Biodiversity is the general term used to describe variety in the living world. It refers to the number and variety of living organisms in a particular area and has 3 components:
Species diversity - refers to the number of different species and the number of individuals of each species within any one community
Genetic divesity - refers to the variety of genes possessed by the individuals that make up any one species.
Ecosystem diversity -refers to the range of different habitats within a particular area
One measure of biodiversity is species diversity. It has 2 components:
the number of different species in a given area
the proportion of the community that is made up of an individual species
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Measuring species diversity
One way of measuring species diversity is to use an index that is calculated as follows:
D = species diversity index
N = total number of organisms of all species
n = total number of organisms of each species
= sum of
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Species diversity and ecosystems
Biodiversity reflects how well an ecosystem functions.The higher the species diversity index the more stable an ecosystem ususally is and the less effected by climate change.
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Impact of agriculture
controlled by humans
farmers select species to populate in an area
number of species and genetic variety of alleles is reduced
any particular area can only support a certain amount of biomass
other species have to compete for little space and resources
pesticides are used to exclude competitive species
overall effect is reduction in species diversity
species diversity is low in agricultural ecosystems
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Impact of deforestation
human intervention
many different species have habitats between the layers of the rainforest
tropical rainforests have the highest species diversity of any ecosystem
deforestation is the permanent destroying of forests and conversion of the land
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