Biology 1201A Lecture Notes - Lecture 6: Allopatric Speciation, Divergent Evolution, Punctuated Equilibrium
2 Oct 2016
School
Department
Course
Professor
Document Summary
Species: a group of individuals capable of interbreeding. Allopatric speciation: population is divided by geographic barrier => interbreeding between two resulting populations is prevented => gene frequencies in two population can diverge due to natural selection, mutation, genetic drift. If gene pool is sufficiently diverge => will not interbreed when barrier is removed => new species formed. Sympatric speciation: formation of new species without present of geographic barrier. Balanced polymorphism: different color in insects, one color can camouflage to different substrate, and the other that can"t will be eaten. Only insects with same color can mate (isolated from other subpopulations). Polyploidy: possession of more than normal two sets of chromosomes (3n, 4n in plants. <= nondisjunction => two viable diploid gametes and two sterile gametes with no chromosomes. => tetraploid 4n zygote formed => repeat with diploid gametes male/female => reproductive isolation with normal gametes).
