Handout 3 - B ILD 3 Fall 2008 Section: Mon 9-9:50 AM...

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BILD 3 – Fall 2008 Section: Mon 9-9:50 AM HANDOUT 3 I. Terms/phrases to know Lecture 8 (10-13-08) o Random genetic drift – random fluctuations in allele frequencies o Population size bottleneck – example of a cause of random genetic drift in which population size is reduced briefly due to natural causes and by chance, an allele may be overrepresented among survivors and passed on to subsequent generations such that its frequency becomes higher than normal o Founder effect – example of a cause of random genetic drift in which a small number of organisms from a population separate and colonize elsewhere; by chance, some founders may carry a mutant allele that will be passed on and as a result, that allele will be present at a higher frequency than expected in later generations o Gene flow – exchange of genes between populations or subpopulations of organisms either through actual movement of individuals of a population or through movement of gametes o Migration – actual movement of individuals along prescribed paths that may or may not result in gene flow o Dispersal – release of gametes by sessile organisms Lecture 9 (10-15-08) o Red Queen races – theory by paleontologist Leigh van Valen that states that when species are confronted with rapidly changing environments and competitors, they must evolve just to keep up with the changes o Sexual selection – selection for mating success o Intrasexual selection – type of sexual selection in which individuals of same sex compete for mates o Intersexual selection – type of sexual selection in which individual of one sex o Primary sexual characters – involved directly in reproduction (ex: organs involved during mating) o Secondary sexual characters – phenotypic characteristics that play role in attraction and mating success (ex: body shape, plumage of birds, etc) Page 1
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BILD 3 – Fall 2008 Section: Mon 9-9:50 AM o Runaway sexual selection – occurs when preference of one sex for extreme characteristics of the other sex is directly selected for, resulting in sexual dimorphism; eventually checked by natural selection if trait becomes disadvantageous in certain environment o Sexual dimorphism – extreme differences in appearance and behavior between the sexes Lecture 10 (10-17-08) o Morphological species – groups of organisms that show clear and consistent phenotypic differences and can be described on basis of morphological criteria
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This note was uploaded on 10/18/2009 for the course BICD BILD 3 taught by Professor Wills during the Fall '08 term at UCSD.

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Handout 3 - B ILD 3 Fall 2008 Section: Mon 9-9:50 AM...

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