Mechanisms of Contraction of the Normal and Failing Heart

and so are involved in food webs." "We are the host and the starting point, however unwillingly or unwittingly, of a variety of parasitic food chains." "Man can still climb trees but is almost exclusively terrestrial." Isolite size and breeding behavior, ecological efficiency and energy transfer are discussed, as are gestation, periods of nursing, infant mortality among recently weaned children, and survival of offspring to reproductive age. The effect of urbanization on the rate of population growth is mentioned. Furthermore, "early urban societies may have overcome density-dependent regulation by the food resource only to have a further density-dependent factor in the form of epidemic disease impose restrictions on population increase."