Evolution Prolonged brain development in Australopithecus afarensis

mha

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A. afarensis still had ape-like brain structure, but longer postnatal brain development, which could be crucial for evolution of humanlike behavior.

Human brains are three times larger, are organized differently, and mature for a longer period of time than those of our closest living relatives, the chimpanzees. Together, these characteristics are important for human cognition and social behavior, but their evolutionary origins remain unclear. To study brain growth and organization in the hominin species Australopithecus afarensis more than 3 million years ago, we scanned eight fossil crania using conventional and synchrotron computed tomography. We inferred key features of brain organization from endocranial imprints and explored the pattern of brain growth by combining new endocranial volume estimates with narrow age at death estimates for two infants. Contrary to previous claims, sulcal imprints reveal an ape-like brain organization and no features derived toward humans. A comparison of infant to adult endocranial volumes indicates protracted brain growth in A. afarensis, likely critical for the evolution of a long period of childhood learning in hominins.

Blog:
https://www.science20.com/news_staf...ionyear_old_lucy_species_just_revealed-246864

Article:
https://advances.sciencemag.org/content/6/14/eaaz4729
 
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