Question 1: A researcher trapped 50 butterflies, marked them, and released them back into the habitat. Later, they trapped 60 butterflies, of which 15 were previously marked. Estimate the total butterfly population using the Capture-Recapture method.

Answer: 200

Question 2: Calculate the population when 80 animals are captured, 20 are marked, and 25 are recaptured with marks.

Answer: 320

Question 3: In a lake, 120 fish are tagged during the first capture. On the second capture, 150 fish are caught, and 30 are found to be tagged. What is the estimated total fish population?

Answer: 600

Question 4: Explain why it is important to assume that the tagged animals have an equal chance of being recaptured in the Capture-Recapture method.

Answer: To ensure the population estimate is unbiased and accurate, all animals must have an equal chance of being recaptured; otherwise, the estimate could be skewed.

Question 5: A bird researcher tags 40 birds. After some time, they capture 80 birds, of which 10 are tagged. What is the estimated bird population?

Answer: 320

Question 6: A class estimates the number of fish in a pond. First, they catch and tag 100 fish. Later, they catch another 150 fish, with 20 tagged. Calculate the estimated pond population.

Answer: 750

Question 7: A wildlife team tagged 200 deer. Later, they captured 180 deer, with 30 marked. What is the estimated total deer population?

Answer: 1200

Question 8: Describe two potential sources of error in the Capture-Recapture method and how they could affect the population estimate.

Answer: Errors include non-random recapture (some animals avoid traps) which can lead to underestimation, and tagged animals losing marks or becoming unrecognizable, leading to inaccuracies in counts.

Question 9: A researcher captures 70 fish, tags them, and releases them. Later, they recapture 80 fish, with 16 tagged. Calculate the estimated fish population and identify any assumptions made.

Answer: 350; assumptions include that tagged fish mix evenly and have equal chance of being recaptured.

Question 10: A population estimate using Capture-Recapture yields a total of 500 animals. If the second capture involved 100 animals and 20 were tagged, how many animals were originally tagged in the first capture?

Answer: 40

Question 11: Identify and correct the mistake in this calculation: 100 tagged, 200 caught later, 50 tagged observed, population estimated as 1000.

Answer: Incorrect calculation: Population should be (tagged first × total second capture) / tagged recaptured; thus, (100×200)/50=400.