Ecologists use the mark-release-recapture method to estimate the population size of mobile organisms within a defined habitat.
An initial sample is captured, counted, marked with a non-toxic and durable marker, and then released back into the wild. After allowing sufficient time for the marked individuals to mix randomly with the rest of the population, a second sample is captured. The total number of individuals in this second sample, along with the number of marked (recaptured) individuals, is recorded.
The population size is estimated using the Lincoln Index formula:
Estimated population size=Number marked in first sample×Size of second sampleNumber of recaptured animals \text{Estimated population size} = \frac{\text{Number marked in first sample} \times \text{Size of second sample}}{\text{Number of recaptured animals}} Estimated population size=Number of recaptured animalsNumber marked in first sample×Size of second sampleAn ecological study was carried out to compare the population size of meadow grasshoppers (Chorthippus parallelusChorthippus\ parallelusChorthippus parallelus) between two grassland habitats with different management regimes: Meadow A (intensively grazed by sheep) and Meadow B (unmanaged meadow).
| Habitat | Number marked in first sample | Size of second sample | Number of recaptured insects | Estimated population size |
|---|---|---|---|---|
| Meadow A (grazed) | 80 | 90 | 24 | ? |
| Meadow B (unmanaged) | 120 | 150 | 45 | 400 |
Using the data in Table 1, calculate the difference in the estimated population size of meadow grasshoppers between Meadow A and Meadow B.
