why the human ancestors started to walk on two legs rather than four

why the human ancestors started to walk on two legs rather than four

Approximately six million years back, human ancestors began walking on two feet rather than traveling on four, according to Gray (1). Bipedalism is the act of moving on two legs, which have been adopted by various species since evolution began. However, most of the species are extinct, which makes the human species unique within the animal kingdom. Human evolution is an ever-changing process in which humans originated from the ape-like lineages. Scientific reports demonstrate that the behavioral and physical characteristics that are shared by humans, in general, originated from ape-like families. Even though one of the earliest and most defining human characteristic is bipedalism, the scientific community differs over what led early humans to abandon quadrupedalism. As a result, several theories explain the reason as to why the human ancestors started to walk on two legs rather than four.

The most recognized theory as to why humans adapted to walking with two fits is that climatic changes encouraged early humans as primates to stand upright to be able to see past the savannah grass for predators and run faster from attackers. Also, the structure would help them in walking longer distances at ease. Bipedalism was the most feasible alternative in a surrounding where trees were uncommon. While standing up, ancestral humans would easily survey the environment covered with long grass for preys and predators. The human ancestors were prompted by the need to survive to adapt to the upright posture. Climatic change across African changed dramatically, and even though savannas were dominant, the ancestral humans would, at times, return to the forest regions.

According to Gray (1), the earliest human ancestors are believed to have deviated from a common lineage with chimpanzees amid 13 and 6 million years back. Human ancestors, however, evolved and developed various unique characteristics that differentiate them from chimpanzees, particularly the ability to walk on two limbs. Despite the fact that the earliest hominids had the capability to walk in an upright structure, they possibly would not get around as humans do today. In that, they reserved most of the primitive traits such as long curved toes and fingers in addition to longer arms than legs. The physical features are an indication that they spent most of their time on trees. However, with the emergence of the Homo-Erectus about 1.89 million years back, hominids became taller by evolving longer legs, and they became fully worldly creatures (Thorpe, Roger and Robin 1328).

An additional theory is that ancestral humans started the bipedal process to enable them to walk easily between trees and collect food in treetops easily. Africa’s luxurious forests were replaced by infertile grasslands, which forced early humans to shift to the savanna land, which held lesser places to hide from their predators and prey (Gray 1). After the alteration to savanna, they were often required to walk from a tree to the other while crossing the grassland, and hence, they became better in terms of walking upright. Bipedalism became very common among human ancestors. The intensity of supernovae is believed by scientists to have increased by about 2.6 million years back (Gray 1). The development caused a major outpouring of lightning strikes, and they burned most of the extensively forested universe. Early humans were forced to learn how to live within and around the forest in order to survive in the open savannas. The adaption meant the ability to cross the exposed grassland at higher speed and identify predators in higher heights than the grassland became vital. A supernova occurs where some kind of stars come to termination of existence (Wayman 1). In brief nature, they can outshine the galaxy by radiating more energy when compared to the sun. The ape-like human ancestors began walking on two limbs due to the emergence of new hunting approaches and also an evolutionary alteration to coping with the African temperatures. As emphasized by Darwin’s theory, walking and standing on two limbs offered more flexibility and capability for throwing weapons at predators (Lieberman 100). Walking upright meant that their hands were free to carry and manipulate the hunting tools. In essence, the bipedal approach resulted from the need for convenience (Thorpe, Roger and Robin 1328). It was easier for them to reach and grasp food from the trees.

Several essential anatomical changes took place, which allows humans to walk upright. From primates, the pelvis structure was transformed from being tall and rather flat to a short bowl-like structure (Wayman 1). The structural changes provided humans with better control for the muscles that support the movement of the hip in an upright structure. Besides, the thigh bone angle changed, pointing inwards, which brought the human feet under the body’s center. The spine additionally became curved, assisting the hip in supporting the weight and pillowing the brain while moving. Ultimately the feet became longer and the arms shorter, thus allowing humans to make longer and more efficient moves (Lieberman 100). While primates had big toes as depicted by apes for grabbing branches while moving from a tree to the next, humans’ toes are smaller and well-aligned, which creates a stronger pedal to push the body up after every step.

Endurance is another reason as to why early humans adapted bipedalism. With the shrinking of the forest and increasing heat, they would walk long distances across the grassland that linked the forest areas. Walking upright was, therefore, an energy-efficient and fast approach. Recent studies have established that chimpanzees normally require 75 percent of energy while walking when compared to bipedal humans (Gray 1). The report offers evidence that bipedalism is an advantageous approach. The changing geographical landscape also helped early humans on successfully shifting to bipedalism. Evidence shows that most early humans lived within East Africa. Living in the wild rift valleys meant that they lived in rather unstable geographical landscapes characterized by scarps and escarpments. The unstable terrain required a more flexible and stable walking technique. The assertion that the posture would allow them to experience less heat based on the increasing temperatures is widely rejected by scientist as irrelevant.

In conclusion, humans walk on two feet because it is efficient and energy conservative approach. Human evolution has been essential in advancing human traits and differentiating humans from other species with similar origins, such as the chimpanzee. While humans portray more advanced characteristics such as the ability to talk and reason, bipedalism is also one of the most fundamental and unique characteristics that humans possess. Early humans are believed to have shifted to bipedalism due to the need for convenience. With the changing climate and landscape, they were forced to cover long distances to access rare tree patches. In maneuvering the long grasslands, they needed to protect themselves from predators. Besides, they needed to walk faster across the long distance. As a result, their bodies evolved to align with the needs, which explain why humans use two feet to walk.