Proportion of individuals in a population who survive.

Proportion of individuals in a population who survive.

Proportion of individuals in a population who survive.

Proportion of individuals in a population who survive.

Proportion of individuals in a population who survive.

Proportion of individuals in a population who survive.

Proportion of individuals in a population who survive.

Proportion of individuals in a population who survive.

Proportion of individuals in a population who survive.

Type I

Proportion of individuals in a population who survive.

Type II

Proportion of individuals in a population who survive.

Type III

Proportion of individuals in a population who survive.

Survivorship decreases at a steady, regular pace
High survivorship until old age, then rapidly decreasing survivorship
High mortality early in life, but those that survive the early years live long lives
Now that we understand the differences between the three types of survivorship curves, let’s apply this knowledge to different animal life histories.
A new species of lizard is discovered living on a tropical island. Scientists studying the lizard population have found that newly-hatched, juvenile, and adult lizards all have the same likelihood of dying.

Type I

Proportion of individuals in a population who survive.

Type II

Proportion of individuals in a population who survive.

Type III

Proportion of individuals in a population who survive.

Female loggerhead sea turtles come ashore to nest on sandy beaches. After laying approximately 100 eggs, the female returns to the sea and provides no care for the developing eggs. After hatching, the baby turtles must run to the sea through a gauntlet of predators. Predation rates on both the eggs and hatchlings are very high; estimates suggest that only between 1 in 100 and 1 in 1000 hatchling turtles will survive to adulthood. After reaching adulthood, the turtles have very few predators and tend to live for a long time.

Type I

Proportion of individuals in a population who survive.

Type II

Proportion of individuals in a population who survive.

Type III

Proportion of individuals in a population who survive.

Female chimpanzees typically give birth to a single baby and invest significant time and effort into caring for its offspring. Chimpanzees have few natural predators and a very high probability of surviving every age interval until old age, when the risk of dying increases dramatically.

Type I

Proportion of individuals in a population who survive.

Type II

Proportion of individuals in a population who survive.

Type III

Proportion of individuals in a population who survive.