Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, reptiles and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, annelids, flatworms, ctenophores, the study of animals is called zoology.
The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Pisces, Amphibia and Mammalia. Since the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms and Protozoa. The protozoa were moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae.
They are distinguished from plants and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
The name cyanobacteria comes from the color of the bacteria. Sometimes, they are called blue-green algae, and incorrectly so, because cyanobacteria are prokaryotes, like other prokaryotes, cyanobacteria have no membrane-sheathed organelles. Photosynthesis is performed in distinctive folds in the membrane of the cell. Biologists commonly agree that chloroplasts found in eukaryotes have their ancestry in cyanobacteria, via a process called endosymbiosis, Cyanobacteria are a group of photosynthetic, nitrogen fixing bacteria that live in a wide variety of habitats such as moist soils and in water. They may be free-living or form relationships with plants or with lichen-forming fungi as in the lichen genus Peltigera. They range from unicellular to filamentous and include colonial species, colonies may form filaments, sheets, or even hollow balls. Cyanobacteria can fix nitrogen in anaerobic conditions by means of specialized cells called heterocysts. Heterocysts may form under the environmental conditions when fixed nitrogen is scarce.
Free-living cyanobacteria are present in the column in rice paddies, and cyanobacteria can be found growing as epiphytes on the surfaces of the green alga, Chara. Cyanobacteria such as, can provide rice plantations with biofertilizer, many cyanobacteria form motile filaments of cells, called hormogonia, that travel away from the main biomass to bud and form new colonies elsewhere. The cells in a hormogonium are often thinner than in the state. To break away from the parent colony, a hormogonium often must tear apart a weaker cell in a filament, each individual cell of a cyanobacterium typically has a thick, gelatinous cell wall. They lack flagella, but hormogonia of some species can move about by gliding along surfaces, many of the multicellular filamentous forms of Oscillatoria are capable of a waving motion, the filament oscillates back and forth. In water columns, some cyanobacteria float by forming gas vesicles and these vesicles are not organelles as such. They are not bounded by membranes, but by a protein sheath.
Cyanobacteria can be found in almost every terrestrial and aquatic habitat—oceans, fresh water, damp soil, temporarily moistened rocks in deserts, bare rock and soil and they can occur as planktonic cells or form phototrophic biofilms. They are found in almost every endolithic ecosystem, a few are endosymbionts in lichens, various protists, or sponges and provide energy for the host. Some live in the fur of sloths, providing a form of camouflage, aquatic cyanobacteria are known for their extensive and highly visible blooms that can form in both freshwater and marine environments
Symbiosis is any type of a close and long-term biological interaction between two different species, be it mutualistic, commensalistic, or parasitic. In 1879, Heinrich Anton de Bary defined it as the living together of unlike organisms, Symbiosis can be obligatory, which means that one or both of the symbionts entirely depend on each other for survival, or facultative when they can generally live independently. When one organism lives on another such as mistletoe, it is called ectosymbiosis, or endosymbiosis when one partner lives inside the tissues of another, as in Symbiodinium in corals. In 1877, Albert Bernhard Frank used the term symbiosis which previously had used to depict people living together in community to describe the mutualistic relationship in lichens. In 1879, the German mycologist Heinrich Anton de Bary defined it as the living together of unlike organisms, symbiotic relationships can be obligate, meaning that one or both of the symbionts entirely depend on each other for survival.
For example, in lichens, which consist of fungal and photosynthetic symbionts, the algal or cyanobacterial symbionts in lichens, such as Trentepohlia, can generally live independently, and their symbiosis is, facultative. Endosymbiosis is any relationship in which one symbiont lives within the tissues of the other, either within the cells or extracellularly. Mutualism or interspecies reciprocal altruism is a relationship between individuals of different species where both individuals benefit, in general, only lifelong interactions involving close physical and biochemical contact can properly be considered symbiotic. Mutualistic relationships may be either obligate for both species, obligate for one but facultative for the other, or facultative for both, a large percentage of herbivores have mutualistic gut flora to help them digest plant matter, which is more difficult to digest than animal prey. This gut flora is made up of cellulose-digesting protozoans or bacteria living in the herbivores intestines, coral reefs are the result of mutualisms between coral organisms and various types of algae which live inside them.
