From the first appearance of early humans in Africa, the story of how Homo sapiens , our own species of human, came to dominate the planet is a complex one. The increased brain capacity of early humans was crucial to their ability to adapt to the environment, especially through the ability to make tools and control fire. This adaptability allowed certain human species, particularly Homo sapiens , to survive and prosper in a wide variety of climates and terrains, from the tropics and the deserts to the steppes and the mountains, and across some of the coldest and hottest environments on the planet.