BIOL 101 Guided Reading Questions GRQs Complete and submit this GRQ as a PDF before lecture and before your online Mastering Assignment L22 GRQs How Populations Evolve II Reading objectives Define genetic drift and how it affects small populations Describe and compare contrast five different forms of natural selection by defining giving examples and drawing representative graphs Module 13 10 13 11 The Hardy Weinberg equation can test whether a population is evolving The Hardy Weinberg equation is useful in public health science 1 TRUE or FALSE FALSE The shuffling of alleles through sexual reproduction leads to changes in the frequencies of alleles in the gene pool 2 In class we ll work with the Hardy Weinberg equations a bit more for now let s examine two equations p q 1 Which variable is the frequency of the dominant allele in the population p What type of individual genotype does each of these variables represent in the population formula p 2 2 pq q 2 p2 frequency of individuals homozygous for dominant allele AA 2pq frequency of heterozygous individuals Aa q2 frequency of individuals homozygous for recessive allele aa If a population is NOT evolving it would satisfy five conditions of genetic equilibrium Hardy Weinberg non evolution a no mutations b random mating c no natural selection d large population size e no gene flow What can the Hardy Weinberg equations tell us that is important to public health Help estimate the prevalence of genetic traits can inform public health by predicting carrier frequencies monitoring population genetics guide strategies for managing hereditary diseases BIOL 101 Guided Reading Questions GRQs Complete and submit this GRQ as a PDF before lecture and before your online Mastering Assignment Module 13 12 Natural selection genetic drift and gene flow can cause microevolution 1 When a population goes from large to small genetic drift is more pronounced in the small population What are two major reasons that populations go from large to small Drift is more pronounced in such populations because smaller populations have less variation and therefore a lower ability to respond favorably 2 Describe gene flow and give at least one example of it that you understand Gene flow leads to genetic variation as new individuals with different gene combinations migrate into a population Sexual reproduction promotes variable gene combinations in a population leading to genetic variation Modules 13 13 13 14 Natural selection is the only mechanism that consistently leads to adaptive evolution Natural selection can alter variation in a population in three ways 1 Natural selection is the only mechanism that consistently leads to evolution For each of the FIVE types of natural selection a define it b give at least one example of it that will help you understand and remember it and c draw a graph if appropriate a Directional selection Natural selection in which individuals at one end of the phenotypic range survive and reproduce more successfully than do other individuals Natural selection that favors intermediate variants by acting against extreme b Stabilizing Selection phenotypes c Disruptive Selection Natural selection in which individuals on both extremes of a phenotypic range are favored over intermediate phenotypes d Sexual Selection A form of natural selection in which individuals with certain inherited traits are more likely than other individuals to obtain mates e Balancing Selection forms in a population Natural selection that maintains stable frequencies of two or more phenotypic Module 13 15 Sexual selection may lead to phenotypic differences between males and females 1 What is sexual dimorphism Differences in physical appearance between males and females of the same species 2 Explain why there might be an advantage to an organism being choosy about its mate investment avoiding genetic defects Improved offspring quality passing on advantageous genes parental BIOL 101 Guided Reading Questions GRQs Complete and submit this GRQ as a PDF before lecture and before your online Mastering Assignment Module 13 17 Diploidy and balancing selection preserve genetic variation 1 What is heterozygote advantage AND what is sickle cell an example Heterozygotes of a particular gene are fitter than homozygotes genetic diversity carriers for the sickle cell allele have a resistance to malaria Module 13 18 Natural selection cannot fashion perfect organisms 1 True or False F New alleles arise as organisms need them F Evolution leads to organisms perfectly adapted to their environments T Evolution builds upon and modifies ancestral forms
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