BIO120H1 Lecture Notes - Lecture 9: Zygosity, Heterosis, Sympatric Speciation

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BIO120H1 Full Course Notes
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BIO120H1 Full Course Notes
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Based on inter-fertility (cross ability) among individuals. First formally defined by ernest mayr, first suggested by bobzhansky. A group of interbreeding natural populations that are reproductively isolated from other such groups. Allopatric: (often know as the theory of geographic speciation since geographical isolation is involved) Anything that creates a barrier/separation between 2 groups of organisms. Stages: finding a compatible mate, mating & fertilization, development of zygote, adult growth & survival, reproduction & fertility of offspring. Speciation involves the evolution of reproductive isolation between populations. 2 types: premating isolation (before zygotes occur) and postmating isolation (after zygotes occur) Mechanical, prevention of gamete fusion (some organisms can fit each other) Postmating: preventing the proper functioning of zygotes once they are formed. Inviability, sterility, or abnormal development of hybrids. The mule is an example of intrinsic postmating isolation, it is a sterile hybrid from crossing donkey and horse.