Animal Adaptations Experiments

8

STEM

Animal Adaptations Experiments

How have Animals and Insects adapted to life in the Arctic/Antarctic?

PURPOSE: To see how animals cope with long-term exposure to cold.

The next series of activities explore the variety of adaptations that animals and insects at both poles have acquired to adjust to life in extreme cold and drought. The activities are split into two age groups and a short discussion is provided as background. Also refer to the Life at the Poles Powerpoint for further information and background.

Background/Discussion

Shrimps, fishes, seals, walruses, and whales thrive in the cold, nutrient-rich waters of the Arctic Ocean. Caribou, moose, and musk oxen roam the tundra. Polar bears prowl the ice. Birds such as ptarmigans and snowy owls live year-round in the cold weather. Many other animals visit arctic lands to feast on summer plants and insects. Some birds, seals, and whales migrate south during the coldest arctic months. Others stay year-round, protected by

thick layers of blubber or dense coats of fur.

Unlike the Arctic, there are no permanent inhabitants in Antarctica. What little exposed rock there is supports only sparse vegetation (mostly algae, lichens, and mosses), microbial life (bacteria and fungi), and a few hardy insects. While a great variety of insects, birds, and land mammals live in the high Arctic year round, only a handful of tiny invertebrates -- not a single land vertebrate -- can survive the Antarctic winter. Yet there is an abundance of life in Antarctic waters -- waters generally considered to be those south of 60 degrees S. latitude. Seabirds, seals, penguins, and whales are perhaps the best known life forms – consuming enormous quantities of fish, squid, and krill. Why are there no permanent inhabitants of Antarctica? Antarctica is the highest and coldest continent -- its average height is three times that of other continents (4,900 meters above sea level) and it is by far the coldest continent with minimum temperatures considerably lower than the Arctic. In the vicinity of the South Pole, the average annual temperature is minus 49 degrees Celsius, and the coldest temperature ever recorded on Earth was recorded at the Soviet outpost Vostok Station, which has the dubious distinction of being known as the "coldest place on Earth". On 21 July 1983 a record low temperature of -89.6 degrees C. (-125.8 degrees F.) was recorded and this did not take into account "wind chill!" The fierce winds characteristic of the area push the harsh temperatures down even further. Moreover, for nearly six months per year, the sun does not rise above the horizon, making an already inhospitable environment even more cheerless. How does anything survive in this hostile environment for even part of the year? By developing, over time, special adaptations have enabled them to become better suited to this environment. The Antarctic Sea is rich with life, unlike the land, and the life forms that survive do so because they get their food from the sea. Antarctic animals spend part of their time on the edge of the ice and part of their time in the water, or entirely in the water. Somehow they survive -- they have adapted to their cold biome. If the temperature in the Antarctic winter averages -50 degrees C, most animals need more protection than just insulation. Seals and penguins spend most of their time in the water with the whales and fish. Does this provide more protection?

Biologists call the physical, physiological and behavioral traits that help an organism survive in a particular environment "adaptations". Organisms that live in the arctic and subarctic must have adaptations to help them survive and raise young despite the periodic extreme cold, persistent winds, short growing seasons and other difficulties posed by their severe environment. Most living things are made up of 70% water. When water freezes, it expands and forms ice crystals. Repeated freezing and thawing can destroy living tissue. The Alaska blackfish overcomes this problem by producing chemicals within its body that lowers the freezing temperature of cell fluids. Much like the antifreeze we add to the water in our vehicles, the "antifreeze" of the Alaska blackfish prevents the formation of large ice crystals within its cells, even at low temperatures. The Alaska blackfish can survive temperatures of-20 degrees C (4 F) and the complete freezing of some body parts, including their heads, for up to several days.

