1.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
2.
Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
3.
Chordate
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Chordates are deuterostomes, as during the embryo development stage the anus forms before the mouth. They are also bilaterally symmetric coelomates, in the case of vertebrate chordates, the notochord is usually replaced by a vertebral column during development, and they may have body plans organized via segmentation. There are also additional extinct taxa, the Vertebrata are sometimes considered as a subgroup of the clade Craniata, consisting of chordates with a skull, the Craniata and Tunicata compose the clade Olfactores. Of the more than 65,000 living species of chordates, the worlds largest and fastest animals, the blue whale and peregrine falcon respectively, are chordates, as are humans. Fossil chordates are known from at least as early as the Cambrian explosion, Hemichordata, which includes the acorn worms, has been presented as a fourth chordate subphylum, but it now is usually treated as a separate phylum. The Hemichordata, along with the Echinodermata, form the Ambulacraria, the Chordata and Ambulacraria form the superphylum Deuterostomia, composed of the deuterostomes. Attempts to work out the relationships of the chordates have produced several hypotheses. All of the earliest chordate fossils have found in the Early Cambrian Chengjiang fauna. Because the fossil record of early chordates is poor, only molecular phylogenetics offers a prospect of dating their emergence. However, the use of molecular phylogenetics for dating evolutionary transitions is controversial and it has also proved difficult to produce a detailed classification within the living chordates. Attempts to produce family trees shows that many of the traditional classes are paraphyletic. While this has been known since the 19th century, an insistence on only monophyletic taxa has resulted in vertebrate classification being in a state of flux. Although the name Chordata is attributed to William Bateson, it was already in prevalent use by 1880, ernst Haeckel described a taxon comprising tunicates, cephalochordates, and vertebrates in 1866. Though he used the German vernacular form, it is allowed under the ICZN code because of its subsequent latinization, among the vertebrate sub-group of chordates the notochord develops into the spine, and in wholly aquatic species this helps the animal to swim by flexing its tail. In fish and other vertebrates, this develops into the spinal cord, the pharynx is the part of the throat immediately behind the mouth. In fish, the slits are modified to form gills, a muscular tail that extends backwards behind the anus. This is a groove in the wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus and it also stores iodine, and may be a precursor of the vertebrate thyroid gland
4.
Bird
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Birds, a subgroup of Reptiles, are the last living examples of Dinosaurs. Birds live worldwide and range in size from the 5 cm bee hummingbird to the 2.75 m ostrich. They rank as the class of tetrapods with the most living species, at ten thousand. Birds are the closest living relatives of crocodilians, the fossil record indicates that birds evolved from feathered ancestors within the theropod group of saurischian dinosaurs. True birds first appeared during the Cretaceous period, around 100 million years ago, Birds, especially those in the southern continents, survived this event and then migrated to other parts of the world while diversifying during periods of global cooling. Primitive bird-like dinosaurs that lie outside class Aves proper, in the broader group Avialae, have been found dating back to the mid-Jurassic period, around 170 million years ago. Birds have wings which are more or less developed depending on the species, the digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have evolved for swimming. Many species annually migrate great distances, Birds are social, communicating with visual signals, calls, and bird songs, and participating in such social behaviours as cooperative breeding and hunting, flocking, and mobbing of predators. The vast majority of species are socially monogamous, usually for one breeding season at a time, sometimes for years. Other species have breeding systems that are polygynous or, rarely, Birds produce offspring by laying eggs which are fertilised through sexual reproduction. They are usually laid in a nest and incubated by the parents, most birds have an extended period of parental care after hatching. Some birds, such as hens, lay eggs even when not fertilised, songbirds, parrots, and other species are popular as pets. Guano is harvested for use as a fertiliser, Birds prominently figure throughout human culture. About 120–130 species have become extinct due to human activity since the 17th century, human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them. Recreational birdwatching is an important part of the ecotourism industry, the first classification of birds was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae. Carl Linnaeus modified that work in 1758 to devise the taxonomic classification system currently in use, Birds are categorised as the biological class Aves in Linnaean taxonomy. Phylogenetic taxonomy places Aves in the dinosaur clade Theropoda, Aves and a sister group, the clade Crocodilia, contain the only living representatives of the reptile clade Archosauria
5.
