BIO120H1 Lecture Notes - Lecture 9: Jerry Coyne, Species Problem, Speciation
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BIO120H1 Full Course Notes
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Hypotheses for the high frequency of ightlessness in island birds: : no selection against mutation that impair ght! Anti-predator mechanism: wings to escape from predators ! However, no predator on islands, ight is not needed! Reduced wings allows them to dive deeper under water! Ernst mayr: rst to de ned the biological species concept bsc ! It was that dobzhansky rst suggested the idea! A group of interbreeding natural populations that are reproductively isolated from other such groups ! Two main modes of speciation:: allopatric (major form of speciation today), also known as geographical speciation! Gene ow barrier created in a population (barrier = geographical isolation)! They eventually come together, but they don"t interbreed: sympatric ! Controversial to many zoologist:: gene ow is occurring, but speciation is also happening at the same time, jerry coyne thinks this doesn"t happen ! Individual in a population becomes genetically differentiated, leading to a new species!