Most land plants and land ecosystems rely on mutualisms between the plants, which fix carbon from the air, and mycorrhyzal fungi, which help in extracting water, an example of mutual symbiosis is the relationship between the ocellaris clownfish that dwell among the tentacles of Ritteri sea anemones. The territorial fish protects the anemone from anemone-eating fish, and in turn the stinging tentacles of the anemone protect the clownfish from its predators, a special mucus on the clownfish protects it from the stinging tentacles. A further example is the fish, which sometimes lives together with a shrimp. The shrimp digs and cleans up a burrow in the sand in which both the shrimp and the fish live. The shrimp is almost blind, leaving it vulnerable to predators when outside its burrow, in case of danger the goby fish touches the shrimp with its tail to warn it. When that happens both the shrimp and goby fish quickly retreat into the burrow, different species of gobies exhibit mutualistic behavior through cleaning up ectoparasites in other fish.
Another non-obligate symbiosis is known from encrusting bryozoans and hermit crabs, the bryozoan colony develops a cirumrotatory growth and offers the crab a helicospiral-tubular extension of its living chamber that initially was situated within a gastropod shell. A spectacular examples of mutualism is between the siboglinid tube worms and symbiotic bacteria that live at hydrothermal vents and cold seeps
Its current priority is the completion of audio-visual profiles for the c.17,000 species on the IUCN Red List of Threatened Species. The project is an initiative of Wildscreen, a UK-registered educational charity, the technical platform was created by Hewlett Packard, as part of the HP Labs Digital Media Systems research programme. It is a member of the Institutional Council of the Encyclopedia of Life, two ARKive layers for Google Earth, featuring endangered species and species in the Gulf of Mexico have been produced by Google Earth Outreach. The first of these was launched in April 2008 by Wildscreens Patron, parsons never lived to see the fruition of the project, succumbing to cancer in November 2002 at the age of 70. He believed the records could be a force in building environmental awareness by bringing scientific names to life. With an initial capacity of up to 74 terabytes of data, using redundant hardware, Media is digitised to the highest available quality without compression and encoded to open standards.
A prototype site was online as early as April 1999, there were several design iterations before the formal launch. By January 2006, the database had grown to 2,000 species,15,000 still images, by 2010, over 5,500 donors had contributed 70,000 film clips and photos of more than 12,000 species. The site was Sunday Times website of the year for 2005
For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies. This name is no longer in use, it is now a synonym of the current scientific name which is Picea abies, unlike synonyms in other contexts, in taxonomy a synonym is not interchangeable with the name of which it is a synonym. In taxonomy, synonyms are not equals, but have a different status, for any taxon with a particular circumscription and rank, only one scientific name is considered to be the correct one at any given time. A synonym cannot exist in isolation, it is always an alternative to a different scientific name, given that the correct name of a taxon depends on the taxonomic viewpoint used a name that is one taxonomists synonym may be another taxonomists correct name. Synonyms may arise whenever the same taxon is described and named more than once, independently. They may arise when existing taxa are changed, as when two taxa are joined to one, a species is moved to a different genus.
To the general user of scientific names, in such as agriculture, ecology, general science. A synonym is a name that was used as the correct scientific name but which has been displaced by another scientific name. Thus Oxford Dictionaries Online defines the term as a name which has the same application as another. In handbooks and general texts, it is useful to have mentioned as such after the current scientific name. Synonyms used in this way may not always meet the strict definitions of the synonym in the formal rules of nomenclature which govern scientific names. Changes of scientific name have two causes, they may be taxonomic or nomenclatural, a name change may be caused by changes in the circumscription, position or rank of a taxon, representing a change in taxonomic, scientific insight. A name change may be due to purely nomenclatural reasons, that is, based on the rules of nomenclature, the earliest such name is called the senior synonym, while the name is the junior synonym. One basic principle of zoological nomenclature is that the earliest correctly published name, synonyms are important because if the earliest name cannot be used, the next available junior synonym must be used for the taxon.
