Animals are multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 millionths of a metre to 33.6 metres and have complex interactions with each other and their environments, forming intricate food webs. The category includes humans, but in colloquial use the term animal refers only to non-human animals; the study of non-human animals is known as zoology. Most living animal species are in the Bilateria, a clade whose members have a bilaterally symmetric body plan; the Bilateria include the protostomes—in which many groups of invertebrates are found, such as nematodes and molluscs—and the deuterostomes, containing the echinoderms and chordates.
Life forms interpreted. Many modern animal phyla became established in the fossil record as marine species during the Cambrian explosion which began around 542 million years ago. 6,331 groups of genes common to all living animals have been identified. Aristotle divided animals into those with those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between animal taxa. Humans make use of many other animal species for food, including meat and eggs. Dogs have been used in hunting, while many aquatic animals are hunted for sport.
Non-human animals have appeared in art from the earliest times and are featured in mythology and religion. The word "animal" comes from the Latin animalis, having soul or living being; the biological definition includes all members of the kingdom Animalia. In colloquial usage, as a consequence of anthropocentrism, the term animal is sometimes used nonscientifically to refer only to non-human animals. Animals have several characteristics. Animals are eukaryotic and multicellular, unlike bacteria, which are prokaryotic, unlike protists, which are eukaryotic but unicellular. Unlike plants and algae, which produce their own nutrients animals are heterotrophic, feeding on organic material and digesting it internally. With few exceptions, animals breathe oxygen and respire aerobically. All animals are motile during at least part of their life cycle, but some animals, such as sponges, corals and barnacles become sessile; the blastula is a stage in embryonic development, unique to most animals, allowing cells to be differentiated into specialised tissues and organs.
All animals are composed of cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. During development, the animal extracellular matrix forms a flexible framework upon which cells can move about and be reorganised, making the formation of complex structures possible; this may be calcified, forming structures such as shells and spicules. In contrast, the cells of other multicellular organisms are held in place by cell walls, so develop by progressive growth. Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, desmosomes. With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues; these include muscles, which enable locomotion, nerve tissues, which transmit signals and coordinate the body. There is an internal digestive chamber with either one opening or two openings. Nearly all animals make use of some form of sexual reproduction, they produce haploid gametes by meiosis.
These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, 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 third germ layer, the mesoderm develops between them; these germ layers differentiate to form tissues and organs. Repeated instances of mating with a close relative during sexual reproduction leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding. In some species, such as the splendid fairywren, females benefit by mating with multiple males, thus producing more offspring of higher genetic quality; some animals are capable of asexual reproduction, which results
The thyroarytenoid muscle is a broad, thin muscle that forms the body of the vocal fold and that supports the wall of the ventricle and its appendix. It functions to relax the vocal folds, it arises in front from the lower half of the angle of the thyroid cartilage, from the middle cricothyroid ligament. Its fibers pass backward and laterally, to be inserted into the base and anterior surface of the arytenoid cartilage; the lower and deeper fibers of the muscle can be differentiated as a triangular band, inserted into the vocal process of the arytenoid cartilage, into the adjacent portion of its anterior surface. The vocal muscle is the upper portion of the thyroarytenoid muscle, involved in producing speech. A considerable number of the fibers of the thyroarytenoid muscle are prolonged into the aryepiglottic fold, where some of them become lost, while others are continued to the margin of the epiglottis, they have received a distinctive name, thyroepiglottic muscle, thyreoepiglotticus or thyroepiglottic, are sometimes described as a separate muscle.
