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Understanding Evolution: Natural Selection and Adaptation

Learn about natural selection, adaptation, genetic variation, and how they drive evolution. Explore the impacts of environmental competition, differential reproduction, and examples like the peppered moths and rock pocket mice.

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Understanding Evolution: Natural Selection and Adaptation

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  1. UNIT 4 - Evolution Today’s agenda: Notes on natural selection Tomorrow and Thursday: study guide Friday: open ended questions I can construct an explanation based on evidence for how natural selection leads to adaptation of populations

  2. IMPORTANT DATES • JUNE 11: FINAL (OPEN-ENDED QUESTIONS) all periods • JUNE 12: I won’t be on campus • JUNE 13: FINAL (MULTIPLE CHOICE) Periods 6 and 5 • JUNE 14: FINAL (MULTIPLE CHOICE) Periods 1 and 2 • JUNE 15: FINAL (MULTIPLE CHOICE) Periods 3 and 4

  3. Evolution https://www.youtube.com/watch?v=Ci9jfMvoLb4

  4. How the different shape of these birds’ beaks affect these organisms?

  5. Activity on beaks– Natural selection

  6. Adaptation • An adaptation is a characteristic that enhances the survival AND reproduction of organisms that bear it. • How did the lab demonstrate the concept of adaptation?

  7. Environmental Competition: Individuals compete (or fight) with other members of their species for food, mates and resources- NOT all members of a population can survive!

  8. Differential reproduction: Individuals that are more adapted to their environment will eat more, survive, and have more babies.

  9. Why did the color of peppered moths change over the years? https://www.youtube.com/watch?v=etsjB-6u-6w

  10. Peppered moths genetic variation

  11. Genetic Variation: Difference between individuals of the same species. Their phenotypes are different. All species have genetic variation

  12. Genetic variation can come from 2 places 1. Sexual reproduction- parents pass different traits to their offspring 2. Mutations- random Changes in DNA

  13. Natural selection Natural selection: mechanism by which individuals that have inherited beneficial adaptations produce more offspring on average than do other individuals. The environment (nature) is the selective agent

  14. What adaptation has to do with evolution?

  15. Think-Pair Share What acts as a selective pressure on a population?

  16. Think-Pair Share What acts as a selective pressure on a population? • Competition for food • Competition for a mate • Changes in the environment • Predators • Parasites

  17. Natural selection vs artificial selection

  18. How do we know natural selection can change a population? • we can recreate a similar process through artificial selection! • Artificial selection: “evolution by human selection” “descendants” of the wolf

  19. Think • Imagine you spray an environment with insecticide. The environment is insects free for a few days, then the environment gets infested and the situation is worse than before. • What might have happened?

  20. Unexpected consequences of artificial selection Pesticide resistance Antibiotic resistance

  21. Insecticide resistance • Spray the field, but… • insecticide didn’t kill all individuals • variation • resistant survivors reproduce • resistance is inherited • insecticide becomes less & less effective

  22. Natural Selection https://www.youtube.com/watch?v=0SCjhI86grU http://www.youtube.com/watch?v=ZPDwyjzRBJ0

  23. BUT THE ONE WHO IS….

  24. You do • What is genetic variation? • Give an example of genetic variation • What are the two places genetic variation comes from? • What is an adaptation? • Give an example of an adaptation • What adaptation might help a cheetah survive? • Why can’t all members of a population survive?

  25. Rock Pocket Mice https://www.youtube.com/watch?v=sjeSEngKGrg

  26. Check for understanding Based on your new acquired knowledge, natural selection acts on • the genotype • the phenotype • both

  27. White board According to artificial selection, who selects? • The environment • Humans • Animals • Scientists • God

  28. White board According to the theory of natural selection, who selects? • The environment • Humans • Nature • Scientists • God

  29. White board The development by scientists of a new color in a rose is the result of 1. natural selection 2. artificial selection 3. descent with modification 4. overproduction

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