Grade 7 Follow-up Experiment “Adaptations”
(From Animals: Mind-Boggling Experiments You Can Turn into Science Fair Projects, Janice VanCleave, John Wiley & Sons, 1993)

Quality Core Curriculum Objectives:

Science                     (Life Science)

            #1 –  Uses process skills of observing, classifying, communicating, predicting, inferring, recording.

            #4 –  Selects, uses multiple sources for information on concepts.

            #20 –Demonstrates understanding of adaptations for survival.

Language Arts                    (Listening/Speaking)

            #18 – Summarizes, interprets, compares and contrasts information presented orally.

            #20 – Interprets literal, inferential, and critical questions.

            #13 – Expands listening vocabulary.

                                                (Reference/Study)

            #50 – Selects relevant information about a subject from various sources.

            #55 – Uses media center as source of information.

Vocabulary:  adaptations, endotherms, conduction, arteries, hypothalamus, nerve impulses

Background:

An adaptation is a variation of structure, physiology or behavior that aids the organism’s survival in its particular environment.  One example of a behavioral adaptation is when an animal uses water to help regulate its body temperature.  For many animals, this behavior is not learned but instinctual.  However, for other animals, it may be learned; and for some animals, it may be both instinctual and learned.

PART 1:  Experiment  – Behavioral Adaptation – “Cooling Off”

Materials:

       Masking tape

            Marking pen

            water

            2 clear glasses                                  (optional:  wooden spoon & ice cubes)

            2 thermometers

            1 bowl

            freezer

Problem:  How is water used to lower an animal’s body temperature?

Procedure: 

1.      Use the masking tape and marking pen to label the glasses #1 and #2.

2.      Fill both glasses one-half full with warm water from a faucet.

3.      Place a thermometer in each glass.

4.      Allow the glasses to stand undisturbed for one minute.

5.      Read and record the temperature shown on each thermometer.

6.      Set glass #1 in the bowl.

7.      Add cold water from the faucet so that there are about 2 inches (5cm) of water in the bowl.

8.      As soon as the cold water is in the bowl containing glass #1, place glass #2 in the freezer and shut the door.

9.      At the end of one minute, read and record the temperature shown on each thermometer.

Results:

The temperature of the water in glass #1 decreased more quickly than did the temperature of the water in glass #2.

Why?

The body temperature of a cold-blooded animal changes with the temperature of its environment, but a warm-blooded animal maintains a constant body temperature regardless of the temperature outside its body.  To regulate its temperature, a warm-blooded animal must increase heat loss from its body in hot weather and reduce heat loss during cold weather. 

One method of increasing heat loss is by bathing, wading, or standing in cold water.  The water conducts heat from the animal’s body more rapidly than does air.  Your experiment demonstrated that heat energy in the water inside glass #1 moved out into the cooler water surrounding the glass.  Heat energy in the water inside glass #2 also moved out into the air but at a slower rate. This movement of heat energy from one substance to the next is called conduction.  Water is a faster conductor of energy than air is.

Let’s Explore:

1.      Would moving water affect the rate of cooling?  Repeat the experiment using a wooden spoon to stir the water in the bowl.  Would animals be cooled faster in a running stream or still pond?  Ask the students to predict which method would be faster and why.  Then have them conduct the experiment and research why one method is faster.

2.      Would placing icy water in the bowl have affected the rate of cooling?  Repeat the experiment placing ice cubes in the bowl of water.

3.      Ask the students to think of five wild animals that use water to maintain their body temperature.

4.      Would water have the same cooling effect on cold-blooded animals?  Do cold-blooded animals need to regulate their body temperature?  If so, how do they do it? 

Part 2:  Physical Adaptations for Temperature Regulation

Background:

Another method of increasing heat loss from the body of animals is accomplished by a part of the brain called the hypothalamus.  The hypothalamus activates nerve impulses that relax the walls of small arteries in the skin.  This allows more blood to circulate to the surface of the body.  The animal has no conscious control over this function.  It happens automatically by the animal’s brain.  This is an example of a physical adaptation.

1.      Ask the students to brainstorm other non-behavioral ways that warm-blooded animals (such as humans) cool their body temperature when the environment is warmer than their body temperature.  How does sweating help with heat loss?

2.       Ask the students to brainstorm and research non-behavioral ways that animals conserve body heat when the environment is cooler than their body temperature.   Polar bears are a great example – what color is a polar bear’s skin?  Why do you think it is not white?  What color is a polar bear’s fur?  What purpose does it serve?  Are birds more similar to mammals or reptiles in how they regulate their body temperature?

3.      Ask the students to pick an animal and research how that animal regulates its body temperature by both cooling off and conserving body heat.  Have them create a chart for their animal showing whether these behaviors are instinctual or learned, or both.