A few fibers extend along the wall of the ventricle from the lateral wall of the arytenoid cartilage to the side of the epiglottis and constitute the ventricularis muscle. The thyroarytenoid muscle, consisting of two parts having different attachments and different directions, are rather complicated as regards their action, their main use is to draw the arytenoid cartilages forward toward the thyroid, thus relax and shorten the vocal folds. But, owing to the connection of the deeper portion with the vocal fold, this part, if acting separately, is supposed to modify its elasticity and tension, while the lateral portion rotates the arytenoid cartilage inward, thus narrows the rima glottidis by bringing the two vocal folds together; this article incorporates text in the public domain from page 1083 of the 20th edition of Gray's Anatomy Anatomy photo:32:st-0605 at the SUNY Downstate Medical Center Atlas image: rsa4p5 at the University of Michigan Health System
The clouded leopard is a wild cat occurring from the Himalayan foothills through mainland Southeast Asia into China. Since 2008, it is listed as Vulnerable on the IUCN Red List, its total population is suspected to be fewer than 10,000 mature individuals, with a decreasing population trend, no single population numbering more than 1,000 adults. It is known as the mainland clouded leopard, to distinguish it from the Sunda clouded leopard, it is the state animal of the Indian state of Meghalaya. Felis nebulosa was proposed by Edward Griffith in 1821 who first described a clouded leopard skin from China. Felis macrosceloides proposed by Brian Houghton Hodgson in 1841 was a clouded leopard specimen from Nepal. Felis brachyura proposed by Robert Swinhoe in 1862 was a clouded leopard skin from Taiwan; the generic name Neofelis was proposed by John Edward Gray in 1867 who subordinated all three to this genus. At present, N. nebulosa is considered a monotypic species due to lack of evidence for subspecification.
The clouded leopard is considered to form an evolutionary link between the Pantherinae and the small cats. It represents the smallest of the pantherine cats, but despite its name, it is not related to the leopard. Phylogenetic analysis indicates; the other Neofelis species is the Sunda clouded leopard, considered a subspecies of N. nebulosa until 2006. Genetic analysis of hair samples of the two Neofelis species indicates that they diverged 1.4 million years ago, after having used a now submerged land bridge to reach Borneo and Sumatra from mainland Asia. The clouded leopard's fur is of a dark grey or ochreous ground-color largely obliterated by black and dark dusky-grey blotched pattern. There are black spots on the head, the ears are black. Fused or broken-up stripes run from the corner of the eyes over the cheek, from the corner of the mouth to the neck, along the nape to the shoulders. Elongated blotches form a single median stripe on the loins. Two large blotches of dark dusky-grey hair on the side of the shoulders are each emphasized posteriorly by a dark stripe, which passes on to the foreleg and breaks up into irregular spots.
The flanks are marked by dark dusky-grey irregular blotches bordered behind by long, irregularly curved or looped stripes. These blotches yielding the clouded pattern suggest the English name of the cat; the underparts and legs are spotted, the tail is marked by large, paired spots. Its legs are short and stout, paws broad. Females are smaller than males, its hyoid bone is ossified. Its pupils contract into vertical slits. Irises are brownish yellow to grayish green. Melanistic clouded leopards are uncommon, it has rather short limbs compared to the other big cats. Its hind limbs are longer than its front limbs to allow for increased jumping and leaping capabilities, its ulnae and radii are not fused, which contributes to a greater range of motion when climbing trees and stalking prey. Clouded leopards weigh between 23 kg. Females vary in head-to-body length with a tail 61 to 82 cm long. Males are larger at 81 to 108 cm with a tail 74 to 91 cm long, its shoulder height varies from 50 to 55 cm. Its skull is low with strong occipital and sagittal crests.
The canine teeth are exceptionally long, the upper being about three times as long as the basal width of the socket. The first premolar is absent; the upper pair of canines measure longer. The clouded leopard is referred to as a “modern-day sabre-tooth” because it has the largest canines in proportion to its body size; the clouded leopard occurs from the Himalayan foothills in Nepal and India to Myanmar, southeastern Bangladesh, Peninsular Malaysia, Indochina to south of the Yangtze River in China. It is regionally extinct in Taiwan; the last confirmed record of a Formosan clouded leopard dates to 1989, when the skin of a young individual was found in the Taroko area. It was not recorded during an extensive camera trapping survey conducted from 1997 to 2012 in more than 1,450 sites inside and outside Taiwanese protected areas. In Nepal, the clouded leopard was thought to be extinct since the late 1860s, but in 1987 and 1988, four individuals were found in the central part of the country, close to Chitwan National Park and in the Pokhara Valley.