Accipitridae
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The Accipitridae, one of the four families within the order Accipitriformes, are a family of small to large birds with strongly hooked bills and variable morphology based on diet. They feed on a range of items from insects to medium-sized mammals, with a number feeding on carrion. The Accipitridae have a distribution, being found on all the worlds continents. Many well-known birds, such as hawks, eagles, kites, harriers, the osprey is usually placed in a separate family, as is the secretary bird, and the New World vultures are also usually now regarded as a separate family or order. The accipitrids have been divided into some five to 10 subfamilies. Most share a similar morphology, but many of these groups contain taxa which are more aberrant. These are placed in their position more for lack of better evidence than anything else. It is thus not very surprising that the layout of the accipitrids has always been a matter of dispute. The accipitrids are recognizable by a rearrangement of their chromosomes. Apart from this, morphology and mtDNA cytochrome b sequence data give a picture of these birds interrelationships. These appear to form a group with the Milvinae, Accipitrinae and Circinae, the Perninae and possibly the Elaninae are older lineages, as are the Old World vultures. The latter are likely also poly- or paraphyletic, with some aberrant species like the bearded. The Accipitridae are a family with a great deal of variation in size. Wingspan can vary from 39 cm in the little sparrowhawk to more than 300 cm in the cinereous, in these extreme species, wing chord length can range from 113 to 890 mm and culmen length from 11 to 88 mm. Most accipitrids exhibit sexual dimorphism in size, although, unusually for birds and this sexual difference in size is most pronounced in active species that hunt birds, such as the Accipiter hawks, in which the size difference averages 25–50%. In a majority of species, such as generalist hunters and rodent-, reptile-, fish-, and insect-hunting specialists, in the carrion-eating Old World vultures and snail eating kites, the difference is almost non-existent. The beaks of accipitrids are strong and hooked, in some species, there is a notch or tooth in the upper mandible. In all accipitrids, the base of the mandible is covered by a fleshy membrane called the cere
6.
Species
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In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
7.
Americas
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The Americas, also collectively called America, encompass the totality of the continents of North America and South America. Together they make up most of the land in Earths western hemisphere, along with their associated islands, they cover 8% of Earths total surface area and 28. 4% of its land area. The topography is dominated by the American Cordillera, a chain of mountains that runs the length of the west coast. The flatter eastern side of the Americas is dominated by river basins, such as the Amazon, St. Lawrence River / Great Lakes basin, Mississippi. Humans first settled the Americas from Asia between 42,000 and 17,000 years ago, a second migration of Na-Dene speakers followed later from Asia. The subsequent migration of the Inuit into the neoarctic around 3500 BCE completed what is regarded as the settlement by the indigenous peoples of the Americas. The first known European settlement in the Americas was by the Norse explorer Leif Ericson, however, the colonization never became permanent and was later abandoned. The voyages of Christopher Columbus from 1492 to 1502 resulted in permanent contact with European powers, diseases introduced from Europe and Africa devastated the indigenous peoples, and the European powers colonized the Americas. Mass emigration from Europe, including numbers of indentured servants. Decolonization of the Americas began with the American Revolution in 1776, the population is over 1 billion, with over 65% of them living in one of the three most populous countries. As of the beginning of the 2010s, the most populous urban agglomerations are Mexico City, New York, Sao Paulo, Los Angeles, Buenos Aires and Rio de Janeiro, all of them megacities. The name America was first recorded in 1507 in the Cosmographiae Introductio, apparently written by Matthias Ringmann and it first applied to both North and South America by Gerardus Mercator in 1538. Amerigen means land of Amerigo and derives from Amerigo and gen, America accorded with the feminine names of Asia, Africa, and Europa. When conceived as a continent, the form is generally the continent of America in the singular. However, without a context, singular America in English commonly refers to the United States of America. In some countries of the world, America is considered a continent encompassing the North America and South America subcontinents, the first inhabitants migrated into the Americas from Asia. Habitation sites are known in Alaska and the Yukon from at least 20,000 years ago, beyond that, the specifics of the Paleo-Indian migration to and throughout the Americas, including the dates and routes traveled, are subject to ongoing research and discussion. Widespread habitation of the Americas occurred during the glacial maximum
8.
