Q.
The diagram given here shows the skulls of two different mammals.
Out of the following, which one accurately describes the differences between these skulls?
In the given figures, the skull-A is that of an Ape, while skull-B is of the humans. Typically, the ape skull does not have a forehead and is prognathous. The face projects beyond the top of the skull. Human skulls, on the contrary, have a prominent forehead and are orthognathous, elevated nose, developed chin, strong-jaw lines.
Mammals started evolving approximately 230 million years ago, in the Triassic period, from Cynodont reptile, which was like shrew-like animals.
Primates evolved during the Palaeocene Epoch of the Tertiary period, sometimes 65 million years ago. The early anthropoids, which are now extinct, evolved in Africa. About 30 million years ago, some of these members migrated to South America and gave rise to the new world monkeys. The remaining members in Africa formed two lines, the old world monkeys and the hominoids. The hominoids include apes and hominids.
Human evolution shows three prominent stages:
The ape-stage, represented by all extinct apes, like Dryopithecus, Ramapithecus, etc. They had a small cranial capacity.
The ape-man stage, represented by Australopithecus. They had more cranial capacity than that of the apes.
The man stage began with the genus Homo. They showed a marked increase in cranial capacity from 800 cc to today 1450 cc.
