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Affinity (taxonomy)
Affinity (taxonomy) – mainly in life sciences or natural history – refers to resemblance suggesting a common descent, phylogenetic relationship, or type. The term does, however, have broader application, such as in geology (for example, in descriptive and theoretical works), and similarly in astronomy (for example, see " Centaur object" in the context of 2060 Chiron's close affinity with icy comet nuclei."Centaur object." Encyclopædia Britannica. Encyclopædia Britannica 2007 Ultimate Reference Suite . Chicago: Encyclopædia Britannica, 2011.) Basis In taxonomy the basis of any particular type of classification is the ''way in which objects in the domain resemble each other''. A resemblance of a type that seems appropriate to the classification that we propose, we may call an ''affinity'', and when we decide how to classify say, a specimen of rock or butterfly, we justify our decision according to the affinities that we observe. Other resemblances we dismiss as being out ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Life Sciences
This list of life sciences comprises the branches of science that involve the scientific study of life – such as microorganisms, plants, and animals including human beings. This science is one of the two major branches of natural science, the other being physical science, which is concerned with non-living matter. Biology is the overall natural science that studies life, with the other life sciences as its sub-disciplines. Some life sciences focus on a specific type of organism. For example, zoology is the study of animals, while botany is the study of plants. Other life sciences focus on aspects common to all or many life forms, such as anatomy and genetics. Some focus on the micro-scale (e.g. molecular biology, biochemistry) other on larger scales (e.g. cytology, immunology, ethology, pharmacy, ecology). Another major branch of life sciences involves understanding the mindneuroscience. Life sciences discoveries are helpful in improving the quality and standard of life an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solifugae
Solifugae is an order of animals in the class Arachnida known variously as camel spiders, wind scorpions, sun spiders, or solifuges. The order includes more than 1,000 described species in about 147 genera. Despite the common names, they are neither true scorpions (order Scorpiones), nor true spiders (order Araneae). Most species of Solifugae live in dry climates and feed opportunistically on ground-dwelling arthropods and other small animals. The largest species grow to a length of , including legs. A number of urban legends exaggerate the size and speed of the Solifugae, and their potential danger to humans, which is negligible. Anatomy Solifuges are moderately small to large arachnids (a few millimeters to several centimeters in body length), with the larger species reaching in length, including legs. In practice, the respective lengths of the legs of various species differ drastically, so the resulting figures are often misleading. More practical measurements refer prima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxonomy
Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. Among other things, a taxonomy can be used to organize and index knowledge (stored as documents, articles, videos, etc.), such as in the form of a library classification system, or a search engine taxonomy, so that users can more easily find the information they are searching for. Many taxonomies are hierarchies (and thus, have an intrinsic tree structure), but not all are. Originally, taxonomy referred only to the categorisation of organisms or a particular categorisation of organisms. In a wider, more general sense, it may refer to a categorisation of things or concepts, as well as to the principles underlying such a categorisation. Taxonomy organizes taxonomic units known as "taxa" (singular "taxon")." Taxonomy is different from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analogy (biology)
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas ''homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of four-legged vertebrates like dogs and crocodiles are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adapted to different purposes as the result of descent with modification from a common ancestor. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this, from Aristotle onwards, and it was explicitly analysed by Pierre Belon in 1555. In developmental biology, organs that developed in the embryo in the same manner and from similar origins, such as from matc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Banteng
The banteng (''Bos javanicus''; ), also known as tembadau, is a species of cattle found in Southeast Asia. The head-and-body length is between . Wild banteng are typically larger and heavier than their domesticated counterparts, but are otherwise similar in appearance. The banteng shows extensive sexual dimorphism; adult bulls are generally dark brown to black, larger and more sturdily built than adult cows, which are thinner and usually pale brown or chestnut red. There is a big white patch on the rump. Horns are present on both sexes, and are typically long. Three subspecies are generally recognised. Banteng are active during the day as well as at night, though activity at night is more in areas frequented by humans. Herds comprise two to forty individuals, and generally a single bull. Herbivores, banteng feed on vegetation such as grasses, sedges, shoots, leaves, flowers and fruits. Banteng can survive without water for long stretches during droughts, but drink regula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuna
A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max length: , weight: ) up to the Atlantic bluefin tuna (max length: , weight: ), which averages and is believed to live up to 50 years. Tuna, opah and mackerel sharks are the only species of fish that can maintain a body temperature higher than that of the surrounding water. An active and agile predator, the tuna has a sleek, streamlined body, and is among the fastest-swimming pelagic fish – the yellowfin tuna, for example, is capable of speeds of up to . Greatly inflated speeds can be found in early scientific reports and are still widely reported in the popular literature. Found in warm seas, the tuna is commercially fished extensively as a food fish, and is popular as a bluewater game fish. As a result of overfishing, some tuna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porpoise
Porpoises are a group of fully aquatic marine mammals, all of which are classified under the family Phocoenidae, parvorder Odontoceti (toothed whales). Although similar in appearance to dolphins, they are more closely related to narwhals and belugas than to the true dolphins. There are eight extant species of porpoise, all among the smallest of the toothed whales. Porpoises are distinguished from dolphins by their flattened, spade-shaped teeth distinct from the conical teeth of dolphins, and lack of a pronounced beak, although some dolphins (e.g. Hector's dolphin) also lack a pronounced beak. Porpoises, and other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates. Porpoises range in size from the vaquita, at in length and in weight, to the Dall's porpoise, at and . Several species exhibit sexual dimorphism in that the females are larger than males. They have streamlined bodies and two limbs that are modified into flippers. Porpoises use e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lungfish
Lungfish are freshwater vertebrates belonging to the order Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, including the presence of lobed fins with a well-developed internal skeleton. Lungfish represent the closest living relatives of the tetrapods. Today there are only six known species of lungfish, living in Africa, South America, and Australia. The fossil record shows that lungfish were abundant since the Triassic. While vicariance would suggest this represents an ancient distribution limited to the Mesozoic supercontinent Gondwana, the fossil record suggests advanced lungfish had a widespread freshwater distribution and the current distribution of modern lungfish species reflects extinction of many lineages subsequent to the breakup of Pangaea, Gondwana and Laurasia. Lungfish have historically been referred to as salamanderfish, but this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedipalp
Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and anterior to the first pair of walking legs. Overview Pedipalps are composed of six segments or articles: the coxa, the trochanter, the femur, the short patella, the tibia, and the tarsus. In spiders, the coxae frequently have extensions called maxillae or gnathobases, which function as mouth parts with or without some contribution from the coxae of the anterior legs. The limbs themselves may be simple tactile organs outwardly resembling the legs, as in spiders, or chelate weapons ( pincers) of great size, as in scorpions. The pedipalps of Solifugae are covered in setae, but have not been studied in detail. Comparative studies of pedipalpal morphology may suggest that leg-like pedipalps are primitive in arachnids. At present, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalopoda
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles (muscular hydrostats) modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology. Cephalopods became dominant during the Ordovician period, represented by primitive nautiloids. The class now contains two, only distantly related, extant subclasses: Coleoidea, which includes octopuses, squid, and cuttlefish; and Nautiloidea, represented by ''Nautilus'' and '' Allonautilus''. In the Coleoidea, the molluscan shell has been internalized or is absent, whereas in the Nautiloidea, the external shell remains. About 800 living species of cephalopods have been identified ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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