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Rodent Evolution

The order Rodentia consists of small, terrestrial mammals with a specialized gnawing apparatus and a high rate of reproduction. Throughout the course of their evolution, these omnivores have experienced remarkable adaptive success. On the basis of jaw and jaw muscle morphology, the order is typically subdivided into the Myomorpha, the Hystricomorpha, and the Sciuromorpha suborders, among others. The evolutionary history of the rodents can be traced back to the emergence of the mammals. During the Triassic, the therapsid reptiles evolved the mammalian anatomical structure. It wasn't until the Eocene, however, that the rodents arose. The origin of Rodentia is primarily based on the acquisition of the following masticatory apparatus specializations: (1) specializations of the incisors; (2) cheek teeth; and (3) the associated musculoskeletal features needed for gnawing. Two hypotheses have been advanced for Rodentia origins. One, the primate hypothesis, suggests that the animals are derived from a primitive Paleocene primate. In contrast, the palaeoryctoid or eurymyloid hypothesis attempts to describe evolutionary relationships by comparing various physical attributes. Once rodents emerged, they rapidly radiated. Unfortunately though, instances of parallel and convergent evolution make Rodentia subordinal classification very difficult. For instance, it has even been suggested that the different rodent types actually represent grade levels of organization rather than monophyletic groupings. Clearly, more research is needed to further delineate Rodentia evolutionary relationships.

Rodents are an important order of the class Mammalia. These animals are, for the most part, small, terrestrial organisms with a highly developed gnawing ability and a high rate of reproduction. The rodents as a group have generally specialized for different trophic strategies. Many rodents are omnivores. However, in temperate grasslands, for ...

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Rodent Evolution. (1969, December 31). In LotsofEssays.com. Retrieved 09:56, March 29, 2024, from https://www.lotsofessays.com/viewpaper/1682574.html