Science 9 Unit A Biological Diversity Section2 Lesson Variation

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Variation
Natural Selection
Charles Darwin
Discrete Variation
Continuous Variation

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Science 9 Unit A Biological Diversity Section2 Lesson Variation

  1. 1. Science 9 Unit A: Biological Diversity Science InAction Section 1.3: Pages 20-24 Section 2.1: Pages 26-29
  2. 2. Lesson #3 <ul><li>Learner Outcomes </li></ul><ul><li>I can identify the role of variation in species survival under changing environmental conditions </li></ul><ul><li>I can describe examples of variation of characteristics within a species, and identify examples of both discrete and continuous variation </li></ul><ul><li>I can distinguish those characteristics that are heritable from those that are not heritable, and identify characteristics for which heredity and environment may both play a role </li></ul>
  3. 3. What is Variation ? <ul><li>Variability within a species population. </li></ul><ul><li>Eg. Red/Blond Hair vs. Brown Hair </li></ul><ul><li>Eg. Blue eyes vs. Green eyes </li></ul><ul><li>Examples of variability in include: </li></ul><ul><li>Red fox (color of coat) </li></ul><ul><li>Antibiotic resistance (bacteria) </li></ul><ul><li>Banded snail (color and design of shell) </li></ul>
  4. 4. Variation of Human Physical Characteristics <ul><li>Skin, eye, complexion colouring </li></ul><ul><li>Hair colour, baldness </li></ul><ul><li>Supernumerary body part (extra parts), or missing body parts </li></ul><ul><li>Cleft Lip and Palate </li></ul>
  5. 5. Variation of Human Physical Characteristics <ul><li>Height – average range </li></ul><ul><li>Dwarfism </li></ul><ul><li>Gigantism </li></ul><ul><li>Blood type </li></ul><ul><li>- Groups A, B, AB, and O </li></ul><ul><li>Somatotype </li></ul><ul><li>Dominance of handedness </li></ul><ul><li>Dexterity and motor skills </li></ul>
  6. 6. Who is This Man?
  7. 7. What is Natural Selection ? <ul><li>Happens when factors in the environment determines, or “selects” which individuals, within a species, will be able to survive. </li></ul><ul><li>Offspring will usually have similar adaptations for survival. Whales </li></ul><ul><li>Charles Darwin – Theory of Evolution – “On the Origin of Species” book - 1859 </li></ul>
  8. 8. The 5 year voyage of the HMS Beagle Surveying and charting coasts
  9. 11. Antibiotic resistance is enhanced by natural selection <ul><li>The top section represents a population of bacteria before exposure to an antibiotic. </li></ul><ul><li>The middle section shows the population directly after exposure, the phase in which selection took place. </li></ul><ul><li>The last section shows the distribution of resistance in a new generation of bacteria. </li></ul><ul><li>The legend indicates the resistance levels of individuals. </li></ul>
  10. 14. Variations <ul><li>Variation is one of the most critical aspects of species survival. </li></ul><ul><li>It may be: </li></ul><ul><li>a genetic (cellular code) modification </li></ul><ul><li>a behavioral tendency </li></ul><ul><li>This enables some individuals within a species to survive , while others, will perish . </li></ul>
  11. 15. Genetic Variability <ul><li>Species of Side-blotched lizards ( Uta stansburiana ) in central California </li></ul>
  12. 16. Give it a TRY – Page 27 <ul><li>Survey the class and find how many people: </li></ul><ul><li>Can or cannot bend their thumb joint “backward” without adding pressure </li></ul><ul><li>Have earlobes that are attached or separate </li></ul><ul><li>Have a pointed or smooth hairline </li></ul><ul><li>Draw a data table to record your results. Create a graph that will best illustrate your results </li></ul>
  13. 17. Inheritance <ul><li>Transmission of characteristics from parents to offspring </li></ul><ul><li>The characteristics of the parents are carried to the next generation by the process of heredity </li></ul>
  14. 18. What are Non-Heritable Traits? <ul><li>Characteristics are acquired and not necessarily passed on from generation to generation. </li></ul><ul><li>Athleticism , artistic ability , leadership qualities are all learned during the early years of life. </li></ul>
  15. 19. Continuous Variation <ul><li>Variations are differences in characteristics that have a multitude of variations , such as height , shoe size , arm length etc… </li></ul>
  16. 20. Discrete Variations <ul><li>Discrete variations are differences in characteristics that have a definite form . </li></ul><ul><li>One characteristic , or the single, other variation, of the characteristic. </li></ul><ul><li>Either the organism has a trait or it does not . </li></ul><ul><li>Example: Either your earlobes are attached or they are not. </li></ul>