One of the most obvious adaptations for life in a cold environment is insulating feathers or fur. Most tundra birds and mammals actually have two coats. Ptarmigan, whose feathery coats and thick down even cover their feet and provide a "snowshoe" effect, have the best insulation of any Alaska bird. They can keep their body temperatures at 40 degrees C (104 degrees F) without increasing their respiration rate, even at air temperatures of-34 C (-29 F). The ptarmigan's white winter feathers (brown during summer) not only help camouflage it in the snow from predators, but radiate less heat back to the frigid air than would dark feathers.

In addition to the insulation provided by feathers and fur, large size and short appendages are adaptations that reduce heat loss and resist cold. Since small animals have more surface area relative to their weight than large animals, they lose heat more quickly. Musk oxen are one of the largest mammals found in the arctic. An average-sized adult bull may weigh 340 kilograms (750 pounds). Their relatively short legs and inconspicuous tails minimize heat loss. Only a small patch between the musk oxen's' nostrils and lips is hairless. The rest of the body, including the head and ears, are all densely haired. In addition to the animal's long, course, guard hairs is an exceptionally effective insulating layer of the finest wool grown by any mammal. Below -40 c (-40 F), musk oxen lie with their backs or sides to the wind and choose sheltered valleys or slopes during storms. Slow movements conserve energy in winter and reduce the likelihood of overheating during the brief but warm temperatures of summer.

For Grades K-5
Blubber, Feathers and Fur: Measuring and Testing Insulation

(This activity is a modification of "blubber bags" from the Marine Mammal Center in San Francisco)

Ask students to first predict which adaptation they think protects an animal best from the cold, blubber, feathers, or fur. Most students will predict "blubber" because "whales live in the ocean and they use blubber, and the polar oceans are always cold" or because "blubber is thicker than feathers or fur."

Materials:
1) A large container full of ice water (any bucket large enough to hold a half gallon of water and several trays of ice cubes will work)
2) A bottle of hot water (representing a warm-blooded animal) for each student

3) One quart-size sealable plastic bag per student
4) Two snack-size sealable plastic bags per student
5) Fur and feathers (available at craft stores)
6) A jar of solid vegetable shortening to represent blubber.
Students select a covering for their animal-fur, feathers, or blubber-and record it on their worksheet. (Younger students can work in pairs.) Then, each student receives a small, sealed plastic water bottle filled with water that ranged from around 90-100*F. Aim for 98*F (mammal body temperature). Students measure the temperature of the water in their "animal" and record the temperature on the data log sheet. Younger students (K-2) can measure the temperature using temperature strips like those used on aquariums-these strips show temperature in whole numbers and use color codes (these can be purchased at any pet store or through many educational supply stores), while older students (grades 3-5) use thermometers.
While students were taking these measurements, distribute the rest of the materials to make the bags. (For younger students (K-2), you could prepare the bags in advance, but older students can make the bags themselves.) Each student receives their chosen "covering" and two snack-size bags. In one bag they place either a small piece of fur, enough feathers to fill the bag, or about 2 tablespoons solid vegetable shortening. They turn the second snack-size bag inside-out and place the inside-out bag into the bag with the covering so that the fur, feathers, or blubber is sandwiched between the two bags. Then, students add the water bottle, representing the animal, to the inner bag and sealed the two bags together. Finally, students put this sealed "animal bag" into a larger (quart-size) sealable plastic bag containing a few rocks. (The rocks ensure that the "covered animal" will be totally submerged when it is later placed in a tank of ice water.) Keep one water bottle without a covering as a control.
Next, students place their "covered animal" in the tank with ice water, submerging it for 30 seconds. When the time is up, they remove the animal and again measure the temperature of the water inside the bottle, recording this information on their data log sheet. In general, students can tell just by feeling the bottle that something happened to the water.

