Primates is a group that consists of all the species that contains the species related to apes, monkeys and lemurs, with humans also included. There are certain similarities amongst primates which is that they have five fingers is characteristic is called Pentadactyly. For primates to be distinguished fingernails come to use. The number of teeth is reduced in primates and categories are incisors, canines, premolars and molars. Primates teeth enables them to eat a variety of foods and process it efficiently.
Anthropoids generally have larger body size, large brain and more rounded skull. Anthropoids consists of the New World monkeys, Old World monkeys and apes including to humans. Every living primates with humans included they all come from earlier that do not exist anymore, to understand how earlier primates were like fossil records plays a huge role together with anatomical and behavior. When we take a look at one of the features like arboreal existence, this feature enabled primates to climb trees easily and obviously to move from one tree to the other. The second feature is the collarbone which makes possible for primates to move shoulders. Humans does not use the collarbone for arboreal activities like apes, its helps them when they want to throw things and other activities that require the movement of the shoulder. To carry out everyday activities vision is much more important for both primates and anthropoids because they all are diurnal.
Much of the primates evolution is yet to be discovered but there is a quite a lot we know. “In the early Eocene epoch about 55 million years ago there were some primates that already existed. In the following Oligocene that’s when we find the monkey and apelike primates started emerging. Many kinds of apes started appearing in the Miocene about 24 million years ago”. Many studies have shown that the earliest primates appeared in the Paloecene, during this epoch the climate was usually damp and mild, but it started getting cooler at the end of the Cretaceous. The factors that contributed the most in the evolution of primates are climate change and plates shifts, extreme change in climate is not good for both primates and their food. It may result in extinction of both and change of features. New species may have evolved as a result of climate change, these species would have different features to those that became extinct. Plate shift caused primates to be found in different continents and plates collision caused different populations of primates to mix and when they mix it is easy for one population dominate the other which may result in extinction. When we take a look back in change in vegetation the studies show that this resulted in an increase in population of insectivores those that fed on insects because they easily adapted in any conditions including underground, in water, shrubs and trees.
The places where studies show that earliest primates emerged are North America, Europe and Asia 55 million years ago, “The anatomy of the diverse Eocene primates suggests that they already had many of the features of modern primates those features include nails rather than claws, a grasping, opposable first toe and a bony bar around the side of the eye socket”. The two groups of the Prosimians that emerged in the early Eocene are Omomyids and Adapids. Omomyids appeared to be small in terms of body size but what was catchy is that their eyes were large, and this suggest that there more effective and productive at night. Nearly all Omomyids had cheek teeth adapted for insectivorous diet and they had grasping hands as well as nails instead of claws and they were found mostly in trees.
Adapids functioned in an opposite way to Omomyids because they were more active during day light and they had small eyes, their dental of four premolars and fewer incisors makes it obvious that they fed on leaves and fruits vegetation. They had all the characteristics that made it possible to live in forest and to leap form tree to tree with their long legs.
From Eocene epoch followed the Oligocene 33 million years ago where in history we find that anthropoids from the Fayum were grouped in these two types Parapithecids and Propliopithecids that emerged during this epoch. Basically, Parapithecids were more monkey like and they also had so much similarities to modern day anthropoids. When we look at the way they fed they only ate fruits and seeds, they were active during the day their dental suggest that they had three premolars. But even now it is still not clear how did anthropoidal primates originally from Africa get to South America with so much distance estimated to be 3000 km and water in between the two continents. Back then anthropoids were not so intelligent to build boats or any kind of transport that could take them from one place to another. Later in Oligocene anthropoids might have taken an advantage of lower Sea levels and used islands to hop and get to South America. Another route in which they could have taken is from Africa through Europe and North America to their destination South America. But its highly unlikely because North and South America were not joined during this time but also possible. Vegetation is believed to be the main reason that made them migrate and led them to this continent and there is high possibility that parapithecids may somehow New World monkeys ancestors and these monkeys are called platyrrhines. Propliopithecids on the other hand shared with Parapithecids the facial and dental features, they had longer lower incisors and projecting canines. Amongst propliopithecids there was a group called Aegyptopithecids, that moved around in trees quadrupedally especially during the day because they had small eyes. Although skull aspects of aegyptopithecids made it look like an ape but the rest of the body was monkeylike.
Moving from Oligocene to Miocene a huge difference in features of monkeys and apes was noticed, in Africa, Europe and Asia it was time for new different kinds of pes to come to existence. It was clear that climate conditions had so much impact in anthropoid evolution. “In early Miocene the temperatures were considerably warmer than in the Oligocene. But from early to late Miocene, conditions became drier particularly in East Africa. The reasons for this relate again to continental drifts”. Sivapithecids appeared 13 to 8 million years ago in Southern and Western Asia and Dryopithecids emerged 13 million years ago in Europe.
Human ancestor the first human hominid (bipedal primate) is believed to have emerged in Africa 5 million years back, and also fossil evidence proves that hominids originated from East Africa. And Monkey fossil evidence from Miocene is very rare but only small number found in South America. To check the relativeness of primates the use of DNA, molecular change and genetic analysis are one of the few techniques used.