biology - 2.1d - monitoring populations

Question 1

What can presence, absence or abundance of indicator species give information of?

Answer 1

Environmental qualities, such as presence of a pollutant.

Question 2

What can be used to monitor an ecosystem?

Answer 2

Susceptible and favoured species.

Question 3

What does an absence or reduced population indicate?

Answer 3

A species is susceptible to some factor in the environment.

Question 4

What does an abundance or increased population indicate?

Answer 4

A species is favoured by the conditions.

Question 5

What can be used as a method for estimating population size?

Answer 5

Procedure for the mark and recapture technique using the formula: N = MC/R

Question 6

What is the procedure for the mark and recapture technique?

Answer 6

A sample of the population is captured and marked (M) and released. After an interval of
time, a second sample is captured (C). If some of the individuals in this second sample
are recaptured (R), then the total population N = MC/R

Question 7

What does the method for the mark and recapture assume?

Answer 7

That all individuals have an equal chance of capture, that there is no immigration or emigration, and that individuals that are marked and released can mix fully and randomly with the total population.

Question 8

What are methods of marking animals?

Answer 8

Banding, tagging, surgical implantation, painting and hair clipping.

Question 9

What must the method of marking and subsequent observation do?

Answer 9

Minimise the impact on the study species.