Question 1: A wildlife researcher captures 150 frogs, tags them, and releases them back into the pond. The next day, they capture 200 frogs, of which 40 are tagged. Estimate the total frog population using the capture-recapture formula.

Answer: 750

Question 2: If the estimated population of fish is 1200 and 300 fish were caught in the second sample with 50 tagged, how many fish were tagged in the first sample?

Answer: 125

Question 3: Calculate the estimated population when 500 animals are tagged initially, 600 are captured in the second sample, and 90 of them are tagged.

Answer: 3333.33

Question 4: A researcher tags 80 birds, releases them, and later captures 160 birds, with 20 tagged. Estimate the bird population, rounding to the nearest whole number.

Answer: 640

Question 5: Explain why the capture-recapture estimate might be inaccurate when the population is highly mobile or has a high birth/death rate.

Answer: High mobility and rapid population changes can lead to inaccurate estimates because the assumptions of a closed population and equal chance of capture are violated.

Question 6: A small pond has a known population of 250 frogs. The researcher captures 60 frogs, tags them, and releases. The next day, they catch 100 frogs, of which 24 are tagged. What is the estimated total population?

Answer: 625

Question 7: Construct a scenario where the capture-recapture method would give an overestimate of the actual population. Describe the situation briefly.

Answer: If tagged animals are more likely to be recaptured because they are less cautious or stay near the capture area, the estimate may be inflated.

Question 8: A researcher tags 100 crabs. Later, they catch 250 crabs, including 50 tagged. Calculate the estimated population, rounded to the nearest whole number.

Answer: 500

Question 9: In a study, 600 fish are initially tagged. The second catch has 300 fish, with 60 tagged. What is the estimated total fish population?

Answer: 3000

Question 10: A total of 400 animals are tagged in a game reserve. In the next capture, 500 animals are caught, and 100 of them are tagged. Calculate the estimate of the total population.

Answer: 2000

Question 11: Identify a common mistake students make when applying the capture-recapture formula and suggest how to correct it.

Answer: Mistake: Using the wrong order of numbers or mixing counts; correction: always ensure tagged animals are in the numerator and the total second sample in the denominator.

Question 12: Plot the graph of y=2x for x-values from 0 to 5 on the grid provided. Draw the line accurately.

Answer: Student draws a straight line passing through (0,0), (1,2), (2,4), (3,6), (4,8), (5,10).