Card Set Information

2011-02-27 23:55:09

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  1. Analogy
    Simiar functions w/o close relationship

    -similarity is result of convergent evolution (evolve independently of each other)
  2. Homology
    Similarity of structures due to common ancestry regardless of function
  3. Vestigial Organs
    Organs w/ no discernable function

    • ex: coccyx of humans
    • legs of snakes and whales
  4. Evolutionary Anachronisms
    Products of nature that can only be explained in light of evolution ("ghosts of evolution past")

    ex: avacado
  5. Exaptations
    Adaptations that evolved originally for a different function

    ex: feathers on birds (evolved as thermoregulation as opposed to flight)
  6. Embryology
    • -study of organismal development
    • -more closely related organisms should share more of their development

    ex: we all had gills at some point and had a 2 chamber heart
  7. Molecular Biology
    Genetics = Study of heredity

    -we should share more of our DNA w/ those organisms we are more closely related to

    ex: chimpanzees and humans share 98% of DNA
  8. Natural Selection = unequal reproductive success
    those individuals with traits (= adaptations) best suited to the local environment will generally leave more fertile offspring
  9. Modern Synthesis (1930's)
    Merging of evolutionary and genetic research/thought
  10. Populations
    a group of individuals of the same species in the same place, at the same time
  11. Hardy-Weinberg Formula
    p2 + 2pq + q2 = 1
  12. Hardy-Weinberg Formula Assumptions
    • 1 Extremely large population size
    • 2 no mutations are occuring
    • 3 no selection happening (ex: no evolution)
    • 4 random mating
    • 5 no gene flow
  13. Microevolution
    A generation-to-generation change in a populations frequency of allels
  14. Genetic Drift
    A change in the gene pool of a small population due to chance
  15. The Bottleneck Effect
    A drastic reduction in population size

    -only a few survive--->therefore certain alleles are overrepresented and others are underrepresented (or lost)

    ex; cheetas (10,000yrs ago & 19th century)
  16. The Founder Effect
    Only a few individuals w/ a different genetic make-up start a new population

    • ex: 1814, 15 British founded a colony on Tristan de Cunha (in the middle of the atlantic ocean)
    • -one had rare retinitis pigmentosa allele
    • -by 1960's, of 240 descendents, 4 had the disease and 9 were known carriers
  17. Gene Flow
    • A gain/loss of alleles from a populationby the movement of individuals/gametes into or out of a population
    • -if gene flow increases, it will decrease the difference among populations
  18. Mutation
    The raw (original) source of genetic variation
  19. Natural Selection
    Leads to variation between population = geographic variation

    • -bc environmental factors are likely to vary across the range of a species
    • -the main driver of microevolution
  20. Directional Selection
    Select one phenotype over another phenotype
  21. Disruptive Selection
    Select against the most common phenotype which drives the evolution of 2 very different phenotypes
  22. Stabilizing Selection
    Select against both extremes (favor most common, intermediate phenotype)

    -most common
  23. Balancing Selection
    Maintain multiple alleles, maintains 2 or more phenotypes at stable frequencies
  24. Heterozygote Advantage
    Individuals who are heterozygus for a certain trait have greater fitness than homozygus individuals
  25. Frequency-Dependent Selection
    The frequency of any 1 phenotype declines if it becomes too common

    • ex: predator prey interactions
    • side blotched lizards (rock, paper, scissors)
  26. Neutral Variation
    Variation that has little or no affect on reproductive success---> it is not selected for or against

    -while this variation may not have any effect today, it may have an impact in the future if the environment changes
  27. Sexual Selection
    Natural selection for mating success

    -can lead to sexual dimorphism
  28. Intrasexual
    Within a sex

    -competition for mates by individuals of the same se

    • ex: peacocks-best plumage
    • Irish elk-biggest antlers
  29. Why sex?
    • 1 production of diploid cells
    • 2 meiosis-production of gametes (to eliminate errors of
    • recombination)
    • 3 sex is good if its optional
    • 4 selection of sexiness
    • 5 maintained by the good, the bad and the ugly
  30. Good
    Maintainance of beneficial mutations

    -the population can evolve faster
  31. Bad
    Weeding out the bad mutations
  32. Ugly
    Avoid boom/bust cycles caused by parasites

    -the Red Queen Hypothesis
  33. Macroevolution
    The major changes in the history of life

    • ex: origin of new species
    • origin of biological novelties (ex: wings)
    • explosive diversification
    • mass extinction
  34. What is a species?
    • -produce fertile offspring
    • -populations
    • -behavioral interactions
    • -morphological features
  35. Biological Species Concept
    A species is a population or group of populations whose members have the potential to interbreed in nature to produce fertile offspring

    • Alternatives:
    • 1 morphological - physical traits
    • 2 ecological
    • 3 genetic similarity
  36. Prezygotic Reproductive Barriers
    before fertilization

    • a mechaanical isolation-the parts dont fit
    • b behavioral isolation-ex: distinctive odors, calls, mating
    • rituals
    • c habitat isolation
    • d temporal isolation-different breeding seasons
    • e gametic isolation-no union of the male and female
    • gametes
  37. Postzygotic Reproductive Barriers
    (after fertilization)

    • a hybrid inviability
    • b hybrid sterility
    • c hybrid breakdown
  38. Hybrid Inviability
    Dies young and doesn't reach sexual maturity
  39. Hybrid Sterility
    No functional gametes produced by the hybrid

    ex: mules
  40. Hybrid Breakdown
    Offspring are feeble/sterile
  41. Allopatric Speciation
    Geographic barrier that physically isolates a splinter population

    • -many splinter groups don't survive
    • -the splinter population MUST be reproductively isolated
  42. Sympatric Speciation
    • New species originates w/o geographic isolation w/in the parent population.
    • -most common

    • a polyploidy-extra set of chromosomes (common in
    • plants)
    • b habitat differentiation
    • c sexual selection