Stimulus and Response Why animals and plants do what they do OR A fancy way of saying cause and effect in the animal world.

After today you will be able to: 1. Identify and classify stimuli as internal or external 2. Define a response. 3. Identify behavior as learned behavior or instinct.

What is a stimulus? Stimulus: any change in an organism’s environment that causes the organism to react. It is a fancy way of saying “cause”. Stimulus – singular Stimuli – plural Example: An animal is cold so it moves into the sun.

What is a response? Response: how the organism reacts to a stimulus and results in a change in behavior. It is a fancy way of saying “effect”. Example: Getting a drink when you are thirsty.

Examples of stimuli and their responses: You are hungry so you eat some food You are hungry so you eat some food A rabbit gets scared so it runs away A rabbit gets scared so it runs away You are cold so you put on a jacket You are cold so you put on a jacket A dog is hot so lies in the shade A dog is hot so lies in the shade It starts raining so you take out an umbrella It starts raining so you take out an umbrella

Plants also respond to their environment. When a plant grows towards the sun we call this phototropism.

Think – Pair - Share Turn to your partner and share two other stimuli and their responses.

There are two types of stimuli: External Stimuli and Internal Stimuli

External Stimulus External stimulus: a stimulus that comes from the external environment (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. A dog feels hot so it goes to lay in the shade.

Internal Stimulus 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 hot so it goes to lay in the shade.

Make a T-chart in your journal and label the columns internal and external. Put the letter of each stimulus in the proper column. A. You have a stomach ache and decide to lay down. B. A bird is thirsty and drinks some water. C. A squirrel sees a cat and runs up a tree. D. A lion gets hungry and eats a gazelle. E. You see a spider and scream.

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.

A mother bear teaching her cubs to fish

Teaching an animal a trick

Training a dog

Even you have learned behavior. For example, you learned to read and to talk.

Instinct: an animal’s natural reaction to a stimulus. It is an automatic reaction that the animal was not taught to do.

Animals natural instinct is to run away from danger. We call this the need for safety.

Animals will naturally find or make themselves a home because they have a need for shelter. An ant colony will build a mound A bird will build a nest A bear will find a den

Animals will naturally look for food and water.

Animals that need to, will naturally migrate. Turtlesfindtheocean

Animals instinctually know to store their food for the winter.

Think – Write - Share In your journal, write down one learned behavior that you have and one instinct that you have.

You should be able to answer these questions: 1. What is a stimulus? 2. What is a response? 3. Give one example of a stimulus and its response. 4. What is an internal stimulus? 5. What is an external stimulus? 6. It is raining and you open up an umbrella. Is this an internal or external response? Justify your answer. 7. What is learned behavior? 8. What is an instinct? 9. When a rabbit runs away from a wolf is this learned behavior or instinct? Justify your answer.