4.6 Biodiversity within a community

Question 1

Define ‘species richness’

Answer 1

The number of different species in a community

Question 2

Define ‘species diversity index’

Answer 2

The relationship between the species richness and the number of individuals in each species

Question 3

What is a habitat

Answer 3

The environment in which an organism or population of organisms usually lives

Question 4

How does monoculture affect biodiversity of an area

Answer 4

Monoculture reduces biodiversity:
- Use of herbicides removes any competitors (Weeds)
- Use of fertilisers
- Removing variety of habitats and food
- Removing flowering plants/pollinators

Question 5

Give 2 reasons why hedgerows are often removed in areas where there are large monocultures

Answer 5

1 - the crops being monocultured are able to use all the moisture and nutrients in the soil rather than the hedgerows
2 - To enable large machinery to be used, and more space for crops

Question 6

Why would the removal of older hedgerows have a greater impact on biodiversity

Answer 6

older hedgerows would be home to a greater variety of species and so a greater variety of food and so a greater variety of habitats

Question 7

What is the formula for the diversity index

Answer 7

sum of 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 8

Why would you want to calculate the diversity index rather than just counting the subjects

Answer 8

To see the number of species AND number of individuals in the species