Center for Astrophysical Research in Antarctica

Program 2: Life in Antarctica, Then and Now

Student Learning Objectives

Students will be able to describe the changes in Antarctica's climate over time, and the co-evolution of life-forms and the continent.
Students will name three animal and three plant species specific to Antarctica today and their adaptations to their environment.
Students will design an imaginary organism that is adapted to the extreme Antarctic environment.
Students will be able to identify an Antarctic animal's habitat, food chain relationships, and unique characteristics.

Summary

As Antarctica changed from a tropical forest, its plants and creatures evolved and adapted or died out. David Harwood and his team go fossil hunting in the Transantarctic Mountains, the site of some of the most spectacular scenery on the continent. We look at one of the most interesting contemporary Antarctic life-forms, the Emperor penguin, with expert Gerry Kooyman, and in McMurdo's aquarium we see one particularly unique adaptation: fish with organic antifreeze! We also explore one of Antarctica's most unusual areas, the Dry Valleys, where life survives inside rocks or at the bottom of lakes that are perpetually ice-covered. Diana Freckman of biologist Robert Wharton's Long-Term Ecological Research (LTER) project shows us the ongoing environmental survey underway in the Dry Valleys, and what researchers hope to learn by careful observation over many years.

Locations in Antarctica

Interior: the Aquarium at McMurdo, containing live specimens
Exterior: if communication links permit, the first-ever live TV broadcast from the Dry Valleys or, alternately, from the ice edge in front of McMurdo Station

Locations in the United States

Maryland
Hawaii

Featured Experts

David Harwood is a paleontologist trying to answer questions about the long-term stability of the Antarctic ice sheets. He studies the fossil remains of marine invertebrates and ancient plant life found in the Transantarctic Mountains. Harwood believes that the climate of Antarctica has fluctuated greatly, relatively recently. He believes that only the onset of warm interglacial periods can account for the amount and character of the fossils that he and his team continue to discover. Harwood's personal history also explains how a student might begin to pursue an interest in a subject as daunting as the ancient history of Antarctica (see on-line).

Gerry Kooyman believes that Emperor penguins are extremely sensitive to minor environmental changes; thus, behavioral or physiological changes in these penguins can serve as indicators of environmental changes. Close examination of the Emperors' foraging behavior and distribution patterns, hunting and diving habits, methods of predator avoidance, and other traits might lead to an early warning system for changes in marine environment. (For more on Antarctica as a bellwether of global change, see Program 4.) Diana Freckman heads her own research project and is a member of a large team of investigators studying Antarctica's McMurdo Dry Valleys as an extreme desert ecosystem. The biology of the Dry Valleys is simple and seems to be constrained by harsh physical realities: perennially ice-covered lakes, ephemeral streams, and extensive soil deposits subject to low temperatures, limited precipitation, and salt buildup.

Activity 1: How Does Nature Adapt to Extremes?

Objective

To have students look at special physical adaptations and behaviors of animals and design an organism (plant or animal) that could survive in the harsh, extreme conditions found in Antarctica

Engage

Organisms have developed unique physical and behavioral attributes that enable them to survive in Antarctica.

An example of a physical adaptation is the seal, which has one-and-a-half to two times the amount of blood relative to body size/mass that other animals have. Oxygen is stored in the blood. An increased proportion of blood in the body means an increase of available oxygen. The more oxygen the seal can store, the longer it can stay under water.

Male Emperor penguins are responsible for incubating the eggs. The egg is wrapped in a loose layer of skin and balanced on the male's feet. A specific behavior would be male Emperor penguins gathering together to keep warm as they incubate their eggs. The Emperor penguins move from the inside to the outside of this group as needed to keep warm. (see fig.2.1)

Explore

Students will design and build an organism with special adaptations and specific behaviors that can survive in Antarctica. This can be a drawing or a 3-D model. Explanations and/or justifications of adaptations and behaviors need to be reported. Students should consider the following:

the ability to survive the extremely cold temperatures
movement throughout their ecosystem
which ecological zone would you find your organism in, and why (sea, dry lakes, ice-free land, or icecap)
advantages of body size or adjusted metabolic rates
ability to survive pressure of deep water
food requirements and place within the food chain

Explain

Discuss the following facts after students have shared their organisms, and encourage students to do more research on the plants and animals of Antarctica:

Since Antarctica spends long periods in darkness, plants need to store energy for months at a time because they are not always able to perform photosynthesis.
Plants tend to grow close to the ground or in the rocks for protection.
Fish produce up to eight different kinds of antifreeze molecules that keep their bodies from freezing.
Large animals lose body heat more slowly than small animals.
Animals have insulators such as extra layers of feathers or blubber.
Animals hibernate or relocate to avoid harsh conditions.
A slow metabolism uses less oxygen and energy.
Soft body parts and removal of air from lungs and body cavities helps the body survive deep ocean pressures.
Salts and other organic compounds are accumulated in the bodies of mollusks. These lower the body temperature and keep them from freezing.

