A-LevelBiologyBiodiversity and conservation9700/42 · Feb/Mar 2019 · Q88 Marks

Explain what is meant by the term biodiversity.

(a)Explain what is meant by the term biodiversity.[3]
(b)(i)Simpson's Index of Diversity (D) is a method of assessing biodiversity. The formula for Simpson's Index of Diversity is: D = 1 - Σ(n/N)² n = number of individuals of each species present in the sample N = total number of all individuals of all species In an investigation of biodiversity in a pond, samples of pond animals were removed using sampling nets. The species of each animal was identified and the number of individuals of each species was recorded. Table 8.1 shows the results of the investigation. Calculate Simpson's Index of Diversity by completing Table 8.1 in the spaces provided. Record your values to three decimal places. Write the value for Simpson's Index of Diversity on the dotted line. Record your value to three decimal places.[3]
(b)(ii)Explain what this value for Simpson's Index of Diversity shows about the diversity of the pond.[2]

Mark scheme

Marking points from the official mark scheme (Feb/Mar 2019). The mark or mark type is shown in brackets.

[3] any three from: 1 variation (with)in, ecosystems / habitats; 2 number / variety, of (different) species; 3 relative abundance of each species; 4 genetic variation within each species ;
[3] n/N column correct; (n/N)² column correct ; allow ecf Simpson's Index of Diversity = 0.727 ; allow ecf species | number | n/N | (n/N)² --- | --- | --- | --- Rana temporaria | 10 | 0.042 | 0.002 Leucorrhinia dubia | 35 | 0.148 | 0.022 Hydrometra stagnorum | 50 | 0.212 | 0.045 Lymnaea stagnalis | 44 | 0.186 | 0.035 Gammarus pulex | 97 | 0.411 | 0.169 total | 236 | | 0.273 Simpson's Index of Diversity (D) = 0.727
[2] (relatively) high value / close(r) to 1 (than 0) ; indicates (fairly) high (species) diversity; allow ecf from 8(b)(i)

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