Question

An ecologist was attempting to measure the size of a population of beavers in Yellowstone National Park. To do this, she captured 65 beavers and marked them with a microchip. Six weeks later, she recaptured another 65 and found that only 10% (1/10) had a microchip. What can she estimate the population size to be? Defend your answer.

a) 650 beavers
b) 130 beavers
c) 520 beavers
d) 6,500 beavers

Answer 1

Using the mark and recapture method, the proportion (M/N = R/C) helps us estimate the beaver population size as 650, considering that 10% of the second capture were originally marked.

Step-by-step explanation:

The question revolves around estimating the population size of beavers using the mark and recapture method. The ecologist in Yellowstone National Park marked 65 beavers and in a later recapturing of another 65, found that only 10% were marked with a microchip. To estimate the population size (N), one can set up a proportion where the number of originally marked beavers (M) to the total population is equal to the number of recaptured marked beavers (R) to the number of beavers in the second capture (C), i.e., M/N = R/C. Using the given data: 65/N = 6.5/65, which simplifies to N=650. Therefore, the estimated population size is 650 beavers (option a).