Brain Expansion in Early Members of the Homo Genus
Loading...
Authors
Sparber, Melonie
Issue Date
2008
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Approximately 5-6 million years ago (MY A) the hominid lineage split from that our
closest relative, the chimpanzee. For the next 3-4 million years, the cranial capacity of the
hominid brain (which was not much larger than that of a chimpanzee), and hominid
technological innovation, both remained relatively static. At the end of the Pliocene Epoch (--2.4
MYA), Africa became significantly more arid, spurring significantly extinction and speciation
events, including among several hominid species. By 1.9 MYA the Homo genus had emerged,
and with it significant brain expansion began. Based on evidence from the fossil record and
comparative studies between the anatomies of modem humans and chimpanzees, this significant
brain expansion was possible due to changes in the hominid diet that accompanied the
emergence of the Homo genus. These changes involved a shift from a diet primarily based on
plant food sources, to a more high quality diet that included meat and fish. This shift was
necessary due to the high metabolic and nutritionally costs associated with having a large brain.
Changes in the anatomical structure of hominids, such as modifications to the skeletal and
muscle structure, large fat deposits in hominid infants, and strengthened mirror neuron networks,
as well as technological innovations, such as the emergence of tool use and cooking, all may
have enhanced hominids access to energy and nutrient rich foods. In addition, climate change at
the end of the Pliocene Epoch, and aquatic environments may also have affected hominids in
ways allowing them greater access to high energy and nutrient rich food sources.
Description
vi, 44 p.
Citation
Publisher
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder. All rights reserved.