Choose any two developments each from Timelines 1 and 2 at the end of the chapter and indicate why you think these are significant.
(A) Two Developments from Timeline 1
1. The first hominids emerged on the earth’s surface about 5-6 million years ago. They evolved from homonids and both had some common features and certain differences. Homonids had a larger brain than that of the homonids. Homonoids were quadruped and walked on all four legs but had flexible forelimb. On contrary, homonids had an upright posture and they walked on two feet and also difference in hand which helped them in making and using tools.
2. Ice age came into being around 2.5 million years ago. It brought major changes in the climate and vegetation of the earth. There was reduction in temperatures as well as in rainfall. That’s why forests were reduced and there was no expansion of grassland areas. It led to extinction of early forms of Australopithecus because they were adapted to live in the forests. They were replaced by species who adapted to drier conditions. Species included the representatives of the genus Homo.
(B) Two Developments from Timeline 2
1. The evolution of the voice box took place around 200, 00 years ago. It gave the power of speech to a man. It was possible for a man to speak and express his views, arguments and expressions. It also helped in the development of new techniques of making tools, hunting and other activities.
2. Sewing needles were invented about 21, 000 years ago. This invention was very helpful for early humans, now it was possible for them to sew fur of animals and wear it as clothes and preparing them as shield for their body in different climates. It provided them warmth and protected them from cold weather and revolutionized files of jute, silk, cotton, etc.