Question

Observe the following figure and answer the questions:
(a)How did the human brain go on changing?
(b)Give examples of human progress?

Answer 1

Hint: With time as humans evolved, the human brain too became evolved to increase its volume and area which in turn lead to high intelligence, cranial capacity, and reasoning. This gave us an advantage over other animals as we could use skills to enhance our survival.

Complete Answer:
(a) The human brains went on changing to increase its cranial capacity. This cranial capacity was increased by enlarging the volume of the brain as well as its surface area by increasing the folds. An increase in the surface area led to the accommodation of more neurons, thus resulting in a faster and smarter brain. There was a remarkable increase in the structures of the cerebellum and neocortex which are areas of the brain associated with learning, conscious thought, and reasoning. This allowed us to become skilled by making our own tools and fire, communication through language, make social groups that helped us survive and finally become self-aware.
(b)Let us look at the stages of human progress and development.
-Dryopithecus and Ramapithecus existed 15 mya and they were hairy gorilla-like. Dyopithecus was more ape-like whereas Ramapithecus was more man-like.
-After 2mya first human-like hominids were living in East African grasslands known as Homo habilis. They had brain capacities around 650-800 cc and did not eat meat.
-The next stage is the Homo erectus which has a large brain of 900cc and probably ate meat.
-The Neanderthal man is the next stage that lived 1,00,000-40,000 years back and had a cranial capacity of 1400cc. They wore hides to protect their body and buried their dead.
-Finally, the Homo sapiens rose between 75,000- 10,000 years ago from Africa and developed into distinct races.

Note:
-Pre-historic cave art began as early as 18,000 years ago.
-The Bhimbetka rock shelter in Raisen district of Madhya Pradesh showcases one such cave painting.
-Once agriculture began around 10,000 years ago it led to human settlements near rivers and fields.