Evolution 3-microevolution

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Evolution 3-microevolution
2014-02-23 08:03:26
biology evolution

the study of evolutionary biology with emphasis on microevolution
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  1. Localized group of individuals that are capable of interbreeding and producing fertile offspring
  2. All of the genes in a population at any one time
    gene pool
  3. Modern synthesis was born from
    Darwinian evolution + Mendelian genetics
  4. Existence of two or more distinct morphs each represented in a population in high enough frequencies to be readily noticeable
    Polymorphism (phenotypic)
  5. Calculate the frequency of alleles
    red allele frequency= all red alleles/total#allele
  6. Hardy-Weinberg Theorem
    • Frequencies of alleles in population gene pool should remain constant across generations
    • p2+2pq+q2=1
  7. Change in DNA nucleotide sequence; corresponding change in mRNA may alter protein synthesis
  8. Random fluctuation in gene pool (especially important in small populations)
    Genetic drift
  9. Sudden event dramatically reduces population size. Sudden event dramatically reduces population size, future variations
    Bottleneck effect- ie: a hurricane devastates a population only leaving certain survivors
  10. Isolated group starts new population with no further gene glow from source population. Some populations are not able to interact with the rest of the group
    Founder effect
  11. Consequence of the bottleneck & founder effects: artificial selection
  12. Genetic input from other populations
    gene flow
  13. Mean proportion of loci that are heterozygous; used to help measure genetic diversity for the population
    • average heterozygosity
    • #heterozygote individ/total population
  14. Gene pool differences among populations
    geographic variation
  15. graded variation in a trait parallels environmental gradient
  16. wild plants from different altitudes were grown in controlled conditions
    common garden experiment
  17. three ways natural selection can alter variation in a population
    directional, disruptive, stabilizing selection
  18. favors intermediate variants by acting against both extremes
    stabilizing selection
  19. favors individuals on both extremes of phenotypic range
    disruptive selection
  20. natural selection that favors individuals at one end of the phenotypic range
    directional selection
  21. natural selection for mating success; may produce
    sexual selection
  22. distinct male vs female adult phenotypes (secondary sex characteristics)
    sexual dimorphism
  23. direct competition for potential mates. Mate choice; one sex usually females are choosy in selecting their mates
    intersexual selection
  24. Maintains stable frequencies of multiple phenotypic forms
    balancing selection
  25. success of one phenoypic morph declines when it becomes too common in the population
    frequency dependent selection