ecology - populations and communities

Question 1

Populations as interacting groups of organisms of the same species living in an area
- Students should understand that members of a population normally breed and that reproductive isolation is used to distinguish one population of a species from another.

Question 2

Estimation of population size by random sampling
Students should understand reasons for estimating population size, rather than counting every individual, and the need for randomness in sampling procedures.

Question 3

Random quadrat sampling to estimate population size for sessile organisms
Both sessile animals and plants, where the numbers of individuals can be counted, are suitable.

Question 4

Capture–mark–release–recapture and the Lincoln index to estimate population size for motile organisms

Students should understand what is indicated by the standard deviation of a mean. Students do not need to memorize the formula used to calculate this. In this example, the standard deviation of the mean number of individuals per quadrat could be determined using a calculator to give a measure of the variation and how evenly the population is spread.

Question 5

Carrying capacity and competition for limited resources
A simple definition of carrying capacity is sufficient, with some examples of resources that may limit carrying capacity.