Mammals and subsequently humanity may not have become dominant on earth had it not been for the global catastrophe that led to the extinction of the dinosaurs 65 million years ago.
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 .
Adaptation is a continuous response to the environment by changeable species.
is heritable) and arises through processes such as mutation and recombination.
 Natural selection, gene flow and random genetic drift (the random change in gene combinations with each generation) drive evolution, resulting in a change in gene frequencies within populations .
erectus (including the Java and Peking hominids - the archetypal Missing Link) and H.
sapiens (including Neanderthals and Cro-Magnon) (see the modern taxonomic classification of humans).
 Adaptation is genetically based and so leads to phenotypic changes that accumulate over time;  Speciation (species formation) evolves through reproductive isolation and (genetic) divergence of populations;  Genetic changes through natural selection lead to new species and eventually new taxa .