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86 Cards in this Set
- Front
- Back
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What is the initial frequency of a mutant allele in a diploid population?
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1/2N
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What is the backwards rate of mutation? forwards?
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v; mu
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When a mutation is recessive, how is q hat found? How can q hat increase?
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square root of mu divided by selection coefficient; if mu is high and s is low
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When a mutation is dominant, how is q hat found? How can q hat be maintained?
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mu divided by selection coefficient; high mu and weak s
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When is it easier to reduce the frequency of q hat, when mutation is recessive or dominant?
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dominant
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At equilibrium, what is the equation for p hat? q hat?
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p hat = v/v+mu
v hat = mu/v+mu |
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What is the difference between zygotic gene flow and gametic gene flow?
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zygotic: whole organism moves
gametic: eggs or sperm moves |
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How is the freq. of A1 in island population at generation t (p'I) calculated?
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(1-migration rate)(pI)+ (migration rate)(pc) where pI is A1 freq. on island and pc is A1 freq. on mainland
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How is the change in freq. of A1 calculated on an island after migration?
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migration rate (pc-pi)
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How is the migration rate calculated?
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number migrants from mainland/island population size
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What are the genetic consequences of gene flow among populations?
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1. Make populations sharing migrants more genetically similar
2. has a homogenizing effect on genetic variation b/t pops 3. slows down differentiation 4. inhibits pop subdivision 5. prevents speciation |
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What is effective population size (Ne)?
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number of individuals in a population that mate and reproduce
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The time to fixation of a neutral allele is directly proportional to which two factors?
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population size; initial allele frequencies
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What is a population bottleneck and how can it affect allele frequencies in a population?
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where population size is drastically reduced due to disaster or disease; alters allele frequencies
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Why do founder events often lead to a decrease in the genetic diversity of a population?
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founder events are a small sample of a population where much of the genetic info is lost--can't carry all the info
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How strong must natural selection be, to overcome the effects of genetic drift in small populations?
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over 1/breeding individuals (Ne)
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What is consanguineous mating?
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mating with a close relative (first cousin or closer)
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What is selfing?
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mating with yourself
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What are the specific genetic effects of inbreeding?
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1. Increase homozygousity
2. Deviation from HWE 3. Exposes deleterious recessive alleles--decrease in fitness |
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Describe alleles identical in state? identical by descent? Which is homozygous, which is autozygous?
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have same nucleotide sequence--homozygous; copy of the same allele from a common ancestor--autozygous
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What is an inbreeding coefficient (F)?
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probability a random individual is autozygous
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What is inbreeding depression?
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decline in average fitness of a population due to exposure of deleterious recessive alleles in
autozygous state |
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What are the 5 properties of quantitative traits?
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1. simultaneous segregation of many genes
2. the more loci that affect the trait, the greater possible phenotypes 3. Each loci has a small effect on the phenotype 4. alleles at different loci add together to produce the phenotype 5. the same genotype may have different phenotypes depending upon environment |
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What are some examples of quantitative traits?
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1. height, swimming speed, IQ
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Which two ways can the same genotype have different phenotypes?
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1. maternal environment
2. phenotype plasticity |
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What are the 3 types of quantitative traits?
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continuous traits, meristic traits, threshold traits
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Describe continuous quantitative traits and give examples.
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continuous distribution of phenotypes--normal distribution; height, weight, growth rate
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Describe meristic quantitative traits and give examples.
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phenotype is expressed in discrete integral classes; litter size, petal number, offspring number
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Describe threshold quantitative traits and give examples.
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trait is governed by some threshold expression of loci involved; color in caterpillars and butterflies
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What is a preadaptation? example?
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existing structure that is modified into a new adaptation; pit viper fangs
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What is an example of an idiosyncratic adaptation?
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gliding ability in squirrels, frogs, snakes, fish
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What is the difference between convergent and idiosyncratic evolution?
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convergent evolve the same adaptation while idiosyncratic evolve different adaptations to the same challenge
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Name a few examples of convergent evolution?
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saltatory animals w/ enlarged hind limbs for jumping (frogs, kangaroos); eyes in vertebrates and octopuses; anteaters
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What are the 3 reasons all organisms aren't perfected adapted?
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1. historical constraints
2. trade-offs 3. lack of genetic variation |
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Describe how historical constraints may not allow organisms to be perfectly adapted?
