Evolution exam 2

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Evolution exam 2
2014-04-06 15:18:16
sfsu evolution

Exam 2
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  1. island model requires these 3
    • pop size equal
    • constant pop size
    • equal migration rate among pop
  2. need to use direct method to get the most current estimate of gene flow
  3. 2 pros of indirect methods of gene flow estimation
    • gives long term levels of gene flow
    • good at estimating rare gene flow
  4. 3 cons of indirect methods of gene flow estimation
    • can be expensive
    • must use mathematical model
    • only measures long term gene flow
  5. individual fitness
    the # of zygotes that a zygote produces
  6. if individuals w/ characteristics to produce more offspring will pass on those traits to produce more offspring
  7. viability selection
    difference among zygotes in their ability to survive until adulthood
  8. sexual selection
    difference among adults in their ability to obtain mates
  9. fecundity selection

    (how many zygotes a zygote can produce)
    differences among individuals in their abilities to produce zygotes
  10. genotype fitness
    fitness of the 3 genotypes at 1 locus w/ 3 alleles
  11. individuals have fitness
  12. genotypic fitness is the average fitness of individuals that have genotype
  13. absolute fitness
    # of babies produced
  14. relative fitness
    the relating of fitness to one of the fitness
  15. need to be in flow and drift to use Fst
  16. balanced polymorphism
    more than one kind of alleles being held at selection frequency
  17. heterozygotes of sickle cell have blood cells that if touched by the malaria virus will cause it to sicklee while the spleen will filter out the virus
  18. selection and drift are always occuring in a population
  19. selection works best on a large pop, otherwise drift will take over and eliminate the alleles rom selection
  20. alleles can be elimated by random chance
    sometimes you can fix for a recessive deleterious allele
    these things can occur due to being in a small pop
  21. 2 forces of evolution
    • selection;
    • gene flow
  22. if the 2 forces are globally selected and forced everywhere then it will be fixed in a pop
  23. eventhough selection is occuring in among 2 populations by navigation
    gene flow can override the action causing the population to adapt
  24. average excess
    the average fitness of an individual that has an allele compared to a pop as a whole
  25. gene flow makes adaptation difficult because it keeps bringing in genes which causes adaptation to be thrown off
  26. 4 factors that affect evolution
    • phenotype-environment interaction
    • genetic architecture
    • population structure
    • history
  27. phenotype-environment interaction (ecology)
    whats the interaction in the environment
  28. 2 forms of gene action
    • additive
    • nonadditive
  29. 2 forms of nonadditive gene flow
    • dominance
    • epistasis
  30. genetic architecture
    • genetic basis of the trait
    • ex: # of loci that effect the trait
    • # of alleles per locus
  31. additive gene action
    what an allele does to a pheno is  indepedent of its genetic context
  32. nonadditive gene action
    the effect of an allele on a pheno depends on its genetic context
  33. in nonadditive gene action 
    dominance is located
    epistasis is located
    • at the loci
    • at different loci
  34. epistasis
    the effect of one gene depends on the presence of one or more background genes
  35. population structure
    factors that effect how gametes come together to create zygotes
  36. quantitative genetics
    the field of study of complex traits that are effected by other loci or the environment
  37. 4 types of selection
    • directional
    • stabilizing
    • disruptive
    • truncation directed
  38. directional selection
    individuals w/ an extreme pheno have high fictness than the rest of the individuals in the pop
  39. in directional selection, high values of the trit have high values of fitness and vice versa
  40. is responsible for most or all biodiversity seen
    directional selection
  41. in this type of selection the mean changes and is similar to typical selection
  42. in directional selection, nonadditive effects it by these 2
    • adding variance or taking it away
    • push selection to go on
  43. stabilizing selection
    when individuals with mean pheno in a pop have the highest fitness
  44. 3 characters to stabilizing selection
    • makes individuals more similar to another
    • keeps means same
    • will eventually get a pop that is correct and is stable (height of humans)
  45. is the most commonly found selection in nature b/c directional selection is efficient in changing pop
  46. disruptive selection
    when individuals w/a mean trait value have the lowest fitness in a single pop
  47. truncation directional selection
    selection divides pop into breeders and nonbreeders based on their pheno
  48. in breeders, your pheno is irrelevant and doesnt matter anymore
  49. dissent generation
    assume parents have babies then die
  50. parents will have a trait value and it will be bigger
  51. selection differential
    measure of difference  betweent the mean of a pop and the mean of selected parents
  52. disruptive selection
    measures the strength of selection on the pheno
  53. heritability
    similarity between pheno of parents and offspring
  54. genetic disorders that is caused by a mutated gene that cant really be fixed on its own
    phenyalanine can be converted to tyrosine via a chemical rxn, if it cannot it will be turned into phenyl ketone, if you do not produce enough tyrosine you can develop phenyl ketonuria
  55. a disorder in which the gene is lacked but can be fixed by an individual
    • L-gulonolactone can be converted to vitamin C by a chem rxn
    • lack the gene that cant produce the rxn to occur 
    • if you cant produce the vita C you can get scruvy
  56. phenotypic variance
    • w/in a single pop 
    • variance among individuals in pheno
  57. genetic variance
    • w/in a single pop
    • variance among individuals caused by difference in geno
  58. environmental variance
    • w/in a single pop
    • variance among individuals caused by difference in environment
  59. just because heritability is high doesnt mean you will be able to determine what the kid will look like
  60. selection after variance is smaller
  61. on average, offspring look like the average of the parents
  62. variane in pheno is equal to variance in geno but not the variance in environment
  63. if you know the pheno you know the geno
  64. traits are genetically determined but is not heritable its inherited
  65. additive genetic variance
    w/in a pop the variance among individuals in pheno caused by genes w/ additive effects
  66. non additive genetic variane
    w/in a pop the variance among individuals in pheno caused by genes w/ non additive effects
  67. contributes to heritability
    additive genetic variance
