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Biodiversity: used to describe variety in the living world
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The table doesn't tell us much about the differences between the two habitats because, in both cases the total
number of species and the total number of individuals is
the same
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One way of measuring species diversity is:

Genetic Diversity: refers to the variety of genes possessed
by the individuals that make up a population of a species
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∑ n (n—1)

Numbers found in
Habitat X

Numbers found in
Habitat Y

A

10

3

B

10

5

C

10

2

D

10

36

E

10

4

No
...
of individuals

50

50

Use the index to calculate the species diversity of
the two habitats
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You then calculate the sum of n
( n—1 ) for each species: (SHOWN IN TABLE)

You then calculate the species diversity index for
each habitat:

Where:
One measure of species diversity is species richness
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Two communities may have the same N = total number of organisms of all species
number of species but the proportions of the community
n = total number of organisms of each species
made up of each species may differ markedly
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However, in the meadow, all 25 species might be equally abundant, whereas in the wheat field, over 95% of the plants
Species
Numbers (n)
mat a single species of wheat
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44
Habitat Y: d= 50(49) ÷ 1300 = 2450 ÷ 1300 = 1
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The species diversity of habitat X is
much greater
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The
higher the species diversity index, the more stable an ecosystem usually is and the less its affected by change like climate change
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In extreme environments such as hot deserts, only a few species have
the necessary adaptations to survive the harsh conditions
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This usually results in an unstable ecosystem in which communities are dominated by climatic factors
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This usually results in a stable ecosystem in which communities are dominated by living organisms rather than climate

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