species are known to spread disease to humans, livestock. The word arthropod comes from the Greek ἄρθρον árthron, joint, and πούς pous, i. e. foot or leg, arthropods are invertebrates with segmented bodies and jointed limbs
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Systematics
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Biological systematics is the study of the diversification of living forms, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees, phylogenies have two components, branching order and branch length. Phylogenetic trees of species and higher taxa are used to study the evolution of traits, Systematics, in other words, is used to understand the evolutionary history of life on Earth. John Lindley provided a definition of systematics in 1830, although he wrote of systematic botany rather than using the term systematics. This is a field with a history that in recent years has experienced a notable renaissance. Part of the material has to do with evolutionary areas. Taxonomy is that part of Systematics concerned with topics to above, however, in modern usage, they can all be considered synonyms of each other. For example, Websters 9th New Collegiate Dictionary of 1987 treats classification, taxonomy, according to this work the terms originated in 1790, c. Europeans tend to use the terms systematics and biosystematics for the field of the study of biodiversity as a whole, all of these biological disciplines can deal both with extinct and with extant organisms. Scientific classifications are aids in recording and reporting information to other scientists, the systematist, a scientist who specializes in systematics, must, therefore, be able to use existing classification systems, or at least know them well enough to skilfully justify not using them. Phenetics was an attempt to determine the relationships of organisms through a measure of overall similarity, from the late-20th century onwards, it was superseded by cladistics, which rejects plesiomorphies in attempting to resolve the phylogeny of Earths various organisms through time. Todays systematists generally make use of molecular biology and of computer programs to study organisms. Taxonomic characters are the attributes that can be used to provide the evidence from which relationships between taxa are inferred. Adaptation, or evolutionary mechanisms Scientific classification and Taxonomy - the result of research in systematics Schuh, Randall T. biological Systematics, Principles and Applications, 2nd edn. ISBN 978-0-8014-4799-0 Simpson, Michael G.2005, ISBN 978-0-12-644460-5 Society of Australian Systematic Biologists Society of Systematic Biologists Willi Hennig Society
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Cladistics
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Therefore, members of a group are assumed to share a common history and are considered to be closely related. The techniques and nomenclature of cladistics have been applied to other disciplines, Cladistics in the original sense refers to a particular set of methods used in phylogenetic analysis, although it is now sometimes used to refer to the whole field. What is now called the cladistic method appeared as early as 1901 with a work by Peter Chalmers Mitchell for birds and subsequently by Robert John Tillyard in 1921, Hennig referred to his own approach as phylogenetic systematics. Phenetics was championed at this time by the numerical taxonomists Peter Sneath and Robert Sokal, originally conceived, if only in essence, by Willi Hennig in a book published in 1950, cladistics did not flourish until its translation into English in 1966. Today, cladistics is the most popular method for constructing phylogenies from morphological, unlike phenetics, cladistics is specifically aimed at reconstructing evolutionary histories. The way for computational phylogenetics was paved by phenetics, a set of commonly used from the 1950s to 1980s. Phenetics did not try to reconstruct phylogenetic trees, rather, it tried to build dendrograms from similarity data, the cladistic method interprets each character state transformation implied by the distribution of shared character states among taxa as a potential piece of evidence for grouping. The outcome of an analysis is a cladogram – a tree-shaped diagram that is interpreted to represent the best hypothesis of phylogenetic relationships. Cladists contend that these models are unjustified, every cladogram is based on a particular dataset analyzed with a particular method. Different datasets and different methods, not to mention violations of the mentioned assumptions, only scientific investigation can show which is more likely to be correct. Since the cladograms provide competing accounts of events, at most one of them is correct. Within the primates, all anthropoids are hypothesized to have had a common ancestor all of whose descendants were anthropoids, the prosimians, on the other hand, form a paraphyletic taxon. When two or more taxa that are not nested within each other share a plesiomorphy, it is a symplesiomorphy, symplesiomorphies do not mean that the taxa that exhibit that character state are necessarily closely related. For example, Reptilia is traditionally characterized by being cold-blooded, whereas birds are warm-blooded, an apomorphy or derived state is an innovation. It can thus be used to diagnose a clade – or even to help define a clade name in phylogenetic nomenclature, features that are derived in individual taxa are called autapomorphies. Autapomorphies express nothing about relationships among groups, clades are identified by synapomorphies, for example, the possession of digits that are homologous with those of Homo sapiens is a synapomorphy within the vertebrates. The tetrapods can be singled out as consisting of the first vertebrate with such digits homologous to those of Homo sapiens together with all descendants of this vertebrate and it is therefore inferred to have evolved by convergence or reversal. Both mammals and birds are able to maintain a constant body temperature
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Phylogenetics
