3.3 Survivorship Curve

Survivorship Curve

A line that shows the survival rate of a cohort (group of same-aged individuals) in a pop. from birth to death

What does a faster drop in the line mean?

Quicker die-off of individuals

What does a slower drop in the line mean?

Longer avg. lifespan

Type 1 is mostly…

K-Selected

Characteristics of type 1 species

High survivorship early in life due to high parental care, high survivorship in midlife due to large size and defensive behavior, rapid decrease in survivorship late in life as old age sets in.

Ex. of type 1 species

Most mammals

Type 2 is…

In between R and K selected species

Characteristic of type 2 species

Steadily decreasing survivorship throughout life

Ex. of type 2 species

Adult birds, rodents

Type 3 is mostly…

R-selected

Charaestics of type 3 species

Low survivorship early in life due to little to no parental care, the few that make it to midlife have a slow and steady decline in survivorship, and those that make it to adulthood also have a slow and steady decline in survivorship.

Ex. of type 3 species

Insects, fish, plants