Radiometric dating is based on the idea that online dating dallas texas
 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 .
I have integrated this web page on human evolution into an electronic text, " Nature's Holism - Holism.
Very simply, there are five basic principles to this theory:  Variation has a genetic origin (i.e.
is heritable) and arises through processes such as mutation and recombination.
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.
Biologists included principles from genetics in evolutionary theory during the 1920s and 1930s.
Between the mid-1930s and mid 1940s geneticists, systematists and palaeontologists collaborated to create a united approach to evolution, the "Modern Synthesis".