ARCH 131 Lecture Notes - Lecture 7: Oligocene, Adaptive Radiation, Omomyidae

• School: Simon Fraser University
• Department: Archaeology
• Course: ARCH 131
• Professor: Dennis Sandgathe

Document Summary

Adaptive radiation: rapid speciation of one or more species to fill different ecological niches usually follows a major change in environmental circumstances e. g. continental drift. Divergent evolution: typical course of natural selection in which related species adapting to different ecological niches slowly diverge from each other in form. Homologies or homologous traits: traits shared by different species due to common ancestry e. g. milk glands in mammals. Parallel evolution: independent evolution of a similar trait(s) in different species, but starting from a similar ancestor. Especially very large brains in humans and dolphins. Convergent evolution: different species which have very different evolutionary ancestral lines evolve similar adaptations e. g. wings and flight in birds, bats and insects, complex eyes in vertebrates and mollusks. Analogies or analogous traits: similar traits shared by different species that resulted from convergent evolutions. Since the late cretaceous (100 to 65mya) and throughout the cenozoic (the last 65mya) there have been five major stages in primate evolution.