Genetics and Evolution

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Genetics and Evolution
2010-09-07 00:37:50

Anthropology chapter 4
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  1. Adaptive (advatageous)
    Certian triats that result in greater reproductive success in particular environment.
  2. Allele
    Each member of a gene pair or group.
  3. Balancing Slection
    When a heterozygous combination of alles (genes) is positively fovored.
  4. Maladaptive (dissavantageous)
    Certain traits that will genreally decline in frequency or even dissaear eventually.
  5. Cline
    The variation of frequency from one end of the region to the other.
  6. Crossing-over
    The exchange sections the pair of homologus chromosomes in meiosis during seperation.
  7. Directional Selection
    Increases the frequency of a trait (the trait is positively fovored and average value shifts over time toward the adaptive trait)
  8. Natural Selection
    The main process that increases the frequency of adaptive traits through time, which involves 3 conditions: variation, heritability, an ddifferential reproductive success.
  9. Normalizing Selection
    Average value does not change, but natural selection removes the extremes.
  10. Segregation
    One cause of shufflig or sorting of chromosomes in meiosis, where an individual could get any of the possible assortments of paternal and maternal chromosomes.
  11. Sources of variability in natural selection (5)
    • Genetics: Genetics rcombination and mutation
    • Processes: Gene flow and Genetic drift
    • Potential surce: Hybirdization
  12. Mutation
    Change in the DNA sequence.
  13. Genetic Drift (Wright Effect)
    Various random processes that affect gene frequencies in small, relatively isolated populations. Two variety of genetic drifts are founder and bottleneck effect.
  14. Gene Flow
    The process whereby genes pass from one population to another through mating and reproduction.
  15. Species
    A population that conssits of organisms able to interbreed and produce fertile and viable offspring.
  16. Hybridization
    The creation of a vible ofspring from two different species.
  17. Speciation
    The development of a new species, may occur if one subgroup of a species finds itself in radically different environment and undergo enough gentic changes to prevent the two population from interbreeding.
  18. Gradualism
    Traits frequencies change only gradually over time.
  19. Punctuated equilibrium
    New species involve quickly; but once a sucessful species emerges; its characteristics are likely to change very little over a long periods of time.