Download Understanding Allele Frequencies & Hardy-Weinberg: Population Genetics & Natural Selection and more Slides Ecology and Environment in PDF only on Docsity! Population Genetics and Evolution by Natural Selection Docsity.com 1) What are the Phenotype Frequencies? Docsity.com 4) Suppose that the frequency of the b allele in the population is .3 . • What is the frequency of the B allele in the population? • What is the frequency of cats with genotype bb? Docsity.com • What is the frequency of cats with genotype BB? • What is the frequency of cats with genotype bB? • What is the frequency of cats with genotype Bb? Docsity.com If p = frequency of first allele, and q = frequency of second allele p2 + 2pq + q2 = 1 (Hardy-Weinberg Equation) Frequency of BB Frequency of Heterozygotes (Bb or bB) Frequency of bb Docsity.com Hardy-Weinberg Principle: • In a population, allele frequencies remain constant in the absence of evolutionary forces Bb bb BB bb Bb Docsity.com Assumptions of Hardy-Weinberg Principle: Bb bb BB bb Bb 1) Random Mating Docsity.com Bb bb BB bb Bb 2) No Mutations Assumptions of Hardy-Weinberg Principle: bb Docsity.com Assumptions of Hardy-Weinberg Principle: Bb bb BB bb Bb 5) Genotypes have Equal Fitness (2 offspring) (10 offspring) BB (6 offspring) Docsity.com Assumptions of Hardy-Weinberg Principle: 1) Random Mating 2) No Mutations 3) Large Population Size 4) No Immigration 5) All Genotypes have Equal Fitness ? How likely is it that a population meets ALL ASSUMPTIONS? Docsity.com Case Study: Peppered Moth (Biston betularia) Biston betularia var. typica Biston betularia var. carbonaria DD, Dd dd Docsity.com 10 5 6 7 9 8 Anoles (Anolis): 150 species in the Caribbean Islands Demonstrating the PROCESS of Adaptive Change Docsity.com Observed Relationship of Hind Limb Length to Vegetation in Brown Anoles (Anolis sagrei) 11 Hind Limb Length 12 13 14 Docsity.com 15 Brown Anole (Anolis sangrei) Introduction of Brown Anole Populations from Staniel Cay Island to 14 Caribbean Islands (with no preexisting Anole Populations) An Experiment to Test for Adaptive Change Docsity.com Question: Phenotypic Plasticity (= Developmental)? Heritable Trait (with Genetic Basis)? Docsity.com Possible Experiment to Test for Phenotypic Plasticity versus Heritability of Leg Length Docsity.com 17 Soapberry Bug 18 Species Native to U.S. (3) Species Introduced to U.S. (3) 19 Soapberry Bugs and Plants in Soapberry Family (Sapindaceae) Demonstrating HERITABILITY in Natural Selection Docsity.com Fig. 4.16 in Molles 2008 Relationship between Beak Length of Soapberry Bugs and Fruit Size in Native and Introduced Soapberry Species Docsity.com Question: Phenotypic Plasticity (= Developmental)? Heritable Trait (with Genetic Basis)? Docsity.com Experiment to Test for Adaptive Change Docsity.com Forms of Natural Selection in Populations: DIRECTIONAL SELECTION Fig. 8.15 in Molles 2006 Docsity.com Forms of Natural Selection in Populations: DISRUPTIVE SELECTION 20 21 22 Genotype: BB Genotype: Bb Genotype: bb 23 24 Docsity.com Forms of Natural Selection in Populations: DISRUPTIVE SELECTION Fig. 8.15 in Molles 2006 Docsity.com
