1. Gene flow: occurs between population that are partly but not completely separated.
2. Genetic Drift: It is the random change in the frequency of allels in a population over successive generations.
4. Geographical isolation: It is caused by mountain ranges, rivers etc. geographical isolation leads to reproductive isolation due to which there is no low of genes between seprated groups of population.
-Answered by A??k Pal On 16 January 2020:11:03:56 AM