Which survivorship curve describes high survival in early and middle life with a rapid decline in older age, and is typical of species that invest little in offspring?

• A. Type II
• B. Type I
• C. Type III
• D. All of the above

Answer: (B)

Survivorship curves show how the chance of surviving changes as organisms age. The pattern described—most individuals live through early and middle life, with mortality increasing rapidly in old age—fits the curve known as Type I. This shape arises when species invest substantial energy in a relatively small number of offspring and provide strong parental care, which boosts juvenile survival so many individuals reach older ages. As aging sets in, mortality climbs steeply.

The other shapes don’t match as well: Type II has a fairly constant risk of death across ages, and Type III has very high mortality early in life with many offspring and little parental care. So the pattern described is best represented by Type I.