Animal science: Teach about animal adaptation with these easy, no-fuss science experiments - Brief Article

Instructor, March, 2001 by Janice VanCleave

As the sky brightens and the days lengthen, it's an excellent time to take some of your hands-on science lessons outdoors. In the following set of experiments, children will learn about animal adaptation. These experiments take a minimum of planning and effort, but will spark exploration and critical thinking in your young students.

Insect Survival Colors Grades 3-6

Purpose: To determine how color camouflage affects an insect population

Materials: 4 pencils; 85 feet (25.5 m) of string; Fourteen 12-inch (30-cm) colored pipe cleaners: 2 black, 2 brown, 2 green, 2 orange, 2 red, 2 white, 2 yellow; 1 paper lunch bag for each student; Timer

Time Needed: 1 hour

Directions:

1. Use the pencils and string to mark off a plot of grass about 20 feet (6 m) square. Freshly mowed grass is not as effective as taller grass. Notify the school gardener of the area and the date you wish to use it so that he or she will not mow the grass before the investigation.

2. Cut each pipe cleaner into 16 pieces that are approximately equal in size. These will be the "insects."

3. On the day of the investigation, while no one is watching, spread the pipe-cleaner insects evenly in the marked-off area.

4. Explain to the class that each colored piece of pipe cleaner represents one species of insect, such as a black beetle, a brown cricket, a green grasshopper, an orange butterfly, and so on. The students will pretend to be birds and must find three insects in order to survive.

5. Give each student a paper lunch bag and have them all stand outside the marked-off grassy area.

6. At your signal, students are to enter the marked-off area and try to find the needed insects for survival. They can collect their insects in the paper bags.

7. At the end of one minute, call a stop to the hunt.

8. Return to the classroom and have each student record in an Insect Data Table (see below) each pipe-cleaner insect found.

* Ask for a show of hands of the students who found enough insects to survive. Did any students share the insects they found with those who had less? Do birds share the insects they find? (Yes, they give them to their young.)

* Using each child's data, compile a class Insect Data Table on the chalkboard. Record the number of each insect color found by the students. From this collected information, determine the color of the insect that would be most likely to survive in the hunting area. Which would be the least likely to survive?

What's Going On?

Protective coloration helps to camouflage animals from predators. In this investigation, the "insect" that was found the least has the best protective color for the marked-off area.

How Do Spiderlings Find a Home?

Grade K-6

Purpose: To model the ballooning of newly hatched spiderlings

Materials: Scissors; Ruler; Sewing thread; Six 3/4-inch (1.9 cm), round, color-coded labels (any color)

Time Needed: 20 to 30 minutes

Directions:

1. Cut 3 pieces of thread, each piece about 6 inches (15 cm) long.

2. Attach one end of each thread to the sticky side of one of the labels.

3. Fold the label, sticky sides together.

4. Repeat steps 1-3 with the remaining labels. These are your six "spiderlings."

(Note: For very young children, it is suggested that the spiderlings be prepared by a teacher.)

5. Lay the spiderlings together in a row on the end of a table (near the edge).

6. Lean toward the table so that your mouth is close to, but not touching, the spiderlings. Then blow as hard as you can. Observe the movement of the spiderlings.

What's Going On?

The spiderlings are moved by your breath to a new area. Some move farther than others. This is similar to the way real spiderlings travel to new homes after they hatch. Once their egg sac breaks open, the spiderlings move away from each other and release strands of fine silk from their bodies. These strands, along with the attached spiderlings, are lifted by the wind and float to new areas. This behavior, called ballooning, is an innate behavior-the spiders are born with this ability.

Camouflage Chameleons

Grades K-6

Purpose: To determine how chameleons change color.

Materials: 2 sheets of colored plastic: 1 blue, 1 yellow; Black-and-white drawing of a chameleon

Time Needed: 10 minutes

Directions:

1. Put the blue sheet of plastic over the drawing of the chameleon.

2. Put the yellow sheet of plastic over the blue plastic. Have students observe the color change of the chameleon.

What's Going On?

Light reflections off the blue and yellow plastic blend together, producing green light. In a similar way, when light reflects off the reflective blue layer of a chameleon's skin and blends with the yellow pigment in the uppermost layer of skin, the chameleon appears green.

Chameleons cannot change into every color. They have basic yellow, red, and dark brown pigments that can blend together, along with reflected blue light, to form different colors. These color changes help the chameleon blend in with its environment. However, chameleons are not able to observe their surroundings and make a conscious decision to change color in order to match those surroundings. Instead, the color changes come about because of alterations in light intensity, temperature, or emotional state.