Topic 4: Biodiversity Flashcards

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1
Q

Biodiversity

A

Variety in the living world

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2
Q

Local biodiversity

A

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

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3
Q

Global biodiversity

A

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

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4
Q

Where is global biodiversity greatest?

A

At the equator
It decreases towards the poles

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5
Q

Species diversity?

A

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

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6
Q

genetic diversity

A

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

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7
Q

Ecosystems diversity

A

The range of different habitats within a particular area

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8
Q

2 ways that biodiversity can be measured

A

Species richness
Index of diversity

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9
Q

What is species richness?

A

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

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10
Q

What is an index of diversity?

A

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

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11
Q

Calculation for index of diversity

A

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

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12
Q

What are the effects of reducing biodiversity?

A

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

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13
Q

Farming practices that reduce biodiversity

A

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

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14
Q

How does removing hedgerows benefit farmers but reduce biodiversity?

A

Increased farmland
Reduces species habitats

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15
Q

What is the impact on biodiversity of crop monocultures?

A

Reduces plant biodiversity which affects food webs

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16
Q

Conservation measure to minimise the effects of hedgerow removal

A

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

17
Q

Conservation measures to minimise the effects of monocultures on biodiversity

A

Create natural meadows

18
Q

Conservation measures to minimise the effects of draining wetlands on biodiversity

A

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

19
Q

Conservation measures to minimise the effects of pesticides on biodiversity

A

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

20
Q

Conservation measures to minimise the effects of inorganic fertilisers on biodiversity

A

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

21
Q

Conservation measures to minimise the effects of herbicides on biodiversity

A

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