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Lemurs are small mammals - AQA - A-Level Biology - Question 5 - 2022 - Paper 1
Question 5
Lemurs are small mammals. Lemurs live in trees and feed on leaves and fruit. Scientists used a computer program to predict the expected distribution of two species o... show full transcript
Worked Solution & Example Answer:Lemurs are small mammals - AQA - A-Level Biology - Question 5 - 2022 - Paper 1
Step 1
Using Figure 2, give three conclusions you can make about the distribution of these lemur species.
Answer
- Eulemur rufifrons is predominantly distributed below the river, indicating a preference for that region.
- The actual distribution of both species is similar to their expected distributions, suggesting that environmental needs are accurately mirrored in their habitat patterns.
- The distribution shows that Eulemur rufifrons has a slightly lesser presence than expected, which may indicate competitive factors or habitat limitations.
Step 2
Using all the information, suggest how speciation happened to produce two species of lemur.
Answer
Speciation can occur through several processes:
- Geographical isolation: The lemurs may have become separated by physical barriers such as rivers or mountains, leading to two distinct populations.
- Reproductive separation/isolation: Once isolated, the two groups may have developed different mating behaviors or preferences, preventing interbreeding.
- Different selection pressures: Each group would face unique environmental challenges, leading to divergent evolutionary paths over time.
Step 3
Step 4
Using the information provided, calculate how many lemurs in the second sample were marked.
Answer
To calculate the number of marked lemurs in the second sample, use the mark-release-recapture formula:
Let M be the number of marked lemurs (30), C be the total number captured in the second sample (25), and N be the estimated total population (250).
Using the formula:
rac{M}{N} = rac{m}{C}
where m is the number of marked lemurs in the second sample. Rearranging gives:
m = rac{M imes C}{N} = rac{30 imes 25}{250} = 3.
Thus, 3 lemurs in the second sample were marked.