These findings extended the known range westward, suggesting it is able to survive and breed in degraded woodlands that harboured moist subtropical semideciduous forest. Since individuals have been recorded in the Shivapuri Nagarjun National Park and in the Annapurna Conservation Area. In India, it occurs in Sikkim, northern West Bengal, Meghalaya subtropical forests, Mizoram, Assam and Arunachal Pradesh. In Pakke Tiger Reserve, a clouded leopard was photographed for the first time in India. In Sikkim, clouded leopards were camera-trapped at altitudes of 2,500–3,720 m between April 2008 and May 2010 in the Khangchendzonga Biosphere Reserve. In Manas National Park, 16 individuals were recorded during a survey in November 2010 to February 2011. Between January 2013 and March 2018, clouded leopards were recorded in Dampa Tiger Reserve, Eaglenest Wildlife Sanctuary and Singchung-Bugun Village Community Reserve, in Meghalaya's Nongkhyllem National Park and Balpakram-Baghmara landscape. In Bhutan, it was recorded in Royal Manas National Park, Jigme Singye Wangchuck National Park, Phibsoo Wildlife Sanctuary, Jigme Dorji National Park, Phrumsengla National Park, Bumdelin
Neofelis is a genus comprising two extant cat species from Southeast Asia: the clouded leopard of mainland Asia, the Sunda clouded leopard of Sumatra and Borneo. The scientific name Neofelis is a composite of the Greek word neo- meaning "new", the Latin word feles meaning "cat" meaning "new cat"; the generic name Neofelis was first proposed by John Edward Gray in 1867 as comprising two species. Reginald Innes Pocock recognized the taxonomic classification of Neofelis in 1917, but admitted only the single species Neofelis nebulosa with several subspecies and macrocelis as the type specimen. For 90 years, the classification of Neofelis as a monotypic genus was accepted. In 2006, Neofelis diardi was found to be distinct from its continental relative Neofelis nebulosa and classified as a separate species. Gray described the genus Neofelis as having an elongate skull, a broad and rather produced face on the same plane as the forehead, a large and elongate nasal, a moderate orbit, a truncated lower jaw and long conical upper and lower canine teeth with a sharp cutting hinder edge.
This skull has resemblances to that of the fossil Smilodon, with much elongated upper canines. Pocock described the skull of Neofelis as recalling in general features that of Panthera pardus in the shortness and wide separation of the frontal and malar postorbital processes, relative proportion of mandibular teeth; the Sunda clouded leopard has a narrower palate between them. Neofelis species range from Nepal and Sikkim eastward to south China and Hainan, southeastward to Burma, the Malay Peninsula, Sumatra and Borneo, they are most associated with primary evergreen tropical rainforest, but make use of other types of habitat. Sightings have been made in secondary and logged forest, as well as grassland and scrub. In the Himalayan foothills they have been recorded up to 1,450 m. Between 1821 and 1862, several felids have been described from Southeast Asia that are subordinated under Neofelis today: Felis nebulosa was first described in 1821 by Edward Griffith based on a specimen brought from Canton in southern China.
Populations range from the Himalayan foothills in Nepal through mainland Southeast Asia into China. Felis diardi was first described in 1823 by Georges Cuvier based on a skin and a drawing received from Java; the Sunda clouded leopard is restricted to the islands of Sumatra and Borneo. In Java only clouded leopard fossils were found. Leopardus brachyurus was first described in 1862 by Robert Swinhoe based on two to three skins from Taiwan. Today the Formosan clouded leopard is considered a subspecies of Neofelis nebulosa under the trinomial Neofelis nebulosa brachyurus, it is now believed to be extinct. Deforestation is the foremost threat for both Neofelis species, they are threatened by commercial poaching for the wildlife trade. Skins and teeth are offered for decoration and clothing and meat as substitute for tiger in traditional Asian medicines and tonics, live animals for the pet trade. Few poaching incidents have been documented, but all range states are believed to have some degree of commercial poaching.
