A mechanism of evolution is natural selection. Populations have the potential to produce more offspring than will survive or than the environment will support. Individuals with traits best suited to the environment leave a larger number of offspring. This increases the proportion of inheritable variations in the next generation. Organisms' adaptations to their environments are the products of natural selection.
Adaptations are the result of the editing process of natural selection.
When exposed to specific environmental pressures, certain inheritable variations favor the reproductive success of some individuals over others. Evolution is the one unifying biological theme . Life evolves . Species change over time and their history can be described as a branching tree of life. Species that are very similar share a common ancestor at a recent branch point on the phylogenetic tree.