ADAPTING TO THE CHANGING ENVIRONMENT: Bipedalism
Bipedalism- the condition of being two-footed or of using two feet for standing and walking.
The hominoid apes flourished at the very beginning of the Miocene epoch, when lush tropical rain forests were the predominant habitat. In the Opinion of many Anthropologists, bipedalism was adaptive for life amid the tall grasses of the savannas.
Baboons and some other old World monkeys also live in savanna- type environments, yet although they can, and do occasionally, stand erect, they have not evolved fully bipedal locomotion.
Other theories stress the importance of freeing the hands. If some hand activity is critical while an animal is moving; selection may favor bipedalism because it frees the hands for other activities at the same time. What hand activities might have been so critical?
One suggestion is that carrying food in the hands may have been increasingly important, particularly if the prehominids were scavenging or hunting meat.
Jane Goodall has seen chimpanzees:
"loading their arms with choices of wild fruits, then walking erect for several yards to a spot of shade before sitting down to eat." " and if they could use a stone or a stick they might easily double their food supply."
Prehominids use some tools in order to chopped, crushed and butcher animal for food. Their teeth and jaws are not sharp an strong enough.
Other consequences of Bipedalism and Tool making:
-Enlargement of the brain
-Division of labor between men and women
The human pelvis is primarily adapted for upright, two-legged waling and running, it also favored the widening of the female pelvis to allow larger- brained babies to be born.
Other effect of bipedalism:
More efficient tool making
more efficient hunting to develop
- There are definite archeological signs that early hominids were hunting or scavenging animals at least as far back as Lower Pleistocene times (12,000 B.C.)
Raymond Dart's Taung Child
-Erect bipedal hominid existed int he Pliocene epocj (2-3 M years ago) -By the teeth he identified the fossil as the remains of a five-year-old child.
Australopithecus Africanus- "southern ape of Africa" more recent fossils found in both East and South Africa confirms that the Australopithecines were definitely bipedal as old as 3.75 million years.
- The brain ease is rounded with a relatively well- developed forehead. Moderate brow ridges surmount a rather projecting face. - Large chinless jaw of the ape, but their dental features was similar to those of modern humans with broad incisors, short canines, and a parabolic dental arch.
- Broom made new hominid fossil descoveries at kromdraai and Swartkrans in South Africa.
- Larger molars and premolars, smaller incisors and canines and well-developed cranial crests and ridges.
J.T. Robinson- "Dietary Hypothesis"
A. Africa nus- carnivore (base on jaw evidence), live in dry period, dry areas. A. rubustus- vegetarian, wetter period environment favoring lush vegetable growth.
Early Homo finds:
- Most Anthropologists define the genus Homo as dependent on culturally pattered behavior.
- designation for the skeletal remains of several hominids found at Olduvai Gorge in Tanzania which date from about 1.6- 1.8 M years ago. - The habilis skull has a cranial capacity of about 650 cc, which is slightly higher kthat the upper limit observed in A. Africanus. - tools found at Olduvai may have been made by habilis.
Mary Leaky- “Homo habilis whose hard bones also indicate a degree of manual dexterity was most likely to have been responsible for the Olduwan ( tool assemblage).
Early Hominid Culture
Tool Traditions (2-2.5 M years ago)
- There tools ssem to be associated with two or three different hominid species, Australopithecines...
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