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prior evolutionary history/adaptations might constrain the future adaptations able to occur
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Describe how trade-offs may not allow organisms to be perfectly adapted? Give an example.
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Phenotype is a compromise between optimal values for individual traits--principle of allocation; biomass of seed is fixed--tradeoff between number and size
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Describe how lack of genetic variation may not allow organisms to be perfectly adapted? Give an example.
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May simply lack the genetic variability to evolve new adaptations; beetles--Many beetle species can only feed on and detoxify certain plants.
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What can a phylogenetic comparative approach can tell us about adaptation?
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1. whether an adaptation is uniquely derived or associated with diversification of a clade
2. whether an adaptation is convergent or derived |
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What is the currency of natural selection? sexual selection? kin selection?
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1. direct fitness
2. mating success 3. inclusive fitness |
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What 2 types of traits are targets of sexual selection?
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1. exaggerated nature of many secondary sexual characteristics
2. sexual dimorphism |
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Why might exaggerated 2' sexual characteristics be sexually selected against?
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1. energetically expensive to maintain
2. increase risk of predation |
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Give 3 examples of sexual dimorphisms.
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red deer
guppies golden toads |
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What are 2 ways costs differ between males and females in sexual selection
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1. cost of gametes
2. cost of parental investment/caring for young |
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How do males maximize their fitness as opposed to females?
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maximize matings; females have a higher investment so they are more choosy
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What are the two ways sexual selection can operate?
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intrasexual selection and intersexual selection
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Describe intrasexual selection; give an example.
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traits are favored that increase the ability of one sex to compete directly with one another for mating (male competition); larger body size in elk
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Describe intersexual selection; give an example.
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traits are favored in one sex that makes them more attractive to the opposite sex; tails in peacocks
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What are the 3 ways males compete?
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1. resources/territories (nesting sites, food for young or female)
2. access to females 3. sperm competition |
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What are 3 examples of males competing for access to females?
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1. leks--communal male display grounds
2. mate guarding 3. harems |
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What are the 3 methods of sperm competition?
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1. sperm displacement
2. alternative male mating strategies (sailfin mollies) 3. infanticide |
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What are the 3 hypotheses to explain why females choose among male phenotypes?
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1. immediate benefit
2. male traits are indications of good genes 3. Fisher's runaway process |
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How might immediate benefit influence females' selection in mates? Give an example.
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certain males make better fathers, males could provide nutritional benefit; hanging fly males are allowed to copulate longer with the bigger gift given to the female
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How might certain male traits being indicators of good genes influence females' selection in mates? Give an example.
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since exaggerated sexual characteristics take more energy to maintain, they must have better genes; length of mating call of frog
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Is the immediate benefit hypothesis of female selection direct, indirect, or no selection? Give an example
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direct selection
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Is the good gene hypothesis of female selection direct, indirect, or no selection?
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indirect
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How might the Fisher Runaway Process influence females' selection in mates? Give an example.
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females choose arbitrary traits that don't confer better fitness; a genetic correlation between the male trait genes and female selective genes ensure sons will have that trait and daughters will be choosy for that trait; females stalk-eyed flies prefer males with longer eyes
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Is the Fisher Runaway Process hypothesis of female selection direct, indirect, or no selection?
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indirect
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Under what conditions can natural selection and sexual selection be opposing forces on the evolution of a male trait? Give an example from nature.
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If a sexual characteristic increases chances of predation; Tungara frog--> more complex calls attracts ladies, since predation rate is high, forced to use more chucks
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What is the relatedness between:
a) parent- offspring? b) half siblings? c) full siblings? d) grandparent-grandchild? e) uncle-nephew? f) cousins? |
a) .5
b) .25 c) .5 d) .25 e) .25 F) .125 |
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Describe the altruistic acts of Belding's ground squirrels. How do these acts benefit the altruist?
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In a colony, closely related females remain close to home while nonrelated males disperse; alarm calls are made to warn about predators (snakes/birds) even though the alarm caller is at risk of predation; calls are given more likely when relatives are out in the open than non relatives and when those relatives are offspring or mothers rather than cousins or nieces
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What are the 4 types of social behavior and describe.
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cooperative- actor and recipient +
selfish- actor +, recipient - altruist- actor-, recipient + spiteful- actor-, recipient - |
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Describe the altruistic acts of white fronted bee eaters. How do these acts benefit the altruist?