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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
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Taxonomy (biology)
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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
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Virus classification
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Virus classification is the process of naming viruses and placing them into a taxonomic system. Similar to the systems used for cellular organisms, virus classification is the subject of ongoing debate. This is mainly due to the nature of viruses, which is to say they are non-living particles with some chemical characteristics similar to those of life. As such, they do not fit neatly into the biological classification system in place for cellular organisms. Viruses are mainly classified by phenotypic characteristics, such as morphology, nucleic acid type, mode of replication, host organisms, accompanying this broad method of classification are specific naming conventions and further classification guidelines set out by the ICTV. A catalog of all the worlds viruses has been proposed, some related preliminary efforts have been accomplished, species form the basis for any biological classification system. The ICTV had adopted the principle that a species is a polythetic class of viruses that constitutes a replicating lineage. In July 2013, the ICTV definition of species changed to state, the International Committee on Taxonomy of Viruses began to devise and implement rules for the naming and classification of viruses early in the 1970s, an effort that continues to the present. The ICTV is the body charged by the International Union of Microbiological Societies with the task of developing, refining. The system shares many features with the system of cellular organisms. However, this system of nomenclature differs from other taxonomic codes on several points, a minor point is that names of orders and families are italicized, unlike in the International Code of Nomenclature for algae, fungi, and plants and International Code of Zoological Nomenclature. The establishment of an order is based on the inference that the families it contains have most likely evolved from a common ancestor. The majority of families remain unplaced. As of 2012, seven orders,96 families,22 subfamilies,420 genera, the orders are the Caudovirales, Herpesvirales, Ligamenvirales, Mononegavirales, Nidovirales, Picornavirales, and Tymovirales. These orders span viruses with varying host ranges, the Ligamenvirales, infecting archaea, are the most recent addition to the classification system. Herpesvirales contain large eukaryotic dsDNA viruses, Ligamenvirales contains linear, dsDNA archaean viruses. Mononegavirales include nonsegmented strand ssRNA plant and animal viruses, Nidovirales are composed of strand ssRNA viruses with vertebrate hosts. Picornavirales contains small strand ssRNA viruses that infect a variety of plant, insect, Tymovirales contain monopartite ssRNA viruses that infect plants
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Family
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In the context of human society, a family is a group of people affiliated either by consanguinity, affinity, or co-residence or some combination of these. Members of the family may include spouses, parents, brothers, sisters, sons. Members of the family may include grandparents, aunts, uncles, cousins, nephews, nieces. Sometimes these are considered members of the immediate family, depending on an individuals specific relationship with them. In most societies, the family is the institution for the socialization of children. As the basic unit for raising children, anthropologists generally classify most family organizations as matrifocal, conjugal, avuncular, sexual relations among the members are regulated by rules concerning incest such as the incest taboo. The word family can be used metaphorically to create more inclusive categories such as community, nationhood, global village, the field of genealogy aims to trace family lineages through history. Family is also an important economic unit studied in family economics, one of the primary functions of the family involves providing a framework for the production and reproduction of persons, biologically and/or socially. This can occur through the sharing of material substances, the giving and receiving of care and nurture, jural rights and obligations, thus, ones experience of ones family shifts over time. From the perspective of children, the family is a family of orientation, from the point of view of the parent, the family is a family of procreation, the goal of which is to produce and enculturate and socialize children. Christopher Harris notes that the conception of family is ambiguous. Diverse data from ethnography, history, law and social statistics, reveal the human family as a social institution, the different types of families occur in a wide variety of settings, and their specific functions and meanings depend largely on their relationship to other social institutions. Sociologists have a special interest in the function and status of family forms in stratified societies, much sociological, historical and anthropological research dedicates itself to the understanding of this variation, and of changes in the family that form over time. Levitan claims, Times have changed, it is acceptable and encouraged for mothers to work. The way roles are balanced between the parents will help children grow and learn life lessons. There is great importance of communication and equality in families, in order to avoid role strain, the term nuclear family is commonly used, especially in the United States of America, to refer to conjugal families. A conjugal family includes only the husband, the wife, sociologists distinguish between conjugal families and nuclear families. Other family structures, such as blended parents, single parents, a matrifocal family consists of a mother and her children
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Portable Document Format
