population ecology

Question 1

What are the three main patterns of population distribution, and what
processes lead to them?

Answer 1

random: individuals are scattered

clumped: individuals are in patches,

uniform: individuals are evenly spaced out

Question 2

How do ecologists estimate population size for mobile vs. sessile organisms?

Answer 2

sessile organisms
- plants, barnacles (non-moving)
- method: quadrats (small square plots) get average density and estimate the total population of the total area.
or transects (lines across a habitat) to count individuals in a defined area

mobile organisms
- birds, cheetahs (moving)
- Method: mark-recapture techniques: capture individuals, mark them, release and then capture them to estimate total population using probability

trade-offs in methods

Question 3

what do life tables and survivorship curves tell us about population trends?

Answer 3

a tool used to track survivorship (lx) → proportion of individuals surviving
to age (x)

track survival and reproductive rates for diff ages of the population

Question 4

calculating survivorship

Answer 4

SURVIVORSHIP for age class x is
calculated by:

dividing the number of
females in that age class (Nx) by
the number of females we started with (N0):

lx = Nx/N0