Objective synonyms refer to taxa with the type and same rank. For example, John Edward Gray published the name Antilocapra anteflexa in 1855 for a species of pronghorn, however, it is now commonly accepted that his specimen was an unusual individual of the species Antilocapra americana published by George Ord in 1815. Ords name thus takes precedence, with Antilocapra anteflexa being a subjective synonym. Objective synonyms are common at the level of genera, because for various reasons two genera may contain the type species, these are objective synonyms
Scleractinia, called stony corals or hard corals, are marine animals in the phylum Cnidaria that live on the seabed and build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by a disc with a mouth. Although some species are solitary, most are colonial, the founding polyp settles on the seabed and starts to secrete calcium carbonate to protect its soft body. Solitary corals can be as much as 25 cm across but in colonial species the polyps are only a few millimetres in diameter. These polyps reproduce by budding but remain attached to other, forming a multi-polyp colony with a common skeleton. The shape and appearance of each coral colony depends not only on the species, but on its location, many shallow-water corals contain symbiont unicellular organisms known as zooxanthellae within their tissues. These give their colour to the coral which thus may vary in hue depending on species of symbiont it contains. Stony corals are related to sea anemones, and like them are armed with stinging cells known as cnidocytes.
Corals reproduce both sexually and asexually, most species release gametes into the sea where fertilisation takes place, and the planula larvae drift as part of the plankton, but a few species brood their eggs. Asexual reproduction is mostly by fragmentation, when part of a colony becomes detached, stony corals occur in all the worlds oceans. Hermatypic corals are colonial and form part of reef structures. Other corals may be solitary or colonial and do not form reefs, stony corals first appeared in the Middle Triassic, but their relationship to the tabulate and rugose corals of the Paleozoic is currently unresolved. Much of the framework of coral reefs is formed by scleractinians. Stony corals numbers are expected to decline due to the effects of global warming, scleractinian corals may be solitary or colonial. Colonies can reach considerable size, consisting of a number of individual polyps. Stony corals are members of the class Anthozoa and like other members of the group, the individual animals are known as polyps and have a cylindrical body crowned by an oral disc surrounded by a ring of tentacles.
The base of the polyp secretes the stony material from which the skeleton is formed. The body wall of the consists of mesoglea sandwiched between two layers of epidermis
A polyp in zoology is one of two forms found in the phylum Cnidaria, the other being the medusa. Polyps are approximately cylindrical in shape and elongated at the axis of the vase-shaped body, the oral end contains the mouth, and is surrounded by a circlet of tentacles. In class Scyphozoa, the stage is dominant, and the polyp stage may or may not be present. Once strobilation is complete, the polyp may die, or regenerate itself to repeat the process again later, with Cubozoans, the planula settles onto a suitable surface, and develops into a polyp. The cubozoan polyp eventually metamorphoses directly into a Medusa, the body of the polyp may be roughly compared in a structure to a sac, the wall of which is composed of two layers of cells. The outer layer is known technically as the ectoderm, the layer as the endoderm. Between ectoderm and endoderm is a layer of structureless gelatinous substance termed mesogloea. The mesogloea may be a thin layer, or may reach a fair thickness. The tentacles are organs which serve both for the sense and for the capture of food.
Polyps extend their tentacles, particularly at night, containing coiled stinging nettle-like cells or nematocysts which pierce and poison, Polyp prey includes copepods and fish larvae. Longitudinal muscular fibrils formed from the cells of the ectoderm allow tentacles to contract when conveying the food to the mouth, circularly disposed muscular fibrils formed from the endoderm permit tentacles to be protract or thrust out once they are contracted. These muscle fibres belong to the two systems, thus allows the whole body to retract or protrude outwards. As a rule there is no opening to the body except the mouth, but in some cases excretory pores are known to occur in the foot. Thus it is seen that a polyp is an animal of very simple structure, the external form of the polyp varies greatly in different cases. The column may be long and slender, or may be so short in the direction that the body becomes disk-like. The tentacles may number many hundreds or may be very few and they may be long and filamentous, or short and reduced to mere knobs or warts.
