4.6 - Biodiversity within a community

Question 1

Define species richness

Answer 1

A measure of the number of different species in a community

Question 2

What does an index of diversity describe?

Answer 2

The relationship between the number of species in a community and the number 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 number of organisms of all species and n = total number of organisms of each species

Question 4

Effect of farming techniques on biodiversity

Answer 4

Farming techniques reduce biodiversity

Question 5

Suggest two 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 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