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.
Very simply, there are five basic principles to this theory:  Variation has a genetic origin (i.e.
Archaeological geology as a science had to precede the proposal of evolution, as an understanding of the immense age of the earth is necessary to understand evolution.Cuvier established amongst the scientific community the fact of extinction.Our hominoid line, humans, gorillas, chimpanzees and lesser apes, is one among the superfamily Hominoidea.See the taxonomic table of primates for two comparative classification shcemes.( Adaptive radiation is the evolution from an unspecialised ancestral stock of many different species that adapt to a variety of ecological roles (see books)).
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.
Between the mid-1930s and mid 1940s geneticists, systematists and palaeontologists collaborated to create a united approach to evolution, the "Modern Synthesis".
Ernst Mayr reduced all the hominid (human ancestor: (see hominid books)) fossil records to three species, A.
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.
Scientists now have accurate methods (see below ) for dating fossils.