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Biological Change over Time

Biological Change over Time. Ms. Cowman SBI3U. Mutations: The Source of Genetic Variation. All species exhibit genetic variation Mutations create new genes that provide a continual supply of new genetic information Mutations may be: NEUTRAL- provide no benefit or harm to the individual

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Biological Change over Time

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  1. Biological Change over Time Ms. Cowman SBI3U

  2. Mutations: The Source of Genetic Variation • All species exhibit genetic variation • Mutations create new genes that provide a continual supply of new genetic information • Mutations may be: NEUTRAL- provide no benefit or harm to the individual HARMFUL- reduce the reproductive success of an organism, do no accumulate over time BENEFICIAL- produce a change in the individuals phenotype that gives the individual an advantage, accumulate over time

  3. Mutations can have significant consequences • Bacteria have developed resistance to antibiotics are becoming more widespread as less-resistant strains are killed off. • Viruses can mutate to become more virulent (harmful), which can increase its ability to spread.

  4. Selective Breeding: Artificial Selection of Traits • Domestication of Animals and Plants • Provide humans with the majority of our food supply • Formed the basis for the development of modern civilization • Domestication is the changing of members of a species to suit human needs through controlled captive breeding (Artificial Selection)

  5. Examples of Artificial Selection First species to be domesticated: Canis lupus, the wolf

  6. Wild Sea Cabbage (1000’s of years) 7 vegetables

  7. How does artificial selection work? • The breeder picks seeds from the plants that have the best flavour or largest fruit and sows them • The plants cross-pollinate each other producing more fruit with the desired trait

  8. Genetic Engineering • Transfer beneficial genes from an individual of one species to an individual of another species • If successful, genetically modified individual is mass produced

  9. Power of Artificial Selection • Production of individuals that exhibit traits that are far beyond the natural variability present in the original population • Can reduce genetic diversity within a population  Breeder favours only certain traits in a population, then many alleles linked to other versions of a particular characteristic are reduced or eliminated

  10. Implications for Natural Populations What do we know about genetics? - All species exhibit genetic variation - Mutations produce heritable changes in individuals, and these changes may be beneficial, harmful, or neutral - Some species, such as bacteria and insects, can change over relatively short periods of time - Some domesticated species have changed dramatically under the influence of artificial selection

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