4.6 - Biodiversity within a community

Question 1

Define species richness

Answer 1

measure of the no. of different species in a community

Question 2

What does an index of diversity describe?

Answer 2

relationship between no. of different species in a community and the no. of individuals in each species

Question 3

Write the equation for the index of diversity

Answer 3

d = N( N-1)/ sum of n(n-1)
(where N = total no. of organisms of all species and n = total no. of organisms of each species)

Question 4

Effect of farming techniques on biodiversity

Answer 4

reduce biodiversity

Question 5

Suggest 2 reasons why populations might show low levels of genetic diversity

Answer 5

• founder effect (colonisation)
• genetic bottleneck (natural disaster)

Question 6

Why is index of diversity higher in one place than another?

Answer 6

• more plant species
• more (types of) food sources
• more habitats

Question 7

Advantage and disadvantage to farmers of replanting hedges

Answer 7

advantage: greater biodiversity so increase in predators of pests
disadvantage: more pests so pesticides used which damage crops

Question 8

Define biodiversity

Answer 8

variety of living organisms

Question 9

Give examples of farming techniques which aim to maintain biodiversity

Answer 9

• reducing use of pesticides
• using hedgerows instead of fences
• intercropping
• preserving wetlands