Hawk
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Hawks are a group of medium-sized diurnal birds of prey of the family Accipitridae which are widely distributed and varying greatly in size. The subfamily Accipitrinae includes goshawks, sparrowhawks, the sharp-shinned hawk and these are mainly woodland birds with long tails and high visual acuity, hunting by sudden dashes from a concealed perch. In the Americas, members of the Buteo group are also called hawks, generally buteos have broad wings and sturdy builds. They are relatively larger winged, shorter-tailed and soar more extensively in areas than accipiters. The terms accipitrine hawk and buteonine hawk may be used to distinguish the two types, in regions where hawk applies to both, the term true hawk is sometimes used for the accipitrine hawks, in regions where buzzard is preferred for the buteonine hawks. All these groups are members of the Accipitridae family, which includes the hawks and buzzards as well as kites, harriers, some authors use hawk generally for any small to medium Accipitrid that is not an eagle. The common names of birds include the term hawk, reflecting traditional usage rather than taxonomy. Falconry was also called hawking, and any bird used for falconry could be referred to as a hawk, aristotle listed eleven types of ἱέρακες, aisalōn, asterias, hypotriorchēs, kirkos, leios, perkos, phassophonos, phrynologos, pternis, spizias, and triorchēs. Pliny numbered sixteen kinds of hawks, but named only aigithos, epileios, kenchrēïs, kybindis, the accipitrine hawks generally take birds as their primary prey. They have also been called hen-hawks, or wood-hawks because of their woodland habitat, the subfamily Accipitrinae contains Accipiter, it also contains genera Micronisus, Urotriorchis, and Megatriorchis. Melierax may be included in the subfamily, or given a subfamily of its own, erythrotriorchis is traditionally included in Accipitrinae, but is possibly a convergent genus from an unrelated group. The Buteo group includes genera Buteo, Parabuteo, Geranoetus, members of this group have also been called hawk-buzzards. Proposed new genera Morphnarchus, Rupornis, and Pseudastur are formed from members of Buteo, the Buteogallus group are also called hawks, with the exception of the solitary eagles. Buteo is the genus of the subfamily Buteoninae. Traditionally this subfamily also includes eagles and sea-eagles, lerner and Mindell proposed placing those into separate subfamilies, leaving just the buteonine hawks/buzzards in Buteoninae. In February 2005, the Canadian ornithologist Louis Lefebvre announced a method of measuring avian IQ in terms of their innovation in feeding habits, Hawks were named among the most intelligent birds based on his scale. Hawks have four types of receptors in the eye. These give birds the ability to not only the visible range but also the ultraviolet part of the spectrum
9.
