3.3

• Biodiversity


  The variety of living organisms
• Biodiversity


  • Can be assessed at different levels; within a habitat at the species level (index of diversity) or within a species at the genetic level (variety of alleles)
• How to calculate index of diversity (d)

  1. N= total number of organisms of all species

  2. n= total number of organisms of each species

  3. Σ = sum of
• Allele


  Different forms of a particular gene, found at the same locus (position) on a chromosome
• Variety of alleles within a species

  Increases diversity
• Reasons to maintain biodiversity

  • More stable, resilient populations
  • Ecotourism opportunities
  • Provide sources of medicine
  • Stabilise soils
  • Increase the gene pool
• 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


  • Protected habitats e.g. National Parks that protect the species there from depletion
  • Education programmes that teach people about the importance of biodiversity
• Advantages of in-situ conservation


  • Protects more than one species, cheap, few resources required
• Disadvantages of in-situ conservation


  • Hard to enforce legislation, populations may still decline
• Ex-situ conservation


  • Zoos where endangered species can be carefully bred to increase genetic diversity and prevent inbreeding
  • Seed banks store seeds carefully to keep them viable, to prevent certain species from going extinct
• Advantages of ex-situ conservation

  • Requires little space, eliminates predators and poachers
• Disadvantages of ex-situ conservation


  • Expensive, can't fully recreate natural habitat, disease spreads quickly