The appearance of modern humans has changed greatly over the 2 million years or so after evolving from the Australopithecines and the appearance of Homo habilis who was the first human ancestor to fall under the homo genus and lived about 2.4 million years ago. Homo Erectus followed living between 1.3 to 1.8 million years ago. Homo erectus fossils have been found in Africa, China, India and Java. here was a cranium found in Bodo, Africa in 1976, the Peking man found in China.
Although they lived in varying environments the Homo Erectus had a number of universal traits. They were about 5.5- 6 ft. tall with postcranial bones, spine and rib cage that looked similar to modern humans. They almost had the same capacity for intelligence because their brain growth was almost finished at 909 cm.
According to paleoanthropologists there are three ways that modern humans developed. They are the Out of Africa theory, The Multi-regional hypothesis or the Molecular Evolutionary Theories. The Out of Africa Theory contends that humans evolved in Africa from the hominoid that did not leave during the first sojourn from Africa. Then when Homo Sapiens Sapiens had evolved into being modern humans they left Africa and replaced the Homo ancestors that had left before. The Multi-regional theory is that earlier hominids such as Homo ergaster and Homo heidelbergensis left Africa and evolved into modern humans in various locations. This theory takes into consideration how adapting to different regions can account for small variations. The Molecular Evolutionary Theory is the idea that through the mitochondrial DNA all maternal lines can be traced back to one female (mitochondrial Eve). While it is not believed that Eve was the only woman to procreate, hers would be the only line to survive into modern times. This theory has also been applied to men through Y-Chromosome Adam.
Reference
Jurmain, Robert, Lynn Kilgore, and Wenda Trevathan. Essentials Of Physical Anthropology. Print.