Swainson's hawk
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Swainsons hawk, is a large Buteo hawk of the Falconiformes, sometimes separated in the Accipitriformes like its relatives. This species was named after William Swainson, a British naturalist and it is colloquially known as the grasshopper hawk or locust hawk, as it is very fond of Acrididae and will voraciously eat these insects whenever they are available. Their breeding habitat is prairie and dry grasslands in western North America and they build a stick nest in a tree or shrub or on a cliff edge. This species or its predecessor is the ancestor of the Galápagos hawk. The latter diverged from the mainland birds perhaps 300,000 years ago, Swainsons hawk is a raptor and a medium-sized member of the Buteo genus. It broadly overlaps in size with the hawk, a related species found as a breeding resident almost throughout North America. Swainsons hawk is on average a little shorter in length, 43–56 cm long, however, Swainsons hawk has a slightly longer wingspan at 117–137 cm, with more slender, elongated wings, than the red-tailed hawk. Female Swainsons hawks, at a weight of 1.15 kg, are somewhat larger and heavier than males. Among standard measurements, the chord is 36. 2–42.7 cm, the tail is 18. 5–23.4 cm, the tarsus is 6. 2–8 cm. In flight, Swainsons hawk holds its wings in a dihedral, it tips back. There are two color variations. The underwings, seen as the bird soars, have light linings and dark flight feathers, the tail is gray-brown with about six narrow dark bands and one wider subterminal band. Juveniles are similar but dark areas have pale mottling and light areas, the chest is pale with some darker marks. The subterminal band of the tail is less obvious, Birds in their first spring may have pale heads because of feather wear. Dark-morph birds are dark brown except for a patch under the tail. There is a variant that is lighter on the underparts with reddish bars. The tails of both these forms resemble those of the light morph, Swainsons hawk inhabits North America mainly in the spring and summer and winters in South America. Breeding areas include south-central Alberta, central Saskatchewan, southwestern Manitoba and they will breed as far north as east-central Alaska, and southwestern Yukon
10.
Red-tailed hawk
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The red-tailed hawk is a bird of prey, one of three species colloquially known in the United States as the chickenhawk, though it rarely preys on standard sized chickens. It breeds throughout most of North America, from western Alaska and northern Canada to as far south as Panama and the West Indies, Red-tailed hawks can acclimate to all the biomes within their range. There are fourteen recognized subspecies, which vary in appearance and range and it is one of the largest members of the genus Buteo in North America, typically weighing from 690 to 1,600 g and measuring 45–65 cm in length, with a wingspan from 110–145 cm. The red-tailed hawk displays sexual dimorphism in size, with females averaging about 25% heavier than males, the bird is sometimes referred to as the red-tail for short, when the meaning is clear in context. The subspecies Harlans hawk is sometimes considered a separate species, the red-tailed hawk occupies a wide range of habitats and altitudes, including deserts, grasslands, coniferous and deciduous forests, agricultural fields and urban areas. It lives throughout the North American continent, except in areas of unbroken forest or the high arctic and it is legally protected in Canada, Mexico and the United States by the Migratory Bird Treaty Act. Because they are so common and easily trained as capable hunters, falconers are permitted to take only passage hawks so as to not affect the breeding population. Adults, which may be breeding or rearing chicks, may not be taken for falconry purposes, passage red-tailed hawks are also preferred by falconers because these younger birds have not yet developed the adult behaviors which would make them more difficult to train. As is the case with many raptors, the red-tailed hawk displays sexual dimorphism in size, as is typical in large raptors, frequently reported mean body mass for Red-tailed Hawks are somewhat higher than expansive research reveals. The heaviest surveyed weights came from migrants in Cape May, New Jersey, males can reportedly measure 45 to 60 cm in total length, females measuring 48 to 65 cm long. The wingspan can range from 105 to 141 cm and, in the scientific method of measuring wing size. The tail measures 188 to 258.7 mm in length, the exposed culmen was reported to range from 21.7 to 30.2 mm and the tarsus averaged 74. 7–95.8 mm. The middle toe can range from 38.3 to 53.8 mm, Red-tailed hawk plumage can be variable, depending on the subspecies and the region. These color variations are morphs, and are not related to molting, the western North American population, B. j. calurus, is the most variable subspecies and has three color morphs, light, dark, and intermediate or rufus. The dark and intermediate morphs constitute 10–20% of the population, though the markings and hue vary across the subspecies, the basic appearance of the red-tailed hawk is consistent. Overall, this species is blocky and broad in shape, often appearing heavier than other Buteos of similar length, a whitish underbelly with a dark brown band across the belly, formed by horizontal streaks in feather patterning, is present in most color variations. Especially in younger birds, the underside may be covered with dark brown spotting. The red tail, which gives this species its name, is uniformly brick-red above, the bill is short and dark, in the hooked shape characteristic of raptors, and the head can sometimes appear small in size against the thick body frame
