BIO120H1 Lecture Notes - Lecture 9: Divergent Evolution, Reproductive Isolation, Theodosius Dobzhansky
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Taxonomic (morphological)- based primarily on distinct morphological differences. Group of interbreeding natural populations that are reproductively isolated from other such groups . Allopatric- barrier to gene flow and over time they diverge. Compatible mate mate and fertilization zygotic dev adult growth/survival healthy offspring. Apple maggot flies: originally on hawthorne plant, but arrival of domestic apple led to host shift, reduces gene flow in sympatry. Monkey flower: 2 flower species have different pollinators, pollinators keep the 2 apart, limited hybridization, also kept apart by elevation, they are inter-fertile, but don"t mate in the field. Preventing proper functioning of zygotes once they are formed. Measure of degree of genetic differentiation between samples. Hypothesis: more genetically differentiated pairs of flies more likely to be reproductively isolated. Mule is sterile hybrid between male donkey and female horse. In natural environment that selects against hybrid crows. Evolution of local adaptation as a result of divergent selection leads to reproductive isolation and speciation.