  17. 21. Variation and the Environment <ul><li>Some variations may be influenced by interactions with the environment. These variations are not inherited . </li></ul><ul><li>Examples include: </li></ul><ul><li>Change in the pigmentation of skin color throughout the seasons due to the sun. </li></ul><ul><li>Height and weight can be influenced by diet. </li></ul>
  18. 22. Give it a TRY – Page 29 <ul><li>Ready…………..set…………GO!!!! </li></ul><ul><li>Quickly clasp your hands together above your head, interlocking your fingers. </li></ul><ul><li>Look to see which thumb is on top. Note which way feels more natural. </li></ul><ul><li>Finish the chart in your notes, indicating Left Thumb on Top vs. Right Thumb on Top </li></ul><ul><li>Decide whether the data is discrete or continuous. Explain your answer. </li></ul>
  19. 23. Is it Discrete or Continuous? Page 29 Action Right Preference Left Preference Type (circle one) Clasping Hands Continuous Discrete Folding Arms Continuous Discrete
  20. 24. Sample Multiple Choice Questions <ul><li>Q1. To better understand variation; scientists explore the characteristics, which are passed on from generation to generation within a species. Those characteristics that are passed on from generation to generation are … </li></ul><ul><li>A. genetic </li></ul><ul><li>B. inherited </li></ul><ul><li>C. non-inherited </li></ul><ul><li>D. non-genetic </li></ul>
  21. 25. Sample Multiple Choice Questions <ul><li>Q2. An albino kangaroo is a kangaroo that is pure white. This characteristic is classified as a … </li></ul><ul><li>A. non-inherited variation </li></ul><ul><li>B. continuous variation </li></ul><ul><li>C. discrete variation </li></ul><ul><li>D. singular variation </li></ul>
  22. 26. Sample Multiple Choice Questions <ul><li>Q3. Variations caused by interactions with the environment are not heritable. Plants that are grown in dim lighting conditions would turn out to be … </li></ul><ul><li>A. identical to their parents in all aspects </li></ul><ul><li>B. much like their parents </li></ul><ul><li>C. very different from their parents </li></ul><ul><li>D. similar to parent plants that were grown in dim light </li></ul>
  23. 27. Sample Multiple Choice Questions <ul><li>Q4. Cats B and C are similar in size, but cat A is taller when standing. Like humans, cats pass down genetic information for height, but cats can mature to be a wide range of heights - it is not an &quot;either/or&quot; characteristic. The characteristic of height in cats can be described as a   </li></ul><ul><li>non-heritable and continuous in variation  </li></ul><ul><li>heritable and discrete in variation  </li></ul><ul><li>heritable and continuous in variation </li></ul><ul><li>non-heritable and discrete in variation  </li></ul>
  24. 28. Answers to Previous Questions <ul><li>B </li></ul><ul><li>C </li></ul><ul><li>D </li></ul><ul><li>C </li></ul>
  25. 29. Did you … <ul><li>… identify the role of variation in species survival under changing environmental conditions? </li></ul><ul><li>… describe examples of variation of characteristics within a species, and identify examples of both discrete and continuous variation? </li></ul><ul><li>… distinguish those characteristics that are heritable from those that are not heritable, and identify characteristics for which heredity and environment may both play a role? </li></ul>
  26. 30. Homework <ul><li>Read pages 20-24, 26-29 </li></ul><ul><li>Check and Reflect page 29, #1-2, #5 </li></ul><ul><li>Update Portfolio </li></ul><ul><li>Read pages 30-36 </li></ul>
  27. 31. Question 1 <ul><li>Give one example of a heritable characteristic and one example of a non-heritable characteristic that we did not discuss in class. </li></ul><ul><li>Heritable __________________________________ </li></ul><ul><li>Non-Heritable __________________________________ </li></ul>
  28. 32. Question #2 <ul><li>What is discrete variation? ______________________________________________________________________________________________________ </li></ul><ul><li>What is continuous variation? ______________________________________________________________________________________________________ </li></ul>
  29. 33. Question #5 <ul><li>A scientist wants to study continuous variation in a mouse population. What mouse characteristics would she or he investigate? ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ </li></ul>

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