Chapter 13 Flashcards
Overshoot
when a population grows beyond its carrying capacity;
often occurs when the carrying capacity of a habitat decreases from one year to next (e.g., because less resources are produced).
Die-off
a substantial decline in density that typically goes well below the carrying capacity.
Die-offs often occur when a population overshoots its carrying capacity.
Population cycles
regular oscillation of a population over a longer period of time.
dN/dt=
rate of change in population size
r=
intrinsic growth rate
N=
current population size at time t
k=
carrying capacity
Delayed density dependence
when density dependence occurs based on a population density at some time in the past.
As the time delay increases, density dependence is ___________ and the population is more prone to both ___________ and ___________ K.
delayed; overshooting and undershooting
When rτ < 0.37…
the population approaches carrying capacity without oscillations.
When 0.37 < rτ < 1.57…
the population exhibits damped oscillations.
Damped oscillations
a pattern of population growth in which the population initially oscillates but the magnitude of the oscillations declines over time.
When rτ > 1.57…
the population will exhibit a stable limit cycle.
Stable limit cycle
a pattern of population growth in which the population continues to exhibit large oscillations over time.
Why may delayed density dependence occur?
the organism can store energy and nutrient reserves.
Delayed density dependence can occur when there is a time delay in development from one life stage to another.
Example:
When populations are low and food is abundant, the water flea Daphnia galeata stores surplus energy as lipid droplets.
When resources are less abundant, adults use this stored energy to reproduce.
