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Evolution - Introduction

Evolution - Introduction. Biological Changes over time. Principles of Evolution. Populations of living things contain variation of individuals Mutations can cause further variation in population Mutations can be beneficial, harmful or neutral

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Evolution - Introduction

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  1. Evolution - Introduction Biological Changes over time

  2. Principles of Evolution • Populations of living things contain variation of individuals • Mutations can cause further variation in population • Mutations can be beneficial, harmful or neutral • If mutation is beneficial can alter gene pool of population

  3. Artificial Selection – a case of synthetic evolution • Domestication has forced changes in organisms to best suit human needs • We have selected certain traits over others causing a change in phenotype of organisms • Referred to as Artificial Selection

  4. Example of artificial selection

  5. Broccoli • A human engineered vegetable with origins to sea cabbage (brassica oleracea)

  6. Selection of Brassica • Agriculture caused ancient farmers (2000 y.a) to select brassica with the largest most desired features • Broccoli was created by selecting plants with the largest stems and flowers and allowing them to breed • Over time stems and flowers became very large and pronounced

  7. Other B. oleraceaoffshoots • Kale • Cabbage • Kohlrabi

  8. Artificial Selection can be powerful!

  9. Science of Breeding • Hypothesis: Breeding selected individuals with certain favoured traits will result in the favoured traits becoming more prevalent and more pronounced

  10. Procedure: 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

  11. Concerns • Selection can lead to loss of genes • Can make organisms susceptible to disease • Some traits can be linked to others that could be detrimental to the population (ie; pure white colour in cats is linked to deafness)

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