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Encyclopedia > Animal
Animals
Fossil range: Ediacaran - Recent
From left to right starting top-left: a Australian Green Tree Frog, Tawny Owl, Siberian Tiger, European garden spider, White-lipped snail, Green Sea Turtle, Solitary bee, Asian arowana, Barbary Macaque, Sawfish and a Marbled White (butterfly).
Scientific classification
Domain: Eukaryota
(unranked) Opisthokonta
Kingdom: Animalia
Linnaeus, 1758
Phyla

Subregnum Parazoa Image File history File links Emblem-important. ... Look up animal in Wiktionary, the free dictionary. ... Animalia cover Animalia is an illustrated childrens book by Graeme Base. ... The Ediacaran[5][6]  â€¢  â€¢  | Neoproterozoic (last æon of the Precambrian) Phanerozoic Axis scale: millions of years ago. ... Image File history File links Size of this preview: 500 × 600 pixelsFull resolution (1000 × 1200 pixel, file size: 244 KB, MIME type: image/jpeg) A collage depicting animal diversity using a featured pictures. ... Binomial name Litoria caerulea (White, 1790) The Australian Green Tree Frog, simply Green Tree Frog in Australia, Whites Tree Frog, or Dumpy Tree Frog (Litoria caerulea) is a species of tree frog native to Australia and New Guinea, with introduced populations in New Zealand and the United States. ... Binomial name Strix aluco Linnaeus, 1758 The Tawny Owl (Strix aluco) is a species of owl resident in much of Europe and southern Russia. ... Trinomial name Panthera tigris altaica Temminck, 1884 Distribution of the Siberian Tiger (in red) The Siberian Tiger (Panthera tigris altaica) is a rare subspecies of tiger (). Also known as the Amur, North China, Manchurian, Ussuri, or Korean Tiger, it is arguably the largest of the 5 extant tiger subspecies. ... Binomial name Araneus diadematus Clerck, 1757 The European garden spider (Araneus diadematus, cross spider) is a very common and well-known orb-weaver spider in Western Europe. ... Binomial name Cepaea hortensis (Müller, 1774) The white-lipped snail (Cepaea hortensis) is a very close relative of the grove snail. ... Binomial name Chelonia mydas (Linnaeus, 1758) This page redirects from Chelonia, which is the genus name of this turtle, but has also been used for the order Testudines of all turtles and tortoises. ... Families Andrenidae Apidae Colletidae Halictidae Megachilidae Melittidae Stenotritidae Bee collecting pollen Bees (Apoidea superfamily) are flying insects, closely related to wasps and ants. ... Binomial name Müller and Schlegel, 1844 Asian arowana refers to several varieties of freshwater fish in the genus Scleropages. ... Binomial name (Linnaeus, 1758) The Barbary Macaque (Macaca sylvanus) is a tail-less macaque. ... See: Sawfish is a window manager for Unix systems running X. Sawfish is a type of cartilaginous fish. ... Binomial name Melanargia galathea (Linnaeus, 1758) The Marbled White (Melanargia galathea) is a butterfly in the family Nymphalidae. ... For other uses, see Scientific classification (disambiguation). ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... The opisthokonts (Greek opistho- rear, posterior + kontos pole i. ... Carl Linnaeus, Latinized as Carolus Linnaeus, also known after his ennoblement as  , (May 13, 1707[1] – January 10, 1778), was a Swedish botanist, physician and zoologist[2] who laid the foundations for the modern scheme of nomenclature. ... Cover of the tenth edition of Linnaeuss Systema Naturae (1758). ... In biological taxonomy, a phylum (Greek plural: phyla) is a taxon in the rank below kingdom and above class. ... This article is about the animal. ...

(alternatively)
Calcarea
Silicarea

Subregnum Eumetazoa For other uses, see Sponge (disambiguation). ... Orders Subclass Calcinea     Clathrinida     Murrayonida Subclass Calcaronea     Leucosoleniida     Lithonida The Calcareous sponges belong to the Class Calcarea and are characterized by spicules made out of calcium carbonate (calcite). ... Silicarea is a proposed new phylum based on molecular studies of the phylum Porifera. ... subgroups Ctenophora Cnidaria Bilateria Eumetazoa is a clade comprising all major animal groups except sponges. ...

Orange elephant ear sponge, Agelas clathrodes, in foreground. Two corals in the background: a sea fan, Iciligorgia schrammi, and a sea rod, Plexaurella nutans.
Orange elephant ear sponge, Agelas clathrodes, in foreground. Two corals in the background: a sea fan, Iciligorgia schrammi, and a sea rod, Plexaurella nutans.

