[OLD] Populations - Investigating Populations

Question 1

What is the Lincoln Index?

Answer 1

N = (MC)/R
where N = estimate of total population size
M = animals marked on first visit
C = animals captured on second visit
R = number of animals recaptured

Question 2

3 ethical issues with the mark, release, recapture method

Answer 2

The marking method may be toxic
The mark may make the animal more conspicuous to predators
The capture and marking method may be harmful or overly stressful to the animal

Question 3

6 sources of error with the mark, release, recapture method

Answer 3

There may be a sudden amount of births or deaths in the time period.
There population may not have a definite boundary - the may migrate.
The mark may be lost or rubbed off.
The marked individuals may not have sufficient time to redistribute themselves evenly.
The proportion of marked to unmarked animals may not be the same in the second sample as in the population as a whole.
The marked may result is a lack of breeding.

Question 4

Name an animal for which the mark, release, recapture method of sampling would not be effective and explain why

Answer 4

Orcas, as they migrate around the world

Question 5

What problems may occur with the mark and recapture method if the second sampling is left too long a time before being repeated?

Answer 5

The animals may migrate away.

There may be a sudden amount of births or deaths in that time period.

Question 6

What problems may occur with the mark and recapture method if the second sampling is too soon after the first sampling?

Answer 6

The animals may not have had enough time to redistribute themselves evenly.

Question 7

Describe two important assumptions being made in this method of sampling, that would cause the method to fail if they were not true

Answer 7

The proportion of marked to unmarked animal sis the same in the second sample as in the population as a whole.
There have been few births and deaths in the time period.