Biology 9700 · AS & A Level · Biodiversity

Biodiversity — practice question

An investigation was done in a temperate woodland that included several areas with two distinct kinds of ground-cover vegetation. • On higher ground, where the soil was drier, the main ground-cover plant was bracken, $\textit{Pteridium aquilinum}$. • On lower ground, where the soil was wetter, the main ground-cover plant was bramble, $\textit{Rubus fruticosus}$.
(a)[4]

Describe how the abundance of the two plant species at higher and lower ground sites could be measured.

(b(i))[1]

The invertebrates could not be identified to genus or species level, and only the wireworm group was identified as far as the taxonomic rank above genus. Name the taxonomic level shown by the wireworm group.

(b(ii))[1]

State the null hypothesis for a statistical test that compares the data from the two site types.

(b(iii))[3]

Simpson’s Index of Diversity for the invertebrates from the soil beneath bracken was calculated as 0.663 using the formula $D = 1 - \sum \left( \frac{n}{N} \right)^2$, where $n$ is the number of individuals of each species present in the sample and $N$ is the total number of all individuals of all species. Calculate Simpson’s Index of Diversity for the invertebrates from the soil beneath brambles. Complete Table 8.2 and use the space provided to show your working. Show all working to three decimal places. Write your final answer on the dotted line.

(b(iv))[2]

Describe what Table 8.1 and the calculated figures for Simpson’s Index of Diversity show about how bracken and bramble vegetation cover affects the diversity and abundance of soil invertebrates in the woodland.

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