Chapter 3

August Weismann proposed the principle of the separation between somatic and germ cells. He also suggested that aging is a nonadaptive trait. Discuss why these two principles might establish the theoretical basis of current thought on the evolution of aging and longevity.

Discuss the importance of reproductive value, as proposed by Fisher, to evolutionary predictions made by Medawar and Hamilton.

Discuss the basic process of genetic drift and how genetic drift could influence aging and longevity.

Explain why the force of natural selection on mortality is always highest before the start of reproduction. Also, explain why the force of natural selection on mortality can be used to demonstrate the relationship between genes selected for survival to reproductive age and the genetic basis of longevity.

G. C. Williams speculated that "natural selection will frequently maximize vigor in youth at the expense of vigor later on and thereby produce a declining vigor." Describe the evolutionary theory of aging that Williams was speculating about.

In terms of the disposable soma theory of aging, discuss the follow statement: "The cost of immortality of the germ line is somatic mortality."