Unit 10
Homeostasis
My Goals
I will know what homeostasis
means.
I will explain the difference
between a stimulus and a
response.
1. Find your heart beat on your neck
or wrist.
2. Count the number of times your
heart beats in 30 seconds.
3. Write this number down on the
table under “At Rest”.
1. Run in place for 30 seconds. (FAST)
2. Find your heartbeat in your neck/wrist.
Count the number of times your heart beats in
30 seconds.
3. Write this number under “After Running”
**When you are more active, you burn more
energy. When your cells burn energy, they
create waste (carbon dioxide).
How do you get rid of this extra
carbon dioxide from your blood?
Breathing
faster!
Think, Pair, Share
With your partner, brainstorm the meaning of the
following words.
1.
2.
3.
4.
5.
6.
Balance
External
Internal
Respond
Environment
Maintain
Key Concept 1:
Organisms respond
to changes in the
external environment
in order to maintain
balance.
We call this balance
homeostasis.
Create a Gesture for:
Homeostasis
Organisms respond to changes in the external
environment in order to maintain balance, this
balance is called homeostasis.
TPS: What is happening in this picture?
Stimulus & Response
The change in the external environment is
called a stimulus, and the resulting reaction
of the organisms is called a response.
What is the stimulus in this picture?
Santa is the stimulus!
What is the cat’s response in this picture?
The cat scratching and hissing is the response!
Stimulus & Response
Organisms have
responses to:
internal changes
and
external stimuli
Does a plant respond to a
stimulus?
1. Which celery stalk has more turgor pressure?
2. What causes turgor pressure?
Think, Pair, Share
With your partner, brainstorm the meaning of the
following words.
1.
2.
3.
4.
5.
6.
Geotropism
Gravity
Photosynthesis
Phototropism
Negative
Positive
Which plant is in a state of
homeostasis?
How do plants respond to stimuli?
Geotropism is a plant’s response to gravity.
Which way are the roots growing? Why?
Roots grow down (towards gravity’s pull) =
Positive Response to Gravity
Leaves and Stem grow upwards (away from
gravity) = Negative Response to Gravity
What is the stimulus in geotropism?
Gravity is the
stimulus!
You say it!
Towards the stimulus =
Positive Response
Away from the stimulus =
Negative Response
What is phototropism?
Phototropism is a plant’s response to light.
What are tropisms?
Tropism = plant’s response
towards/away from a stimulus
(sun or gravity)
What are 2 stimuli
that plants respond
to?
Phototropism is a plant’s response to light.
Geotropism is a plant’s response to gravity.
What is Homeostasis?
Frank the Squirrel
Frank the squirrel has mad basketball skills.
1. When he gets hot during a basketball game, he
perspires. Why does he sweat?
2. What is the stimulus to sweating?
Quiz Time!
What is the stimulus in this situation?
What is the response in this situation?
Which animal is in a state of homeostasis?
What is the stimulus in this photo?
What is the response in this photo?
What word is described with these photos?
______ ________
What word is described with these photos?
___________
Which human is in a state of homeostasis?
1. How do you feel when your body
is in a state of homeostasis?
or…..
1. What words can you use to
describe how you feel when you are
in homeostasis?