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Calculate the index of diversity for this site using the formula: d = \frac{N(N-1)}{\sum(n(n-1))} Where: - N = total number of individuals sampled - n = number of individuals of each species From Table 1: - Hydrocyte vulgaris: 3 - Plantago maritima: 19 - Ranunculus acris: 3 - Hieracium pilosella: 3 - Callitrogo cuspidatum: 10 - Prunella vulgaris: 16 - Pseudoscledropodium purum: 6 Total number of individuals (N) = 3 + 19 + 3 + 3 + 10 + 16 + 6 = 60 So, N = 60, and N - 1 = 59 - AQA - A-Level Biology - Question 4 - 2017 - Paper 3
Question 4
Calculate the index of diversity for this site using the formula: d = \frac{N(N-1)}{\sum(n(n-1))} Where: - N = total number of individuals sampled - n = number of ... show full transcript
Worked Solution & Example Answer:Calculate the index of diversity for this site using the formula: d = \frac{N(N-1)}{\sum(n(n-1))} Where: - N = total number of individuals sampled - n = number of individuals of each species From Table 1: - Hydrocyte vulgaris: 3 - Plantago maritima: 19 - Ranunculus acris: 3 - Hieracium pilosella: 3 - Callitrogo cuspidatum: 10 - Prunella vulgaris: 16 - Pseudoscledropodium purum: 6 Total number of individuals (N) = 3 + 19 + 3 + 3 + 10 + 16 + 6 = 60 So, N = 60, and N - 1 = 59 - AQA - A-Level Biology - Question 4 - 2017 - Paper 3
Step 1
Calculate the index of diversity using the provided formula
Answer
Step 1: Find N
Total number of individuals (N) = 60.
Step 2: Calculate \sum(n(n-1))
- Hydrocyte vulgaris: 6
- Plantago maritima: 342
- Ranunculus acris: 6
- Hieracium pilosella: 6
- Callitrogo cuspidatum: 90
- Prunella vulgaris: 240
- Pseudoscledropodium purum: 30
Total = 720.
Step 3: Calculate d
Using the formula:
d = \frac{60(59)}{720} \approx 4.92.
Step 2
Outline a method the ecologists could have used to determine the plant species richness at one site.
Answer
Step 1: Select sampling sites at random
Ecologists could use a random number generator to select quadrats.
Step 2: Identify plant species
Ecologists could identify plant species present at each selected quadrat.
Step 3: Count number of different plant species
Finally, they would count the number of different plant species observed at each site.
Step 3
Does these data show that there were significant changes in the grassland communities on these islands? Give reasons for your answer.
Answer
Step 1: Significant increases in species richness
There is a significant increase in species richness on Islay (p < 0.001) and Colonsay (p < 0.001).
Step 2: Change in diversity
The change in diversity on Islay shows significance (p < 0.001), while Colonsay shows significance (p < 0.001), but Harris does not (p > 0.05).
Step 3: Interpret results
Since Colonsay and Islay show significant results while Harris does not, this indicates differing ecological impacts across the islands. The changes are statistically significant in the context of species richness.