Bio Review Notes #93
PRIMATES

Most primate characteristics arose as adaptations to life in trees. These features include grasping hands and feet, opposable thumbs, reliance on vision, expansion of the brain, higher intelligence, increased emphasis on learned behavior, single births, and greatly increased parental care. The group to which we belong, the catarrhines, have protruding noses, reduced tails, and only two premolars in each jaw.

Order Primates: Monkeys, apes, humans, lemurs, tarsiers, and related animals.

Primate characteristics, mostly related to arboreal adaptations (life in the trees):
  • Arboreal locomotion
  • Grasping hands and feet (which wrap around branches)
  • Opposable thumb and/or big toe (wrap around in opposite direction from other digits)
  • Increased freedom of rotation in forearm
  • Increased reliance on vision (including color) and less on smell
  • Binocular, stereoscoptic vision (in depth)
  • Expanded visual centers in brain; more folds in brain surface
  • Visual inspection and manipulation of objects
  • Increased intelligence
  • Greater reliance on learned behavior; juvenile inexperience
  • Longer and more intense parental care
  • Uteri fuse into uterus simplex
Plesiadapoidea or Paromomyiformes: Extinct, archaic primates.

Lemuroidea or Strepsirhini: Lemurs, lorises, and galagos.

Tarsioidea: Tarsius and its extinct relatives.

Platyrrhina: New World monkeys and marmosets, with 3 premolars in each jaw, flat noses, and strong tails that aid in locomotion.

Catarrhina: Old World monkeys, apes (gibbons, orangutan, gorilla, chimpanzee) and humans, with 2 premolars in each jaw, protruding noses (nostrils opening downward), and reduced tails, native to Africa, Asia, and Europe.

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