variation and evolution

• describe variation

  differences in characteristics of individuals in a population
• give factors affecting variation

  • genes
  • environment
• describe evolution

  change in inherited characteristics of population over time through natural selection may result in formation of new species
• describe theory of evolution by natural selection

  all species evolved from simple life forms that first developed 3 billion years ago
• describe process of evolution through natural selection

  1. mutation result in changed phenotype
  2. phenotype more suited to environment
  3. more likely to survive, reproduce and pass on gene
  4. process repeat for multiple generations
  5. changed phenotype become more common
• describe speciation

  new species formed by evolution that cannot reproduce to give fertile offspring
• give reasons why theory of evolution not widely accepted

  • against religious beliefs
  • insufficient evidence
  • could not explain inheritance of genes