4.2.1

• biodiversity


  A measure of the variety of of living organisms within an area
• species diversity


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


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


  the range of different habitats within an area
• species richness


  the number of different species in a particular area at the time of measurement
• community


  a interacting group of various species within a common location
• species evenness


  the relative abundance of each different species within the community. Calculated using the number of species present and the number of individuals of each species present at the time of measurement.
• population


  all members of a single species that live in a habitat
• species


  If two organisms can breed to produce fertile offspring.
• polymorphic gene


  a gene that has more than 1 allele
• allele


  an alternative form of a gene
• how is genetic diversity calculated

  by examining the number of polymorphic genes within an isolated or selectively bred population.
• proportion of polymorphic gene loci =


  number of polymorphic gene loci / total number of loci
• the larger the proportion of polymorphic gene loci

  the greater the genetic diversity within a population
• loci


  the location of a gene on a chromosome
• Simpsons index of diversity formula

  n = total number of individuals of a species present

  N = total number of organisms of any species present

  
• Simpsons index of diversity results are between

  0-1 , the higher the value the higher the biodiversity.
• Simpsons index of diversity is a measure of

  quantitative biodiversity
• what is sampling used for

  the measure the biodiversity of a habitat and find the number of organisms present at that time
• when sampling how do you make the sample representative

  use a large sample - so mean and standard deviation can be calculated to find a difference or correlation

  random - to avoid bias
• random sampling


  Decide on the area to measure and create a grid out of it.

  Use a random number generator to pick the coordinates of a square within the grid to sample.
• types of non random sampling

  opportunistic

  stratified

  systematic
• opportunistic sampling


  sample the organisms you see and are available
• problems with opportunistic sampling

  bias
• stratified sampling


  splitting the habitat into different areas and taking a random sample from each

  
• systematic sampling


  taking a sample along a set regular distance of a habitat. Usually done with a belt transect. Measures distribution within a habitat.

  
• when are quadrats used

  in all sampling techniques
• what are quadrats used to sample

  plants and slow moving organisms
• point quadrat

  A horizontal bar with holes at set intervals allowing long pins to be pushed through to the ground. Anything a pin touches is recorded

  
• frame quadrat


  a square frame open or gridded is placed on the flat ground.

  
• what can be recorded from a quadrat

  density

  frequency

  percentage cover
• density


  the number of individuals present with the quadrat
• frequency


  the number of squares in a frame quadrat containing an individuals of the species meaning a % can be found.
• percentage cover


  estimating the % of each small square within a frame quadrat is covered by that species.

  x - subjective and lowers accuracy
• sampling techniques for animals

  sweeping net

  pitfall trap

  pooter

  tullgren funnel

  kick sample
• sweeping nets


  swept through tall plants to catch insects

  
• pitfall traps


  holes in the ground that invertebrates fall into and cant escape from. A small roof is placed over and researchers must come and look at it everyday.

  
• pooters


  a jar with two long tubes. one is placed over the small insect and the other is sucked by the researcher. The decrease in pressure in the jar pulls the small insect into the jar. The sucking tube end in the jar is covered so the researcher does not suck the insect into their mouth.

  
• tullgren funnel


  a soil sample is taken and placed under a bright light to imitate the sun. The small soil organisms move downwards as they dislike the light causing them to fall down the funnel and into the jar.

  
• kick sample


  researcher kicks the river / sea bed in the direction of the current and another stands oppositely in front of them holding a net into the water to collect the water organisms that have been moved from the waterbed.