Part 3: Success of Bi-pedal Primates

Survival Issues

Predators - Early hominids would have faced predation from a variety of animals - big cats, wolves, hyenas, crocodiles etc. These predators, capable of hunting down and killing hominids, would have forced hominids to engage in defensive behavior against them. The ability to see predators from afar, to flee them on foot, and to possibly fight them if necessary are all abilities that hominids could use to avoid predation. Bipedal locomotion aids in all of these tasks. First, walking bipedally elevates the head, allowing hominids to see predators from afar and thus avoid them. Secondly, bipedal locomotion allows efficient walking over long distances. This ability could have allowed hominids to flee predators or to go out of their way to avoid them in the first place. If an early hominid did happen to engage in a confrontation with a predator, it is possible that having two hands free could have aided it in surviving an attack. If this kind of defense gave a hominid even a slight advantage in surviving and reproducing, evolution by natural selection would have favored this trait in hominid populations.

Climate change - The Pleistocene epoch was a time of great change. The northern hemisphere experienced many glacial periods, in which massive ice sheets covered whole continents, while southern parts of the globe became much more arid.  Following these cold periods that lasted approximately 80,000 years, periods lasting about 20,000 which is characterized by speciation, alteration of the appearance of fuana, migration routes, as well as regional weather patterns. It was these key concepts that greatly affected the evolution of modern homo and its ancestors. Humans of the Ice Age faced with the limited availability of resources were forced to alter migration routes that were cut off by glacial advancement. It forced many small hominid populations into geographical isolation. Some became evolutionary dead ends, while others became the ancestors of modern humans.



Obtaining food: Early hominids had a diet that consisted mainly of plant life. This was due to their lack of tools that could be used to cut through meat. Once they were able to create tools that would allow them to eat meat, they began to expand their diet to include small animals, or the carcasses of animals that were killed by bigger predators. They were not able to add a consistent amount of meat to their diets until the discovery of tools such as spearheads. The creation of spears allowed humans to hunt larger animals with less risk of being injured.

Physical Characteristics

-Increased limb length allowed for more efficient bipedalism, and therefore, a greater ability to migrate. Bipedal primates could better react to changes in weather and follow food sources with their increased mobility. They could hunt game over great distances. For example, they could merely injure an animal and then travel behind it until it was incredibly weakened, reducing the danger of going after large prey.

-Larger, more robust body types also helped with this stamina. However, this was not conducive to arboral brachiation. Bigger bodies also required more fuel, which put greater pressure on resources and further spurred movement to new areas.




-Increased cranium size was a distinctive development that followed bipedalism. This meant considerable brain enlargement and larger mental capacity became an important advantage. Hominids could now be more efficient hunters and scavengers. They were able to outsmart larger prey that could possibly be predators otherwise. Meat from other carnivores proved to be an excellent source of protein. Intelligence allowed them to exploit a wider range of nutrients through more logical foraging as well.



-However, the most direct physical disadvantage resulting from bipedalism was reduced climbing ability. Upright primates evolved flat feet for standing and gave up ones that were better for clinging to tree limbs. Pelvises adapted for bipedalism were also not suited to arboral living. The tradeoffs required for walking on two feet made reaching high-up food and escaping predators by going up in trees more difficult.

Behavioral Characteristics

Archaeologists can determine that early hominids lingered near bodies of water as indicated by the fossils excavated in areas such as Lake Turkana, Allia Bay, and Olduvai Gorge. Fossil record displays an outward expansion of Africa. These strata show a pattern migration movement along various coasts. This activity infers early hominids relied heavily on resources available to them in surrounding areas.






Further archaeological evidence uncovered with skeletal remains are numerous tools projected to have been used in various ways. Continuously modified flakes were fashioned into more enhanced tools; tools like the scraper, the hand face also known the biface, burins and awls provided a primitive technological innovation that aided in the reproductive success of bi-pedal primates. As the tool industry developed anthropologists can infer as well as correlate a ratio between increased cranial capacity and cranium size. The complex and coordinated steps necessary for preforming various tool techniques suggest increased cognitive abilities among early homos.

Tool design transformed overtime becoming more "technological" for better hunting skills. Enhanced weaponry correlated with increased body size; a hypothesized reason for this relationship lies in the food sources available during those periods. Fossil record evidence displays exploitation of seasonal food sources suggested increased meat consumption which is associated with metabolic chemicals that increased body size. Throughout the early homo's migration toward Europe and Asia hunting efficiency increased along with the transport of stone materials. This type of behavior implies a more sophisticated organized social networks in early hominids.

Interaction with larger numbers of individuals was another major evolutionary step that pressured homo sapien ancestors to manifest a form a communication in order to carry out daily tasks or other important information that needed to be conversed. Socializing with other groups in early homos can explain the diffusion and migration of tool industries among different regions. Relationship between members in populations were crucial because this meant that work load was distributed. Early homos needed each other to survive the environmental pressures they were facing. More amount of time spent in groups also could have led to longer maturation periods.