In recent years, substantial domestic markets existed in Indonesia and Vietnam. Both Neofelis species are protected over most of their range. Hunting is banned in Bangladesh, Cambodia, India, Malaysia, Nepal, Taiwan and Vietnam. Hunting regulations apply in Laos
A chordate is an animal constituting the phylum Chordata. During some period of their life cycle, chordates possess a notochord, a dorsal nerve cord, pharyngeal slits, an endostyle, a post-anal tail: these five anatomical features define this phylum. Chordates are bilaterally symmetric; the Chordata and Ambulacraria together form the superphylum Deuterostomia. Chordates are divided into three subphyla: Vertebrata. There are extinct taxa such as the Vetulicolia. Hemichordata has been presented as a fourth chordate subphylum, but now is treated as a separate phylum: hemichordates and Echinodermata form the Ambulacraria, the sister phylum of the Chordates. Of the more than 65,000 living species of chordates, about half are bony fish that are members of the superclass Osteichthyes. Chordate fossils have been found from as early as the Cambrian explosion, 541 million years ago. Cladistically, vertebrates - chordates with the notochord replaced by a vertebral column during development - are considered to be a subgroup of the clade Craniata, which consists of chordates with a skull.
The Craniata and Tunicata compose the clade Olfactores. Chordates form a phylum of animals that are defined by having at some stage in their lives all of the following anatomical features: A notochord, a stiff rod of cartilage that extends along the inside of the body. Among the vertebrate sub-group of chordates the notochord develops into the spine, in wholly aquatic species this helps the animal to swim by flexing its tail. A dorsal neural tube. In fish and other vertebrates, this develops into the spinal cord, the main communications trunk of the nervous system. Pharyngeal slits; the pharynx is the part of the throat behind the mouth. In fish, the slits are modified to form gills, but in some other chordates they are part of a filter-feeding system that extracts particles of food from the water in which the animals live. Post-anal tail. A muscular tail that extends backwards behind the anus. An endostyle; this is a groove in the ventral wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus.
It stores iodine, may be a precursor of the vertebrate thyroid gland. There are soft constraints that separate chordates from certain other biological lineages, but are not part of the formal definition: All chordates are deuterostomes; this means. All chordates are based on a bilateral body plan. All chordates are coelomates, have a fluid filled body cavity called a coelom with a complete lining called peritoneum derived from mesoderm; the following schema is from the third edition of Vertebrate Palaeontology. The invertebrate chordate classes are from Fishes of the World. While it is structured so as to reflect evolutionary relationships, it retains the traditional ranks used in Linnaean taxonomy. Phylum Chordata †Vetulicolia? Subphylum Cephalochordata – Class Leptocardii Clade Olfactores Subphylum Tunicata – Class Ascidiacea Class Thaliacea Class Appendicularia Class Sorberacea Subphylum Vertebrata Infraphylum incertae sedis Cyclostomata Superclass'Agnatha' paraphyletic Class Myxini Class Petromyzontida or Hyperoartia Class †Conodonta Class †Myllokunmingiida Class †Pteraspidomorphi Class †Thelodonti Class †Anaspida Class †Cephalaspidomorphi Infraphylum Gnathostomata Class †Placodermi Class Chondrichthyes Class †Acanthodii Superclass Osteichthyes Class Actinopterygii Class Sarcopterygii Superclass Tetrapoda Class Amphibia Class Sauropsida Class Synapsida Craniates, one of the three subdivisions of chordates, all have distinct skulls.
