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Phylogenetic Bracketing
Phylogenetic bracketing is a method of inference used in biological sciences. It is used to infer the likelihood of unknown traits in organisms based on their position in a phylogenetic tree. One of the main applications of phylogenetic bracketing is on extinct organisms, known only from fossils, going back to the last universal common ancestor (LUCA). The method is often used for understanding traits that do not fossilize well, such as soft tissue anatomy, physiology and behaviour. By considering the closest and second-closest well-known (usually extant) organisms, traits can be asserted with a fair degree of certainty, though the method is extremely sensitive to problems from convergent evolution. Method Extant Phylogenetic Bracketing requires that the species forming the brackets be extant. More general forms of phylogenetic bracketing do not require this and may use a mix of extant and extinct taxa to form the bracket. These more generalized forms of phylogenetic bracketing hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inference
Inferences are steps in logical reasoning, moving from premises to logical consequences; etymologically, the word '' infer'' means to "carry forward". Inference is theoretically traditionally divided into deduction and induction, a distinction that in Europe dates at least to Aristotle (300s BC). Deduction is inference deriving logical conclusions from premises known or assumed to be true, with the laws of valid inference being studied in logic. Induction is inference from particular evidence to a universal conclusion. A third type of inference is sometimes distinguished, notably by Charles Sanders Peirce, contradistinguishing abduction from induction. Various fields study how inference is done in practice. Human inference (i.e. how humans draw conclusions) is traditionally studied within the fields of logic, argumentation studies, and cognitive psychology; artificial intelligence researchers develop automated inference systems to emulate human inference. Statist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hair
Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and fine vellus hair. Most common interest in hair is focused on hair growth, hair types, and hair care, but hair is also an important biomaterial primarily composed of protein, notably alpha-keratin. Attitudes towards different forms of hair, such as hairstyles and hair removal, vary widely across different cultures and historical periods, but it is often used to indicate a person's personal beliefs or social position, such as their age, gender, or religion. Overview Meaning The word "hair" usually refers to two distinct structures: #the part beneath the skin, called the hair follicle, or, when pulled from the skin, the bulb or root. This organ is located in the dermis and maintains stem cells, which not only re-grow the hair afte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithorhynchidae
The Ornithorhynchidae are one of the two extant families in the order Monotremata, and contain the platypus and its extinct relatives. The other family is the Tachyglossidae, or echidnas. Within the Ornithorhynchidae are the main Cenozoic genera '' Ornithorhynchus'' and '' Obdurodon'', and several potential stem-genera dating back to the Late Cretaceous, of which the oldest is possibly '' Dharragarra''. Although fossil evidence suggests the presence of ornithorhynchids in the Cretaceous, phylogenetic evidence has largely found that they and the Tachyglossidae only diverged during the Cenozoic, although this varies based on the specific constraints used. Taxonomy The following species are known: *Family Ornithorhynchidae **Genus '' Ornithorhynchus'' (Pliocene to present) ***'' Ornithorhynchus anatinus'' (the modern platypus) **Genus †'' Obdurodon'' (Oligocene to Miocene) ***†'' Obdurodon dicksoni'' ***†'' Obdurodon insignis'' ***†'' Obdurodon tharalkooschild'' **Genu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cimolomyidae
Cimolomyidae is a family of fossil mammala within the extinct order Multituberculata. Representatives are known from the Late Cretaceous of North America and Mongolia, from the late Santonian to their extinction at the end of the Maastrichtian. The family is part of the suborder Cimolodonta. Other than that, their systematic relationships are hard to define. Some authors have placed the taxon within Taeniolabidoidea. Kielan-Jaworowska and Hurum (2001) expressly don't. The family Cimolomyidae was named by Othniel Charles Marsh in 1889. It contains the following genera: * '' Cimolomys'' * '' Buginbaatar'' * '' Essonodon'' * '' Meniscoessus'' * ?'' Parikimys'' * ?'' Paressonodon'' Notes References * Marsh (1889), "Discovery of Cretaceous Mammalia. Part II". ''Am. J. Sci.'' 3, 38, p. 81-92. * Kielan-Jaworowska Z & Hurum JH (2001), "Phylogeny and Systematics of multituberculate mammals". ''Paleontology'' 44'', p. 389-429. * Much of this information has been derived fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eobaataridae
