behavioral isolation
where species use different courtship and other mating clues to find and attract a mate
temporal isolation
where different species breed at different times of the year
ecological isolation
very similar species may occupy different habitats within a region
mechanical isolation
is where differences in morphological features may make two species incompatible
gametic isolation
where male gametes may not be able to recognize and fertilize an egg of a different species
homologous structure
similar physical features in an organisms that share common ancestors but features serve as different functions