Animals are a major group of multicellular organisms, of the kingdom Animalia or Metazoa. Their body plan becomes fixed as they develop, usually early on in their development as embryos, although some undergo a process of metamorphosis later on in their life. Most animals are motile - can move spontaneously and independently. Binomial name Trichoplax adhaerens F.E. von Schultze, 1883 Trichoplax adhaerens is a simple balloon-like marine animal with a body cavity filled with pressurized fluid. ... Phyla Cnidaria Ctenophora The Radiata are the radially symmetric animals of the Eumetazoa subregnum. ... Classes Tentaculata Nuda Ctenophores are jellyfish-like animals commonly called comb jellies, sea gooseberries, sea walnuts, or Venus girdles. ... Subphylum/Classes[1] Anthozoa — corals and sea anemones Medusozoa:[2] Cubozoa — sea wasps or box jellyfish Hydrozoa — hydroids, hydra-like animals Polypodiozoa Scyphozoa — jellyfish Staurozoa — stalked jellyfish unranked: Myxozoa - parasites Cnidaria[3] (IPA: [4]) is a phylum containing some 11,000 species of apparently simple animals found exclusively in aquatic... Trilobozoa (three-lobed animals) is an extinct phylum of what are presumed to be animals which displayed tri-radial symmetry. ... For other uses, see Extinction (disambiguation). ... Illustration of the different types of symmetry of Life Forms On Earth. ... Orthonectida is a small phylum of poorly-known parasites of marine invertebrates that are among the simplest of multi-cellular organisms. ... Rhombozoa, or Dicyemida, is a phylum of tiny parasites that live in the renal appendages of cephalopods. ... The Acoelomorpha are a phylum of animals formerly considered flatworms, but now known to be a separate group, basal among the Bilateria. ... Classes Archisagittoidea Sagittoidea Chaetognatha is a phylum of predatory marine worms that are a major component of plankton worldwide. ... Phyla Echinodermata Hemichordata Chordata Xenoturbellida Chaetognatha (uncertain) Vetulicolia † Deuterostomes (taxonomic term: Deuterostomia; from the Greek: second mouth) are a superphylum of animals. ... Typical Classes See below Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. ... Classes Enterepneusta Pterobranchia Planctosphaeroidea Hemichordata is a phylum of worm-shaped marine deuterostome animals, generally considered the sister group of our own, the chordates. ... Classes Subphylum Homalozoa Gill & Caster, 1960 Class Homostelea Class Homoiostelea Class Stylophora Gill & Caster, 1960 Class Ctenocystoidea Robison & Sprinkle, 1969 Subphylum Crinozoa Class Eocrinoidea Jaekel, 1899 Class Paracrinoidea Regnéll, 1945 Class Cystoidea von Buch, 1846 Class Blastoidea Class Crinoidea Subphylum Asterozoa Class Ophiuroidea Class Asteroidea Subphylum Echinozoa Helicoplacoidea †  ?Arkarua... Species  Westblad, 1949  Israelsson, 1999 Xenoturbella is a genus of bilaterian animals; it is a marine worm. ... Vetulicolia are primitive deuterostomes from the very early Cambrian of China. ... For other uses, see Extinction (disambiguation). ... Phyla Scalidophora (288 species)   Priapulida (16 species)   Kinorhyncha (150 species)   Loricifera (122 species) Nematoda (20,000+ species) Nematomorpha (320 species) Panarthropoda (6,181,000-10,193,000+ species)   Onychophora (200 species)   Tardigrada (1,000+ species)   Arthropoda (6,180,000-10,192,000+ species) The Ecdysozoa are a group of protostome... Orders Cyclorhagida Homalorhagida Kinorhyncha (Gr. ... Loricifera is a small phylum of marine sediment-dwelling animals with about a dozen known species. ... Priapulida (priapulid worms or penis worms, from Gr. ... Classes Adenophora    Subclass Enoplia    Subclass Chromadoria Secernentea    Subclass Rhabditia    Subclass Spiruria    Subclass Diplogasteria The roundworms (Phylum Nematoda) are one of the most common phyla of animals, with over 20,000 different described species. ... Classes Nectonematoida Gordioidea Nematomorpha (sometimes called Gordiacea, and commonly known as horsehair worms or Gordian worms) are a phylum of parasitic animals which are morphologically and ecologically similar to nematode worms, hence the name. ... Lobopodia are a collection of poorly understood animals from the Early Cambrian -- the beginning of well fossilized animal life. ... For other uses, see Extinction (disambiguation). ... Genera Peripatus . ... Classes Heterotardigrada Mesotardigrada Eutardigrada Tardigrades (Tardigrada), or water bears, are a phylum of small, segmented animals, similar and related to the Arthropods. ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - Trilobites (extinct) Subphylum Chelicerata Arachnida - Spiders, Scorpions, etc. ... The Platyzoa are a group of protostome animals. ... Classes Monogenea Trematoda Cestoda Turbellaria The flatworms (Platyhelminthes, Greek platy: flat; helminth: worm) are a phylum of relatively simple soft-bodied invertebrate animals. ... The gastrotrichs are a phylum of microscopic animals, found in fresh water and marine environments. ... Classes Seisonoidea Bdelloidea Monogononta The rotifers make up a phylum of microscopic, pseudocoelomate animals. ... Classes Archiacanthocephala Palaeacanthocephala Eoacanthocephala The Acanthocephala (gr. ... Gnathostomulids, or jaw worms, are a small phylum of microscopic marine animals. ... Binomial name Limnognathia maerski Kristensen & Funch, 2000 Limnognathia maerski is a microscopic animal, discovered in Greenland in 2000, that is given its own phylum, Micrognathozoa. ... Binomial name Symbion pandora Funch & Kristensen, 1995 Symbion is a genus of peculiar animals, with a single species, . It was discovered in 1995 by Reinhardt Kristensen and Peter Funch on the mouthparts of the Norwegian lobster Nephrops norvegicus. ... Phyla Trochozoa Mollusca Annelida Sipuncula Nemertea Lophophorata Brachiopoda Phoronida Bryozoa Entoprocta The Lophotrochozoa are one of two or three major groups of protostome animals. ... The Sipuncula, sipunculid worms or peanut worms, are a phylum of marine worms with a tentacle surrounded mouth on a completely invertible head end. ... Hyolitha are enigmatic animals with small conical shells. ... For other uses, see Extinction (disambiguation). ... Classes Anopla Enopla The phylum Nemertea (also Rhynchocoela, Nemertina, Nemertinea or Nemertini) contains the ribbon worms or proboscis worms, which are a group of unsegmented marine invertebrates. ... Genera Phoronis Phoronopsis Phoronids (Phoronida) are a relatively small animal phylum: twelve species are known, in two genera, Phoronis and Phoronopsis. ... Classes Stenolaemata Gymnolaemata Phylactolaemata Bryozoans are tiny colonial animals that generally build stony skeletons of calcium carbonate, superficially similar to coral. ... Orders Barentsiidae (Urnatellidae) Loxokalypodidae Loxosomatidae Pedicellinidae Entoprocta (Gr. ... Classes Lingulata Paterinata (extinct) Craniforma Chileata (extinct) Obolellata (extinct) Kutorginata (extinct) Strophomenata (extinct) Rhynchonellata Brachiopods (from Latin bracchium, arm + New Latin -poda, foot) make up one of the major animal phyla, Brachiopoda. ... Classes Caudofoveata Aplacophora Polyplacophora Monoplacophora Bivalvia Scaphopoda Gastropoda Cephalopoda † Rostroconchia † Helcionelloida † ?Bellerophontidae The molluscs (British spelling) or mollusks (American spelling) are members of the large and diverse phylum Mollusca, which includes a variety of familiar animals well-known for their decorative shells or as seafood. ... Classes and subclasses Class Polychaeta (paraphyletic?) Class Clitellata    Oligochaeta - Earthworms and others    Acanthobdellida    Branchiobdellida    Hirudinea - Leeches Class Myzostomida Class Archiannelida (polyphyletic) Class Echiura *Some authors consider the subclasses under Clitellata to be classes The annelids, collectively called Annelida, are a large phylum of animals, comprising the segmented worms, with about... The Echiura, or spoon worms, are a small group of marine animals. ... Download high resolution version (835x1214, 364 KB)An orange Elephant Ear sponge (Agelas clathrodes) at the Florida Keys National Maritime Sanctuary. ... Download high resolution version (835x1214, 364 KB)An orange Elephant Ear sponge (Agelas clathrodes) at the Florida Keys National Maritime Sanctuary. ... A sea fan is a form of sessile colonial cnidarian, similar to a sea pen or a soft coral, found in tropical and subtropical seawater. ... Multicellular organisms are those organisms containing more than one cell, and having differentiated cells that perform specialized functions. ... Life on Earth redirects here. ... Ernst Haeckels presentation of a three-kingdom system (Plantae, Protista, Animalia) in his 1866 Generelle Morphologie der Organismen). ... This article or section is in need of attention from an expert on the subject. ... Ontogeny (also ontogenesis or morphogenesis) describes the origin and the development of an organism from the fertilized egg to its mature form. ... For other uses, see Embryo (disambiguation). ... A Pieris rapae larva An older Pieris rapae larva A Pieris rapae pupa A Pieris rapae adult Metamorphosis is a process in biology by which an individual physically develops after birth or hatching, and involves significant change in form as well as growth and differentiation. ... Motile A term to describe Intelligent Mobile Applications. ...

