Final answer:
Survivorship curves graphically show how individuals within a population survive over time, with three types of curves representing different life strategies: Type I with low early mortality and substantial parental care, Type II with constant mortality, and Type III with high early mortality and large numbers of offspring.
Step-by-step explanation:
A survivorship curve is a graphical representation used by population ecologists that demonstrates how the number of individuals within a population survives across different age intervals over time. There are three distinct types of survivorship curves that characterize different life strategies:
- Type I survivorship curve: Represents species like humans and most mammals where mortality rates are low during the early and middle years, with most deaths occurring in older individuals. Species with this curve type tend to have few offspring and provide substantial parental care.
- Type II survivorship curve: Represents species, such as many birds, where mortality rates are relatively constant throughout life, meaning that individuals are equally likely to die at any age.
- Type III survivorship curve: Characterizes species that have high mortality rates in the early stages of life, such as trees and marine invertebrates. However, individuals who survive past these early challenges are more likely to live for longer periods. These species typically produce a large number of offspring with minimal or no parental care.