The best explanation for senescence is that a population must make room for younger generations. Because of the general frailty of older people, deleterious mutations acting late in life are selected against most strongly. The antagonistic pleiotropy model ascribes senescence to genetic alleles that increase fitness early in life at the price of reduced fitness later. Methane originates from cattle and landfills. Chlorofluorocarbons result from the synthesis of fertilizers.
Sulfur dioxide is released during fossil fuel combustion.
B. Name two epidemic diseases of humans. D. Discuss the hypothesis proposed by Jared Diamond to explain the unidirectional transfer of epidemic diseases during the colonizations of the Americas. Imagine you are a field agent with the CIA and you are recruiting informants. One of your applicants seems to be a smart woman, but you have a hunch she might be a disguised male. You want to test the validity of your suspicion by asking her to take a few standardized tests in which the avarage scores of men and women differ significantly.