Contents

Etymology

The word "animal" comes from the Latin word animal, of which animalia is the plural, and is derived from anima, meaning vital breath or soul. In everyday colloquial usage, the word usually refers to non-human animals. The biological definition of the word refers to all members of the Kingdom Animalia. Therefore, when the word "animal" is used in a biological context, humans are included. For other uses, see Latin (disambiguation). ... This article is about modern humans. ...


Characteristics

Animals have several characteristics that set them apart from other living things. Animals are eukaryotic and usually multicellular[1] (although see Myxozoa), which separates them from bacteria and most protists. They are heterotrophic,[2] generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls.[3] All animals are motile,[4] if only at certain life stages. Embryos pass through a blastula stage, which is a characteristic exclusive to animals. Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... Multicellular organisms are those organisms containing more than one cell, and having differentiated cells that perform specialized functions. ... Classes Malacosporea Myxosporea The Myxozoa are a group of microscopic, parasitic animals. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Typical phyla Chromalveolata Chromista Heterokontophyta Haptophyta Cryptophyta (cryptomonads) Alveolata Dinoflagellata Apicomplexa Ciliophora (ciliates) Cabozoa Excavata Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Archaeplastida (in part) Rhodophyta (red algae) Glaucophyta (basal archaeplastids) Amoebozoa Choanozoa Many others; classification varies Protists (IPA: (RP); (GenAm)), Greek protiston -a meaning the (most) first of all... Flowchart to determine if a species is autotroph, heterotroph, or a subtype A heterotroph (Greek heterone = (an)other and trophe = nutrition) is an organism that requires organic substrates to get its carbon for growth and development. ... For other uses, see Plant (disambiguation). ... A seaweed (Laurencia) up close: the branches are multicellular and only about 1 mm thick. ... Subkingdom/Phyla Chytridiomycota Blastocladiomycota Neocallimastigomycota Glomeromycota Zygomycota Dikarya (inc. ... Plant cells separated by transparent cell walls. ... Blastulation. ...


Structure

With a few exceptions, most notably the sponges (Phylum Porifera), animals have bodies differentiated into separate tissues. These include muscles, which are able to contract and control locomotion, and nerve tissue, which sends and processes signals. There is also typically an internal digestive chamber, with one or two openings. Animals with this sort of organization are called metazoans, or eumetazoans when the former is used for animals in general. For other uses, see Sponge (disambiguation). ... Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ... The Human Nervous System. ... For the industrial process, see anaerobic digestion. ... Branch Radiata Bilateria The Eumetazoa are a major group of animals, comprising the Radiata and Bilateria - all animals except the sponges (Parazoa or Porifera) and mesozoans. ...


All animals have eukaryotic cells, surrounded by a characteristic extracellular matrixes composed of collagen and elastic glycoproteins. This may be calcified to form structures like shells, bones, and spicules. During development it forms a relatively flexible framework upon which cells can move about and be reorganized, making complex structures possible. In contrast, other multicellular organisms like plants and fungi have cells held in place by cell walls, and so develop by progressive growth. Also, unique to animal cells are the following intercellular junctions: tight junctions, gap junctions, and desmosomes. Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... Tropocollagen triple helix. ... A glycoprotein is a macromolecule composed of a protein and a carbohydrate (an oligosaccharide). ... Various seashells Danielle A shell is the hard, rigid outer covering, or integument, allanimals. ... This article is about the skeletal organs. ... Spicules Spicules are skeletal structures that occur in most sponges. ... Diagram of Tight junction. ... A gap junction is a junction between certain animal/plant cell-types that allows different molecules and ions to pass freely between cells. ... Cell adhesion in desmosomes A desmosome (also known as macula adherens (Latin for adhering spot ) is a cell structure specialized for cell-to-cell adhesion. ...


Reproduction and development

A newt lung cell stained with fluorescent dyes undergoing mitosis, specifically early anaphase.

Nearly all animals undergo some form of sexual reproduction. Adults are diploid or polyploid. They have a few specialized reproductive cells, which undergo meiosis to produce smaller motile spermatozoa or larger non-motile ova. These fuse to form zygotes, which develop into new individuals. Image File history File links An image of a newt lung cell stained with flourescent dyes undergoing mitosis, specifically during early anaphase. ... Image File history File links An image of a newt lung cell stained with flourescent dyes undergoing mitosis, specifically during early anaphase. ... “Eft” redirects here. ... Human respiratory system The lungs flank the heart and great vessels in the chest cavity. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Staining is a biochemical technique of adding a class-specific (DNA, proteins, lipids, carbohydrates) dye to a substrate to qualify or quantify the presence of a specific compound. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized cadmium selenide (CdSe) quantum dots. ... Look up dye in Wiktionary, the free dictionary. ... Mitosis divides genetic information during cell division. ... Newt lung cell during late anaphase. ... Diploid (meaning double in Greek) cells have two copies (homologs) of each chromosome (both sex- and non-sex determining chromosomes), usually one from the mother and one from the father. ... Polyploid (in Greek: πολλαπλόν - multiple) cells or organisms contain more than one copy (ploidy) of their chromosomes. ... For the figure of speech, see meiosis (figure of speech). ... A spermatozoon or spermatozoan ( spermatozoa), from the ancient Greek σπέρμα (seed) and (living being) and more commonly known as a sperm cell, is the haploid cell that is the male gamete. ... A human ovum Sperm cells attempting to fertilize an ovum An ovum (plural ova) is a haploid female reproductive cell or gamete. ... It has been suggested that Biparental zygote be merged into this article or section. ...


Many animals are also capable of asexual reproduction. This may take place through parthenogenesis, where fertile eggs are produced without mating, or in some cases through fragmentation. It has been suggested that Parthenogenesis be merged into this article or section. ... For the religious belief, see Virgin Birth of Jesus. ... For other uses, see fragmentation. ...


A zygote initially develops into a hollow sphere, called a blastula, which undergoes rearrangement and differentiation. In sponges, blastula larvae swim to a new location and develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement. It first invaginates to form a gastrula with a digestive chamber, and two separate germ layers - an external ectoderm and an internal endoderm. In most cases, a mesoderm also develops between them. These germ layers then differentiate to form tissues and organs. It has been suggested that Biparental zygote be merged into this article or section. ... Blastulation. ... Invagination is one of the morphogenetic processes by which an embryo takes form, and is the initial step of gastrulation, the massive reorganization of the embryo from a simple spherical ball of cells, the blastula, into a multi-layered organism, with a differentiated endoderm, mesoderm, and ectoderm. ... 1 - blastula, 2 - gastrula; orange - ectoderm, red - endoderm. ... Organs derived from each germ layer. ...