They include the hagfish. Michael J. Benton commented that "craniates are characterized by their heads, just as chordates, or all deuterostomes, are by their tails". Most craniates are vertebrates; these consist of a series of bony or cartilaginous cylindrical vertebrae with neural arches that protect the spinal cord, with projections that link the vertebrae. However hagfish have incomplete braincases and no vertebrae, are therefore not regarded as vertebrates, but as members of the craniates, the group from which vertebrates are thought to have evolved; however the cladistic exclusion of hagfish from the vertebrates is controversial, as they ma
The phenotype of an organism is the composite of the organism's observable characteristics or traits, including its morphology or physical form and structure. An organism's phenotype results from two basic factors: the expression of an organism's genetic code, or its genotype, the influence of environmental factors, which may interact, further affecting phenotype; when two or more different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented polymorphism is Labrador Retriever coloring. Richard Dawkins in 1978 and again in his 1982 book The Extended Phenotype suggested that bird nests and other built structures such as caddis fly larvae cases and beaver dams can be considered as "extended phenotypes"; the genotype-phenotype distinction was proposed by Wilhelm Johannsen in 1911 to make clear the difference between an organism's heredity and what that heredity produces. The distinction is similar to that proposed by August Weismann, who distinguished between germ plasm and somatic cells.
The genotype-phenotype distinction should not be confused with Francis Crick's central dogma of molecular biology, a statement about the directionality of molecular sequential information flowing from DNA to protein, not the reverse. The term "phenotype" has sometimes been incorrectly used as a shorthand for phenotypic difference from wild type, bringing the absurd statement that a mutation has no phenotype. Despite its straightforward definition, the concept of the phenotype has hidden subtleties, it may seem that anything dependent on the genotype is a phenotype, including molecules such as RNA and proteins. Most molecules and structures coded by the genetic material are not visible in the appearance of an organism, yet they are observable and are thus part of the phenotype, it may seem that this goes beyond the original intentions of the concept with its focus on the organism in itself. Either way, the term phenotype includes inherent traits or characteristics that are observable or traits that can be made visible by some technical procedure.
A notable extension to this idea is the presence of "organic molecules" or metabolites that are generated by organisms from chemical reactions of enzymes. Another extension adds behavior to the phenotype. Behavioral phenotypes include cognitive and behavioral patterns; some behavioral phenotypes may characterize psychiatric syndromes. Phenotypic variation is a fundamental prerequisite for evolution by natural selection, it is the living organism as a whole that contributes to the next generation, so natural selection affects the genetic structure of a population indirectly via the contribution of phenotypes. Without phenotypic variation, there would be no evolution by natural selection; the interaction between genotype and phenotype has been conceptualized by the following relationship: genotype + environment → phenotype A more nuanced version of the relationship is: genotype + environment + genotype & environment interactions → phenotype Genotypes have much flexibility in the modification and expression of phenotypes.
The plant Hieracium umbellatum is found growing in two different habitats in Sweden. One habitat is rocky, sea-side cliffs, where the plants are bushy with broad leaves and expanded inflorescences; these habitats alternate along the coast of Sweden and the habitat that the seeds of Hieracium umbellatum land in, determine the phenotype that grows. An example of random variation in Drosophila flies is the number of ommatidia, which may vary between left and right eyes in a single individual as much as they do between different genotypes overall, or between clones raised in different environments; the concept of phenotype can be extended to variations below the level of the gene that affect an organism's fitness. For example, silent mutations that do not change the corresponding amino acid sequence of a gene may change the frequency of guanine-cytosine base pairs; these base pairs have a higher thermal stability than adenine-thymine, a property that might convey, among organisms living in high-temperature environments, a selective advantage on variants enriched in GC content.
Richard Dawkins described a phenotype that included all effects that a gene has on its surroundings, including other organisms, as an extended phenotype, arguing that "An animal's behavior tends to maximize the survival of the genes'for' that behavior, whether or not those genes happen to be in the body of the particular animal performing it." For instance, an organism such as a beaver modifies its environment by building a beaver dam. When a bird feeds a brood parasite such as a cuckoo, it is unwittingly extending its phenotype.
