Tuesday, December 17, 2024

How Humans looked 3.8 million years ago while living in trees and the ground: Australopithecus anamensis (afarensis)

 

 Australopithecus anamensis at 3.8 million years ago is considered the direct ancestor of Australopithecus afarensis, which is thought to be an ancestor of the human genus, Homo.  Australopithecus anamensis is thought to have marked a major transition from life in trees to life on the ground.  Australopithecus anamensis had adaptations for habitual bipedalism.

 A 2019 discovery of a nearly complete cranium showed that Australopithecus anamensis differed from Australopithecus afarensis more than previously thought. The cranium also indicated that the two species overlapped in time for at least 100,000 years. Some scientists now propose that Australopithecus anamensis individuals are actually members of Australopithecus afarensis.

 https://humanorigins.si.edu/evidence/human-fossils/species/australopithecus-anamensis

 So the big toe bone still has some flexibility and divergence - showing prehensile grasping ability for tree living. The human big toe bone is used just for "pushing off" the ground and thus does not diverge.

 Neither Chimp foot nor human foot! Fascinating.

 Lucy, reconstructed naked body.

Humans have greater subcutaneous fat layer as a "nutritional buffer" for the brain during food scarcity.

 So Homo Erectus as 12 years old would have more body fat than Australopithecus

 

 the Homo Sapiens population explosion! 

 

 12 to 13 million years ago was the ancestor, Sivapithecus, of the Orangutan, gorilla, chimp and human

 Sexual Dimorphism was still 2 to 1 male to female size difference for Australopithecus

 Brain size small like chimps but hips - the Pelvic Girdle - completely different!!

 But the shoulder joints were vertically aligned and the limbs were longer - like chimps - for tree climbing!! Wow. 

Lucy probably died from falling out of a tree!!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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