They may be simple and unbranched, or they may be feathery in pattern, the mouth may be level with the surface of the peristome, or may be projecting and trumpet-shaped. As regards internal structure, polyps exhibit two well-marked types of organization, each characteristic of one of the two classes and Anthozoa, in the class Hydrozoa, the polyps are indeed often very simple, like the common little fresh water species of the genus Hydra
Nitrogen is a chemical element with symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772, although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. Nitrogen is the lightest member of group 15 of the periodic table, the name comes from the Greek πνίγειν to choke, directly referencing nitrogens asphyxiating properties. It is an element in the universe, estimated at about seventh in total abundance in the Milky Way. At standard temperature and pressure, two atoms of the element bind to form dinitrogen, a colourless and odorless diatomic gas with the formula N2, dinitrogen forms about 78% of Earths atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids, in the nucleic acids, the human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen and hydrogen.
The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds, many industrially important compounds, such as ammonia, nitric acid, organic nitrates, and cyanides, contain nitrogen. The extremely strong bond in elemental nitrogen, the second strongest bond in any diatomic molecule. Synthetically produced ammonia and nitrates are key industrial fertilisers, and fertiliser nitrates are key pollutants in the eutrophication of water systems. Apart from its use in fertilisers and energy-stores, nitrogen is a constituent of organic compounds as diverse as Kevlar used in high-strength fabric, Nitrogen is a constituent of every major pharmacological drug class, including antibiotics. Many notable nitrogen-containing drugs, such as the caffeine and morphine or the synthetic amphetamines. Nitrogen compounds have a long history, ammonium chloride having been known to Herodotus. They were well known by the Middle Ages, alchemists knew nitric acid as aqua fortis, as well as other nitrogen compounds such as ammonium salts and nitrate salts.
The mixture of nitric and hydrochloric acids was known as aqua regia, celebrated for its ability to dissolve gold, the discovery of nitrogen is attributed to the Scottish physician Daniel Rutherford in 1772, who called it noxious air. Though he did not recognise it as a different chemical substance, he clearly distinguished it from Joseph Blacks fixed air. The fact that there was a component of air that does not support combustion was clear to Rutherford, Nitrogen was studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley, who referred to it as burnt air or phlogisticated air. Nitrogen gas was inert enough that Antoine Lavoisier referred to it as air or azote, from the Greek word άζωτικός. In an atmosphere of nitrogen, animals died and flames were extinguished
Anthozoa is a class within the phylum Cnidaria. Unlike other cnidarians, anthozoans do not have a stage in their development. Instead, they release sperm and eggs that form a planula, some anthozoans can reproduce asexually through budding. More than 6,100 species have been described, the name comes from the Greek words άνθος and ζώα, hence ανθόζωα = flower animals, a reference to the floral appearance of their perennial polyp stage. Like those of cnidarians, the individual polyps have a cylindrical body crowned by a ring of tentacles surrounding the mouth. The mouth leads into a tubular pharynx which descends for some distance into the body opening into the gastrovascular cavity that fills the interior of the body. Unlike other cnidarians, the cavity is subdivided by a number of radiating partitions, the gonads are located within the cavity walls. All cnidarian species can feed by catching prey with nematocysts, sea anemones are capable of catching fish and certain species of coral live in isolation, most corals form colonies of genetically identical polyps.
These closely resemble anemones in structure, although they are much smaller. Stony coral are found in most seas, the extant orders are shown to the right. Hexacorallia includes coral reef builders, the corals, sea anemones. Genetic studies of ribosomal DNA has shown Ceriantharia to be a monophyletic group, sea whips and sea fans, known as gorgonians, are part of Alcyonacea and historically were divided into separate orders. Ceriantharia comprises the related tube-dwelling anemones, tube-dwelling anemones or cerianthids look very similar to sea anemones, but belong to an entirely different subclass of anthozoans. They are solitary, living buried in soft sediments, tube anemones live and can withdraw into tubes, which are made of a fibrous material, which is made from secreted mucus and threads of nematocyst-like organelles, known as ptychocysts. A number of orders of corals have been classified as their calcium skeleton forms a prolific fossil record. Data related to Anthozoa at Wikispecies
Wikispecies is a wiki-based online project supported by the Wikimedia Foundation. Its aim is to create a free content catalogue of all species. Jimmy Wales stated that editors are not required to fax in their degrees, Wikispecies is available under the GNU Free Documentation License and CC BY-SA3.0. Benedikt Mandl co-ordinated the efforts of people who are interested in getting involved with the project. Databases were evaluated and the administrators contacted, some of them have agreed on providing their data for Wikispecies, the board of directors of the Wikimedia Foundation voted by 4 to 0 in favor of the establishment of a Wikispecies. The project was launched in August 2004 and is hosted at species. wikimedia. org and it was officially merged to a sister project of Wikimedia Foundation on September 14,2004. On October 10,2006, the project exceeded 75,000 articles, on May 20,2007, the project exceeded 100,000 articles with a total of 5,495 registered users. On September 8,2008, the project exceeded 150,000 articles with a total of 9,224 registered users, on October 23,2011, the project reached 300,000 articles.
