4.1.2 biodiversity

• species diversity


  the number of different species and individuals within each species in a community
• genetic diversity


  the variety of genes amongst all individuals in a population
• habitat diversity


  range of different habitats
• reductions in genetic diversity

  • captive breeding in zoos results in a small number of individuals breeding
  • Inbreeding
  • Genetic bottlenecks are when a small number of the population survives an event therefore the gene pool is reduced
  • Founder effect is when a small number of individuals from a population decide to colonise a new isolated area
• genetic diversity calculation


  Proportion of polymorphic gene loci = number of 

  polymorphic gene loci/ total number of loci

  • a polymorphic gene is one with more than 1 allele and the higher this proportion the larger the genetic diversity within the population
• simpson's equation


  The biodiversity of a habitat is measured using Simpson's equation

  1 is the lowest and the larger number indicates a greater level of diversity
• sampling


  Sampling is a way to get a representative of a population and you need a large sample so you can calculate a mean and stats test
• random sampling


  Lay tape measures and use a random number generator for coordinates
• what are the types of non-random sampling

  • Opportunistic (bias)
  • Stratified (separated into groups eg. Regions of the lake)
  • Systematic (set intervals and record data)
• Quadrats

  used to sample plants or slow-moving organisms and there are 3 methods

  • density count of all individuals
  • Frequency count how many squares species are present out of 100 for a percentage
  • Percentage cover is estimating the percentage but can be subjective
• other sampling techniques

  • Sweep nets - nets used to capture insects in long grass
  • Pitfall traps - trapped in holes in the ground
  • Pooters - suction to draw insects into the pot
• species richness


  Species richness is the number of different species present
• species evenness


  Species evenness is the relative abundance of different species in an area
• factors affecting biodiversity

  • human population
  • agriculture
  • climate change
• benefits of biodiversity

  • economically 
  • aesthetically 
  • ecologically
• in situ examples

  • marine conservation zones 
  • wildlife reserves
• ex situ examples

  • botanical gardens 
  • seed banks 
  • captive breeding
• international and local conservation agreements

  • Convention on International Trade in Endangered Species
  • Rio Convention on Biological Diversity
  • CITES regulates the trade of international animals plants and products
• what are the 3 agreements in CBD

  • Countries must come up with strategies for sustainable development
  • To stabilise greenhouse gas emissions and concentrations within the atmosphere
  • To prevent the destruction of fertile land into desert and reduce drought effects