Question 1: A wildlife researcher captures 150 animals, marks them, and releases them. Later, they capture 120 animals, of which 30 are marked. Estimate the total population using Capture-Recapture.

Answer: 600

Question 2: If in a second capture, 50 animals are marked and 20 of the third capture are marked, what is the estimated population?

Answer: 125

Question 3: Calculate the number of animals in the population if 200 are captured first, 180 are captured second, and 45 are marked in the second capture.

Answer: 800

Question 1: A researcher captures 250 fish, marks them, and releases. Later, they catch 200 fish, of which 40 are marked. Explain why simply dividing the second sample size by the number of marked fish might lead to errors, and describe how the Capture-Recapture formula corrects for bias.

Answer: Students should explain the bias in assuming proportionality directly and how the formula N = (M x C) / R accounts for the likelihood of recapturing marked animals.

Question 2: A population estimate using Capture-Recapture is 500. In the first catch, 100 animals are marked. The second catch has 150 animals, with 30 marked. Calculate the actual number of marked animals in the second catch and identify the estimate's accuracy.

Answer: 30; the estimate is accurate because R=30 matches the actual marked recaptures.

Question 1: A conservation team captures 180 deer, marks them, and releases. Later, they trap 160 deer, of which 35 are marked. What is the estimated total deer population? Explain any assumptions made.

Answer: Estimated population = (180 x 160) / 35 ≈ 822.86; assumptions include random mixing and equal catchability.

Question 2: A wildlife survey estimates a bird population of 1200 using Capture-Recapture. If the first sample caught 300 birds, and the second caught 250, with 50 marked in the second sample, verify the calculation and discuss possible sources of error.

Answer: Population estimate = (300 x 250) / 50 = 1500; errors could include non-random mixing or behavior affecting catchability.

Question 1: In a study, 400 animals are initially captured and marked. Later, in a second capture, 380 animals are caught, with 70 marked. If the marked animals' population is suspected to be underestimated, suggest methods to improve accuracy and discuss potential biases.

Answer: Methods include multiple recaptures, stratified sampling, or using alternative models; biases may include trap-shyness or trap-happy behaviors.

Question 2: A researcher notices that the estimated population frequently exceeds known counts by 20%. Identify common misconceptions that might cause this overestimation and how to correct them.

Answer: Misconceptions include assuming perfect mixing and equal catchability; correction involves adjusting for trap-shyness or trap-happiness.

Question 1: A student calculates the population as (150 x 120) / 50 = 360, but the actual recaptured marked animals R is 30. Identify the mistake and recalculate correctly.

Answer: Mistake: used incorrect recaptured marked count; correct calculation: (150 x 120) / 30 = 600.

Question 2: A student assumes that the population estimate is valid only if the marked animals are evenly distributed among the captured animals. Is this correct? Explain why or why not.

Answer: Incorrect; the assumption of even distribution simplifies calculations, but in practice, uneven distribution can bias estimates.