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TRAIT: Pea Flower Color

TRAIT: Pea Flower Color. Do you think that variation in this trait is: Under genetic control Under environmental control Under a combination of genetic and environmental control Insufficient information to determine. Day 1: activity 1. TRAIT: puppy appearance.

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TRAIT: Pea Flower Color

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  1. TRAIT: Pea Flower Color Do you think that variation in this trait is: Under genetic control Under environmental control Under a combination of genetic and environmental control Insufficient information to determine Day 1: activity 1

  2. TRAIT: puppy appearance Do you think that variation in this trait is: Under genetic control Under environmental control Under a combination of genetic and environmental control Insufficient information to determine

  3. TRAIT: Near Sightedness Do you think that variation in this trait is: Under genetic control Under environmental control Under a combination of genetic and environmental control Insufficient information to determine

  4. TRAIT: Plant height in two populations of Joshua trees Do you think that variation in this trait is: Under genetic control Under environmental control Under a combination of genetic and environmental control Insufficient information to determine

  5. TRAIT: Puppy Appearance TRAIT: Near Sightedness Assignment: What kind of information would you need to answer the question: is it genetic variation, environmental variation, or both? List the type(s) of data and/or experiments that will provide evidence about genetic versus environmental contributions to trait variation. TRAIT: Pea Flower Color TRAIT: Tree height in two populations of Joshua trees

  6. So what would a plot look like if we plotted a trait that had a strong genetic basis? Offspring arm length Short Long Short Long Parental Arm Length Day 1: activity 2

  7. Offspring Height (in) Offspring Flower Width (mm) Parent Height (in) Parent Flower Width (mm) Do the relationships above allow you to make an hypothesis about the contribution of genetics to trait variation? Which of these traits has a larger genetic contribution to trait variation? Day 1: activity 3

  8. Homework • Plot the data provided (by hand or using Excel) • Interpret what this plot indicates about the degree to which variation in this trait is due to genetic differences between individuals. • Be prepared to discuss your interpretation at the start of the next class period. Day 1: homework

  9. SAMPLE OF STUDENT GRAPH OFFSPRING BEAK SIZE (mm) PARENT BEAK SIZE (mm) Day 2: activity 1

  10. Offspring Flower Width (mm) • What would this graph look like if seeds were transplanted to different environments? • Even # tables: you plant seeds in a greenhouse with carefully controlled homogeneous environments. • Odd # tables: you plant seeds in a field with variable moisture and nutrient conditions. Parent Flower Width (mm) Day 2: activity 2

  11. Reading and assignment • Read textbook chapter on Natural Selection • Read excerpt of Into Thin Air by Jon Krakauer on climbing Mt. Everest • Think about the photo above • Class collaboration document • Ways that high altitude cause a stress on organisms • How the two men in the photo are different Day 3-0

  12. Selective forces at high altitude Day 3-1

  13. Day 3-1

  14. Class collaborative document with discussion • High altitude stresses: • Low oxygen • Cold temperatures • Less food • Higher UV • Shorter growing seasons • How the two men are different • One requires oxygen to be at high altitude • Effects of low oxygen • Breathing problems • Sleeping problems • High altitude sickness Day 3-1

  15. Short term effects of low oxygen (less oxygen in the blood) Day 3-2

  16. How low altitude animals handle low oxygen • Breathe more • Carry more oxygen in the blood • Pump more blood • Make more blood Day 3-2

  17. Hemoglobin saturation (%) Oxygen partial pressure in body tissue (mm Hg) Day 3-2 Adapted from Storz2007

  18. Day 3-3

  19. Day 3-3

  20. A low altitude native visits a high-altitude native. Which one burns more energy sleeping?A. High-altitude nativeB. Low-altitude nativeC. They are both the same Day 3-3 Adapted from Beall 2009

  21. Background information: • Variation: Native Tibetans have two physiological phenotypes • Low oxygensaturation • High oxygen saturation • Variation is genetically determined: oxygen saturation phenotype has a genetic basis (Mendelian trait) • What other information do we need to demonstrate that this trait is under natural selection? Day 3-3

  22. Data measured at high elevation Physiological phenotype Adapted from Beall et al 2004 Day 3-3

  23. Which of the following represents the best prediction for the relative frequencies of the two oxygen saturation types in the Tibetan population? Day 3-3

  24. Day 3-4

  25. Deer Mice Adapted from Storz 2007 Day 3-4

  26. Minute essay In one sentence, summarize the major points of today’s lesson. Day 3-4

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