Name:
Date:
Subject:
Plant Tropisms
Objectives
Objective 1: ASWBAT describe what plant tropism is and distinguish between negative
and positive tropism.
Objective 2: ASWBAT describe three types of plant tropisms.
On a scale of 1 – 3 how well you can do on this objective now.
(1 – Not at all
2 – I know it a little bit
3 – I know it very well)
Highlight your choice.
Objective: 1
Objective: 2
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Key Vocabulary Words
On a scale of 1 – 3 how well you know the vocabulary words below.
(1 – Not at all 2 – I know it a little bit 3– I know it very well)
Tropism
Negative Tropism
Positive Tropism
Phototropism
Gravitropism
Thigmotropism
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Pre-quiz
Do your best to answer the following questions.
1. What is primary growth?
Answer:
2. What is secondary growth?
Answer:
3. What is germination? What two things trigger it?
Answer:
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Plant Tropisms
Tropism is the movement of a plant due to some outside stimulus. A stimulus is something
that an organism reacts to. An example of a stimulus for plants is light or temperature.
Tropisms can be classified into two different categories, negative tropism and positive
tropism. Negative tropism is a response in movement away from a stimulus. An example
of this is when roots grow away from light. Positive tropism is a response in movement
toward a stimulus. An example of this is when leaves grow toward the sun.
1. What is a plant tropism?`
Answer:
2. What is negative tropism? Give an example.
Answer:
3. What is positive tropism? Give an example.
Answer:
Phototropism
The movement of a plant in response to light is called phototropism. This allows the plants
to grow toward or away from light source. When a plant grows toward the light it is called
positive phototropism and when it grow away from the light it is negative phototropism.
Positive Phototropism
Video Link: Phototropism http://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/tropisms.html
1. What is phototropism?
Answer:
Gravitropism
The movement of a plant in response to gravity is called gravitropism. When a plant grows
down with gravity it is called positive gravitropism and when a plant grow up against
gravity it is called negative gravitropism. Gravitropism is how the roots from a seed know
to go down in order to find water.
Negative Gravitropism
Positive Gravitropism
Video Link: Gravitropism http://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/tropisms.html
1. What is gravitropism?
Answer:
Thigmotropism
The movement in response to touch or contact with something else is called
thigmotropism. This is what allows some vines to wrap themselves around the branches
of other plants.
Thigmotropism of a vine tendril
Video Link: Thigmotropism http://www.youtube.com/watch?v=_SIJ4ov_FxA&feature=related
1. What is thigmotropism?
Answer:
Quiz
Directions: Answer the following questions to see if you met the objectives.
1. What is plant tropism?
Answer:
2. What is negative tropism? Give an example of a plant demonstrating negative
tropism.
Answer:
3. What is positive tropism? Give an example of a plant demonstrating postive tropism.
Answer:
4. What is phototropism?
Answer
5. What is gravitropism?
Answer:
6. What is thigmotropism?
Answer: