Question

There are two significant evolutionary developments which distinguish hominins from their other primate "cousins": encephalization and habitual bipedalism From an evolutionary perspective which came first and when did the other begin truly to evolve? Was one development completed before the other began or did they at some point co-evolve? What evidence do we have for either the completion of one and the start of the other or for their co-evolution?

Answer 1

The two characteristics that differentiates the hominins from the other primate cousin are encephalization and habitual bipedalism. Encephalization means there is an increase in brain mass in ratio to the body mass during the evolution of the species. Bipedalism is the ability to walk on two foot and has taken place through steps of evolution. It is found according to research that bipedalism came first and this was followed by encephalization. It is considered that bipedalism is sort of a pre-requisite for encephalization.

· There are many scenarios which can be thought to have evolved the bipedalism first and that led to the evolution of encephalization. The bipedalism evolution means that the forelimbs are no longer needed for locomotion and hence gradually the forelimbs are used for other activities like tool making. This leads to gradually enlargement of brain and hence further encephalization.

· Bipedalism tends to adapt to body to habits like hunting for prey etc. There is a shift in the movement and gradually this led to the change in the diet. With the evolution of the bipedalism, there is a shift to brain size due to the change in the diet and hence this leads to evolution of the encephalization.

· Another reason why encephalization developed and evolved post the bipedalism is because hominins show social behavior. The hominins are hunters and gatherers and as they work together with their social skill, they tend to become adaptive in their behavior. This leads to encephalization and development of the brain.