What is optically stimulated luminescence dating absolute dating volcanic ash layers
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.
Once multicellular organisation became possible as atmospheric oxygen levels rose, the early multicellular organisms rapidly diverged into many adaptive forms.
Mass extinction events and an organism's unique adaptations mark the history of evolution, both of which may lead to adaptive radiation.
 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 .
 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 .
( Adaptive radiation is the evolution from an unspecialised ancestral stock of many different species that adapt to a variety of ecological roles (see books)).
methods rely on characteristic faunal and geological patterns to bracket the period when the fossil existed.
sapiens (including Neanderthals and Cro-Magnon) (see the modern taxonomic classification of humans).
This formed the foundation of the neo-Darwinian evolutionary theory.
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.