BIOC51H3 Lecture : BGYB51H3 Lecture 21 Notes Nov 19

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11 Aug 2010

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BGYB51H3 Lecture 21 Notes

-females are the agents of selection in intrasexual selection

-females increase their fitness through direct or indirect benefits

-sperm transfer ends after 20 minutes of copulation even if female is still eating prey, males

take prey from female after 20 minutes

-genetic quality involves males having heritable traits that can give higher fitness for offspring

-experimental manipulation eliminates confounding variables that might mask possible sexual

selection

-females prefer males with the most elaborated ornaments

-cross-fostering offspring involves assuming equal environmental effects between offspring in

order to determine their heritability

-offspring with more elaborated ornaments have better genetic quality than other less

ornamented offspring

-males have much traits that are not connected to good genes that provide survival or

predator/parasite resistance

-sexy sons hypothesis is that certain traits give higher mating success for sons of females; not

indicators of genetic quality

-no survival benefits with traits that are not connected to good genes

-benefit of choosing male with trait only occurs if a large number of other females also prefer

this trait

-preferences in females may already exist as innate in their sensory system (sensory bias

hypothesis)

-certain arbitrary stimuli can cause female responsiveness because of innate sensory system

-competition and choice act together in many populations to cause both direct and indirect

benefits together

-sex role reversal involves male parental care or large nutrient gift increasing parental

investment

-sex role reversal involves male having a higher parental investment than females; females

compete while males are choosy

-variation in number of mating in females and less variation in males in sex role reversal

-basic differences in parental investment affect sex roles rather than sex roles depending on

maleness or femaleness

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Document Summary

Females are the agents of selection in intrasexual selection. Females increase their fitness through direct or indirect benefits. Sperm transfer ends after 20 minutes of copulation even if female is still eating prey, males take prey from female after 20 minutes. Genetic quality involves males having heritable traits that can give higher fitness for offspring. Experimental manipulation eliminates confounding variables that might mask possible sexual selection. Females prefer males with the most elaborated ornaments. Cross-fostering offspring involves assuming equal environmental effects between offspring in order to determine their heritability. Offspring with more elaborated ornaments have better genetic quality than other less ornamented offspring. Males have much traits that are not connected to good genes that provide survival or predator/parasite resistance. Sexy sons hypothesis is that certain traits give higher mating success for sons of females; not indicators of genetic quality. No survival benefits with traits that are not connected to good genes.

Related Questions

Praying mantis females often eat the males following copulation(similar to the redback spiders). One hypothesis for this behaviorin the male mantids is that by doing so, the male benefits becausethe female can then produce more, larger offspring. These offspringthen have better survival and reproductive success. If thishypothesis is true, what is the best prediction?

A.Females that consume males will have more, larger offspringthan females that do not consume males

B.Larger mantids have higher survival rates Males that avoidbeing eaten during copulation are able to mate with multiplefemales

C. All of the above

D.A and B only

salmontrout306

there could be more than one answer or no answer at all

1. _____ Females that reproduce sexually versus asexually are said to incur a âtwo-fold cost of sexual reproduction.â Which of the following costs are associated with sexual reproduction for females?

A) MALES! That do-nothing lot really does not directly contribute offspring to the next generation. Females would be better off making all daughters.

B) FEMALES! In most natural settings, those daughters compete with their mothers for potential mates and resources needed to successfully reproduce.

C) MITOSIS! Since sexual reproduction can produce many more offspring than asexual reproduction, there are energetic costs associated with the mitotic divisions required to produce those offspring.

D) MEIOSIS! Every time a gamete is produced, the parent loses a little bit of itself. Half to be precise since only half of its genes are passed on to sexually produced offspring.

E) DIVERSITY! Mothers maximize fitness if all offspring are genetically just like them. Sexual reproduction causes genetic diversity, which ultimately lowers the fitness of both parents.

Calvin Bridgesâs classic study of nondisjunction of sex chromosomes provided support for the chromosome theory of inheritance. Bridges performed crosses with fruit flies, tracking the sex-linked eye-color trait. Red-eyed males were crossed with white-eyed females. Which of the following is an accurate explanation of his findings?

a. The offspring were mostly white-eyed females and red-eyed males, but 1/ 2,000 offspring were white-eyed females (genotype XX) or red-eyed males (genotype XY).

b. The offspring were mostly white-eyed males and red-eyed females, but 1/ 2,000 offspring were white-eyed females (genotype XXY) or red-eyed males (genotype XO).

c. The offspring were mostly white-eyed females and red-eyed males, but 1/ 2,000 offspring were white-eyed females (genotype XXY) or red-eyed males (genotype XO).

d. The offspring were mostly white-eyed males and red-eyed females, but 1/ 2,000 offspring were white-eyed females (genotype XX) or red-eyed males (genotype XO).

e. The offspring were mostly white-eyed males and red-eyed females, but 1/ 2,000 offspring were white-eyed females (genotype XXX) or red-eyed males (genotype XY).

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BIOC51H3 Lecture : BGYB51H3 Lecture 21 Notes Nov 19

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