Morphology in biology is the study of the form and structure of organisms and their specific structural features.
15-409: Euarchontoglires (from: Euarchonta ("true rulers") + Glires ("dormice")), synonymous with Supraprimates , is a clade and a superorder of mammals , the living members of which belong to one of the five following groups: rodents , lagomorphs , treeshrews , primates , and colugos . The Euarchontoglires clade is based on DNA sequence analyses and retrotransposon markers that combine
30-647: A vermiform appendix , this feature evolved as a result of convergent evolution . Euarchontoglires probably split from the Boreoeutheria magnorder about 85 to 95 million years ago, during the Cretaceous , and developed in the Laurasian island group that would later become Europe . This hypothesis is supported by molecular evidence; so far, the earliest known fossils date to the early Paleocene . The combined clade of Euarchontoglires and Laurasiatheria
45-509: A famous debate , which is said to exemplify the two major deviations in biological thinking at the time – whether animal structure was due to function or evolution. Most taxa differ morphologically from other taxa. Typically, closely related taxa differ much less than more distantly related ones, but there are exceptions to this. Cryptic species are species which look very similar, or perhaps even outwardly identical, but are reproductively isolated. Conversely, sometimes unrelated taxa acquire
60-529: A similar appearance as a result of convergent evolution or even mimicry . In addition, there can be morphological differences within a species, such as in Apoica flavissima where queens are significantly smaller than workers. A further problem with relying on morphological data is that what may appear morphologically to be two distinct species may in fact be shown by DNA analysis to be a single species. The significance of these differences can be examined through
75-544: Is recognized as Boreoeutheria . The hypothesized relationship among the Euarchontoglires is as follows: Laurasiatheria Lagomorpha ( rabbits , hares , pikas ) [REDACTED] Rodentia (rodents) [REDACTED] Scandentia ( treeshrews or banxrings) [REDACTED] Dermoptera (colugos) [REDACTED] Primates [REDACTED] One study based on DNA analysis suggests that Scandentia and Primates are sister clades, but does not discuss
90-716: The morphology -based Archonta should be trimmed down to exclude Chiroptera . Further DNA sequence analyses supported the Euarchonta hypothesis. Despite multiple papers pointing out that some mitochondrial sequences showed unusual properties (particularly murid rodents and hedgehogs) and were likely distorting the overall tree, and despite earlier studies showing near total congruence of mtDNA-based and nuclear-based trees when such sequences were excluded, some authors continued to produce misleading trees. A study investigating retrotransposon presence/absence data has claimed strong support for Euarchonta. Some interpretations of
105-467: The ancestral Euarchontoglires. [REDACTED] Euarchonta The Euarchonta are a proposed grandorder of mammals : the order Scandentia (treeshrews), and its sister Primatomorpha mirorder, containing the Dermoptera or colugos and the primates ( Plesiadapiformes and descendants). The term "Euarchonta" (meaning "true rulers") appeared in 1999, when molecular evidence suggested that
120-632: The clades Glires (Rodentia + Lagomorpha) and Euarchonta (Scandentia + Primates + Dermoptera). It is usually discussed without a taxonomic rank but has been called a cohort, magnorder, or superorder. Relations among the four cohorts (Euarchontoglires, Xenarthra , Laurasiatheria , Afrotheria ) and the identity of the placental root remain controversial. So far, few, if any, distinctive anatomical features have been recognized that support Euarchontoglires; nor does any strong evidence from anatomy support alternative hypotheses. Although both Euarchontoglires and diprotodont marsupials are documented to possess
135-616: The early Paleocene , 65 million years ago, but one study claims it to be a non-placental eutherian. Although it is known that Scandentia is one of the most basal clades of Euarchontoglires, the exact phylogenetic position is not yet considered resolved, and it may be a sister of Glires, Primatomorpha or Dermoptera or to all other Euarchontoglires. Lagomorpha (rabbits, hares, pikas) Rodentia (rodents) Scandentia (treeshrews) Dermoptera (colugos) Primates († Plesiadapiformes , Strepsirrhini , Haplorrhini ) [REDACTED] Morphology (biology) This includes aspects of
150-453: The four eutherian clades. The current hypothesis, based on molecular clock evidence, suggests that the Euarchonta arose in the late Cretaceous period, about 88 million years ago, and diverged 86.2 million years ago into the groups of tree shrews and Primatomorpha. The latter diverged prior to 79.6 million years into the orders of Primates and colugos. The earliest fossil species often ascribed to Euarchonta ( Purgatorius coracis ) dates to
165-552: The molecular data link Primates and Dermoptera in a clade ( mirorder ) known as Primatomorpha , which is the sister of Scandentia . In some, the Dermoptera are a member of the primates rather than a sister group. Other interpretations link the Dermoptera and Scandentia together in a group called Sundatheria as the sister group of the primates. Euarchonta and Glires together form the Euarchontoglires , one of
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#1732779559094180-465: The outward appearance (shape, structure, color, pattern, size), i.e. external morphology (or eidonomy ), as well as the form and structure of internal parts like bones and organs , i.e. internal morphology (or anatomy ). This is in contrast to physiology , which deals primarily with function. Morphology is a branch of life science dealing with the study of the gross structure of an organism or taxon and its component parts. The etymology of
195-464: The position of Dermoptera. Although it is known that Scandentia is one of the most basal Euarchontoglires clades, the exact phylogenetic position is not yet considered resolved, and it may be a sister of Glires, Primatomorpha or Dermoptera or to all other Euarchontoglires. Some old studies place Scandentia as sister of the Glires, invalidating Euarchonta. Whole-genome duplication may have taken place in
210-576: The use of allometric engineering in which one or both species are manipulated to phenocopy the other species. A step relevant to the evaluation of morphology between traits/features within species, includes an assessment of the terms: homology and homoplasy . Homology between features indicates that those features have been derived from a common ancestor. Alternatively, homoplasy between features describes those that can resemble each other, but derive independently via parallel or convergent evolution . The invention and development of microscopy enabled
225-774: The word "morphology" is from the Ancient Greek μορφή ( morphḗ ), meaning "form", and λόγος ( lógos ), meaning "word, study, research". While the concept of form in biology, opposed to function , dates back to Aristotle (see Aristotle's biology ), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Friedrich Burdach (1800). Among other important theorists of morphology are Lorenz Oken , Georges Cuvier , Étienne Geoffroy Saint-Hilaire , Richard Owen , Carl Gegenbaur and Ernst Haeckel . In 1830, Cuvier and Saint-Hilaire engaged in
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