Tropisms

1. Tropisms

2. Today… • Complete and turn in stomata lab • Roots, stems and leaves review sheet • Tropisms notes • Tomorrow we will be setting up 2 labs… • Grades go in today… all makeup work must be turned in. Did you know – there is more fecal matter on a shopping cart at the grocery store than there is on the toilet at the grocery store!

3. It costs an average of $5,000 to raise a dog to ten years old. • Dalmatian puppies do not have any spots on them when they are born. They actually develop them as they get older. • There is a doggy disco held in Italy every year where owners can dance with their dogs.

4. Plant hormones produced by the plant affect growth and development.  • Plants are sensitive to light, gravity and moisture.

5. Phototropism—response to light • Geotropism—response to gravity • Hydrotropism—response to water • Thigmotropism—response to touch

6. A tropism is a growth movement whose direction is determined by the direction from which the stimulus strikes the plant. • Positive = the plant, or a part of it, grows in the direction from which the stimulus originates. • Negative = growth away from the stimulus.

7. Plants respond to: • Light = phototropism • Stems are positively phototropic. • Roots are negatively phototropic. • Gravity = gravitropism • Stems are negatively gravitropic while • roots are positively gravitropic.

8. The adaptive value of these tropisms is clear. • Roots growing down and/or away from light are more likely to find the soil, water, and minerals they need. • Stems growing up and toward the light will be able to expose their leaves so that photosynthesis can occur.

9. Complete the help wanted brain teaser… • We will begin our lab shortly • Three strategically placed trees around a home can save that household 50% on air conditioning bills.