Survivorship Curves _ r-/k- strategists

Survivorship Curves

describe reproductive strategies of organisms

Type III

-Low survivorship at young age
-once at maturity, survivorship = high
-Frogs = lay lots of eggs, some may not hatch.
-oak tree = lots of offspring spread, most may not seed

-young are not equipped to survive at young age

Type II

Survival is likely throughout all stages of life.
-birds, predated upon when young and when mature.

Type I

Nearly 100% survivorship at young age
-Humans
-still high survivorship at end of life
--> parental investment in life
--> Few young birthed,

r-strategists

make many with few surviving

-little to no parental care
-do well in unpredictable/ changing environments

--> rats = large litter + dandelions = lots of seeds

Organismal Biology

evolutionary approach to reproduction

k-strategists

few with mostly surviving

-reproduce later in life
-longer lifespan
-parental care
- stable environment

--> whale
--> humans
--> elephant

Turtle is which strategist?

Bit of both
- lay lots of eggs and leave
(r)
-but live a long time
(k)