Two of the most distinct features that separate humans from the other great apes are bipedalism and large brain to body size. But how did these features become so prominent? Approximately 6-7million years ago, the hominid lineage began to separate from the other ape species. Tracing the evolutionary history through fossil evidence explains how early hominids evolved to become today’s most prolific primate species. The goal of this paper is to discuss the physical characteristics that indicate the evolution of bipedalism and large brain size in the hominid line. To achieve this I will address the anatomical differences between humans and apes that make bipedalism efficient form of locomotion, the increase of brain size, and which of these
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It is estimated that human brain size has tripled since our ancestors of the Pliocene epoch existed. Why have our brains evolved to be so large and what evolutionary force is behind the increase? According to a paper published in the Journal of Physical Activity and Health, “The first major burst of evolutionary change in hominid brain size occurs at about 2.0 to 1.7 million years ago, associated with the emergence and evolution of early members of the genus Homo. Before this, our earlier hominid ancestors, the australopithecines, showed only modest brain size evolution from 438 to 530 cm' over a 2-million year span, with all the australopithecines having brain sizes comparable to modern apes.” (Leonard). Brain size continued to increase throughout the hominid line, some of the influencing factors, in addition to natural selection, for increased brain size are: bipedalism enabled early hominids to explore new environments, the use of simple tools and manipulation of resources increased cognitive ability, a higher protein diet promoted brain growth, and changing climates required new thinking methods in order to adapt and …show more content…
However, that theory has been discredited with the discoveries of early hominid remains. For example, the 4.4 million year old female Ardipithecus ramidus, nicknamed “Ardi,” indicates an anatomical connection between early hominids and our closest living relative, the chimpanzee. Some of the physical similarities described in an article posted in Discover Magazine are, “the lower part of Ardi's hip was powerfully primitive, adapted for climbing. In contrast, the upper part of the hip, the ilium, was surprisingly broad -- a humanlike adaptation for walking on the ground.”(Niemark). However, based on Ardi’s remains, her brain size is estimated to be approximately 300-350 cubic centimeters. Fossil specimens such as Ardi, prove that bipedalism evolved before increased in brain size in early hominids. Examining the fossil record undoubtedly demonstrates how bipedalism contributed to the advancement of the hominid lineage, including the increase of brain size. Physical adaptations allowed humans to separate from the other great ape species and begin walk upright, which lead to the global expansion of the hominid line. Increased brain size also greatly contributed to hominid success. Simple tool use, ability to manipulate resources, and the search of new environments are just a few behaviors that resulted from the increase in brain size and improved survival and adaption of
It is estimated that human brain size has tripled since our ancestors of the Pliocene epoch existed. Why have our brains evolved to be so large and what evolutionary force is behind the increase? According to a paper published in the Journal of Physical Activity and Health, “The first major burst of evolutionary change in hominid brain size occurs at about 2.0 to 1.7 million years ago, associated with the emergence and evolution of early members of the genus Homo. Before this, our earlier hominid ancestors, the australopithecines, showed only modest brain size evolution from 438 to 530 cm' over a 2-million year span, with all the australopithecines having brain sizes comparable to modern apes.” (Leonard). Brain size continued to increase throughout the hominid line, some of the influencing factors, in addition to natural selection, for increased brain size are: bipedalism enabled early hominids to explore new environments, the use of simple tools and manipulation of resources increased cognitive ability, a higher protein diet promoted brain growth, and changing climates required new thinking methods in order to adapt and …show more content…
However, that theory has been discredited with the discoveries of early hominid remains. For example, the 4.4 million year old female Ardipithecus ramidus, nicknamed “Ardi,” indicates an anatomical connection between early hominids and our closest living relative, the chimpanzee. Some of the physical similarities described in an article posted in Discover Magazine are, “the lower part of Ardi's hip was powerfully primitive, adapted for climbing. In contrast, the upper part of the hip, the ilium, was surprisingly broad -- a humanlike adaptation for walking on the ground.”(Niemark). However, based on Ardi’s remains, her brain size is estimated to be approximately 300-350 cubic centimeters. Fossil specimens such as Ardi, prove that bipedalism evolved before increased in brain size in early hominids. Examining the fossil record undoubtedly demonstrates how bipedalism contributed to the advancement of the hominid lineage, including the increase of brain size. Physical adaptations allowed humans to separate from the other great ape species and begin walk upright, which lead to the global expansion of the hominid line. Increased brain size also greatly contributed to hominid success. Simple tool use, ability to manipulate resources, and the search of new environments are just a few behaviors that resulted from the increase in brain size and improved survival and adaption of