14.1.8 14.11–14.13: Ecology influences the evolution of aging in a population.

From a population perspective, aging is an increased risk of dying with increasing age, after reaching the age of maturity.

Question 14.23

The death rate of organisms in a population exhibiting a type III survivorship curve is:

  • a) unrelated to age.
  • b) usually correlated with density-independent causes.
  • c) higher in the post-reproductive than in the pre-reproductive years.
  • d) lower after the organisms survive beyond the earliest age groups.
  • e) more or less constant throughout their lives

Question 14.24

Which of the following is a major trade-off in life histories?

  • a) size of offspring for amount of parental investment
  • b) size of offspring for number of reproductive events
  • c) growth for reproduction
  • d) size for life span
  • e) number of reproductive events for number of offspring per reproductive event

Question 14.25

Natural selection:

  • a) does not influence aging, because aging is determined by an individual’s environment.
  • b) cannot reduce the frequency of alleles that cause mortality among individuals who have not yet reached maturity.
  • c) cannot weed out from a population any alleles that do not reduce an individual’s relative reproductive success, even if these alleles increase an individual’s risk of dying.
  • d) can influence aging but not longevity.
  • e) leads to an increase in the frequency of any illness-inducing alleles that have their effect when an organism can reproduce.

Question 14.26

Which of the following statements about the hazard factor of a population is incorrect?

  • a) It is a measure of organisms’ risk of death from external sources.
  • b) It is lower for a population of porcupines than for a population of guinea pigs.
  • c) It is a measure of the ratio of mortality risk from external (environmental) causes relative to internal (genetic) causes.
  • d) It is responsible for the rate of aging among individuals in the population.
  • e) It is a measure of how quickly the individuals in a population age.