Describe the structure and function of the nucleus - AQA - A-Level Biology - Question 1 - 2022 - Paper 1

One reason is that individual organisms could not be easily identified or separated, making it difficult to collect accurate counts of distinct species.

To calculate the index of diversity, we first determine the total shoot biomass: Total shoot biomass = 2 + 4 + 5 + 7 + 15 + 36 + 51 = 120 g/m². Next, we apply the index diversity equation:

$d = 1 - \sum_{i=1}^n \left( \frac{n_i}{N} \right)^2$ Where $n_i$ represents the shoot biomass of each species and $N$ is the total shoot biomass. Calculating the necessary ratios:

• For Poa compressa: $(\frac{2}{120})^2 = 0.00027778$
• For Achillea millefolium: $(\frac{4}{120})^2 = 0.00069444$
• For Aster cordifolius: $(\frac{5}{120})^2 = 0.00173611$
• For Aster nova-angliae: $(\frac{7}{120})^2 = 0.00347222$
• For Chrysanthemum leucanthemum: $(\frac{15}{120})^2 = 0.015625$
• For Daucus carota: $(\frac{36}{120})^2 = 0.090000$
• For Fragaria virginiana: $(\frac{51}{120})^2 = 0.220225$

Total = $0.00027778 + 0.00069444 + 0.00173611 + 0.00347222 + 0.015625 + 0.090000 + 0.220225 = 0.331 Now, substituting into the equation: d = 1 - 0.331 = 0.669

In areas previously used to grow crops, plant biodiversity is likely to be lower compared to land not used for cropping. This occurs because farming often reduces the variety of plant species, as it typically involves monoculture practices that favor the growth of a single crop, decreasing overall diversity. Consequently, the index of biodiversity may reflect this reduced diversity, resulting in a lower value when compared to areas with natural ecosystems, where a wider variety of species coexists.