BIOL 2200 Lecture Notes - Lecture 6: Sympatric Speciation, Polyploid, Meiosis
30 Jan 2017
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Document Summary
Balancing selection = maintains multiple forms of alleles. Heterozygote advantage = heterozygotes have greater fitness than either homozygotes. Frequency-dependent selection = fitness depends on how common the phenotype is in the population. Ex: purple orchids are more common than yellow orchids, and therefore does not get pollinated as much because pollinators learn that they will not get food in return. Ex: people do not grow to be twelve feet tall. Adaptation only can occur if genetic resources exist. Being more fit for one task are less fit for another. Ex: peacocks with big, colorful tails are more apparent to foxes. Phenotypic plasticity = the ability to change your phenotype. The ability to change is heritable, but the actual phenotype is not heritable. Ex: the cactus wren can change the direction of its brood based on when they are laid. Biological species concept = groups of actually or potentially interbreeding populations, which are reproductively isolated from other such groups.
