This type of a life history strategy exhibited by the green sea turtle can perhaps be more easily understood by comparing it to other patterns that we see in nature. Over time, all populations of living organisms show characteristic patterns of survivorship. These patterns, called survivorship curves , can be graphically illustrated by plotting the average number of individuals of a particular species alive at each age against time. There are three different types of survivorship curves that characterize most living organisms. Populations with convex survivorship curves have relatively low levels of mortality of offspring.
Most individuals survive to old age.
Species with convex survivorship curves produce relatively few offspring per reproductive effort and tend to invest a great deal of energy in the parental care of each individual. Convex survivorship curves are characteristic many large animals, including humans. A concave survivorship curve is characteristic of organisms that produce large numbers of offspring per reproductive effort and employ little to no parental care, leaving the offspring to compete for their own resources. Mortality is very high among offspring, but those that do reach adulthood have a good chance of surviving to old age. This type of survivorship curve is exhibited by the green sea turtle, all other species of sea turtles, as well as most species of plants, invertebrates and fishes.