4.4 genetic diversity and adaptation

• What is meant by genetic diversity?

  total number of different alleles of genes in a population
• what is meant but allele frequency?


  the relative frequency of an allele at a particular locus in a population, expressed as a fraction or percentage
• natural selection principles: offspring who have the most advantageous phenotype will survive, reproduce and ass on their alleles to their offspring
• what is directional selection?

  Directional selection is a type of natural selection where individuals with traits that are more extreme in one direction are favored by the environment. distribution curve shifts slightly left or right
• what is stabilising selection?

  the selection favours the average individuals in a population. distribution curve becomes narrower and taller
• what can be used to clarify evolutionary relationships?

  - dna base sequences

  • amino acid sequences
  • immunological comparisons
• what is gene technology?

  sampling DNA or mRNA in order to read and compare base sequences of organisms
• what are the 3 types of adaptation?

  • anatomical (body structure)
  • physiological (body processes)
  • behavioural (actions)
• how does resistance to a disease happen?

  1. Mutation that produces allele

  2. Those with allele/resistance less likely to get the disease

  3. So they are more likely to reproduce and pass on the

  allele

  4. Over generations allele frequency

  increases