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The Portable Document Format is a file format used to present documents in a manner independent of application software, hardware, and operating systems. Each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, graphics, PDF was developed in the early 1990s as a way to share computer documents, including text formatting and inline images. It was among a number of competing formats such as DjVu, Envoy, Common Ground Digital Paper, Farallon Replica, in those early years before the rise of the World Wide Web and HTML documents, PDF was popular mainly in desktop publishing workflows. Adobe Systems made the PDF specification available free of charge in 1993 and these proprietary technologies are not standardized and their specification is published only on Adobe’s website. Many of them are not supported by popular third-party implementations of PDF. So when organizations publish PDFs which use proprietary technologies, they present accessibility issues for some users. In 2014, ISO TC171 voted to deprecate XFA for ISO 32000-2, on January 9,2017, the final draft for ISO 32000-2 was published, thus reaching the approval stage. The PDF combines three technologies, A subset of the PostScript page description programming language, for generating the layout, a font-embedding/replacement system to allow fonts to travel with the documents. A structured storage system to bundle these elements and any associated content into a single file, PostScript is a page description language run in an interpreter to generate an image, a process requiring many resources. It can handle graphics and standard features of programming such as if. PDF is largely based on PostScript but simplified to remove flow control features like these, often, the PostScript-like PDF code is generated from a source PostScript file. The graphics commands that are output by the PostScript code are collected and tokenized, any files, graphics, or fonts to which the document refers also are collected. Then, everything is compressed to a single file, therefore, the entire PostScript world remains intact. PDF supports graphic transparency, PostScript does not, PostScript is an interpreted programming language with an implicit global state, so instructions accompanying the description of one page can affect the appearance of any following page. Therefore, all preceding pages in a PostScript document must be processed to determine the appearance of a given page. A PDF file is a 7-bit ASCII file, except for elements that may have binary content. A PDF file starts with a header containing the magic number, the format is a subset of a COS format. A COS tree file consists primarily of objects, of which there are eight types, Boolean values, representing true or false Numbers Strings, enclosed within parentheses, objects may be either direct or indirect
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PubMed Identifier
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PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez system of information retrieval, from 1971 to 1997, MEDLINE online access to the MEDLARS Online computerized database primarily had been through institutional facilities, such as university libraries. PubMed, first released in January 1996, ushered in the era of private, free, home-, the PubMed system was offered free to the public in June 1997, when MEDLINE searches via the Web were demonstrated, in a ceremony, by Vice President Al Gore. Information about the journals indexed in MEDLINE, and available through PubMed, is found in the NLM Catalog. As of 5 January 2017, PubMed has more than 26.8 million records going back to 1966, selectively to the year 1865, and very selectively to 1809, about 500,000 new records are added each year. As of the date,13.1 million of PubMeds records are listed with their abstracts. In 2016, NLM changed the system so that publishers will be able to directly correct typos. Simple searches on PubMed can be carried out by entering key aspects of a subject into PubMeds search window, when a journal article is indexed, numerous article parameters are extracted and stored as structured information. Such parameters are, Article Type, Secondary identifiers, Language, publication type parameter enables many special features. As these clinical girish can generate small sets of robust studies with considerable precision, since July 2005, the MEDLINE article indexing process extracts important identifiers from the article abstract and puts those in a field called Secondary Identifier. The secondary identifier field is to store numbers to various databases of molecular sequence data, gene expression or chemical compounds. For clinical trials, PubMed extracts trial IDs for the two largest trial registries, ClinicalTrials. gov and the International Standard Randomized Controlled Trial Number Register, a reference which is judged particularly relevant can be marked and related articles can be identified. If relevant, several studies can be selected and related articles to all of them can be generated using the Find related data option, the related articles are then listed in order of relatedness. To create these lists of related articles, PubMed compares words from the title and abstract of each citation, as well as the MeSH headings assigned, using a powerful word-weighted algorithm. The related articles function has been judged to be so precise that some researchers suggest it can be used instead of a full search, a strong feature of PubMed is its ability to automatically link to MeSH terms and subheadings. Examples would be, bad breath links to halitosis, heart attack to myocardial infarction, where appropriate, these MeSH terms are automatically expanded, that is, include more specific terms. Terms like nursing are automatically linked to Nursing or Nursing and this important feature makes PubMed searches automatically more sensitive and avoids false-negative hits by compensating for the diversity of medical terminology. The My NCBI area can be accessed from any computer with web-access, an earlier version of My NCBI was called PubMed Cubby
. PMID 20106856.