Most animals grow by indirectly using the energy of sunlight. Plants use this energy to convert sunlight into simple sugars using a process known as photosynthesis. Starting with the molecules carbon dioxide (CO2) and water (H2O), photosynthesis converts the energy of sunlight into chemical energy stored in the bonds of glucose (C6H12O6) and releases oxygen (O2). These sugars are then used as the building blocks which allow the plant to grow. When animals eat these plants (or eat other animals which have eaten plants), the sugars produced by the plant are used by the animal. They are either used directly to help the animal grow, or broken down, releasing stored solar energy, and giving the animal the energy required for motion. This process is known as glycolysis. Prism splitting light High Resolution Solar Spectrum Sunlight in the broad sense is the total spectrum of the electromagnetic radiation given off by the Sun. ... This article deals with sugar as food and as an important, widely traded commodity; the word also has other uses; see Sugar (disambiguation) A sugar is a form of carbohydrate; the most commonly used sugar is a white crystalline solid, sucrose; used to alter the flavor and properties (mouthfeel, perservation... The leaf is the primary site of photosynthesis in plants. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... The word glycolysis is derived from Greek γλυκύς (sweet) and λύσις (rupture). ...


Animals who live close to hydrothermal vents and cold seeps on the ocean floor are not dependent on the energy of sunlight. Instead, chemosynthetic archaea and eubacteria form the base of the food chain. A hydrothermal vent A hydrothermal vent is a fissure in a planets surface from which geothermally heated water issues. ... Tubeworms, soft corals and chemosynthetic mussels at a seep located 3,000 metres down on the Florida Escarpment. ... Chemosynthesis is the biological conversion of 1-carbon molecules (usually carbon dioxide or methane) and nutrients into organic matter using the oxidation of inorganic molecules (e. ... Phyla Crenarchaeota Euryarchaeota Korarchaeota Nanoarchaeota ARMAN The Archaea (), or archaebacteria, are a major group of microorganisms. ... Subgroups Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular: bacterium) are microscopic, unicellular organisms. ...


Origin and fossil record

Animals are generally considered to have evolved from a flagellated eukaryote. Their closest known living relatives are the choanoflagellates, collared flagellates that have a morphology similar to the choanocytes of certain sponges. Molecular studies place animals in a supergroup called the opisthokonts, which also include the choanoflagellates, fungi and a few small parasitic protists. The name comes from the posterior location of the flagellum in motile cells, such as most animal spermatozoa, whereas other eukaryotes tend to have anterior flagella. This article is about evolution in biology. ... Flagellata from Ernst Haeckels Artforms of Nature, 1904 Parasitic excavate (Giardia lamblia) Green alga (Chlamydomonas) Flagellates are cells with one or more whip-like organelles called flagella. ... The choanoflagellates are a group of flagellate protozoa. ... In science, a molecule is the smallest particle of a pure chemical substance that still retains its chemical composition and properties. ... The opisthokonts (Greek opistho- rear, posterior + kontos pole i. ... Subkingdom/Phyla Chytridiomycota Blastocladiomycota Neocallimastigomycota Glomeromycota Zygomycota Dikarya (inc. ... Typical phyla Chromalveolata Chromista Heterokontophyta Haptophyta Cryptophyta (cryptomonads) Alveolata Dinoflagellata Apicomplexa Ciliophora (ciliates) Cabozoa Excavata Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Archaeplastida (in part) Rhodophyta (red algae) Glaucophyta (basal archaeplastids) Amoebozoa Choanozoa Many others; classification varies Protists (IPA: (RP); (GenAm)), Greek protiston -a meaning the (most) first of all... For the insect anatomical structure, see Antenna (biology). ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ...


The first fossils that might represent animals appear towards the end of the Precambrian, around 575 million years ago, and are known as the Ediacaran or Vendian biota. These are difficult to relate to later fossils, however. Some may represent precursors of modern phyla, but they may be separate groups, and it is possible they are not really animals at all. Aside from them, most known animal phyla make a more or less simultaneous appearance during the Cambrian period, about 542 million years ago. It is still disputed whether this event, called the Cambrian explosion, represents a rapid divergence between different groups or a change in conditions that made fossilization possible. The Precambrian (Pre-Cambrian) is an informal name for the eons of the geologic timescale that came before the current Phanerozoic eon. ... Dickinsonia costata, an Ediacaran organism of unknown affinity, with a quilted appearance. ... For other uses, see Cambrian (disambiguation). ... The Cambrian explosion is the geologically kukko sudden appearance in the fossil record of the ancestors of familiar animals, starting about 542 million years ago (Mya). ...


Groups of animals

The sponges (Porifera) diverged from other animals early. As mentioned above, they lack the complex organization found in most other phyla. Their cells are differentiated, but in most cases not organized into distinct tissues. Sponges are sessile and typically feed by drawing in water through pores. Archaeocyatha, which have fused skeletons, may represent sponges or a separate phylum. The sponge, in the phylum Porifera, is a very primitive and specialized animal. ... The Archeocyatha, also called Archaeocyathids, were sessile, reef-building marine organisms that lived during the Lower Cambrian period (500-600 million years ago). ...


Among the eumetazoan phyla, two are radially symmetric and have digestive chambers with a single opening, which serves as both the mouth and the anus. These are the Cnidaria, which include sea anemones, corals, and jellyfish, and the Ctenophora or comb jellies. Both have distinct tissues, but they are not organized into organs. There are only two main germ layers, the ectoderm and endoderm, with only scattered cells between them. As such, these animals are sometimes called diploblastic. The tiny Placozoans are similar, but they do not have a permanent digestive chamber. Subphylum/Classes[1] Anthozoa — corals and sea anemones Medusozoa:[2] Cubozoa — sea wasps or box jellyfish Hydrozoa — hydroids, hydra-like animals Polypodiozoa Scyphozoa — jellyfish Staurozoa — stalked jellyfish unranked: Myxozoa - parasites Cnidaria[3] (IPA: [4]) is a phylum containing some 11,000 species of apparently simple animals found exclusively in aquatic... Families Many, see text. ... Extant Subclasses and Orders Alcyonaria    Alcyonacea    Helioporacea Zoantharia    Antipatharia    Corallimorpharia    Scleractinia    Zoanthidea [1][2]  See Anthozoa for details For other uses, see Coral (disambiguation). ... Bold text For other uses, see Jellyfish (disambiguation). ... Classes Tentaculata Nuda Ctenophores are jellyfish-like animals commonly called comb jellies, sea gooseberries, sea walnuts, or Venus girdles. ... This article is about the biological unit. ... Diploblastic is a condition of the ovum in which there are two primary germinal layers: the ectoderm and endoderm. ... Trichoplax adhaerens is a simple balloon-like marine animal with a body cavity filled with pressurized fluid. ...


