Chapter 16&17

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Chapter 16&17
2013-12-08 17:25:42
bio 103

How populations evolve and speciation
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  1. population-
    all memebers of a single species occupying an ares at the same time
  2. gene pool-
    all the genes or alleles of all the individuals in the population
  3. macroevolution-
    any evolutionary cahnge at or above the species level
  4. micorevolution-
    occurs when there is a change in the allele frequency of genetic chracteristics within a population
  5. variations-
    raw material for evolutionary change in a population
  6. gene mutations-
    • frameshift
    • point
  7. chromosome mutations-
    • number 
    • structure
  8. recombinations-
    • crossing over
    • fertilization
  9. calculation gene frequency-hardy weinburg law-
    • provides a base line to judge whether evolution has occured 
    • 1=p^2+2pq+q^2
  10. the frequencies of alleles in a population will remain the sme in each succeeding generation as long as:
    • no mutations
    • no gene flow-noimmigration and no emigration
    • random mating-each individual has an equal cahnce to mate with any other individual
    • no genetic drift-no random cahnges in allele frequency due to cahnce
    • no natural selection-each individual is as fit as all the other organisms
  11. agents of evolutionary change-
    • mutations
    • geneflow-initially increases diversity but as it continues two populations become more similar
    • non random mating-1. interbreeding-mating between relatives 2.assortive mating-organisms tend to mate with those of similar phonotype (physical appearance)
    • genetic drift
    • natural selection-only thing that results in adaptation forces that limit the reproductive success
  12. founder effect-
    occurs when small number of individuals rep a fracting of the original population found a colony and only certain of the original alleles are passed on
  13. bottleneck effect-
    when a population is subjected to near extinction due to natural disorder, junting, habitat lost
  14. natural selection requirements-
    • variations
    • inheritance
    • defferential adaptiveness
    • defferential reproduction
  15. directional selection-
    occurs when the environment is changing. phenotype selected: extrme over average
  16. stablizing selection-
    occurs when the environment is constant. phenotype selected:average over extreme
  17. disruptive selection-
    phenotype selected:extreme over extreme
  18. maintnecance of variations-
    is beneficial because the enviromental may change
  19. speciation-
    the splitting of 1 species into 2 or the transformation of 1 species into new species overtime
  20. species-
    potentially interbreeding organisms
  21. premating mechanisms-
    • habitat-where organisms lives, reproduces
    • temporal-what time mate
    • behavioral-sounds, visuals, signals, pheramones
    • mechanical-reproductive structures
  22. postmating mechanisms-
    • gamete mortality-death at egg or sperm
    • zygote mortality-death of fertilized egg
    • hybrid sterility-offspring steril
    • f2fitness-grandchikd sterile
  23. speicalization occurs when populations diverge from one another to the extent that memebers of 1 population no longer capable of successful reproduction with members of another population
  24. allopatric spciation-
    populations separated by geographic barriers that prevent them from reproducing. variations accumalate until reproductively isolated
  25. sympatric speciation-
    members of a single population develop a gentic differnce that prevents them from reproducing wiht the parent type
  26. adaptive radiation-
    rapid development from a single anestral species of many new species