Transcript Stimulus and Response - ESC-2

Stimulus and Response
Why animals and plants do what they do
OR
A fancy way of saying cause and effect
in the animal world.
Describe a situation in
which you were immediately
scared and/or reacted
quickly to something. Write
at least 1 complete sentence
describing your experience.
What is a stimulus?
any change in an organism’s
environment that causes to the
organism to react. It is a fancy way
of saying “cause”.
Example: An animal is cold so it moves into the
sun.
Example: Getting a drink when you are thirsty.
What is a response?
how the organism reacts to a
stimulus and results in a
change in behavior. It is a
fancy way of saying “effect”.
Example: An animal is cold so it moves into
the sun.
Example: Getting a drink when you are thirsty.
Examples of stimuli and their
responses:
Circle the stimulus and underline the
response:
• You are hungry so you eat some food
On your own, complete the rest of
question 4
Plants also respond to their
environment. They are called
tropisms
phototropism
thigmotropism
gravitropism
Think – Pair - Share
Turn to your table partner and
share two other stimuli and their
responses.
There are two types of
stimuli:
External Stimuli
and
Internal Stimuli
External Stimulus
a stimulus that comes
from outside an
organism.
Examples:
1. You feel cold so you put on a jacket.
2. A snake lunges at a rabbit so it runs
away.
3. It is a very hot, sunny day so a dog sits
in the shade.
Internal Stimulus
a stimulus that comes
from inside an organism.
Examples:
1. You feel hungry so you eat some food.
2. A cat feels thirsty so it drinks water.
3. A dog feels sick so it’s body triggers a
fever.
Animals can respond to stimuli
in two ways:
1. In a way that they learned. We call
this learned behavior.
OR
2. In a way that they were just born
knowing how to do. We call this
instinct.
Learned behavior:
a response to a stimulus that an
animal was taught.
Examples: chimps
and monkeys
learning to use
tools
bear teaching her
cubs to fish
Learned behavior:
Pavlov’s Dog
Famous dog experiment done by
Ivan Pavlov
ring a bell
feed dog
dog salivates
over time, the dog will
salivate when it hears
the bell.
Instinct:
an animal’s natural reaction to a
stimulus. It is an automatic
reaction that the animal was not
taught to do.
Examples: getting
away from danger
Examples: finding
or building a shelter
Homeostasis
• An organisms response to internal and
external stimuli helps to maintain
homeostasis
– Homeostasis – balance or equilibrium inside a
living organism
• Blood sugar levels
• Sweating/shivering
• Fever
• Vomiting
• Plant tropisms
Blood Glucose Levels
• In order to maintain homeostasis, your
body tries to keep a certain blood glucose
level
• When blood glucose is low, you should eat
• When blood glucose is high, your
pancreas should release insulin
• Problems with this system can create
diabetes