Evolution of Primates & Patterns in Primate Evolution

A detailed of the evolution of primates , beginning in the Paleocene (60 million years ago ) to present day

Introduction

The hierarchical groups-within-groups Linnaean classification pattern is a result of both

the extinction of certain species and sub-species and the branching of new forms from a

common ancestor as new ecological niches arose . The evidence that humans and other primates evolved from non-human and non primate species is at least as strong as the evidence of descent is in other groups of living creatures . The fossil records found in rocks of

various ages show that in the earliest , the Azoic or no life period there were no life forms These began to appear during the Archaeozoic period , gradually developed during the Proterozoic and Paleozoic periods . The Mesozoic age brought forth the reptiles and only after this , in the Cenozoic age did the first mammals appear . It was in the Paleozoic age that some of the biggest changes occurred with many new complex life forms appearing However the records also show at least 6 periods when major extinctions took place , each coinciding with the end of a particular era , At the end of the Mesozoic period some 76 of species wiped out and similar things occurred at the end of the Triassic period , the Permian , in the late Devonian period and the same with the Ordovician and the Cambrian periods . The result was a positive one for the relatively few species which survived as they were then able to expand into new ecological niches created by what is sometimes referred to as a biological vacuum This process of moving into new niches is called adaptive radiation . The best known example occurred after the extinction of the dinosaurs some 65 and a half million years ago , which made room for the rapid expansion of placental mammals Chart of the Emergence of Various Life forms taken from `How Old is Old

Primate origins

Primates then made a relatively late debut into the world . They are of course the ancestors of all modern humans and if there is a desire to understand humanity then the study of other primates must play its part . Of all the species that have lived on earth most were already extinct before the first primates made their debut . Scientists believe the world to have been in existence for some 4 .55 billion years and can date the earliest life forms to at least 3 .5 billion years ago or even earlier the primates date only from about 60 million years ago , a small fraction of the time . However even such vague dating as this remains uncertain . Following fieldwork in China for instance in 1994 ,mentioned in an article entitled `Asian link proposed for primate evolution ' a large number of fossil fragments were discovered the article describing the finds includes these words :-

Early simians may have originated more than 65 million years ago , Martin concludes . But Simons disagrees , noting that the oldest well-established

higher primates lived about 40 million...