biodiversity

• biodversity


  variety of living organisms in an area

  
  

  - high biodiversity = lots of different species
• habitat


  where an organism lives
• community


  all the different species in a habitat that interact with each other
• 3 ways to define biodiversity

  - species diversity

  - habitat diversity

  - genetic diversity
• species diversity


  Number of different species in an area
• habitat diversity


  The number of different habitats in an area
• genetic diversity


  The number of different alleles of genes in a population
• what is used to estimate population size

  quadrants

  > quadrants are placed randomly through out the habitat to avoid bias

  > the amount of species in the gird are counted

  > quadrant placed i next transect
• 2 ways of sampling

  random o non-random
• 3 types of non-random sampling

  1. Opportunistic

  2. Stratified

  3. Systematic
• opportunistic sampling


  drawing a sample from part of the population that is conveniently available
• statified sampling


  The population is divided into​ subgroups​ (strata) based on some​ characteristic. Then a random sample is taken from each stratum
• systematic sampling


  Every nth item in the target population is selected
• when is systematic sampling used in measuring biodiversity


  when there's an environmental gradient
• techniques of collecting a sample

  - quadrants

  - sweep nets

  - pitfalls

  - traps

  - potters
• how is species diversity measured

  by calculating the index of diversity
• Index of diversity takes into account....

  number of different species and the abundance of each species

  
  

  - closer to 1 the higher the biodiversity of the habitat
• index of diversity (D)

  = 1-(sum of ( n/N)^2)

  
  

  n = num of single organism

  N = total num of organisms

  
  

  - as biodiversity increases so does the index of diversity (D)
• genetic diversity


  a measure of the number of different alleles within a population
• consequence of low genetic diversity

  unable to adapt to changing environmental cnditions and are vulnerable to extinction
• what populations typically exhibits low genetic diversity

  isolated populations

  
  

  eg. in zoos or pedigree breeds
• ways of measuring genetic diversity

  genetic polymorphism
• Polymorphism


  where a position on a chromosome has two or more alleles
• genetic polymorphism


  The existence of two or more distinct alleles at a given locus in a population's gene pool
• proportion of polymorphic gene loci =

  number of polymorphic gene loci/total number of loci
• species richness


  the number of different species in a community
• measuring species richness


  counting the number of different species in a specific area

  by a survey or observation
• species evenness


  how evenly distributed the individuals of different species are within a community
• measuring specie evenness


  - Simpson's diversity index

  - Shannon wiener diversity index
• Interpreting Simpson's Index of diversity (D)


  higher > greater diversity
• 5 human impacts on reduction of biodiversity

  - deforestation

  - pollution

  - introduction of invasive species

  - hunting and poaching

  - climate change
• deforestation


  to make houses, roads and furniture or fuel
• how does deforestation impact animals

  loss of food and habitat > ability to survive
• how many of the indonesian rainforests remain

  10%
• pollution


  burning fossil fuels such as oil, coal and gases remain in the air as particle pollutants or fall as acid rain

  >> acidification of lakes, streams and sensitive forest soils damaging trees
• what does acid rain primarily compose of

  sulphuric an nitric acid
• chemical pollutants


  pesticides and herbicides leach into soils and watersheds

  >> polluted streams for freshwater species

  >> concentration of toxic chemicals in food chain
• Introduction of invasive species


  introducing a non-native species to a new habitat accidentally or on purpose as a form of blogical control
• why would introducing an invasive species cause a reduction in biodiversity

  > reproduce faster and don't have any natural predator

  > out compete native species
• example of introducing an invasive species

  grey squirrel causing a reduction in number of native red squirrels