  68. does not contribute to heritability
    non additive genetic variance
  69. you need to have additive gene variance to get any heritiability among offspring
  70. the degree to which parents look like their offspring depends on the degree of additive and nonadditive genetic variance
  71. additive genetic variance changes allele freq has no effect
  72. non additive changes allele freq has a drastic effect on whether or not there is an effect on heritibility
  73. whether or not an allele is dominant doesnt mean its heritable
  74. the more environmental variance you have the less heritability you have
  75. when Ve=0 the geno and pheno is the same
  76. the environment plays no part in heritability only allele freq
  77. same genetic basis causes allele to have diff freq
  78. most sick individuals reproduce to make healthy babies
  79. 2 sick individuals will produce sick and healthy babies
    2 healthy individuals can produce sick and healthy kids
  80. recessive deleterious alleles hide in the zygotes of healthy and sick individuals
  81. 2 subjects when it comes to the complexity of
    • logistics
    • conceptual
  82. 2 forms of logistics
    • sample size
    • phenoo similarity caused by shared environments
  83. when it comes to sample size of logisticsyou need a large amount of samples to get an accurate reading
  84. pheno similarity caused by shared environment
    some pheno is similar between full siblings because they shared the same unterus
  85. 6 forms when it comes to conceptual
    • H2 doesnt apply to individuals
    • does produce specific families if E is not zero
    • heritability is specific to a particular pop
    • H2 is specific to a particular environment
    • H2 says nothing about causes of variance among pop
    • high heritability that an individuals pheno will not be changed by environment change
  86. meaning of conceptual in complexity of H2
    H2 is phenotypic similarity between P and O in a pop in a given environment on average what could go wrong
  87. recessive genetic diseases are not heritable
  88. you cant predict heritability to be similar because of additive gene action
  89. difference among a pop can be more than genetic but environmental
  90. 2 types of selection
    • artificial
    • natural
  91. artificial selection
    when a human determines the fitness of individuals based on the pheno of those individuals
  92. natural selection
    make the environment determine the fitness of individuals based on the pheno of these individuals
  93. NS is still considered such even if humans change the environment
  94. 3 costs of reproduction
    • eggs are expensive
    • pregnancy/gravidity is expensive
    • parental care is expensive
  95. how are eggs expensive
    • it takes the female energy to produce compared to sperm
    • *exclusive to females*
  96. how is pregnancy expensive 2
    • it takes E for the female to hold and care for the babies
    • they need to provide for the baby so it can survive
    • *exclusive to females*
  97. how is parental care expensive 2
    • it takes energy to care for the offspring
    • parents have to help their offspring to survive
    • *exclusively for males and females*
  98. cost of reproduction is higher in females and less for males
  99. because of the cost reproduction, females can increase fitness by increasing offspring quality, females can evolve choosiness
  100. How males respond to female to choosiness 2
    • Increase offspring quality 
    • Increase offspring number
  101. How do males increase the number of offspring they produce
    Can mate with multiple females so it increases their chances of their genes being passed on
  102. difference between sexes is variance of reproductive success
  103. females choose mates depending on quality, however; in the end all females end up with a mate despite the mate not being of their choice
  104. in a pop where there is a 1 to 1 ratio of males and females, if one male mates with both females
    sometimes the other male who didnt mate may die off and not get to pass on its genes
  105. sexual selection is stronger in
  106. 2 basic catergories of models of sexual selection
    • intersexual
    • intrasexual
  107. intersexual selection
    when the force that drives sexual selection is female choice
  108. similarity between inter and intra selection
    • males compete to be choosen by the female
    • sometimes they do it in a variety of ways
  109. intrasexual selection
    female choice is not the driving force for sexual selection
  110. direct male to male competition for mates
    males will fight with each other for the best mating territory where all the females are
  111. results of males fighting will have larger males favored by the females because they are bigger and possibly stronger. At least strong enough to fight off others for their spot
  112. results of male to male competition are due to these 3
    • larger bodies
    • weapons/armor
    • alternative strategies
  113. 2 examples of direct male to male competition when it comes to fighting
    • the ungulates  horns that females do not posses. they will fight for territory, the most equipped one wins, they are selected for mutation that causes an increase in horn or body size to win
    • frogs will fight using spikes they possess on their arms. those with stronger or bigger spikes will win and usually be choosen 
  114. intersexual selection example is when birds with long tails had their tails cut off and placed on another bird. That bird was favored by females and produced more offspring
  115. 4 forms of alternative strategies
    • satellite males
    • sperm competition
    • mate guarding
    • genitial plug
  116. satellite males aka sneaky fighters
    these are males who are known that they will lose fights against the bigger males but still manage to get a mate
  117. some satellite males will look like females so they can hang around and the males wont scare them away. 
    • examples:
    • male fish who are trying to fertilize the eggs in the water, other males who are sneaky fighters will come in and release their sperm into the egg area so they can fertilize the eggs as well
    • frogs will hang around where the larger males call the females. en when the female comes the sneaky male will quickly mate with the females
  118. sperm competition example is when the mosquito places its sperm sack into the female. then another male will insert his sperm packet and remove the other males so only his gets fertilized and not the other ones
  119. both inter and intra sex selection can occur at the same time
  120. mate guarding
    when the male will guard the female until she lays her eggs so they can make sure they can spread their sperm so there wont be sperm competition
  121. genital plug
    sometimes after mating the male places a plug into the female to prevent other males from displacing their sperm
  122. sometimes males will guard the female only if there are many other males around. however if there isnt then they will leave to go off and do what ever