Many species tend to have limited diets and habitat requirements, and an organism must compete with members of his own species to secure these necessities.Of primary importance, however, is procuring a mate.
sperm and egg)) while males develop from unfertilized eggs (so there is no male contribution to the male genome). They noticed that when they crossed individuals from different species, only males were produced. They found out that this was the result of microorganisms in the cytoplasm of the gametes destroying the males chromosomes from his sperm.
As I said in part one, I have two goals in for this series.
One, to show that evolution is an accepted branch of mainstream science.
For many years, speciation theorists thought that virtually all speciation occured when the two subsets of the population where separated by geographical boundaries.
(ie, the species became split by a river, mountain range or a small group migrated out of the main region inhabited by the species.) Reproductive isolation followed physical isolation as the two, now separate lineages, diverged.