3.3 Survivorship Curves

Explain survivorship curves.

• A survivorship curve is a line that displays the relative survival rates of a cohort—a group of individuals of the same age—in a population, from birth to the maximum age reached by any one cohort member. There are Type I, Type II, and Type III curves.
• Survivorship curves differ for K-selected and r-selected species, with K-selected species typically following a Type I or Type II curve and r-selected species following a Type III curve.
• Enduring understanding ERT-3: Populations change over time in reaction to a variety of factors.