The evolution of a species is linked to the environment.
Living orders of placental mammals , be it bats, humanity, whales or camels, have as their common ancestor a small insectivore creature that went through a major phase of adaptive radiation during the Early Cenozoic Era .
We humans are first animals, then mammals, then primates.
This environment has a living (other animals) and non-living component (e.g. Widgets A unique adaptation usually precedes the entry into a new niche .
Tool use by our early ancestors is one such adaptation.
At the onset of the 20th century, most scientists had accepted the great antiquity of the earth, the theory of evolution and that humanity had evolved from an ape ancestor, but by 1908 the fossil evidence of early man was scarce.