variation

• variation


  differences in characteristics of indivuals in population
• genetic variation:

  • all organisms have characteristics similar to parents
  • characteristics determinted by inherited genes
  • genes passed on in gametes
  • combination of genes from mother and father causes genetic variation
  • some characteristics are only determined by genes
  • eye colour
  • blood group
  • inherited disorders
• environmental variation:

  • environment causes differences in members of same species
  • plant grown in sun with be green
  • plant grown in darkness will be tall and have yellow leaves
• both genetic and environmental variation:

  • most characteristics controlled by both
  • maxiumum height organism can grow is determined by genes
  • but whether it grows that tall is depended on environment e.g food
• mutations:

  • mutations are chnages in sequence of bases in DNA
  • most mutatio have no effect on phenotype
  • environmental changes can cause new phenotype more suited to environment, and characteristic can have rapid change by natural selection in species