biodiversity

• biodiversity- the variety of living organisms present in an area
• habitat biodiversity- number of different habitats found within an area
• habitat biodiversity

  • each habitat can support a number of different species
  • greater the habitat biodiversity, greater the species biodiversity
• species biodiversity

  richness- number of different species

  eveness- comparison of each species
• genetic biodiversity- variety of genes that make up a species
• genetic biodiversity

  • greater genetic biodiversity allows for better adaptation to a changing environment
• sampling- taking measurements of a limited number of individual organisms present in an area
• use of sampling

  • can be used to estimate number of organisms without having to count them all
  • can be used to measure a particular characteristic
• random sampling

  1. mark out a grid on an area
  2. use a random number generator to determine x and y coordinates
• non random sampling

  opportunistic- uses organisms that are conveniently available
• non random sampling

  stratified- population can be divided into sub groups e.g gender
• non random sampling

  systematic- different areas within a habitat are identified and then sampled separately
• reliability

  • bias
  • chance (selected organisms may not be represented of the whole population)
• sampling techniques for animals

  • pooter
  • sweep nets
  • pitfall traps
  • tree beating
  • kick sampling
• sampling techniques used in plants

  • quadrats
  • transects
• estimating population size

  1. capture, mark and release organisms
  2. allow for redistribution
  3. recapture
  4. compare marked/unmarked individuals
• advantages of sensors

  • rapid changes detected
  • human errors reduced
  • high degree of precision
  • data stored on computer
• proportion of polymorphic gene loci= number of polymorphic gene loci/ total number of gene loci
• mutations- create new alleles
• interbreeding- alleles are transferred between two populations (gene flow)
• selective breeding- only a few individuals are bred for advantageous characteristics
• captive breeding programmes- small number of individuals available for breeding
• natural selection- species evolve only to contain primarily the alleles which code for advantageous characteristics
• genetic bottleneck- few individuals survive an event or change
• deforestation- permanent removal of large areas of forest
• deforestation

  • if only a specific tree is felled, species diversity is reduced
  • destroys animal species food source and home
  • neighbouring areas may increase in biodiversity due to migration
• agriculture

  • deforestation
  • removal of hedgerows
  • use of chemicals only one species of crop grown
• agriculture- land is farmed to feed the growing population
• climate change- release of CO2 from burning fossil fuels increases global temperature
• climate change

  • melting of polar ice caps
  • rising sea levels
  • higher temperatures
  • low rainfall
• aesthetic reasons for maintaining biodiversity

  • human pleasure through nature
  • reduces stress
• economic reasons for maintaining biodiversity

  • soil erosion as a result of deforestation
  • species can become instinct
  • high biodiversity provides protection against disease
• ecological reasons for maintaining biodiversity

  • removal of one species causes knock on effect
  • all species dependant on each other
• conservation- preservation and careful management of the environments
• in situ- within natural habitat

  ex situ- out of natural habitat
• abundance in the world

  • extinct
  • extinct in the wild
  • endangered
  • vulnerable
• sustainable development- meeting the needs of people today without compromising those of the future
• in situ

  • controlled grazing
  • restricted human access
  • controlled poaching
  • reintroduction of species
  • removal of invading species
  • feeding animals
• ex situ

  • botanic gardens
  • seed banks
  • captive breeding programmes
• conservation agreements

  INCN- assist in securing agreements between nations

  CITES- regulates the international trade of wild plants and animal specimens