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Evolution of Populations

Evolution of Populations. DO NOW. Is evolution random or non-random? Be prepared to discuss. . DO NOW. Hand in Chapter 22 Homework and signed contract (place in folder marked with your class period)

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Evolution of Populations

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  1. Evolution of Populations

  2. DO NOW Is evolution random or non-random? Be prepared to discuss.

  3. DO NOW • Hand in Chapter 22 Homework and signed contract (place in folder marked with your class period) (2) Write your name and class period on your lab supply item and place it in the corner of the classroom in the spot marked with your class period (3) Put away bags and cell-phones – we will begin with the quiz

  4. Selection In Action • Peppered moths • Darwin’s finches • Antibiotic-resistant bacteria • Lactose tolerance in humans

  5. Modern Evolutionary Synthesis • Darwin’s theory of evolution by natural selection lacked an explanation for the basis of heredity. Genetics helped explain this, creating a synthesis between the idea of Darwinian selection and Mendelian genetics.

  6. Evolution of Populations Population: localized group of individuals belonging to the same species Evolution happens on a larger level than the individual organism – evolution occurs at the level of populations.

  7. Population genetics: the study of genetic variability within populations • Gene pool: combined aggregate of genes in a population at any one time • Species: a group of populations that have the potential to interbreed and produce fertile offspring in nature

  8. Hardy-Weinberg principle • states that allele and genotype frequencies will remain constant from generation to generation in the absence of other evolutionary influences

  9. Hardy-Weinberg Theorem Assumptions • Very large population size • No migration • No net mutations • Random mating • No natural selection

  10. Mechanics of Hardy-Weinberg p = allele 1 q = allele 2 p + q = 1 (100% of population) Note: This is for calculating frequencies of genotypes when there are only 2 alleles for a single locus

  11. Punnett Square for Hardy-Weinberg p2 + 2pq + q2 = 1

  12. Microevolution

  13. Bottleneck Effect

  14. Genetic Drift

  15. Founder Effect

  16. Steps of The Scientific Method

  17. Experimental Method • Only one variable must be tested at a time, with the result being compared against a control • Independent and dependent variable

  18. Genetic Variation Within Populations • Polymorphism • Gene diversity • Nucleotide diversity

  19. Geographic variation Cline

  20. Maintaining Genetic Variation In Populations • Diploidy • Heterozygote advantage • Frequency-dependent selection • Neutral variation

  21. Modes of Selection

  22. Intrasexual selection Direct competition among individuals of the same sex

  23. Intersexual selection Also known as mate choice, when members of one sex are choosy in selecting mates of opposite sex

  24. Balanced polymorphism • Ability of natural selection to maintain stable frequencies of two or more phenotypic forms

  25. Heterozygote advantage • When individuals that are heterozygous at a particular locus have a greater survivorship and reproductive success

  26. Frequency-dependent selection • Survival and reproduction of any one morph declines if the phenotypic form becomes too common

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