Chapter 24 Bio T1 **

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  1. population genetics
    • purpose of sex is genetic variability (variability is good!).
    • phenotype variation - environment and evolution
  2. gene pool
    source of all DNA in a population (every allele every single gene)
  3. monomorphic allele
    • single allele/fixed gene 
    • vital genes for making certain proteins. If wrong you... die
  4. single nucleotide polymorphism (SNP)
    • 90% of variation is from here
    • little changes in a gene 
    • large, healthy population = high genetic diversity
  5. hardy weinberg equation
    • p + q = 1
    • p^2 + 2pq + q^2 = 1

    • p is dominant (from gene pool)
    • q is recessive
    • p^2 is frequency of dominant GENOTYPE 
    • 2pq F of heterozygous genotype 
    • q^2 is F of homozygous recessive genotype
  6. equilibrium can only occur
    • the population is very large
    • mating is random
    • no selection
    • no net change in pool due to mutation 
    • no migration in or out
  7. If not in equilibrium
    an evolutionary mechanism is at work
  8. Microevolution
    • new genetic variation 
    • mutation 
    • gene duplication 
    • horizontal gene transfer (ie bacteria)
    • no major factor dictating allele frequency
  9. macroevolution
    • evolutionary mechanism 
    • random genetic drift
    • migration
    • nonrandom mating
    • widespread
  10. natural selection
    beneficial traits that are heritable become more common in successive generations

    • overtime NS results in adaption 
    • (ie elephant nose, giraffe neck)
  11. NS reproductive success
    • surviving long enough to reproduce (get to reproductive age)
    • reproduce more than competitors
  12. Modern Natural Selection
    • Variation in population 
    • Some have proteins that can live longer
    • Contribute to gene pool of the next generation
    • Can alter characteristics of population over time
  13. NS Patterns
    • Directional 
    • Stabilizing
    • Distributive
    • Balancing
  14. Directional selection
    Image Upload 1
  15. Stabilizing selection

    middle is favoured Image Upload 2
  16. Disruptive Selection

    both extremes survive
    Image Upload 3
  17. Balancing Selection
    heterozygote has the advantage (so sort of like balancing)
  18. sexual selection
    • deciding who you're going to mate with 
    • instrasexual - within same sex (ie M vs M for F)
    • intersexual - female choice
  19. Genetric Drift
    • More of an issue in smaller population
  20. Fixation
    • only 1 allele in population 
    • ie mitochondria gene
  21. bottle neck
    population is dramatically reduced then rebuilds (have less diversity and not good b/c if something happens that has that trait, then will die out
  22. founder effect
    one group starts a new population. As multiply, grow and diversify
  23. non random mating
    • assoratative mating - like phenotypes more likely to mate
    • disassortive mating -(opposites attract) favours heterozygosity
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Chapter 24 Bio T1 **
biology test 1 chapter 24
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