How did the environment affect early human life?

Humans have been present on this Earth for nearly 3.5 million years when "Homo erectus" first evolved with an upright posture enabling the use of hands (Ponting). "Homo erectus" evolved into "Homo sapiens" one hundred thousand years ago and both lineages lived in small, mobile groups. For nearly two million years, their way of life was based around hunting and gathering food until ten to twelve thousand years ago when agriculture evolved. Early humans depended upon their knowledge of crops and seasons in order for survival. Eventually, as brain size increased and more humans adapted to different environments, advances were made in human technology. Humans began to work with and occasionally against their environment to create a stable way to acquire food as well as a more stable lifestyle. On the other hand, the environment, the climate in particular, definitely dictated the movement and survival methods of early humans.