Topic 4: Biodiversity

Question 1

Biodiversity

Answer 1

Variety in the living world

Question 2

Local biodiversity

Answer 2

The variety of different species living in a small, local habitat

Question 3

Global biodiversity

Answer 3

Variety of species on earth
Recent estimates put the number of species at 8.7 million

Question 4

Where is global biodiversity greatest?

Answer 4

At the equator
It decreases towards the poles

Question 5

Species diversity?

Answer 5

The number of different species and the number of individuals of each species within any one community

Question 6

genetic diversity

Answer 6

The variety of genes (alleles) possessed by the individuals that make up any one species

Question 7

Ecosystems diversity

Answer 7

The range of different habitats within a particular area

Question 8

2 ways that biodiversity can be measured

Answer 8

Species richness
Index of diversity

Question 9

What is species richness?

Answer 9

A measure of the number of different species in a community
- 2 communities may have the same number of species but the proportions of the community made up of each species may differ significantly

Question 10

What is an index of diversity?

Answer 10

The relationship between the number of species in a community and the number of individuals in each species
It provides a number that makes it easier to compare species richness in different habitats
The larger the value, the greater species richness

Question 11

Calculation for index of diversity

Answer 11

D= N(N-1)/sum of n(n-1)
D= index of diversity
N= no. Organisms of all species
n=no. Of organisms of each species

Question 12

What are the effects of reducing biodiversity?

Answer 12

It reduces the variety of habitats
Reduces the variety of species
Reduces the variety of food sources

Question 13

Farming practices that reduce biodiversity

Answer 13

Removing hedgerows
Creating monocultures
Draining wetlands
Overgrazing of land
Use of pesticides,inorganic fertilisers and herbicides

Question 14

How does removing hedgerows benefit farmers but reduce biodiversity?

Answer 14

Increased farmland
Reduces species habitats

Question 15

What is the impact on biodiversity of crop monocultures?

Answer 15

Reduces plant biodiversity which affects food webs

Question 16

Conservation measure to minimise the effects of hedgerow removal

Answer 16

Maintains existing hedgerows to the most beneficial height
Plant hedges rather than using fences

Question 17

Conservation measures to minimise the effects of monocultures on biodiversity

Answer 17

Create natural meadows

Question 18

Conservation measures to minimise the effects of draining wetlands on biodiversity

Answer 18

Maintain existing ponds or create new ones
Leave wet corners of fields

Question 19

Conservation measures to minimise the effects of pesticides on biodiversity

Answer 19

Use biological control or let wildflowers grow at the field edge as habitats for insect predators

Question 20

Conservation measures to minimise the effects of inorganic fertilisers on biodiversity

Answer 20

Use organic fertilisers
Use crop rotation with a nitrogen fixing crop to improve soil fertility

Question 21

Conservation measures to minimise the effects of herbicides on biodiversity

Answer 21

Use intercropping (growing 2 crops at once so you dont leave bare soil)
Rather than using herbicides to control weeds