Activity 9.4 (Form 5 Biology Textbook Exercise and Answer)

Activity 9.4:
To carry out a field study to estimate the population size of animals

Paint brush, Indian ink or nail polish, a pen, papers

1. Choose a suitable area in the school compound where you can carry out a study.

2. Identify the type of animals which is abundant in that area to become a sample.

3. Capture five samples of the chosen organism (P) in the study area.

4. Mark all the captured organisms.

5. Release all the marked (P) organisms in the same area where they have been captured.

6. After a few days, recapture another five samples of organisms (Q) in the same area.

7. Record the total of marked samples in the second capture (R).

8. Estimate the population size of the organisms by using the formula:

1. What is the substance that you used to mark the captured animals? Justify the substance that you have chosen.

2. State the interactions that have happened between the studied organisms with both biotic and abiotic components in that area.

3. State the basic needs that enable the studied organisms to inhabit the area.


1. Nail polish. Does not harm the organism and causes death / migration to another area.

2. Biotic: Feed on smaller insects; small plants take shelter from sunlight.
Abiotic: Oxygen to breathe; water maintains the humidity of skin; stones for hiding.

3. Oxygen, food, water

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