1. TROPISMS AND OTHER RESPONSES AND ADAPTATIONS HELP PLANTS SURVIVE.

2. DEFINITION Tropism: bending toward or away from a stimulus “Trop”
the Greek word for turning
“ism”
means the act of

3. “trop”
turning
“ISM” THE ACT OF + =
“trop”
turning
“ism” the act of

4. Flash = Stimulus Blink = Response
Response and Stimulus
Anything in the environment that produces a response is called a stimulus.
Example:
A camera’s flash goes off…
Your eyes blink…
Flash = Stimulus Blink = Response

5. Three Types of Tropisms
HYDROTROPISM: response to water
Example: a plant’s roots grow towards a water source

6. Three Types of Tropisms
GRAVITROPISM: response to gravity
Example: a plant’s roots go down

7. Three Types of Tropisms
PHOTOTROPISM: response to light
Example: a plant’s stem bends toward the sun

8. Tropism Video Video of Tropisms
The following link is a YouTube video made by a third grade student that shows and explain how phototropism effects a plant
Tropism Video

9. Auxins Plants chemicals that help the plant grow
Auxins cause the plant to bend during all kinds of tropisms
When one side of the plant is exposed to light, the auxins move to the other side and down. Cells then grow, which makes the plant bend.

10. What are the three types of tropisms?
Review Questions
What is a tropism?
Bending toward or away from a stimulus
What is a stimulus?
Anything in the environment that produces a response
What are the three types of tropisms?
gravitropism, phototropism, hydrotropism

11. What chemical causes plants to bend?
Review Questions
What is gravitropism?
response to gravity
What is phototropism?
response to light
What is hydrotropism?
response to water
What chemical causes plants to bend?
auxins

12. POWER POINT PRESENTATION PRODUCED BY…
Mr. Reader Inc.
Where humor and looks meet education…