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Evolution > ch.11: sexual consequences and outcomes > Flashcards

ch.11: sexual consequences and outcomes Flashcards

1
Q

Cell Division

A

asexual reproduction without meiosis or fusion of haploid gametes through fertilization
EX: bacteria

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2
Q

Parthenogenesis

A

mode of reproduction in which female sex cells undergo meiosis but are NOT fertilized by sperm (all female and each produce ONLY daughters)

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3
Q

Hermaphrodites

A

reproduction that produces female and male gametes
EX: flatworms

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4
Q

Twofold cost of sex

A

asexual lineages multiply faster than sexual lineages

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5
Q

Mullers Ratchet

A

the process by which the genomes of an asexual population acculmate deleterious mutations in an irreversible manner
*asexual
*has genetic hitchhiking

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6
Q

Genetic Load

A

the burden imposed by the accumulation of deleterious mutations

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7
Q

Deleterious alleles become ____ in ____ populations but are purged from ____ populations.

A

fixed
asexual
sexual

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8
Q

Red Queen Effect

A

for coevolving population, to maintain relative fitness, each population must constantly adapt to the other
EX: New Zealand Snails

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9
Q

Anisogamy

A

sexual reproduction involving the fusion of two dissimilar gametes

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10
Q

Operational Sex Ratio (OSR)

A

ratio of males to females capable of reproducing at a given time and slower rate of reproduction by females leads to male biased OSR

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11
Q

Intrasexual

A

within a sex
female vs. female
male vs. male

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12
Q

Intersexual

A

between sex
female vs. male

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13
Q

Ornaments

A

attractive traits that increase mating success

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14
Q

Arnaments

A

weaponry used to outcompete other individuals

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15
Q

Direct choice

A

benefit the female directly
EX: food, nest sites, protection

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16
Q

Indirect benefits

A

benefits that affect the genetic quality of the females offspring

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17
Q

Female preferences are often _____.

A

consistent (gets passed down to offspring)

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18
Q

Sex Role Reversal

A

females compete over access to
EX: wattled jacanas, sea horses, pipefish

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19
Q

Fisher’s Principle: Frequency-dependent selection

A

fitness is dependent on the frequency of a phenotype or genotype in a population

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20
Q

Trivers-Willard Hypothesis (1973)

A

proposed that natural selection could drive OSR away from 1:1 under certain conditions

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21
Q

Males benefit when mother invests ____ in current offspring.

A

more

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22
Q

Females benefit by _____ for future offpsring.

A

saving resources

23
Q

Senescence

A

the deterioration in the biological functions of an organism as it ages

24
Q

Senescence results from a ____ of reproduction early in life verses body maintenance for longevity

A

trade off

25
Q

Disadvantages of Sex

A
  1. Twofold Cost of Sex
  2. Search Cost
  3. Reduced Relatedness
  4. Risk of Sexually Transmitted Infections
26
Q

Twofold Cost of Sex (dis)

A

asexual lineages grow more rapidly in each generation because all progeny can produce offspring

27
Q

Search Cost (dis)

A

Males and females must locate each other in order to mate
*involves time, energy and risk of predation

28
Q

Reduced relatedness (dis)

A

sexually reproducing organisms pass only half of their alleles to their offspring

29
Q

Risk of Sexually Transmitted Infections (dis)

A

mating between males and females provides an effective means of transmission for many pathogens

30
Q

Advantages of Sex

A
  1. Combining Beneficial Mutations
  2. Generation of Novel Genotypes
  3. Faster Evolution
  4. Clearance of Deleterious Mutations
31
Q

Combining Beneficial Mutations (adv)

A

sexual reproduction can bring separate beneficial mutations together in a single individual faster

32
Q

Generation of Novel Genotypes (adv)

A

through recombination, meiosis provides an opportunity for paired chromosomes to cross over which creates a unique combo of alleles

33
Q

Faster Evolution (adv)

A

offspring of sexual parents will be more genetically variable than offspring of asexual reproducing parents
*can increase speed of evolutionary response to selection and is critical for maintaining resistance to parasites (red queen effect)

34
Q

Clearance of Deleterious Mutations (adv)

A

sexual populations can purge themselves of harmful mutation with genetic recombo & asexual populations steadily and irreversibly accumulate mutations until a lineage driven extinct (Muller’s ratchet)

35
Q

What makes sex beneficial?

A

red queen effect

36
Q

How does anisogamy result?

A

differential investment in reproduction

37
Q

Females have ____ paternity.
Males have _____ paternity.

A

certain
uncertain

38
Q

What alters OSR?

A

asymmetrical parental care

39
Q

Why might female preferences arise?

A

may arise from preexisting sensory bias

40
Q

Monogamy

A

one male pairs with one female

41
Q

Sexual Monogamy

A

exclusive

42
Q

Social Monogamy

A

may cheat

43
Q

Polygyny

A

males mate with multiple females

44
Q

Polyandry

A

females mate with multiple males

45
Q

Polyandry ____ for male traits that ____ paternity rates.

A

selects, increase

46
Q

Sperm Competition

A

a form of sexual selection that arises after mating when males compete for fertilization of a females egg

47
Q

What does sperm competition do for evolution?

A

drives evolution of larger testes

48
Q

Sexual Conflict

A

traits that confer a fitness benefit on one sex but cost to the other
**traits coevolve antagonistically

49
Q

Sexual conflict leads to ____ between males and females.

A

antagonistic coevolution

50
Q

How does anisogamy influence sexual selection?

A

females invest more into reproduction than males because female gametes are more costly to produce more than male gametes
-males usually maximize fitness by mating with more females
-female fitness is limited by fecundity = don’t increase their fitness by mating with multiple males
-females attract more mates is not necessarily favored

51
Q

How does OSR influence sexual selection?

A

-if ratio skewed it can intensify sexual selection
-more male biased then males will experience intense competition for access to mates

52
Q

How does the opportunity for selection influence sexual selection?

A

-arises from variance in fitness in a population
-stronger on males when there is more variance in male fitness

53
Q

Good Genes Hypothesis

A

the traits females choose when selecting a mate are honest indicators of the males ability to pass on genes that will increase the survival or reproductive of female offspring

54
Q

Sensory Bias Hypothesis

A

sexual selection of females mating preferences are by products of natural selection

Evolution (9 decks)

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