Eobaataridae is a family of fossil mammals within the order Multituberculata. Remains are known from the Lower Cretaceous of Europe and Asia. They are among the most derived representatives of the informal suborder "Plagiaulacida", and closely related to Cimolodonta. Most eobaatarids are only known from isolated teeth, though several reasonably complete members are known, including '' Sinobaatar'' and '' Jeholbaatar''. The body of ''Sinobaatar'' is generalised, while ''Jeholbaatar'' displays clear adaptations for scansoriality (climbing) due to its elongated digits. Due to the morphology of the cheek teeth, '' Eobaatar'' and ''Jeholbaatar'' are inferred to be omnivorous, likely feeding on plants and invertebrates. '' Indobaatar'' from the Early Jurassic Kota Formation has been suggested to be the earliest known multituberculate, let alone the earliest eobaatarid, and may stretch the eobaatarid-cimolodontan group much earlier than previously thought. However its referral to the fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multituberculata
Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct Order (biology), order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, and reached a peak diversity during the Late Cretaceous and Paleocene. They eventually declined from the mid-Paleocene onwards, disappearing from the known fossil record in the late Eocene. They are the most diverse order of Mesozoic mammals with more than 200 species known, ranging from mouse-sized to beaver-sized. These species occupied a diversity of ecological niches, ranging from burrow-dwelling to squirrel-like arborealism to jerboa-like hoppers. Multituberculates are usually placed as Crown group, crown mammals outside either of the two main groups of living mammals, Theria — placentals and marsupials — and Monotremata,Agustí-Antón 2002, pp 3-4 but usually as closer to Theria than to monotremes. They are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammalia
A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors diverged in the Carboniferous Period over 300 million years ago. Around 6,640 extant species of mammals have been described and divided into 27 orders. The study of mammals is called mammalogy. The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, moles and shrews). The next three are the primates (including humans, monkeys and lemurs), the even-toed ungulates (including pigs, camels, and whales), and the Carnivora (including cats, dogs, and seals). Mammals are the only living members of Synapsida; this clade, together with Sauropsida (reptiles and birds), constitut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kryptobaatar
''Kryptobaatar'', also known as ''Gobibaatar'' or ''Tugrigbaatar'', is an extinct mammalian genus dating from the Upper Cretaceous Period and identified in Central Asia. This animal was a member of the extinct order of Multituberculata within the suborder Cimolodonta, and was a member of the family Djadochtatheriidae. It lived contemporaneously with some of the dinosaurs. Its skull had a length of perhaps 3 cm. The generic name ''Kryptobaatar'' is derived from Greek : ''kruptós'', "hidden," (alludes to the ventral position of infraorbital foramen) and Mongolian : ''baatar'', "hero" (alludes to the name of the capital of Mongolia, Ulan Baatar). The specific name ''dashzevegi'' is named in honour of Mongolian palaeontologist Demberelyin Dashzeveg. The derivation of its synonym ''Gobibaatar parvus'' is Gobi (occurring in the Gobi Desert, Mongolia) and baatar ("a hero", the same as ''Kryptobaatar''). Another synonym ''Tugrigbaatar saichanensis'' is a generic name derived from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sauropoda
Sauropoda (), whose members are known as sauropods (; from ''wikt:sauro-, sauro-'' + ''wikt:-pod, -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their body), and four thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land. Well-known genus, genera include ''Apatosaurus'', ''Argentinosaurus'', ''Alamosaurus'', ''Brachiosaurus'', ''Camarasaurus'', ''Diplodocus,'' and ''Mamenchisaurus''. The oldest known unequivocal sauropod dinosaurs are known from the Early Jurassic. ''Isanosaurus'' and ''Antetonitrus'' were originally described as Triassic sauropods, but their age, and in the case of ''Antetonitrus'' also its sauropod status, were subsequently questioned. Sauropod-like sauropodomorph tracks from the Fleming Fjord Formation (Greenland) might, however, indicate the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Warm-blooded
Warm-blooded is a term referring to animal species whose bodies maintain a temperature higher than that of their environment. In particular, homeothermic species (including birds and mammals) maintain a stable body temperature by regulating metabolic processes. Other species have various degrees of thermoregulation. Because there are more than two categories of temperature control utilized by animals, the terms ''warm-blooded'' and '' cold-blooded'' have been deprecated in the scientific field. Terminology In general, warm-bloodedness refers to three separate categories of thermoregulation. * Endothermy is the ability of some creatures to control their body temperatures through internal means such as muscle shivering or increasing their metabolism. The opposite of endothermy is ectothermy. * Homeothermy maintains a stable internal body temperature regardless of external influence and temperatures. The stable internal temperature is often higher than the immediate environme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
