finalreview-1[1] - Biology 101 Final Review Donovan; Winter...

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Biology 101 Final Review Donovan; Winter 2008 Population change 1. What are the areas of science and who are the scientists that influenced Darwin and “set the stage” for his theory of evolution by natural selection? Study finches on in the Galapagos islands on his voyage. Thomas Malthus, a clergyman and economist, wrote essay that Darwin read on his return to England. Argued that as population size increases, resources dwindle, the struggle to live intensifies, and conflict increases 2. What is genetic equilibrium? What are the circumstances in which it occurs? Allele frequencies at a locus are not changing, population is not evolving. There are five conditions for genetic equilibrium: No mutation, Random mating, Gene doesn’t affect survival or reproduction, Large population, No immigration/emigration 3. What is microevolution? What are potential causes (forces) of microevolution? Drive a population away from genetic equilibrium. Small-scale changes in allele frequencies brought about by: Natural selection, Gene flow, Genetic drift 4. What is natural selection? Describe how it occurs. Natural selection among individuals of a population is an outcome of variation in traits that affect which individuals survive and reproduce in each generation. This process results in adaptation to the environment (increases fitness) 5. What are the three main types of natural selection? Graph and give an example of each one. A shift in the range of value for a given trait in some direction Stabilization of an existing range of values Disruption of an existing range of values. 6. How does resistance to antibiotics evolve? Antibiotics first came into use in the 1940s. Overuse has led to increase in resistant forms and most susceptible cells died out, while resistant forms multiplied 7. What is sexual selection? How does it lead to changes in populations? Sexual selection favors certain secondary sexual characteristics. Through nonrandom mating, alleles for preferred traits increase. Leads to increased sexual dimorphism (difference in the looks of males and females) 8. Genetic drift can be caused by bottleneck effects, founder effects, and inbreeding. Define and give an example of each. What are the potential ramifications of each? Random change in allele frequencies brought about by chance. Effect is most pronounced in small populations. Bottleneck effect: severe reduction in pop. size. (ex: elephant seal pop.) Founder effect: when a small number of individuals start a new pop. (ex: birds being onto an island) Inbreeding: Nonrandom mating between related individuals and leads to increased homozygosity. (ex: Cheetahs) 9. What is gene flow? How does it counteract genetic changes in populations? Physical flow of alleles into a pop. that tends to keep the gene pools of pops. Similar. Counter the
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This note was uploaded on 04/08/2008 for the course BIO 101 taught by Professor Staff during the Spring '08 term at Western Washington.

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finalreview-1[1] - Biology 101 Final Review Donovan; Winter...

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