ANT203H5 Lecture Notes - Brachiation, Quadrupedalism, Orangutan
Document Summary
The evolution of primates can be traced back to the late cretaceous/early paleocene. Primates probably evolved from a small, ground-dwelling shrewlike insectivorous mammal. Probably, the earliest primate ancestors looked like the tree shrew depicted below: the tree shrew are the closet relatives to the primates. Recall that there was a mass extinction around 65 mya (dinosaurs disappeared). It was the beginning of an adaptive radiation of placental mammals. Probably, there was a shift in diet from insects to fruits and seeds. This is evident in some fossils from the late cretaceous, such as purgatorius. Plesiadapiforms differ, in many ways, from modern primates, and are classified in a different order (plesiadapiformes) There are evidence where they have characteristics that are primitive. It is believed they have claws, and don"t have oppositable toes (so primitive compared to other primates) This includes a large gap in the diastema (which isn"t found in primates, including early primates)
