=Primates= [image:] Primates are a group including '''prosimians, monkeys''', and '''apes'''. They are of particular interest because they provide insights into our ancestry. Humans actually belong to the African apes with whom we share many features. Get used to it – we are apes! While none of today’s primates are our direct ancestors, we share a common evolutionary ancestor. By comparing the differences found between the different primate groups, we gain a little insight into some of the possible characteristics of our now long extinct ancestors. ==Primate Features== [image:] Primates are a group that branched off from other mammals over 65 million years ago. Primates evolved from mammals that had begun to occupy a three-dimensional world within the trees. This selected for certain characteristics. The ancestors of primates probably had the sense of smell as a dominant sense. However, among the upper trees the ability to distinguish ripe fruit, fresh leaves, predators and a safe hand-hold placed a greater importance on vision. Catching a branch also requires the ability to judge distance and this can be accomplished by having two forward facing eyes, with overlapping (binocular) vision. Swinging through the branches also selected for greater joint mobility, nails, sensitive pads and an opposable thumb for grasping and feeling the pressure of your grip. It also became an advantage to be able to rest, sitting in an upright position. Their arboreal (tree dwelling) habitat ultimately caused primates to evolve the following features. [image:] '''Primate Skeleton''': *Forward facing orbits(eye-sockets)for '''binocular/3D vision''' *Grasping hands and feet that show a '''pentadactyl''' pattern (five digits) * Plantigrade posture (flat feet) * Long, mobile limbs (Increased wrist, hip and shoulder mobility) * Large clavicle (collar bone) for increased shoulder mobility * Prognathism (snout) reduced when compared to other mammals * Tail retained for balance * Bony ridges to protect larger eyes '''General Features''': *Arboreal (tree dwelling) *Large eyes & brain *Quadrupedal locomotion (walked on four limbs) '''Vision''': *Large eyes *3D / binocular vision *Colour vision (most other mammals are red-green colour blind) * Greater vision acuity (detail) '''Brain''': *Primates have large brains for their relative size when compared with other mammals. To avoid falling out of the trees, an animal must be able to process information from the eyes, balance organs and skin very rapidly. Equally rapidly, it must be able to send out appropriate information to the muscles. '''Reproduction & Parental Care''': *Primates invest considerable energy into the care of their young, more than any other mammal. Single young are usual in monkeys and apes, and considerable energy is invested after the birth to allow further development. '''Posture''': *Nearly all primates rest sitting upright, enabling them to turn their heads without losing their balance. This makes it easier for them to look over their shoulder, something that is necessitated by their forward facing eyes . '''Social Life''': *All monkeys and apes (except the orangutan) live in cooperative social structures / hierarchies. This has advantages in terms of detecting and defending against predators, finding food and avoiding inbreeding. It also allows for individuals to begin learning from each other. '''Skin''': *Nails instead of claws on most digits, sensitive finger pads (to register the pressure of their grip) *Skin on the tips of the digits have ridges, increasing sensitivity to touch