The study of human evolution is complicated. It involves many disciplines including Anthropology, Primatology, Archaeology, Linguistics, Embryology, and Genetics.

Hominoids lived on tress and were only food gatherers. Hominids adapted to land dwelling. They began to use caves and extended stone boulders as shelters. The shortage of food made them to scavenge for food. They covered long distances to forage or scavenge for naturally dead animals or leftovers of animals killed by predators. The above activities made them gradually develop an upright posture and consequently the bipedal motion. Planned hunting and making tools stimulated the growth in the brain size. 

The growth in brain size in turn helped them to plan and make better tools.

Domestication of animals was followed by the commencement of agriculture. Humans became food growers. They overcame the effects of the climate changes like the ice age by adapting to domestication of animals and agriculture. Dogs were domesticated first followed by sheep, goat, cow, cat, camel, and horse. The rearing of animals made humans, nomads. Commencement of agriculture is considered as a revolutionary change in the history of human evolution. This was an important aspect of the Neolithic age. Humans began to grow various crops like wheat, rice, millets etc. It made them lead a settled life. This resulted in the formation of human settlements termed villages and later towns which were the foundations of civilizations.

The Hominoids were quadrupeds. The Hominids adapted an upright posture. Hominines further adapted to bipedalism. The skeletal structure and the muscles also adjusted over a period of time to the upright posture and the bipedal motion, which freed the forelimbs. The forelimbs developed precision grip and power grip and evolved into hands. This greatly helped in hunting and defending from predators as hands could be used to make tools and also use them. Walking on two legs also provided a greater long distance vision and helped them to cover long distances without spending much energy.

The use of tools by humans was another remarkable progress. Wood, bones and stones were used to make tools. They were mainly used for hunting or defending from predators. The making and use of stones tools were responsible to the evolution of forelimbs into hands and also the growth in brain size. In course of time, humans began to,produce metals from ores and make copper, bronze and iron tools which are studied in history as the respective metal ages. The making of stone tools from naturally available stones and using them is positively identified to have begun with Homo habilis.