OBJECTIVES:
Students will be able to:
1. define stimulus and response
2. classify stimulus/response
interactions
3. describe stimulus/response
interactions in an ecosystem
(abiotic vs. biotic)
Living Things Respond to Stimuli
What is the response
to the phone
ringing?
Answer the phone and say: “Hello.”
Yes, you answer the phone and
say:
•Hello!!!!!
• Stimulus: The phone
rings (Hear the phone
ringing)
• Response: Answer the
phone and say, “Hello.”
• A stimulus is a change in an
organism’s environment
that affects the activity of
the organism.
• A response is any
reaction of a living thing
to stimulus.
• Let’s try another example.
• Partner on the left close your
eyes for one full minute. When I
say open your eyes, the other
partner will watch your pupils to
see what happens. Partners on
the left, close your eyes.
What happens????
• What is the stimulus?
• Let’s try it again with the
other partner.
• What is the reaction?
• The stimulus is the light
shining in the eye.
• The response is the pupil
getting smaller.
What is the stimulus???
•See if you can guess
what the stimulus is
that causes the
“heard” response:
What is the stimulus?
The sun comes out…
• Stimulus: Sun comes out
• Response: Rooster crows
•Let’s try another
one. Listen
carefully.
What is the stimulus?
•The response is…….
Stimulus Possibilities
• Someone put a toy in the
hallway, and I tripped over it.
• My foot got stuck in my pant
leg, and I fell down the stairs.
• Was everyone’s idea the
same???
• Is there only one way to
respond to a stimulus?
•Now listen again.
•The response is……..
•What is the stimulus?
Stimulus possibilities
• Parents received your grade
card and you are grounded.
• You were licking a double dip
ice cream cone and it fell onto
the floor.
• When you hear the two-minute bell in
the morning, you (should) head to your
first hour class. This is an example of a
living thing (you) responding to a
stimulus. In this example, what is the
stimulus?
•The stimulus is the
bell ringing.
•What is the response?
•The response is
heading to class on
time!!!!
Living Organisms
• One characteristic that distinguishes living
organisms from nonliving things is the ability
to sense and respond to conditions or changes
in the environment. Any substance or
condition in the environment that causes an
organism to react is called a stimulus. The
reaction of the organism to a stimulus is called
a response.
• Living organisms are able to sense and
adjust to a variety of stimuli in the
environment using special sensory
receptors that help them detect changes
in light, odor, sound, and
• textures.
Sensory receptors can be as simple as
the sensory cells in jellyfish that are
connected in a net-like arrangement, or
as complex as the sensory organs in
humans, such as eyes,
ears, or a nose.
Why is it important for
organisms to be able to
respond to/interact with
both the living and nonliving parts of their
environments?
• In order to meet the needs of a
living organism and stay alive,
there is a constant exchange of
materials between an organism
and the non-living parts of the
environment.
NOT “BIO”
• The non-living parts of
an organism’s
environment is called
abiotic. A = not
•
• What are some
examples of abiotic
factors in an ecosystem?
Abiotic = nonliving
•water, light, soil,
rocks, wind
•What are the living
parts of an
organism’s
environment called?
Biotic
•What are some
examples of biotic
factors in an
ecosystem?
Biotic = Life
•Animals, trees,
plants, etc.
Exit Slip
• Write the definition of
abiotic and biotic on a
piece of paper and
examples of each.
Practice Time:
• Stimulus vs. Response
• Ruler Drop