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Unit 3 – Evolution Lesson 1 – Mutations and Artificial Selection

Unit 3 – Evolution Lesson 1 – Mutations and Artificial Selection. Unit 3 – Evolution. Evolution. What is evolution and why is it important?. Genetic Diversity and Evolution. The mechanism that drives evolution is natural selection.

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Unit 3 – Evolution Lesson 1 – Mutations and Artificial Selection

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  1. Unit 3 – EvolutionLesson 1 – Mutations and Artificial Selection

  2. Unit 3 – Evolution

  3. Evolution • What is evolution and why is it important?

  4. Genetic Diversity and Evolution • The mechanism that drives evolution is natural selection. • Natural Selection: the way in which nature favours the reproductive success of some individuals within a population over others. • Genetic diversity must be present for nature to favour some individuals over other

  5. Mutations and Genetic Diversity • Mutations are the source of genetic variation • What mechanisms have we studied that increases this genetic diversity?

  6. How Mutations Occur SubstitutionA substitution is a mutation that exchanges one base for another (i.e., a change in a single "chemical letter" such as switching an A to a G). -Such a substitution could cause a small change in the protein produced. For example,sickle cell anemia is caused by a substitution in the beta-hemoglobin gene, which alters a single amino acid in the protein produced.

  7. Sickle Cell Anemia • Heritable disease • Codominant • Chronic pain caused by RBCs moving through blood vessels. • Stroke, other cardiovascular complications

  8. How Mutations Occur InsertionInsertions are mutations in which extra base pairs are inserted into a new place in the DNA. DeletionDeletions are mutations in which a section of DNA is lost, or deleted.

  9. Types of Mutations • Neutral mutation - a mutation that does not result in any selective advantage or disadvantage. • Harmful mutation - any mutation that reduces the reproductive success of an individual and is therefore selected against; harmful mutations do not accumulate over time • Beneficial mutations - are favoured by natural selection and accumulate over time

  10. Articifical Selection Artificial selection - directed breeding in which individuals that exhibit a particular trait are chosen as parents of the next generation; artificial selection is used to produce new breeds or varieties of plants and animals

  11. Guide to Artificial Selection 1. Choose a useful species that can be bred in captivity. 2. Breed a large number of individuals. 3. Choose a trait that you wish to favour, such as large size, a particular colour, or sweetness. 4. Identify individuals that exhibit the favoured trait most strongly. 5. Breed only these individuals to produce the next generation of individuals. 6. Repeat Steps 4 and 5 over many generations.

  12. Limitations of Artificial Selection • Artificial Selection is limited by the genes that are present in the current population.

  13. Induced Mutations

  14. Thalidomide

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