On June 16,2014, the project reached 400,000 articles, on January 7,2017, the project reached 500,000 articles. Wikispecies has disabled local upload and asks users to use images from Wikimedia Commons, Wikispecies does not allow the use of content that does not conform to a free license
Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, a linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide, short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides, or sometimes oligopeptides. The individual amino acid residues are bonded together by peptide bonds, the sequence of amino acid residues in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the code specifies 20 standard amino acids, however. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groups or cofactors, proteins can work together to achieve a particular function, and they often associate to form stable protein complexes.
Once formed, proteins only exist for a period of time and are degraded and recycled by the cells machinery through the process of protein turnover. A proteins lifespan is measured in terms of its half-life and covers a wide range and they can exist for minutes or years with an average lifespan of 1–2 days in mammalian cells. Abnormal and or misfolded proteins are degraded more rapidly due to being targeted for destruction or due to being unstable. Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are essential parts of organisms, many proteins are enzymes that catalyse biochemical reactions and are vital to metabolism. Proteins have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton, other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle. In animals, proteins are needed in the diet to provide the essential amino acids that cannot be synthesized, digestion breaks the proteins down for use in the metabolism.
Methods commonly used to study structure and function include immunohistochemistry, site-directed mutagenesis, X-ray crystallography, nuclear magnetic resonance. Most proteins consist of linear polymers built from series of up to 20 different L-α-amino acids, all proteinogenic amino acids possess common structural features, including an α-carbon to which an amino group, a carboxyl group, and a variable side chain are bonded. Only proline differs from this structure as it contains an unusual ring to the N-end amine group. The amino acids in a chain are linked by peptide bonds. Once linked in the chain, an individual amino acid is called a residue, and the linked series of carbon, nitrogen. The peptide bond has two forms that contribute some double-bond character and inhibit rotation around its axis, so that the alpha carbons are roughly coplanar
Such a name is called a binomial name, a binomen, binominal name or a scientific name, more informally it is called a Latin name. The first part of the name identifies the genus to which the species belongs, for example, humans belong to the genus Homo and within this genus to the species Homo sapiens. The formal introduction of system of naming species is credited to Carl Linnaeus. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus. Although the general principles underlying binomial nomenclature are common to these two codes, there are differences, both in the terminology they use and in their precise rules. Similarly, both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a name is usually given, at least when it is first mentioned. In zoology Patella vulgata Linnaeus,1758, the original name given by Linnaeus was Fringilla domestica, the parentheses indicate that the species is now considered to belong in a different genus.
The ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, in botany Amaranthus retroflexus L. – L. is the standard abbreviation used in botany for Linnaeus. – Linnaeus first named this bluebell species Scilla italica, Rothmaler transferred it to the genus Hyacinthoides, the ICN does not require that the dates of either publication be specified. Prior to the adoption of the binomial system of naming species. Together they formed a system of polynomial nomenclature and these names had two separate functions. First, to designate or label the species, and second, to be a diagnosis or description, such polynomial names may sometimes look like binomials, but are significantly different. For example, Gerards herbal describes various kinds of spiderwort, The first is called Phalangium ramosum, Branched Spiderwort, is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia. The Latin phrases are short descriptions, rather than identifying labels, the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words.
The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné. It was in his 1753 Species Plantarum that he first began using a one-word trivial name together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as an epithet or specific name