The Permian is a geologic period and system which spans 47 million years from the end of the Carboniferous Period 298.9 million years ago, to the beginning of the Triassic period 251.902 Mya. It is the last period of the Paleozoic era; the concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the city of Perm. The Permian witnessed the diversification of the early amniotes into the ancestral groups of the mammals, turtles and archosaurs; the world at the time was dominated by two continents known as Pangaea and Siberia, surrounded by a global ocean called Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, who could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors; the Permian ended with the Permian–Triassic extinction event, the largest mass extinction in Earth's history, in which nearly 96% of marine species and 70% of terrestrial species died out.
It would take well into the Triassic for life to recover from this catastrophe. Recovery from the Permian–Triassic extinction event was protracted; the term "Permian" was introduced into geology in 1841 by Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Édouard de Verneuil; the region now lies in the Perm Krai of Russia. Official ICS 2017 subdivisions of the Permian System from most recent to most ancient rock layers are: Lopingian epoch Changhsingian Wuchiapingian Others: Waiitian Makabewan Ochoan Guadalupian epoch Capitanian stage Wordian stage Roadian stage Others: Kazanian or Maokovian Braxtonian stage Cisuralian epoch Kungurian stage Artinskian stage Sakmarian stage Asselian stage Others: Telfordian Mangapirian Sea levels in the Permian remained low, near-shore environments were reduced as all major landmasses collected into a single continent—Pangaea; this could have in part caused the widespread extinctions of marine species at the end of the period by reducing shallow coastal areas preferred by many marine organisms.
During the Permian, all the Earth's major landmasses were collected into a single supercontinent known as Pangaea. Pangaea straddled the equator and extended toward the poles, with a corresponding effect on ocean currents in the single great ocean, the Paleo-Tethys Ocean, a large ocean that existed between Asia and Gondwana; the Cimmeria continent rifted away from Gondwana and drifted north to Laurasia, causing the Paleo-Tethys Ocean to shrink. A new ocean was growing on its southern end, the Tethys Ocean, an ocean that would dominate much of the Mesozoic era. Large continental landmass interiors experience climates with extreme variations of heat and cold and monsoon conditions with seasonal rainfall patterns. Deserts seem to have been widespread on Pangaea; such dry conditions favored gymnosperms, plants with seeds enclosed in a protective cover, over plants such as ferns that disperse spores in a wetter environment. The first modern trees appeared in the Permian. Three general areas are noted for their extensive Permian deposits—the Ural Mountains and the southwest of North America, including the Texas red beds.
The Permian Basin in the U. S. states of Texas and New Mexico is so named because it has one of the thickest deposits of Permian rocks in the world. The climate in the Permian was quite varied. At the start of the Permian, the Earth was still in an ice age. Glaciers receded around the mid-Permian period as the climate warmed, drying the continent's interiors. In the late Permian period, the drying continued although the temperature cycled between warm and cool cycles. Permian marine deposits are rich in fossil mollusks and brachiopods. Fossilized shells of two kinds of invertebrates are used to identify Permian strata and correlate them between sites: fusulinids, a kind of shelled amoeba-like protist, one of the foraminiferans, ammonoids, shelled cephalopods that are distant relatives of the modern nautilus. By the close of the Permian, trilobites and a host of other marine groups became extinct. Terrestrial life in the Permian included diverse plants, fungi and various types of tetrapods; the period saw a massive desert covering the interior of Pangaea.
The warm zone spread in the northern hemisphere. The rocks formed at that time were stained red by iron oxides, the result of intense heating by the sun of a surface devoid of vegetation cover. A number of older types of plants and animals became marginal elements; the Permian began with the Carboniferous flora still flourishing. About the middle of the Permian a major transition in vegetation began; the swamp-loving