Evolution Ch 12

Why does menopause occur?

-risk of childbirth increases with age -remaining fertile can detract from investing in current offspring -older mothers are likely to die before offspring reach independence -grandmother effect

What is genomic imprinting?

Genomic imprinting refers to different expression of a gene depending on whether it was inherited from the male parent or the female parent.

What is senescence?

The gradual decline of all organ systems, leading inevitably to death

What is IGF2 gene?

a growth hormone gene

what is IGF2r

a growth inhibiting gene

to make a mule we must use what

a male donkey and a female horse

why does natural selection favor antagonistic pleiotropy?

because organisms can reproduce earlier in life

what happens as animals get older?

cells accumulate malformed proteins, immune system becomes less effective, cancer goes up

What is intralocus sexual conflict?

conflict between the fitness effects of alleles of a given locus on males and females

what is the parent of origin effect?

describes an effect on the phenotype of an offspring caused by an allele inherited from a particular parent

what can bring about rapid evolution of life history traits?

environmental change

what happens if the OSR is unbiased?

females and males will spend near equal time with offspring and sexual selection will be much weaker

what happens if the osr is female based?

females fight for access to males

what sex normally has an active copy of IGF2

males

why do scientist think senescence has evolved?

natural selection has selected alleles that enhance growth and reproduction early in life

what are examples of life history traits?

organisms age at first reproduction, the duration of reproduction, the # and size of offspring produced in a population

what is the limit of self repair?

our bodies require continual repair so natural selection favors levels of repair that are good enough to keep an organism in sound condition only for as long as it has a reasonable chance for reproducing

What is the Trivers-Willard hypothesis?

predicts greater investment in male offspring by a female in good condition and greater investment in female offspring if the female is in poor condition

what is frequency dependent selection?

the fitness of a phenotype depends on how common it is in the population, this maintains variation within populations

what happens if the females copy of iGF2r is disabled?

the mouse is born very large

what happens if the males copy of IGF2r is disabled?

the mouse is large if the mothers copy is also disabled

in guppie populations without predators what do the offspring look like?

the offspring are larger but less are produced

What is life history?

the pattern of investment an organism males in growth and reproduction

what is antagonistic pleiotropy?

the theory that some animals posses genes that help them in early life but harm them in later life

What is the p53 gene?

tumor suppressor gene, helps prevent tumors in early life but can be harmful later in life

When do trade-offs occur?

when investment in one trait results in lower investment of another trait

what is parental-offspring conflict?

when parents benefit from withholding resources from some offspring and giving it to others

what is parental conflict?

when parents have an evolutionary conflict of interest over the optimal strategy for parental care

sex ratio in seychelles warblers

with high resources, females favored (up to 3) with low resources, males favored (disperse away from poor habitat)