The evolutionary history of simian primates is traced from the divergence of New World and Old World groups to the emergence of the genus Homo. Key developments include the advent of bipedalism, the use of tools, and the speciation of great apes and early hominids. Fossil evidence like Australopithecus afarensis and Homo erectus sheds light on these transformative epochs in primate and human evolution.
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Simian primates diverged into two infraorders, Platyrrhini and Catarrhini, which include New World and Old World monkeys, apes, and humans
Loss of tapetum lucidum
The divergence of simian primates is associated with the loss of the tapetum lucidum, an eye layer aiding nocturnal vision
Development of color vision
The development of color vision is a key adaptation to a diurnal lifestyle in simian primates
The ancestors of New World monkeys are believed to have colonized South America through a dispersal event, possibly by rafting on mats of vegetation or via a land bridge
The Catarrhini infraorder split into the superfamilies Cercopithecoidea (Old World monkeys) and Hominoidea (apes, including humans)
Emergence of trichromatic color vision
The split between Old World monkeys and apes was marked by the emergence of trichromatic color vision in some lineages
Reduction of the vomeronasal organ
The vomeronasal organ, involved in pheromone detection, was reduced in the evolution of Old World monkeys and apes
The genus Proconsul, displaying a combination of monkey and ape traits, is considered a potential common ancestor to both groups
The family Hominidae, encompassing the great apes, diverged from the lesser apes (gibbons) and the subfamily Homininae separated from the lineage leading to orangutans
Repositioning of the larynx
The larynx began to reposition lower in the throat in the evolution of the tribe Hominini, important for complex vocalization
Emergence of early hominin genera
Genera such as Ouranopithecus and Sahelanthropus provide insight into the evolution of early hominins
Fossil evidence, such as Ardipithecus, suggests a transitional stage in the evolution of walking on two legs in early hominins
Australopithecus afarensis, known for the Laetoli footprints, provides evidence of bipedalism in early hominins
Transitional species
Homo habilis represents a transitional stage between Australopithecus afarensis and Homo erectus
Dispersal out of Africa
The discovery of stone tools in China suggests an early dispersal of hominins out of Africa
Homo erectus is notable for its control of fire, increased brain size, and spread throughout Eurasia
00
Simian primates split into two infraorders: ______, found in South and Central America, and ______, which includes species from Africa and Asia.
Platyrrhini
Catarrhini
01
The evolutionary divergence of simian primates led to adaptations for daytime living, including the loss of the ______ and the development of ______.
tapetum lucidum
color vision
02
The ancestors of ______ may have reached South America by rafting on vegetation or via a land bridge, while ______ evolved in Africa.
New World monkeys
Old World simians
