3.4.6 Biodiversity Within a Community

define genetic diversity

the number of different alleles of genes in a population.

define species diversity

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

define ecosystem diversity

refers to the range of different habitats from a small local habitat to the whole of the earth

what does biodiversity generally describe?

the variety in the living world

what is species richness?

a measure of species diversity number of different species in a particular area at a given time (community)

what is index of diversity?

describes the relationship between the number of different species and the abundance of individuals in each of these species within a community

how does agriculture reduce biodiversity?

farmers select species for particular qualitities genetic diversity of alleles reduced to the few that exhibit favourable alleles

what are some examples of practices that have reduced species diversity directly?

removal of hedgerows and grubbing out woodland, creating monocultures, for example replacing natural meadows with cereal crops or grass for silage, filling in ponds and draining marsh and other wetland, over-grazing of land, for example upland areas by sheep, thereby preventing regeneration of woodland.

what are some examples of practices that have reduced species diversity indirectly?

use of pesticides and inorganic fertilisers

what are some examples of techniques that conserve species diversity?

Maintain existing hedgerows at the most beneficial height and shape. An A-shape provides better habitats than a rectangular one.