Biology AS AQA Unit 2 Biodiversity

Made these notes for my year 12 summer exam to revise and read over. There are spelling mistakes in most of my files but due to the busy exam schedule I had no time to correct them (sorry).

Most files have more information than what is needed but I feel it helps you feel more confident walking into the exam if you have a greater knowledge background and may help when having to apply knowledge to questions. Good luck :)

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  • Created by: Chelcie
  • Created on: 02-09-13 12:42
Preview of Biology AS AQA Unit 2 Biodiversity

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Biodiversity
SPECIES DIVERSITY
It is the number of different species and number of individuals of each species within any one
community.
GENETIC DIVERSITY
It is the variety of genes possessed by the individuals that make up any one species.
ECOSYSTEM DIVERSITY
It is the range of habitats within a particular area.
SPECIES DIVERSITY INDEX
d= species diversity index
N=total number of organisms of all species
n=total number of organisms of each species.
The higher the species diversity index the more stable the ecosystem is.
IMPACT OF AGRICULTURE
Agricultural ecosystems are controlled by humans.
Genetic diversity is reduced (due to reduced number of alleles) and therefore the species
diversity index is low.
There is a limit of biomass in any particular area. If one species takes the majority of land,
competition increases between remaining species, and as not many survive the biodiversity
is reduced.
Pesticides also reduce biodiversity by killing competition for the yield to grow.
IMPACT OF DEFORESTATION
It is the permanent clearing of the forests and the conversion of land to other uses.
Man made pollutants which cause acid rain contributes, as well as forest fires.
Loss of biodiversity.
Tropical rainforests account for ½ of the world's species yet only cover 7% of the world.

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