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live in colonies where nest sites are limited leading to extra adults in nest sites. helpers don't breed and instead help increase survival of nest offspring; helps close relatives the most
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Describe the altruistic acts of naked mole rats. How do these acts benefit the altruist?
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lives in large underground colonies expanded by digging new tunnels, however growth of colony is limited to suitable soil and effort to expand; in order to not over-produce there is a lot of interbreeding and supression of reproduction is females other than the queen
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What are the four potential mechanisms by which individuals might come to recognize kin?
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1. spatial proximity
2. associative learning 3. phenotype matching 4. recognition alleles |
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How is spatial proximity used to recognize kin? example?
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individuals in same nest are kin; birds
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How is associative learning used to recognize kin? example?
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individuals who one often interacts with are kin; if a fish is raised by itself it can't find kin, if raised with kin can recognize kin, if raised with stranger thinks stranger is kin
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How is phenotype matching used to recognize kin?
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individuals that resemble individuals one often interacts with are kin; if a fish is raised by itself, it can't recognize kin, if raised with kin it can recognize kin, if raised with stranger it can't recognize kin
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How are recognition alleles used to recognize kin?
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individuals who share the same alleles are kin; doesn't matter if a fish is raised by itself, kin, or a stranger, it can recognize kin
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Why did sterile workers challenge Darwin's theory of natural selection?
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they gave up reproduction--the whole point of fitness and natural selection
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What are the three conditions common to all eusocial societies that potentially contribute to evolution of this type of social system?
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1. among closely related individuals
2. when worker reproduction is controlled 3. when nest sites are limited |
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What are the relationships between evolution and human health?
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1. pathogen evolution (antibiotic resistance, new strains, virulence evo)
2. humans and selection |
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Name 4 ways bacteria acquire resistance?
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1. mutations
2. lateral transfer of plasmids 3. viral transfer of resistance gene 4. scavenging of resistance gene |
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What is an example of a point mutation in bacteria that increased resistance?
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Rifampin resistant tuberculosis
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What are the 3 main hypotheses for the evolution of virulence?
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1. coincidental evolution
2. short-sighted evolution 3. trade-off hypothesis |
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Describe the coincidental evolution hypothesis for evolution of virulence. Give an example.
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The virulence of some pathogens in humans may be accident and not due to direct selection for them in humans; C. tetanae is a soil bacterium, virulence in humans is just a byproduct
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Describe the short-sighted evolution hypothesis for evolution of virulence. Give an example.
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pathogens evolve in a host for many generations, leading to new strains that benefit them in the host but doesn't transmit to others; poliovirus usually infects digestive tract then infects nervous system
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Describe the trade-off hypothesis for evolution of virulence. Give an example.
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directly transmitted pathogens evolve lower virulence in exchange for being able to infect more people while vector transmitted pathogens have a higher virulence but can't infect quite as many people; direct: cold, flu; vector: malaria
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Describe 2 ways natural selection can lead to cancer.
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1. selection for increased sperm production--> increased spermatogenesis--> cancer in somatic cells
2. selection for better placenta building genes--> hijacked by cancer cells |
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How do scientists design flu vaccines?
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Since antigenic sites are most likely to mutate, researchers determine which of the living strains are more likely to survive, being the ones with the most mutations on antigenic sites
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What determines fitness of a virus?
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stronger stabilizing selection--lower Ka to Ks ratio--Ka= nonsynonomous
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How does the hypothesis of human adaptation to our hunter-gatherer past help explain the prevalence of some current human diseases?
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our lifestyle was much different--more reproduction, physical activity, less food; myopia came about from us looking at computer screens and books and ipods; increase of menstrual cycles increase breast cancer
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How does a Darwinian approach to medicine influence how physicians treat the symptoms of common diseases, and why?
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smoke alarm; our bodies react strongly to potential threats because the cost of a false alarm is low but the cost of not reacting to a real alarm is high--morning sickness
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Give an example of a highly hereditable trait.
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beak depth in song sparrows
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How do stabilizing and disruptive selection differ and how are each related to overdominance and underdominance respectively?
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stabilizing is where intermediate phenotype is more fit, disruptive is where both extreme phenotypes are more fit. overdominance is where heterozygote phenotype rules while underdominance is where homozygous phenotypes rule
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Give an example of stabilizing selection
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human birth weight
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Give an example of disruptive selection.
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African butterfly coloration
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