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WARM UP p. 46*

WARM UP p. 46*. Glue HW “Graphing Practice” to p. 46 RIGHT. Create a page called 46*. The star indicates it is a preAP only page. On the LEFT of this page, write/draw at least 3 things you know about plants. Plant Forces. Somewhere, something incredible is waiting to be known. Carl Sagan.

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WARM UP p. 46*

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  1. WARM UP p. 46* • Glue HW “Graphing Practice” to p. 46 RIGHT. • Create a page called 46*. The star indicates it is a preAP only page. • On the LEFT of this page, write/draw at least 3 things you know about plants.

  2. Plant Forces Somewhere, something incredible is waiting to be known. Carl Sagan

  3. Guiding Questions • What forces affect the motion of plants? • What forces affect the motion of animals? • What are some examples of force? • Does applying a force always cause a change in position? • Does a change in position always involve a force?

  4. Topics/Questions: • What forces affect motion in everyday life such as emergence of seedlings, turgor pressure, and geotropism? Part 1) effect of turgor pressure on plants Part 2) effect of geotropism and phototropism on plants

  5. Background Vocabulary Stimulus/Response Turgor pressure - stiffness of plant stems, roots, and leaves due to the presence of water in their cells Geotropism (gravitropism) - response to gravity Phototropism – response to light Thigmotropism – response to touch Hydrotropism – response to water • http://www.nasa.gov/mov/196822main_057_Tropisms_of_Plants.mov

  6. History – Adaptations of Plants • Charles Darwin in 1880 showed that growing tips of plants bend toward a light source (phototropism.) • The turning is due to the action of the plant chemical hormone auxin, which causes elongation. On the side of a plant facing the light the auxin is inactivated, and only the side away from the light elongates • Phototropism helps the plant plants avoid excessive shading by other plants. • Vines exhibit thigmotropism to help them climb and anchor • Seedlings exhibit root geotropism to help them anchor in the soil

  7. Teacher Notes Part 1 • Model cells in baggies with various water amounts • Celery in distilled water, salt water • Potato pieces in distilled water, salt water • Bend the slices between the fingers to test their comparative firmness. The cells are full of water and thus turgid. Put the slices in a 3% solution of common salt and leave for about half an hour. Again bend the slices between the fingers to test their comparative firmness. The slices become flabby.

  8. Part 1: Turgor Pressure in Plants • Plants exhibit turgor pressure when they stand erect and return to their original position after being bent. • This rigidity in plants is the result of the firmness of each water-filled cell (look at models). • Pressure is related to force. Celery/potatoes Cells in a bag

  9. Part 1: Turgor Pressure in Plants Data: Model cell with a lot of water: Model cell with a little water.

  10. Part 1: Turgor Pressure in Plants Data:

  11. Teacher Notes for Part 2: • Use dried pinto beans from the grocery store. Any dried beans should work for this activity. They are inexpensive and one package should have more than enough for the whole class. • The lab suggests that you presoak the beans. However, we did not have time and our beans sprouted just fine. Allow one extra day for the beans if you have not soaked them. The beans take about 4 days to sprout. • Ziploc baggies, Paper towels, soaked pinto beans (10 beans per group) • United Streaming Germination clip 2 min • NASA clips embedded

  12. Set up the experiment • http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/How_Plants_Grow_in_Space.html • Set up 2 baggies each with 5 seeds on damp paper towels. • Label the bags with your group number and the date and the conditions. • Hang one baggie in the dark storage spot. • Hang one baggie in the light storage spot. • Wait at least 4 days.

  13. DAY 2

  14. Set up the experiment • http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/How_Plants_Grow_in_Space.html • Set up 2 baggies each with 5 seeds on damp paper towels. • Label the bags with your group number and the date and the conditions. • Hang one baggie in the dark storage spot. • Hang one baggie in the light storage spot. • Wait at least 4 days.

  15. Part 2: Bean seed germination – Geotropism and Phototropism • What does germination mean? (Watch United Streaming clip) • We are going to do two experiments at once (kind of).

  16. Part 2: Geotropism

  17. Earth Results – Control Group • Record all observations, quantitative and qualitative (be gentle with the seedlings). • Phototropism • Geotropism Constants?

  18. NASA Results – Experimental Group http://www.nasa.gov/mov/196824main_059_Evaluting_Experimental_Treatment.mov http://www.nasa.gov/mov/196825main_060_Discussion_Points.mov • http://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/tropismmenu.html • Watch sunflower phototropism, cool corn phototropism, sunflower gravitropism, coleus shoot gravitropism

  19. LEFT PAGE Conclusions • This is a picture of a plant that has accidentally been turned over. Draw the picture on your left page and then use the words geotropism, gravity, force, and turgor pressure to explain how the plant will adapt to being on its side. • This is a picture of a plant that has been exposed to light only from the left side. Draw the plant and then use the words phototropism, force, and turgor pressure to explain how the plant will adapt to the light.

  20. Animal Tropisms (Taxis) • Chemotropism - the response to chemical stimuli is called Ex: Flies and other insects are attracted to certain odors emanating from the chemical decomposition of meat and are stimulated to lay their eggs in that medium. Ex: The same insects react negatively to certain smokes and fumes, which are often used to repel them.

  21. Other commonly observed tropisms include… Galvanotropism or electrotropism - movement in response to an electric current Rheotropism - or orientation in response to the direction of a current of water Anemotropism - or movement with respect to the wind Thermotropism - or movement in relation to unequal conditions of temperature. Thigmotropism in many lower animals enables them to respond to specific crevices and to differentiate between rough and smooth areas. Neurotropism - the attraction or repulsion that certain substances exercise upon regenerating nerve fibers.

  22. Teacher Notes Part 3 • You can give the bean sprouts a day to “harden” before you plant them by letting some air into the bag. Plant them and place them in the boxes. It should only take 3-4 days to see the effects of phototropism. • Markers • Short plastic cups • Soil/potting mix

  23. Part 3: • Plant two of the seedlings from Part 2 in two cups. • Cover each with the same amount of potting soil and water with the same amount of water. • After the seedlings emerge from the soil at least

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