Data Sheet

Name:

Prediction:

After students collect the data, they calculate how much temperature their "animal" lost when it was submerged in the ice water. Students record the difference in temperatures on their individual data log sheet as well as on a class data log sheet--a table drawn on the board or a large piece of paper with columns for each covering.
Using the data from the class log sheet, students then calculate the average temperature lost for each covering. (For younger students, you can calculate this number. Remember to tell students that all animals are different and that some animals will lose a little more or a little less heat than others, but this average number is the value that represents what that group of animals lost. With kindergarten students, you can look at the change in color on the thermometer strips-they usually go from red to green-and give them the temperature value for these colors.)
Then, together, create a class graph depicting the average temperature lost for each kind of covering. As you discuss the graph, Explain that the average temperature loss for the animal from the class data is a more accurate picture of how much temperature is lost than an individual student's data for that animal. Discuss that the actual amount of temperature lost depends upon the initial temperature of the water in the bottle. And, during the class period, the water temperature decreased in the bottles. Discuss why this happened, and that this is the reason scientists repeat experiments before they draw conclusions.
For Grades 6-12

Two Antarctic Adaptations – Insulate or AntiFreeze?

Discuss the information from the Background session (or wait and discuss afterwards if adopting a more inquiry based approach). Talk about the difference between insulating against cold and adapting to cold to prevent freezing (ice crystal formation in the body). Students should have a good understanding that the interior of the Antarctic continent is too cold and lacks vegetation, and therefore, no life can be found there. And preferably be able to correctly identify whales, penguins, seals, and fish as inhabitants of the ocean and continent's edge. These experiments can be done in tandem or in a “centers” approach.

Part IA. INSULATION

Materials

1) 8 oz. yogurt containers with lids, or small plastic vials with foil, or plastic test tubes with foil

2) 24 oz. cottage cheese containers with lids, or any large container to hold ice

3) Celsius thermometers

4)100ml graduated cylinders

5) Rectangular pieces of 2.5cm thick (or thicker) foam rubber, approximately 21cm x 28cm

6) Scissors

7) Masking or electrical tape

8) Pieces of fur or stringed feathers (available at craft and fabric stores) or heavy winter thermal socks, mittens, or scarves.

9) Saline solution.

10) Graph paper.

Procedure

1-Mark the small containers 1, 2, and 3. These represent your "animals."

2-Measure 125 ml. of 45°C water into each small container. The water in each

"animal" should be the same temperature.

3-Carefully punch a hole in each lid, just large enough to insert the

thermometer. Or place foil on top of container and push thermometer through foil.

4-Insert the thermometers and close each lid

5-Leave "animal 1" as is to represent no fat or fur/feathers layer. Wrap

"animal 2" in the foam jacket (secure with tape) and "animal 3" in the

piece of fur or winter clothing. These represent two different kinds of cold

weather adaptations (blubber layer and fur/feathers layer).

6-Ask students for predictions at this point. Which "animal" do you think

will stay the warmest? Which "animal" do you think will cool the fastest?

7-Record the temperature of the "animals" every two minutes for 16 minutes

(this can be changed if teacher chooses).

8-This activity may be done in the classroom. However, on a cool day, the

results would be much more dramatic if students work outdoors.

9-Record temperatures in form of Data Table 1.

Animal Temperature

10-Draw a graph making a line for each "animal" (using a different color or

symbol for each "animal"). Plot time on the x axis and temperature on the

y axis.

11-Questions to ask after the lab:

a-What effect does a layer of insulation have on the temperature of a

warm-blooded animal?

b-How does a layer of insulation keep the animal warm? (Prevents loss of

body heat).

c-In the experiment, the temperature continued to fall even with the best

insulator. How do you think the Antarctic animals make up for this loss?

(Metabolic energy-body uses food to produce heat energy.)

PART 1B - ADAPTING TO THE COLD - HABITAT

PROCEDURE

1-Set up 2 small containers with hot water as before, to represent "animal

1" and "animal 2". "Animal 1" will remain on the edge of the ice

surrounded only by the cold air but out of the wind, so put it inside one

of the larger containers. Poke a hole in the lid of the large container