Biodiversity

• Species diversity


  The number of different species and individuals within each species in a community
• Species richness


  The number of different species in a particular area at the particular time
• Genetic diversity


  The variety of genes amongst all the individuals in a population of one species
• Habitat diversity


  The range of different habitats
• Reductions in genetic diversity- limited gene pool


  Captive breeding: in zoos results in a small number of indivduals breeding

  Genetic bottleneck: only a small number of a population have survived an event. Gene pool is decreased and only the alleles in the remaining population can be passsed on to future offspring.

  Founder effect: a small number of individuals from a population decide to colonise a new, isolated area.
• The higher the proportion of polymorphic gene loci, the larger the genetic diversity within the population
• Random sampling


  Lay out two tape measures at right angles to each other to create a gridded area

  Use a random number generator to generate two number to serve as coordiates on the grid
• Non-random sampling

  • Opportunistic

  This method is unlikely to result in a sample that accurately represents the population. This method involves sampling organisms which are conveniently available and therefore involves bias.
• Non-random sampling

  • Stratified

  Some populations or habitats can be seperated into groups to sample from. For example splitting a pond area into three regions: surface,shallow and deep-water region. You would then take random samples within each strata.
• Non random sampling

  • Systematic

  Involves identifying different area within a habitat to sample. Used when there is a change in the distrubiton of species within the habitat and you want to investigate the impact of the change on biodiversity.
• Factors affecting biodiversity
• Factors affecting biodiversity- human population

  Population is increasing at an exponential rate

  Increased need for space for housing, farming and industry- requiring deforestation
• Factors affecting biodiversity- agriculture

  Increasing to feed everyone.

  Clearing land for agriculture results in the destruction of habitats, chemcial pesticides or fertilisers may be added to the land and monocultures may be grown.

  All of this reduces the number of habitats and range of food soucres
• Factors affecting biodiversity- climate change

  Melting polar ice caps, loss of habitats

  Sea levels rising, increased flooding, reduced biodiversity

  Plants and animals are unable to survive
• Ecological reasons to maintain biodiversity

  Removal of natural habitats, all organisms are interdependent so therefore the loss of one species impacts all others.
• Economic reasons to maintain biodiversity


  Deforestation resulting in soil erosion and monocultures means soil becoming in particular minerals that the crop absorbs a lot of. Soil depletion negatively impacts a country's ability to grow crops .

  Tourism often relies on people visiting areas of natural beauty, reduction in tourism= impact on economy.

  Many medicines based on chemicals naturally occuring in plants
• Aesthetic reasons to maintain biodiversity

  Being in nature around animals and plants enriches people's lives

  Improves peoples mental health
• In situ conservation


  Happens within the habtiat

  GBD is maintained, individuals are not bred captively

  Prevents extinction of one species as all organisms are interdependant

  Aim to conserve wildlife
• Ex situ conservation


  Botancial gardens, seed banks, captive breedings

  Seeds of a variety of plants stored in water in a temp controlled environment to keep them viable for longer

  Reproducing animals in zoos and aquariums to increase the number of endangered species and for them to be reintroduced into the wild