Summary
All primate species possess adaptations for climbing trees, as they all probably descended from tree-dwellers, although not all species are arboreal. Other characteristics of primates are brains that are larger than those of other mammals, claws that have been modified into flattened nails, typically only one young per pregnancy, stereoscopic vision, and a trend toward holding the body upright. Primates are divided into two groups: prosimians and anthropoids. Monkeys evolved from prosimians during the Oligocene Epoch. Apes evolved from catarrhines in Africa during the Miocene Epoch.
Apes are divided into the lesser apes and the greater apes. Hominins include those groups that gave rise to our species, such as Australopithecus and H. erectus, and those groups that can be considered “cousins” of humans, such as Neanderthals. Fossil evidence shows that hominins at the time of Australopithecus were walking upright, the first evidence of bipedal hominins. A number of species, sometimes called archaic H. sapiens, evolved from H. erectus approximately 500,000 years ago. There is considerable debate about the origins of anatomically modern humans or H. sapiens sapiens.
Glossary
anthropoid
monkeys, apes, and humans
Australopithecus
genus of hominins that evolved in eastern Africa approximately 4 million years ago
brachiation
movement through trees branches via suspension from the arms
Catarrhini
clade of Old World monkeys
Gorilla
genus of gorillas
hominin
species that are more closely related to humans than chimpanzees
hominoid
pertaining to great apes and humans
Homo
genus of humans
Homo sapiens sapiens
anatomically modern humans
Hylobatidae
family of gibbons
Pan
genus of chimpanzees and bonobos
Platyrrhini
clade of New World monkeys
Plesiadapis
oldest known primate-like mammal
Pongo
genus of orangutans
Primates
order of lemurs, tarsiers, monkeys, apes, and humans
prognathic jaw
long jaw
prosimian
division of primates that includes bush babies of Africa, lemurs of Madagascar, and lorises, pottos, and tarsiers of Southeast Asia
stereoscopic vision
two overlapping fields of vision from the eyes that produces depth perception