Answers to Hands on Pg 91-93

8.3 Capture, mark, release and recapture method
Aim : To estimate the population size of woodlice using the capture, mark, release and recapture method
Results

Number of woodlice in first capture	30
Number of woodlice in second capture	25
Number of marked woodlice in second capture	10
Estimated population size of woodlice	30 x 25 = 75 10

Discussion
1. To prevent the ink from harming the woodlice and from being washed off.
2. a) To allow the marked woodlice to mix freely with the rest of the woodlice.
b) Because the population may change due to emigration, death or birth of woodlice over a long period of time.
3.

1. The marked woodlice can mix randomly in the population before the second sample is taken.
2. Marked and unmarked woodlice in second sample are caught randomly
3. The substance used to mark the woodlice should not be poisonous or affect the activity of the woodlice and yet not easily removed.
4. The death rate and the birth rate are the same.
5. The population to be estimated is stable/ the rate of the migration is equal to the rate of emigration of the woodlice.
6. There are no predators of woodlice in the habitat to be studied. (any 2)

4. Increasing the number of catches//repeat the experiment
Conclusion
The estimated population size of woodlice is 75.