Speciation occurs when 1 original population of the same species becomes reproductively isolated, making 2 populations of the same species, but cannot breed together
Speciation results in the accumulation of differences in their gene pools to the extent that they cant breed to make fertile offspring
Allopatric speciation is due to geographical isolation e.g. new mountain
Sympatric speciation are the changes in reproductive mechanisms e.g. random mutation impacting reproductive behaviour like courtship