3.3 Survivor-ship Curves 

• Survivor-ship Curve: line that shows the survival rate of a cohort (group of same-aged individuals) in a pop. from birth to death 
  • Faster drop in line = quicker die-off of individuals
  • Slower drop in line = longer avg. lifespan

Type I, II, and III

Type I (mostly K-selected)

• High survivorship early in life due to high parental care
• High survivorship in mid life due to large size & defensive behavior
• Rapid decrease in survivor-ship in late life as old age sets in
  • Ex: most mammals

Type II (in between r & K)

• Steadily decreasing survivor-ship throughout life 

Type III (mostly r-selected)

• High mortality (low survivor-ship) early in life due to little to no parental care 
• Few make it to midlife; slow, steady decline in survivor-ship in mid life
• Even fewer make it to adulthood; slow decline in survivor-ship in old age
• Ex: insects, fish, plants

\
\
\