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# Variation lab day2

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### Variation lab day2

1. 1. Reminders<br />End of the semester is in a week a half!<br />Check your student view<br />Make an appointment with Miss Baker for make-up work!<br />Re-take for Natural Selection Exam Due Friday<br />
2. 2. Variation Lab<br />
3. 3. Purpose<br />Why did we do this lab?<br />What relevance does it have to your life?<br />
5. 5.
6. 6.
7. 7. How we look at our data:<br />Did you all get measurements in cm?<br />If you didn’t take all your measurements in cm, can you easily compare heights using different units of measurement? Why or why not?<br />Did you all measure the apple circumferences the same way as neighboring groups from which you received data? How can you be sure?<br />Why were our graphs so problematic?<br />Do your graphs tell you anything with a degree of certainty about a population of spinach plants? Why or why not?<br />Can we learn about selective pressures from our small amount of data? Why or why not?<br />Why do we need a larger sample size?<br />
8. 8. Let’s combine our data to make a class data set <br /><ul><li>Report your data on the white boards around the classroom.
9. 9. Write down the total variation for spinach leaf width in the population in a data table in your lab and create a new graph.
10. 10. Answer the questions in the end of your lab packet with the new data set.
11. 11. You will have 15 minutes to do this!
12. 12. Use this new information to answer your homework, this power point is on the wiki page.</li></li></ul><li>Types of Selection:<br />Stabilizing<br />Directional<br />Disruptive<br />
13. 13. Directional Selection:<br />
14. 14. Stabilizing Selection:<br />
15. 15. Disruptive Selection:<br />
16. 16. Re-evaluating the data:<br />What are some possible reasons (selection pressures) for the shape of the class spinach leaf graph?<br />How could we test these hypotheses?<br />
17. 17. Make some predictions:<br />If we saw the population of an apple-eating-insect grow in size, and we saw an apple fruit circumference size grow over time, what could we call this evolution pattern?<br />
18. 18. Definitions<br />Adaptation-a trait that provides some type of advantage to organisms in the struggle for survival<br />examples <br />
19. 19. Selection Pressure<br /><ul><li>Anything that can prevent an organism from passing on its genetic material
20. 20. Some good examples are: predators, and competition for food, shelter, or mates</li></li></ul><li>Variation<br /><ul><li>Variety (or differences) of traits WITHIN A SPECIES.</li></ul>How do we get variation?<br />Genetic Shuffling in Anaphase I of meiosis<br />Mutation to DNA passed down to offspring (very rare!)<br />
21. 21. Evolution is:<br />Genetic change in population over time.<br />These changes are seen in populations not in individuals<br />