Evolution

The theory of evolution is that "modern organisms descended, with modification, from pre-existing life forms". Audesirk & Audesirk state a common consensus among biologists when they call evolution "the unifying concept of biology" and "the most important concept in biology".

The natural processes involved are

1. genetic variation among members of a population
2. inheritance of those variations by offspring
3. natural selection, the survival and enhanced reproduction of organisms with favorable variations.