Final answer:
The Lincoln Index formula N = M x n/m is used to estimate the total population size (N) in ecology, where M is the number of marked individuals, n is the size of the second sample, and m is the number of marked individuals recaptured.
Step-by-step explanation:
The Lincoln Index is a method used in ecology to estimate the population size of a species within a given area. In the Lincoln Index formula N = M x n/m, the variables are defined as follows: N is the total population size, M is the number of individuals initially marked, n is the total number of individuals captured in the second sample, and m is the number of marked individuals that were recaptured in the second sample. This method assumes that the ratio of marked to unmarked individuals in the second sample reflects the ratio of the entire population.
For example, if a biologist initially captures and marks 100 insects (M), and then later captures a second sample of 200 insects (n), out of which 50 are marked (m), the estimated population size (N) can be calculated using the formula:
N = (M x n) / m = (100 x 200) / 50 = 400
Hence, the estimated population size, N, would be 400 insects.