5.03 Primate Evolution

Question 1

Primates:

Answer 1

A mammal of the order Primates, including the anthropoids (monkeys, apes, and humans) and prosimians (lemurs and tarsiers), characterized by refined development of the hands and feet, forward-set eyes and binocular vision, a shortened snout, and a relatively large brain

Question 2

Prosimii and Anthropoidea:

Answer 2

Two suborders of modern-day primates are the Prosimii and Anthropoidea. The prosimians, meaning “pre-monkey,” are believed to closely resemble some of the early primate ancestors. This suborder includes the lemurs of Madagascar and the lorises, pottos, and tarsiers of tropical Africa and southern Asia. The anthropoids include monkeys, apes, and humans. The earliest anthropoid fossils are those of monkey-like primates that probably evolved from prosimian ancestors in Africa around 40 million years ago.

Question 3

New World Monkeys:

Answer 3

Monkeys are divided into two categories, New World monkeys and Old World monkeys, which have been evolving along separate pathways for millions of years. The New World monkeys are found in the Americas. They are small to midsized primates that are arboreal, have prehensile tails, and have flat noses with side-facing nostrils.

Question 4

Old World Monkeys:

Answer 4

The Old World monkeys found in Africa, Europe, and Asia include some arboreal and some ground-dwelling species. They are medium to large primates that have downward-facing nostrils, tails that are not prehensile, and tough seat pads. Old World monkeys include baboons, mandrills, macaques, and rhesus monkeys.

Question 5

Apes:

Answer 5

Four genera of apes exist today: gibbons, orangutans, gorillas, and chimpanzees. They are found in tropical regions of Africa and Asia. With the exception of gibbons, apes are larger than monkeys and have long legs and no tails. Gibbons and orangutans live primarily in trees, while chimpanzees and gorillas are mostly ground dwelling. Apes have larger brains than monkeys, with more adaptable behavior. Gorillas and chimpanzees are both highly social.

Question 6

Humans:

Answer 6

Humans can be categorized as hominids because they belong to the family Hominidae. Hominids walk upright on their hind legs, an adaptation called bipedalism, a feature that separates them from other primates. They also have long hind legs and relatively large brains compared to other primates. This group also includes all the species in the human lineage. Most of the fossils of ancient hominids fall into two major groups: the genus Australopithecus and the genus Homo (in which modern day humans, or Homo sapiens, belong).