Different groups of the population are prevented in some way from interbreeding

similar early stage development in related species

rainfall, temperature, salinity, ocean current, sunlight

Where there is a geographical barrier - mountain, river, ocean or gorge in the way

DNA analysis

This is because natural selection is involved and selection can only act on variation that is already present in a population

Once groups of populations are isolated, natural selection affects the genotype of each group, leads to changes that prevent groups from breeding

Fossils are the preserved evidence in rocks or soil of organisms that once existed on earth

The black moths blended into the trees more than the white moths, meaning they lived longer and passed on their genes more frequiently

This is the process of crossing one individual with a desirable feature with another individual with a different desirable features. Hopefully, the offspring sh

Stromatolites are laminated fossils formed by blue-green algae and sediment

Amber

The effect of the selective agents on the population are known as selective pressures.