The remaining animals form a monophyletic group called the Bilateria. For the most part, they are bilaterally symmetric, and often have a specialized head with feeding and sensory organs. The body is triploblastic, i.e. all three germ layers are well-developed, and tissues form distinct organs. The digestive chamber has two openings, a mouth and an anus, and there is also an internal body cavity called a coelom or pseudocoelom. There are exceptions to each of these characteristics, however - for instance adult echinoderms are radially symmetric, and certain parasitic worms have extremely simplified body structures. In phylogenetics, a group is monophyletic (Greek: of one stem) if all organisms in that group are known to have developed from a common ancestral form, and all descendants of that form are included in the group. ... Illustration of the different types of symmetry of Life Forms On Earth. ... Triploblastic is a condition of the ovum in which there are three primary germinal layers: the ectoderm, mesoderm, and endoderm. ... Classes Subphylum Homalozoa Gill & Caster, 1960 Class Homostelea Class Homoiostelea Class Stylophora Gill & Caster, 1960 Class Ctenocystoidea Robison & Sprinkle, 1969 Subphylum Crinozoa Class Eocrinoidea Jaekel, 1899 Class Paracrinoidea Regnéll, 1945 Class Cystoidea von Buch, 1846 Class Blastoidea Class Crinoidea Subphylum Asterozoa Class Ophiuroidea Class Asteroidea Subphylum Echinozoa Helicoplacoidea †  ?Arkarua...


Genetic studies have considerably changed our understanding of the relationships within the Bilateria. Most appear to belong to four major lineages:

  1. Deuterostomes
  2. Ecdysozoa
  3. Platyzoa
  4. Lophotrochozoa

In addition to these, there are a few small groups of bilaterians with relatively similar structure that appear to have diverged before these major groups. These include the Acoelomorpha, Rhombozoa, and Orthonectida. The Myxozoa, single-celled parasites that were originally considered Protozoa, are now believed to have developed from the Bilateria as well. Phyla Chaetognatha Echinodermata Hemichordata Chordata Deuterostomes (from the Greek: second the mouth) are one of the two superphyla of animals in the taxonomic branch bilateria, the other being the protostomes. ... Phyla Scalidophora (288 species)   Priapulida (16 species)   Kinorhyncha (150 species)   Loricifera (122 species) Nematoda (20,000+ species) Nematomorpha (320 species) Panarthropoda (6,181,000-10,193,000+ species)   Onychophora (200 species)   Tardigrada (1,000+ species)   Arthropoda (6,180,000-10,192,000+ species) The Ecdysozoa are a group of protostome... The Platyzoa are a group of protostome animals. ... Phyla Trochozoa Mollusca Annelida Sipuncula Nemertea Lophophorata Brachiopoda Phoronida Bryozoa Entoprocta The Lophotrochozoa are one of two or three major groups of protostome animals. ... The Acoelomorpha are a phylum of animals formerly considered flatworms, but now known to be a separate group, basal among the Bilateria. ... Rhombozoa, or Dicyemida, is a phylum of tiny parasites that live in the renal appendages of cephalopods. ... Orthonectida is a small phylum of poorly-known parasites of marine invertebrates that are among the simplest of multi-cellular organisms. ... Classes Malacosporea Myxosporea The Myxozoa are a group of microscopic, parasitic animals. ...


Deuterostomes

Superb Fairy-wren, Malurus cyaneus
Superb Fairy-wren, Malurus cyaneus

Deuterostomes differ from the other Bilateria, called protostomes, in several ways. In both cases there is a complete digestive tract. However, in protostomes the initial opening (the archenteron) develops into the mouth, and an anus forms separately. In deuterostomes this is reversed. In most protostomes cells simply fill in the interior of the gastrula to form the mesoderm, called schizocoelous development, but in deuterostomes it forms through invagination of the endoderm, called enterocoelic pouching. Deuterostomes also have a dorsal, rather than a ventral, nerve chord and their embryos undergo different cleavage. Image File history File linksMetadata Download high-resolution version (1280x960, 843 KB) Summary From en. ... Image File history File linksMetadata Download high-resolution version (1280x960, 843 KB) Summary From en. ... Binomial name Ellis, 1782 Superb Fairy-wren range  ;   Subspecies The Superb Fairy-wren (Malurus cyaneus), also known as Superb Blue-wren or colloquially as Blue wren, is the best-known of all fairy-wrens, and found in a wide range of habitat types in south-eastern Australia. ... Phyla Echinodermata Hemichordata Chordata Xenoturbellida Chaetognatha (uncertain) Vetulicolia † Deuterostomes (taxonomic term: Deuterostomia; from the Greek: second mouth) are a superphylum of animals. ... Groups Ecdysozoa Lophotrochozoa Platyzoa Protostomes (from the Greek: first the mouth) are a taxon of animals. ... The archenteron is an indentation that forms early on in a developing blastula. ... Invagination is one of the morphogenetic processes by which an embryo takes form, and is the initial step of gastrulation, the massive reorganization of the embryo from a simple spherical ball of cells, the blastula, into a multi-layered organism, with a differentiated endoderm, mesoderm, and ectoderm. ...


All this suggests the deuterostomes and protostomes are separate, monophyletic lineages. The main phyla of deuterostomes are the Echinodermata and Chordata. The former are radially symmetric and exclusively marine, such as starfish, sea urchins, and sea cucumbers. The latter are dominated by the vertebrates, animals with backbones. These include fish, amphibians, reptiles, birds, and mammals. Classes Asteroidea Concentricycloidea Crinoidea Echinoidea Holothuroidea Ophiuroidea Echinoderms (Echinodermata) is a phylum of marine animals found in the ocean at all depths. ... Typical Classes See below Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. ... Orders Brisingida (100 species[1]) Forcipulatida (300 species[2]) Paxillosida (255 species[3]) Notomyotida (75 species[4]) Spinulosida (120 species[5]) Valvatida (695 species[6]) Velatida (200 species[7]) For other uses, see Starfish (disambiguation). ... Subclasses Euechinoidea Superorder Atelostomata Order Cassiduloida Order Spatangoida (heart urchins) Superorder Diadematacea Order Diadematoida Order Echinothurioida Order Pedinoida Superorder Echinacea Order Arbacioida Order Echinoida Order Phymosomatoida Order Salenioida Order Temnopleuroida Superorder Gnathostomata Order Clypeasteroida (sand dollars) Order Holectypoida Perischoechinoidea Order Cidaroida (pencil urchins) Sea urchins are small spiny sea creatures... Orders Subclass Apodacea Apodida Molpadiida Subclass Aspidochirotacea Aspidochirotida Elasipodida Subclass Dendrochirotacea Dactylochirotida Dendrochirotida Wikispecies has information related to: Holothuroidea The sea cucumber is an echinoderm of the class Holothuroidea, with an elongated body and leathery skin, which is found on the sea floor worldwide. ... This article does not cite any references or sources. ... For other uses, see Fish (disambiguation). ... For other uses, see Amphibian (disambiguation). ... Reptilia redirects here. ... For other uses, see Bird (disambiguation). ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including those that produce milk, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex...


