Speciation:
Process by which populations evolve into different species.
Species:
Group of organisms that can interbreed and produce fertile offspring
Hybrids:
Offspring from cross breeding of 2 different species. They are infertile
Evolution:
Change of heritable characteristics of a species across generations.
Reproductive isolation:
2 populations of the same species can no longer successfully mate together
Post zygotic isolation:
Parents can form a zygote but the zygote is unfit.
Ex: no development of embryo, birth always resulting in miscarriages, too big to be born
Pre zygotic isolation:
Parents do not form an zygote together.
This can be due to behavioural changes within the species or due to being separated by huge distances or physical barriers.
Allopatric speciation:
When 1 species diverges into 2 or more due to geographic reasons
It is of 2 types:
Peripatric:
When the populations are separated by barriers
Parapatric:
When the population is spread over a large area
Sympatric speciation:
When 1 species diverges into 2 or more without geographic reasons