Type I survivorship curve

Type I survivorship curve, in ecology, a curve displayed on a semilogarithmic scale that tracks organisms that tend to live long lives. Survivorship curves can be created by plotting the number of those members of a cohort that are still alive at each age. Organisms that follow the Type I survivorship curve are characterized by having a low death rate (or high survivorship rate) over much of their lives. As they approach the limits of their natural life expectancies, however, there is a dramatic increase in the death rate.

Species such as human beings (Homo sapiens) and other large mammals (such as elephants, hippopotamuses, and gorillas), which have fewer numbers of offspring but invest much time and energy in caring for their young (that is, K-selected species), usually follow the Type I survivorship curve. This relatively flat curve reflects low juvenile mortality, with most individuals living to old age.