Survivorship Curves Flashcards
r-selected and k-selected species vary on how much parental care they give their offspring and they also vary on:
the survivorship of their offspring/how likely they are to survive infancy and reach adulthood
how does a survivorship curve work?
it shows a group of individuals of the same species and it plots how many of them are still alive at each age the group reaches
what is the y-axis of a survivorship curve?
the number of individuals surviving in a population
what is the x-axis of a survivorship curve?
time (RELATIVE age of individuals)
what is a survivorship curve?
a line that displays the relative survival rates of a cohort in a population from brith to the maximum age reached by any one cohort member; shows survival rate of a cohort in a population from birth to death
what is a cohort?
a group of individuals of the same age in a population
what are the three types of survivorship curves?
type I, type II, type III
late loss, constant loss, early loss
survivorship curves usually differ for k-selected and r-selected species
which survivorship curve do k-selected species usually follow?
k-selected species typically follow a type I (late loss) or type II (constant loss) curve
survivorship curves usually differ for k-selected and r-selected species
which survivorship curve do r-selected species usually follow?
r-selected species typically follow a type III curve (early loss)
what does a fast drop in a line mean for a survivorship curve?
quick die-off of individuals
what does a slow drop in a line mean for a survivorship curve?
longer average lifespan/more individuals reach that age
what is a type I survivorship curve?
high survivorship in early life and mid life and a rapid decrease in survivorship in late life as old age sets in
why is there high survivorship in early/mid life for k-selected species/species with a type I survivorship curve?
- high survivorship in early life due to high parental care
- high survivorship in mid life due to large size and defensive behavior
what is a type II survivorship curve?
steadily decreasing survivorship throughout life, both r and k-selected species but typically k-selected
what is a type III survivorship curve?
high mortality (low survivorship) early in life due to little to no parental care, few make it to midlife, slow steady decline in survivorship in midlife, even fewer make it to adulthood, slow decline in survivorship in old age
