Describe the structure and function of the nucleus.

Name the main polymer that forms the following cell walls.

Plant cell wall

Fungal cell wall

Scientists investigated the effect of the number of fungal species in soil on the diversity of plant species.

Table 1 shows their raw data for soil containing 14 fungal species.

Suggest one reason the scientists used biomass instead of the number of individuals of each plant species when collecting data to measure diversity.

The scientists used this equation to calculate the plant species index of diversity.

d = 1 − Σ(n/N)2

where n = shoot biomass of each plant species and N = total shoot biomass of all plant species

Use this equation to calculate the index of diversity for the data in Table 1.

Index of diversity

Figure 1 shows the plant species index of diversity the scientists calculated when the soil contained 0, 1, 2, 4 and 8 fungal species.

Sometimes farmers stop growing crops on an area of land to allow the natural ecosystem to recover. The plant species index of diversity of these areas previously used to grow crops is different from nearby land that has never been used to grow crops.

Suggest and explain how the plant species index of diversity would be different in these areas previously used to grow crops.

Use Figure 1 and your knowledge of the effect of farming on biodiversity in your answer.