Lesson 4: Stimuli

Foundation Science

SC 22101

We will Study Types of Responses to Stimuli….

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What kind of animal is this?

What is the stimulus it

responds to?

ReflexesGuesses?Reflex – a response that

happens fast and unconscious (unconscious = do not have to think)

Examples of reflexes? Blinking, sneezing, knee jerk, pupil dilating, shivering

Stimuli for these reflexes?

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Reflexes

Brain not used in reflex reactions – we don’t think about it!

Why are reflexes so much faster than learned behaviors?The signals in nerves don’t have to travel to brain

Reflex arc video…

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List of Reflexes

Instincts

Instincts – behaviors that are “programmed” into the DNA.

Animals DO NOT learn instincts.

Examples of instincts?

-Birds fly south for the winter

-Salmon find the way back to the same exact river they were born in

-Baby snakes can catch insects right after they are born

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What Stimuli Trigger Instincts?

Our examples:

Birds that fly south for winter – stimulus = amount of daylight (=time of year)

Salmon find their way back to same river – stimulus = earth’s magnetic field and smell

Learned Behaviors

Learned behaviors - come from practice or experience.

Examples:-Teaching your dog to sit down when he hears the word “sit” (Stimulus?)-Seagulls following a fishing boat for food (Stimulus?)

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Do You Now Know the Difference Between Instincts, Reflexes and

Learned Behaviors?

Instinct? Reflex?

or Learned Behavior…….?

Questions1. What is reaction time (we studied this in lab)?2. What is the difference between an instinct and a reflex?3. Give 3 examples of instinctive behaviors, and 3 examples of learned

behaviors. 4. Give one example of an instinct in dogs.5. What does unconscious mean?6. Your reaction time for grabbing the ruler in lab was about 0.25 seconds.

Do you think your reaction time when you touch a hot cup would be faster or slower? Why?