4.7 investigating diversity

• can investigate genetic diversity by comparing

  • the frequency of measurable or observable characteristics
  • the base sequence of DNA
  • the base sequence of mRNA
  • the amino acid sequence of the proteins encoded by DNA and mRNA
• interspecific variation: variation among different species
• intraspecific variation: variation among the same species
• quantitative investigations of variation within a species involve

  • collecting data from random samples
  • calculating a mean value of the collected data and the standard deviation of that mean
  • interpreting mean values and their standard deviators
• avoid effect of sample bias by using a random sample
• void effect of chance in sampling by using large sample sizes
• random sampling process

  1. divide area into a grid by stretching 2 x 100 m tape measures at right angles to each other
  2. generate 2 coordinates using a random number generator
  3. walk to coordinates, place a quadrant and measure [whatever you're investigating] with [ruler etc]
  4. repeat 50 times
  5. calculate a mean
  6. calculate s.d. of sample
• how many samples to take

  • at least 10% of total area
  • until you achieve a running mean