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Modern Evolutionary Biology I. Population Genetics A. Overview B. The Genetic Structure of a Population C. The Hardy-Weinberg Equilibrium Model D. Deviations From HWE: 1. Mutation 2. Migration 3. Non-Random Mating: 4. Populations of Finite Size and Sampling Error - "Genetic Drift"
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Modern Evolutionary Biology • I. Population Genetics • A. Overview • B. The Genetic Structure of a Population • C. The Hardy-Weinberg Equilibrium Model • D. Deviations From HWE: • 1. Mutation • 2. Migration • 3. Non-Random Mating: • 4. Populations of Finite Size and Sampling Error - "Genetic Drift" • 5. Natural Selection • 1. Fitness Components:
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • Fitness = The mean number of reproducing offspring / genotype • - probability of surviving to reproductive age • - number of offspring • - probability that offspring survive to reproductive age
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • Fitness = The mean number of reproducing offspring / genotype • - probability of surviving to reproductive age • - number of offspring • - probability that offspring survive to reproductive age • 2. Constraints: • i. finite energy budgets and necessary trade-offs:
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • Fitness = The mean number of reproducing offspring / genotype • - probability of surviving to reproductive age • - number of offspring • - probability that offspring survive to reproductive age • 2. Constraints: • i. finite energy budgets and necessary trade-offs: GROWTH METABOLISM REPRODUCTION
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • 2. Constraints: • finite energy budgets and necessary trade-offs: • TRADE OFF #1: Survival vs. Reproduction Maximize probability of survival Maximize reproduction GROWTH METABOLISM GROWTH METABOLISM REPRODUCTION REPRODUCTION
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • 2. Constraints: • finite energy budgets and necessary trade-offs: • TRADE OFF #1: Survival vs. Reproduction • TRADE OFF #2: Lots of small offspring vs. few large offspring METABOLISM REPRODUCTION REPRODUCTION METABOLISM A few large, high prob of survival Lots of small, low prob of survival
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • 2. Constraints: • finite energy budgets and necessary trade-offs: • Contradictory selective pressures: Photosynthetic potential Water Retention Leaf Size
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • 2. Constraints: • finite energy budgets and necessary trade-offs: • Contradictory selective pressures: Rainforest understory – dark, wet Photosynthetic potential Water Retention Big leaves adaptive Leaf Size
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • 2. Constraints: • finite energy budgets and necessary trade-offs: • Contradictory selective pressures: Desert – sunny, dry Photosynthetic potential Water Retention Small leaves adaptive Leaf Size
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • Constraints: • Modeling Selection: • a. Calculating relative fitness
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • Constraints: • Modeling Selection: • a. Calculating relative fitness • b. Modeling Selection
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • Constraints: • Modeling Selection: • 4. Types of Selection
D. Deviations From HWE: • 5. Natural Selection • Fitness Components: • Constraints: • Modeling Selection: • 4. Types of Selection Sexual Selection Some traits that decrease survival may be selected for because they have a direct and disproportional benefit on probability of mating. Intrasexual – competition within a sex for access to mates. Intersexual – mates are chosen by the opposite sex.
Modern Evolutionary Biology I. Population Genetics A. Overview B. The Genetic Structure of a Population C. The Hardy-Weinberg Equilibrium Model D. Deviations From HWE E. Summary; The Modern Synthetic Theory of Evolution Sources of Variation Agents of Change Mutation Natural Selection Recombination Genetic Drift - crossing over Migration - independent assortment Mutation Non-random Mating VARIATION