10/7/03 2nd hr.

Since the beginning of time, man has evolved through primate evolution. Each primate has acquired different characteristics over a period of millions of years. The ecosystem has experienced an enormous change in this phase. Most major changes have occurred due to the phenomenon of continental drift. Other such factors are deforestation, natural calamities and, more recently, global warming. These changes have caused primates to become less arboreal and more and more terrestrial. In order to survive the pressures of natural selection, terrestrial life and other factors primates have developed more upright locomotion, changes in body configuration, increase in size and loss of hair. Over a period of millions of years, the planet has gone through a number of changes. To adjust to these changes the residents of this planet have also had to adapt. For the time span encompassing vertebrate evolution, there are three eras: the Paleozoic, the Mesozoic and the Cenozoic. The highly successful mammalian adaptive radiation is almost entirely within the most recent era of geological history, the Cenozoic. There are seven epochs in the Cenozoic - Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene and Holocene. In Paleocene (65 m.y.a.), the Lemuroids were the group of primates that existed. The Ruffed Lemur originated in the tropical rainforests of Madagascar. They ate mostly fruits, flowers, and leaves. Lemurs feature a somewhat elongated snout with a slight overlap on their eyes. They are large in size and are adapted to the ground. That ahs made them slower and thus they find it to harder to escape from their predators. They have gaps between their teeth and are extremely loud because of their strong vocal cords. They have muzzled faces, which are pointed with whiskers, and wet noses making them look less like humans. The Coquerel’s Sifaka are another example from this era. They originated from the forests of Northwest Madagascar. They eat mostly leaves, flowers and fruits. They are the second largest lemurs. Sifakas have long legs, which enable them to jump from tree to tree in an upright position. Another primate belonging to this era is the Galago. They are bushed babies varying from cat to rat size. The most striking features of the Galago are its huge eyes, long tail and large hind legs. Brain size is average and their vision and hearing are well adapted to nocturnal insect hunting. Their limbs enable them to make rapid leaps from branch to branch. They claim territory with their scent leaving smelly footprints. The Crowned Lemur, which is also an example of this era, is found in extreme Madagascar. They eat fruits, flowers and leaves. They stay mainly in trees and are active during the day and at dusk. The crowns on their heads are furry head caps. Females have a lighter crown then males do. The second epoch is Eocene (53 m.y.a.). A group of primates called the tarsiers came into existence in this era. They came from Southeast Asia in the tropical forests. Tarsiers usually leap onto their preys from lower branches and shrubs. They classify as prosimians and are related to lemurs and lorises. The similarities are pertaining to their body size, large ears and grooming claws. They have very long toes and fingers and their fingertips seem to be composed of a rubbery and sticky membrane. The Tarsiers also seem to have very large eyes, which dominates manner. Tarsiers seem to have a combination of prosimians and anthropoids due to the similarities from both. The tamarins are another group that existed during the Eocene era and probably one of the last. Tamarins are the most primitive of monkeys. Tamarins are found in the forests of Peru, Bolivia, and northwest Brazil. This is one of the species that is not much larger than a mouse and weighs only 2.5 oz (70 grams) to 2.2 lbs (1000 grams). They have claws instead of nails and usually give birth to twins. Their diet is composed of tree gum and fruit. Their locomotion is quadrupedal. Claws allow them to climb vertical tree trunks. They leap and cling as a form of travel. Tamarins are family oriented and the males are one of the few that participate in infant care. The third grade is the Oligocene (35 million years ago). In