Selective pressures influence trade-offs in terms of number and size of offspring. Organisms that produce many offspring are unable to provide intensive parental care, leading to a smaller survival rate. However, those with few offspring are able to offer much care and thus increase their survival rate.
Work Step by Step
Selection for traits that are favored at high-densities is referred to as K-selection or density dependent selection. Selection for traits that maximize reproductive success in less dense environments is known as r-selection.