Biodiversity

• Biodiversity


  The variety of living organisms
• Biodiversity

  • Can be measured in terms of species diversity (number of species in a community), habitat diversity (range of different habitats) and genetic diversity (variety of alleles within a species)
• Species richness

  The number of species in an area
• Species evenness


  Measure of the abundance of the different species within a given area.
• Random sampling


  No particular system, however aim is still to be representative
• Opportunistic sampling


  Those that are encountered first are chosen
• Stratified sampling

  Population divided into smaller groups based on a characteristic, then sampled
• Systematic sampling

  Follows a particular pattern
• We cannot study the whole population as it is impractical. Using a representative sample instead allows us to investigate the population easily.
• Simpson's Index of Diversity

  A measurement of the total number of organisms compared to the total number of organisms of each species. A high index of diversity means several different species are equally abundant, whereas a low index means one or two species dominate over others.
• Genetic diversity assessment

  Proportion of polymorphic gene loci = number of polymorphic gene loci / total number of loci
• Factors affecting biodiversity

  • Population growth
  • Deforestation for agriculture
  • Climate change affecting habitats
• Reasons to maintain biodiversity

  • Ecological (protecting species, maintaining resources)
  • Economic (reducing soil depletion)
  • Aesthetic (protecting landscapes)
• Conservation

  The protection and management of species and habitats, in order to maintain biodiversity. Can be in-situ (in an organism's habitat) or ex-situ (outside an organism's habitat).
• In-situ conservation

  • Marine conservation zones
  • Wildlife reserves
• Ex-situ conservation

  • Seed banks
  • Botanic gardens
  • Zoos
• Agreements to protect species and habitats

  • Convention on International Trade in Endangered Species (CITES)
  • Rio Convention on Biological Diversity (CBD)
  • Countryside Stewardship Scheme (CSS)