In addition to these, the deuterostomes also include the Hemichordata or acorn worms. Although they are not especially prominent today, the important fossil graptolites may belong to this group. Classes Enterepneusta Pterobranchia Planctosphaeroidea Hemichordata is a phylum of worm-shaped marine deuterostome animals, generally considered the sister group of our own, the chordates. ... Graptolites (Graptolithina) are fossil colonial animals known chiefly from the Upper Cambrian through the Mississippian (Lower Carboniferous). ...


The Chaetognatha or arrow worms may also be deuterostomes, but more recent studies suggest protostome affinities. Classes Archisagittoidea Sagittoidea Chaetognatha is a phylum of predatory marine worms that are a major component of plankton worldwide. ...


Ecdysozoa

Yellow-winged Darter, Sympetrum flaveolum
Yellow-winged Darter, Sympetrum flaveolum

The Ecdysozoa are protostomes, named after the common trait of growth by moulting or ecdysis. The largest animal phylum belongs here, the Arthropoda, including insects, spiders, crabs, and their kin. All these organisms have a body divided into repeating segments, typically with paired appendages. Two smaller phyla, the Onychophora and Tardigrada, are close relatives of the arthropods and share these traits. Image File history File links Download high resolution version (2567x1574, 603 KB) Yellow-winged Darter This image shows an about 1. ... Image File history File links Download high resolution version (2567x1574, 603 KB) Yellow-winged Darter This image shows an about 1. ... Binomial name Sympetrum flaveolum (Linnaeus, 1758) The Yellow-winged Darter, Sympetrum flaveolum, is a European dragonfly. ... Phyla Scalidophora (288 species)   Priapulida (16 species)   Kinorhyncha (150 species)   Loricifera (122 species) Nematoda (20,000+ species) Nematomorpha (320 species) Panarthropoda (6,181,000-10,193,000+ species)   Onychophora (200 species)   Tardigrada (1,000+ species)   Arthropoda (6,180,000-10,192,000+ species) The Ecdysozoa are a group of protostome... Ecdysis is the molting of the cuticula in arthropods and related groups (Ecdysozoa). ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - Trilobites (extinct) Subphylum Chelicerata Arachnida - Spiders, Scorpions, etc. ... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... Diversity 111 families, 40,000 species Suborders Mesothelae Mygalomorphae Araneomorphae  See table of families Wikispecies has information related to: Spiders Spiders are predatory invertebrate animals that have two body segments, eight legs, no chewing mouth parts and no wings. ... Superfamilies Dromiacea Homolodromioidea Dromioidea Homoloidea Eubrachyura Raninoidea Cyclodorippoidea Dorippoidea Calappoidea Leucosioidea Majoidea Hymenosomatoidea Parthenopoidea Retroplumoidea Cancroidea Portunoidea Bythograeoidea Xanthoidea Bellioidea Potamoidea Pseudothelphusoidea Gecarcinucoidea Cryptochiroidea Pinnotheroidea * Ocypodoidea * Grapsoidea * An asterisk (*) marks the crabs included in the clade Thoracotremata. ... Genera Peripatus . ... Classes Heterotardigrada Mesotardigrada Eutardigrada Tardigrades (Tardigrada), or water bears, are a phylum of small, segmented animals, similar and related to the Arthropods. ...


The ecdysozoans also include the Nematoda or roundworms, the second largest animal phylum. Roundworms are typically microscopic, and occur in nearly every environment where there is water. A number are important parasites. Smaller phyla related to them are the Nematomorpha or horsehair worms, which are invisible to the unaided eye, and the Kinorhyncha, Priapulida, and Loricifera. These groups have a reduced coelom, called a pseudocoelom. Classes Adenophora    Subclass Enoplia    Subclass Chromadoria Secernentea    Subclass Rhabditia    Subclass Spiruria    Subclass Diplogasteria The roundworms (Phylum Nematoda) are one of the most common phyla of animals, with over 20,000 different described species. ... Classes Nectonematoida Gordioidea Nematomorpha (sometimes called Gordiacea, and commonly known as horsehair worms or Gordian worms) are a phylum of parasitic animals which are morphologically and ecologically similar to nematode worms, hence the name. ... Orders Cyclorhagida Homalorhagida Kinorhyncha (Gr. ... Priapulida (priapulid worms or penis worms, from Gr. ... Loricifera is a small phylum of marine sediment-dwelling animals with about a dozen known species. ...


The remaining two groups of protostomes are sometimes grouped together as the Spiralia, since in both embryos develop with spiral cleavage.


Platyzoa

Bedford's flatworm, Pseudobiceros bedfordi
Bedford's flatworm, Pseudobiceros bedfordi

The Platyzoa include the phylum Platyhelminthes, the flatworms. These were originally considered some of the most primitive Bilateria, but it now appears they developed from more complex ancestors. Image File history File links Download high resolution version (1024x768, 663 KB) Bedfords Flatworm (Pseudobiceros bedfordi) photographed by Jan Derk in March 2006 in Fihalhohi, Maldives. ... Image File history File links Download high resolution version (1024x768, 663 KB) Bedfords Flatworm (Pseudobiceros bedfordi) photographed by Jan Derk in March 2006 in Fihalhohi, Maldives. ... The Platyzoa are a group of protostome animals. ... Classes Monogenea Trematoda Cestoda Turbellaria The flatworms (Platyhelminthes, Greek platy: flat; helminth: worm) are a phylum of relatively simple soft-bodied invertebrate animals. ...


A number of parasites are included in this group, such as the flukes and tapeworms. Flatworms lack a coelom, as do their closest relatives, the microscopic Gastrotricha. A parasite is an organism that lives in or on the living tissue of a host organism at the expense of it. ... Look up Fluke in Wiktionary, the free dictionary. ... Orders Subclass Cestodaria Amphilinidea Gyrocotylidea Subclass Eucestoda Aporidea Caryophyllidea Cyclophyllidea Diphyllidea Lecanicephalidea Litobothridea Nippotaeniidea Proteocephalidea Pseudophyllidea Spathebothriidea Tetraphyllidea Trypanorhyncha In biology, Cestoda is the class of parasitic flatworms, called cestodes or tapeworms, that live in the digestive tract of vertebrates as adults and often in the bodies of various animals... The gastrotrichs are a phylum of microscopic animals, found in fresh water and marine environments. ...


