The First Hominins and the Origins of Bipedalism

Abstract

Molecular and paleontological evidence now point to the last common ancestor between chimpanzees and modern humans living between five and seven million years ago. Any species considered to be more closely related to humans than chimpanzees we call hominins. Traditionally, early hominins have been conspicuous by their absence in the fossil record, but discoveries in the last 20 years have finally provided us with a number of very important finds. We currently have three described genera, Ardipithecus, Orrorin and Sahelanthropus, of which Ardipithecus is extremely well represented by cranial, dental, and postcranial remains. All three genera are argued to be hominins based on reduced canine size and an increased capacity for bipedal locomotion. The evolutionary relationships between these taxa and both earlier hominoids and later hominins are somewhat disputed, but this is to be expected for any species thought to be close to the root of the hominin lineage.

Risk perception and terrestriality in primates: A quasi‐experiment through habituation of chacma baboons (Papio ursinus) in Gorongosa National Park, Mozambique

“…Modern humans are unique among primates in both their obligate terrestriality and bipedalism. There has been more focus on the evolution of bipedality than terrestriality in our lineage, but their origins are not necessarily linked (Harcourt‐Smith, 2010; Richmond et al, 2001).…”

Age constraints for the Trachilos footprints from Crete

“…The evolutionary history and dispersal patterns of hominins are matters of debate 1 . One unresolved aspect is the origin and identification of the first representatives of the hominin lineage 2 . Despite numerous publications suggesting an origin in Africa e.g., 2 – 5 , there are evidences that the earliest hominins might have evolved in Eurasia 6 , 7 .…”

“…One unresolved aspect is the origin and identification of the first representatives of the hominin lineage 2 . Despite numerous publications suggesting an origin in Africa e.g., 2 – 5 , there are evidences that the earliest hominins might have evolved in Eurasia 6 , 7 . Evidence for a Miocene hominin presence in Europe includes both body and trace fossils.…”

Thinking, Walking, Talking: Integratory Motor and Cognitive Brain Function

“…It is characteristically human (even though birds on the ground, some mammals, and primates possess that function as well); thus, humans are dedicated to this mode of locomotion. Birds have a larger encephalization index than do their reptile cousins, with that difference being explainable, in part, by bipedalism ( 1 ). Bipedalism in humans is both constant and employs an upright spine, unlike other organisms with that skill.…”