The other platyzoan phyla are microscopic and pseudocoelomate. The most prominent are the Rotifera or rotifers, which are common in aqueous environments. They also include the Acanthocephala or spiny-headed worms, the Gnathostomulida, Micrognathozoa, and possibly the Cycliophora. These groups share the presence of complex jaws, from which they are called the Gnathifera. Classes Seisonoidea Bdelloidea Monogononta The rotifers make up a phylum of microscopic, pseudocoelomate animals. ... Classes Archiacanthocephala Palaeacanthocephala Eoacanthocephala The Acanthocephala (gr. ... Gnathostomulids, or jaw worms, are a small phylum of microscopic marine animals. ... Binomial name Limnognathia maerski Kristensen & Funch, 2000 Limnognathia maerski is a microscopic animal, discovered in Greenland in 2000, that is given its own phylum, Micrognathozoa. ... Binomial name Symbion pandora Funch & Kristensen, 1995 Symbion is a genus of peculiar animals, with a single species, . It was discovered in 1995 by Reinhardt Kristensen and Peter Funch on the mouthparts of the Norwegian lobster Nephrops norvegicus. ... The Gnathifera are a group of four animal phyla, considered monophyletic based on genetic and structural data: Rotifera Acanthocephala Gnathostomulida Micrognathozoa Except for the Acanthocephala, all these phyla share characteristics such as the structure of their jaws and pharynx. ...


Lophotrochozoa

Roman snail, Helix pomatia
Roman snail, Helix pomatia

The Lophotrochozoa include two of the most successful animal phyla, the Mollusca and Annelida. The former includes animals such as snails, clams, and squids, and the latter comprises the segmented worms, such as earthworms and leeches. These two groups have long been considered close relatives because of the common presence of trochophore larvae, but the annelids were considered closer to the arthropods, because they are both segmented. Now this is generally considered convergent evolution, owing to many morphological and genetic differences between the two phyla. ImageMetadata File history File links Download high resolution version (1024x604, 92 KB) Picture of a grapevine snail (Helix pomatia). ... ImageMetadata File history File links Download high resolution version (1024x604, 92 KB) Picture of a grapevine snail (Helix pomatia). ... Binomial name Helix pomatia Linnaeus, 1758 Escargot cooked with garlic and parsley butter in a shell The Burgundy snail or Roman Snail or Edible Snail (Helix pomatia) is species of land gastropod of family Helicidae. ... Phyla Trochozoa Mollusca Annelida Sipuncula Nemertea Lophophorata Brachiopoda Phoronida Bryozoa Entoprocta The Lophotrochozoa are one of two or three major groups of protostome animals. ... Classes Caudofoveata Aplacophora Polyplacophora Monoplacophora Bivalvia Scaphopoda Gastropoda Cephalopoda † Rostroconchia † Helcionelloida † ?Bellerophontidae The molluscs (British spelling) or mollusks (American spelling) are members of the large and diverse phylum Mollusca, which includes a variety of familiar animals well-known for their decorative shells or as seafood. ... Classes and subclasses Class Polychaeta (paraphyletic?) Class Clitellata    Oligochaeta - Earthworms and others    Acanthobdellida    Branchiobdellida    Hirudinea - Leeches Class Myzostomida Class Archiannelida (polyphyletic) Class Echiura *Some authors consider the subclasses under Clitellata to be classes The annelids, collectively called Annelida, are a large phylum of animals, comprising the segmented worms, with about... For other uses, see Snail (disambiguation). ... For other uses, see Clam (disambiguation). ... For other uses, see Squid (disambiguation). ... Families   Acanthodrilidae   Ailoscolecidae   Alluroididae   Almidae   Criodrilidae   Eudrilidae   Exxidae   Glossoscolecidae   Lumbricidae   Lutodrilidae   Megascolecidae   Microchaetidae   Ocnerodrilidae   Octochaetidae   Sparganophilidae Earthworm is the common name for the largest members of the Oligochaeta (which is either a class or subclass depending on the author) in the phylum Annelida. ... For other uses, see Leech (disambiguation). ... trochophore A - episphere B - hyposphere 1 - ganglia 2 - apical tuft 3 - prototroch 4 - metatroch 5 - nephridium 6 - anus 7 - protonephridia 8 - gastrointestinal tract 9 - buccal opening 10 - blastocoele A trochophore (or trocophore) is a type of larva with several bands of cilia. ... In evolutionary biology, convergent evolution is the process whereby organisms not closely related, independently evolve similar traits as a result of having to adapt to similar environments or ecological niches. ...


The Lophotrochozoa also include the Nemertea or ribbon worms, the Sipuncula, and several phyla that have a fan of cilia around the mouth, called a lophophore. These were traditionally grouped together as the lophophorates, but it now appears they are paraphyletic, some closer to the Nemertea and some to the Mollusca and Annelida. They include the Brachiopoda or lamp shells, which are prominent in the fossil record, the Entoprocta, the Phoronida, and possibly the Bryozoa or moss animals. Classes Anopla Enopla The phylum Nemertea (also Rhynchocoela, Nemertina, Nemertinea or Nemertini) contains the ribbon worms or proboscis worms, which are a group of unsegmented marine invertebrates. ... The Sipuncula, sipunculid worms or peanut worms, are a phylum of marine worms with a tentacle surrounded mouth on a completely invertible head end. ... Freshwater bryozoan with lophophore extended The lophophore is a characteristic feeding organ possessed by three major groups of animals: the Brachiopoda, Bryozoa, and Phoronida. ... Paraphyletic - Wikipedia /**/ @import /skins-1. ... Classes Lingulata Paterinata (extinct) Craniforma Chileata (extinct) Obolellata (extinct) Kutorginata (extinct) Strophomenata (extinct) Rhynchonellata Brachiopods (from Latin bracchium, arm + New Latin -poda, foot) make up one of the major animal phyla, Brachiopoda. ... Orders Barentsiidae (Urnatellidae) Loxokalypodidae Loxosomatidae Pedicellinidae Entoprocta (Gr. ... Genera Phoronis Phoronopsis Phoronids (Phoronida) are a relatively small animal phylum: twelve species are known, in two genera, Phoronis and Phoronopsis. ... Classes Stenolaemata Gymnolaemata Phylactolaemata Bryozoans are tiny colonial animals that generally build stony skeletons of calcium carbonate, superficially similar to coral. ...


Model organisms

Because of the great diversity found in animals, it is more economical for scientists around the world concert their efforts on a small number of chosen species so that connections can be drawn from their work and conclusions extrapolated about how animals function in general. Because they are easy to keep and breed, the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans have long been the most intensively studied metazoan model organism, and among the first lifeforms to be genetically sequenced. This was facilitated by the severely reduced state of their genomes, but the double-edged sword here is that with many genes, introns and linkages lost, these ecdysozoans can teach us little about the origins of animals in general. The extent of this type of evolution within the superphylum will be revealed by the crustacean, annelid, and molluscan genome projects currently in progress. Analysis of the starlet sea anemone genome has emphasised the importance of sponges, placozoans, and choanoflagellates, also being sequenced, in explaining the arrival of 1500 ancestral genes unique to the Eumetazoa.[5] Binomial name Meigen, 1830[1] Drosophila melanogaster (from the Greek for black-bellied dew-lover) is a two-winged insect that belongs to the Diptera, the order of the flies. ... Binomial name Maupas, 1900 Caenorhabditis elegans (IPA: ) is a free-living nematode (roundworm), about 1 mm in length, which lives in temperate soil environments. ... A model organism is a species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... For other uses, see Gene (disambiguation). ... Diagram of the location of introns and exons within a gene. ... Genetic linkage occurs when particular alleles are inherited jointly. ... Genome projects are scientific endeavours that ultimately aim to determine the complete genome sequence of an organism (be it an animal, a plant, a fungus, a bacterium, an archaean, a protist or a virus). ... Binomial name Stephenson, 1935 The starlet sea anemone (Nematostella vectensis) is a species of sea anemone that lives along the coast of southeast England and the east and west coasts of the United States. ... The choanoflagellates are a group of flagellate protozoa. ...


An analyse of the homoscleromorph sponge Oscarella carmela also suggests that the last common ancestor of sponges and the eumetazoan animals were more comlex than previously assumed.[6]


Other model organisms belonging to the animal kingdom include the mouse (Mus musculus) and zebrafish (Danio rerio}. Binomial name Mus musculus Linnaeus, 1758 Mus musculus is the common house mouse. ... Binomial name Danio rerio (Hamilton-Buchanan, 1822) The Zebra Danio or Zebrafish (Brachydanio rerio or Danio rerio) is a tropical fish belonging to the minnow family (Cyprinidae). ...


History of classification

Carolus Linnaeus, known as the "father of modern taxonomy".
Carolus Linnaeus, known as the "father of modern taxonomy".

Aristotle divided the living world between animals and plants, and this was followed by Carolus Linnaeus in the first hierarchical classification. Since then biologists have begun emphasizing evolutionary relationships, and so these groups have been restricted somewhat. For instance, microscopic protozoa were originally considered animals because they move, but are now treated separately. Image File history File linksMetadata Carolus_Linnaeus_(cleaned_up_version). ... Image File history File linksMetadata Carolus_Linnaeus_(cleaned_up_version). ... Carl Linnaeus, Latinized as Carolus Linnaeus, also known after his ennoblement as  , (May 13, 1707[1] – January 10, 1778), was a Swedish botanist, physician and zoologist[2] who laid the foundations for the modern scheme of nomenclature. ... Look up taxonomy in Wiktionary, the free dictionary. ... This article is about the philosopher. ... For other uses, see Plant (disambiguation). ... Carl Linnaeus, Latinized as Carolus Linnaeus, also known after his ennoblement as  , (May 13, 1707[1] – January 10, 1778), was a Swedish botanist, physician and zoologist[2] who laid the foundations for the modern scheme of nomenclature. ... Leishmania donovani, (a species of protozoan) in a bone marrow cell Protozoa (in Greek proto = first and zoa = animals) are one-celled eukaryotes (that is, unicellular microbes whose cells have membrane-bound nuclei) that commonly show characteristics usually associated with animals, mobility and heterotrophy. ...


In Linnaeus' original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, the Chordata, whereas the various other forms have been separated out. The above lists represent our current understanding of the group, though there is some variation from source to source. Carl Linnaeus, Latinized as Carolus Linnaeus, also known after his ennoblement as  , (May 13, 1707[1] – January 10, 1778), was a Swedish botanist, physician and zoologist[2] who laid the foundations for the modern scheme of nomenclature. ... Vermes (worms) is an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals. ... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... For other uses, see Fish (disambiguation). ... For other uses, see Amphibian (disambiguation). ... For other uses, see Bird (disambiguation). ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including those that produce milk, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex... Typical Classes See below Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. ...


See also

Fauna is a collective term for animal life of any particular region or time. ... This lists various names animals can have. ... Ethology is the scientific study of animal behaviour (particularly of social animals such as primates and canids), and is a branch of zoology. ... Animal liberation redirects here. ... This is a list of animals by number of neurons in their brain. ... The Dodo, a bird of Mauritius, became extinct during the mid-late 17th century after humans destroyed the forests where the birds made their homes and introduced animals that ate their eggs. ...

Notes

  1. ^ National Zoo. Panda Classroom (English). Retrieved on September 30, 2007.
  2. ^ Jennifer Bergman. Heterotrophs (English). Retrieved on September 30, 2007.
  3. ^ Davidson, Michael W.. Animal Cell Structure (English). Retrieved on September 20, 2007.
  4. ^ Saupe, S.G. Concepts of Biology (English). Retrieved on September 30, 2007.
  5. ^ N.H. Putnam, et al. (Jul 2007). "Sea anemone genome reveals ancestral eumetazoan gene repertoire and genomic organization". Science 317 (5834): 86-94. doi:10.1126/science.1139158. 
  6. ^ Mitochondrial Genome of the Homoscleromorph Oscarella carmela (Porifera, Demospongiae) Reveals Unexpected Complexity in the Common Ancestor of Sponges and Other Animals Oxford Journals

is the 273rd day of the year (274th in leap years) in the Gregorian calendar. ... is the 273rd day of the year (274th in leap years) in the Gregorian calendar. ... is the 263rd day of the year (264th in leap years) in the Gregorian calendar. ... is the 273rd day of the year (274th in leap years) in the Gregorian calendar. ... Science is the journal of the American Association for the Advancement of Science (AAAS). ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

References

  • Klaus Nielsen. Animal Evolution: Interrelationships of the Living Phyla (2nd edition). Oxford Univ. Press, 2001.
  • Knut Schmidt-Nielsen. Animal Physiology: Adaptation and Environment. (5th edition). Cambridge Univ. Press, 1997.

External links

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  • Scientific American Magazine (December 2005 Issue) - Getting a Leg Up on Land About the evolution of four-limbed animals from fish.

  Results from FactBites:
 
Animal Planet :: Animals A to Zoo (335 words)
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Animal Law Review (1011 words)
Animal Law was created by the same group of innovative and far sighted Lewis & Clark law students who founded the very first chapter of the Student Animal Legal Defense Fund in 1992.
Animals were seen as commodities whose interests were intertwined with agricultural and environmental policy.
Animal Law is pleased to introduce as a new annual feature a bibliography of animal law-related articles published in law reviews and law journals during the previous year.
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