Expand

Have students create an organism for another environment such as a hot desert or rain forest.

Activity 2: Fossils: Clues to the Past

Objective

To have students understand how a fossil forms and what can be learned from it

Engage

Fossils are the preserved remains of animals and plants that died millions of years ago. Fossils give scientists clues about how environments have changed over time, and can be used to determine what lived where and when. Most fossils are formed in the layers of mud and silt in oceans and lakes; as animal and plant matter died, it settled to the bottom of lakes and oceans or were covered by silt and mud on land. Decay removed the soft parts of these animals and plants, leaving skeletal remains to be buried and pressed under layers of silt and clay. After millions of years, the plant and animal remains turned to stone.

Explore

Part 1: How Fossils are Formed

Students will create a model of the layers of the Earth in a cup and observe the changes of objects trapped in their soil.

Materials: (per group)

plastic container, cup, butter dish (the taller the container, the more layers can be built)
enough sand to fill half the cup
plaster of Paris--enough to fill half the cup
water to mix the plaster of Paris
container to mix the plaster of Paris
spoon or stick to mix the plaster
items to bury different types of plant and animal remains such as leaves, fruit, seeds, bark, raw chicken bones, twigs

Procedure

Have students organize and sketch their fossil cup, starting with a layer of plaster, sand, item, plaster, sand, item.
Plaster can harden very quickly so the person who is mixing or pouring the plaster needs to be ready to mix small amounts and pour quickly. Follow the directions on the box for mixing plaster.
Pour about 2 cm of plaster into the cup to make a layer.
Pour 1 cm of sand on top of the plaster.
Place "like" items (e.g., a few leaves) in the sand, close to the edge of the cup so they can be observed.
After a few minutes the plaster will harden. Repeat steps 3, 4, 5 until your container is full. Use different items for each layer.
Let the container sit for 24 hours to allow the plaster to dry.
Remove the cup and observe the buried items. Are any of the items changing? What parts of the items will decay and which will turn into "fossils"?
Make a chart and record the changes you see. Your environment will determine how quickly changes are seen. Be patient.
Analyze the earth cup. What is the "oldest" item? Explain.

Part 2: Ice Preservation

Antarctica is a frozen continent covered with sheets of ice. Just as plant and animal matter can be preserved in silt and mud, it can also be preserved in ice. How might items preserved in ice be different from items preserved in silt and mud?

Materials: (per group)

3 containers (cut-off soda bottles would work well)
3 samples of different types of plant and animal remains (see Procedure)
sand to fill 3/4 of the container
organic soil to fill 3/4 of the container
water to fill 3/4 of the container
heat lamp
freezer to make ice

Procedure

Students should select different types of plant and animal remains such as leaves, fruit, seeds, bark, raw chicken bones, dead bugs. Each group will need three samples of each item.
Have students weigh, measure, and describe each item. Have them predict what would happen to each item if it were buried in: the hot dry desert sand of the Torrid Zone; the fertile soil of the flood plains in the Temperate Zone; the icy glaciers in the Frigid Zone.
Have students place items in the following simulated environments:
- Desert: sand with a heat lamp source
- Flood Plain: organic soil, watered every day
- Glacier: water to be frozen
Leave items in these "environments" for at least 2 weeks. When students are ready to "dig up" samples, discuss the techniques that paleontologists use to recover fossils. Have students recover each of the fossils, carefully removing any sand, soil, or water. Have students weigh, measure, and describe each sample and then compare these data with your original observations of the items. How are these items similar and how are they different? What do students think would happen to each of these items in the different "environments" over an even longer time?
Explain
Scientists study the fossils of plant and animal remains trapped in the ice. These fossils have included ferns, reptiles and even small mammals. What does the presence of these fossils suggest about the past of Antarctica? Was it always an ice desert? Encourage students to discuss the meaning of these clues.
Expand
Borrow fossil samples for your students to analyze. What statements or theories might they be able to come up with about a place from the fossils that were found there?
Check with local geologists to see where you might take your students to hunt for fossils. What can they tell you?

Listening To Silence
1:30 A.M. It is as if the Ice Falls, the Labyrinth, the Asgard and Olympus Ranges are all repositories of profound knowledge, and if I sit here and am attentive enough, I can sense a language being spoken. It is not a vocabulary with words as we know them, but rather a dialect with a deep-seated, darker structure that has to be sensed and attended to. Its story is one of drifting continents and geological convulsions over eons of time approaching infinitude. I have no choice but to be a listener here, for there is nothing to say to this place that it does not already know. The primal sensation is one of total insignificance, as if having suddenly wandered into the presence of God. Standing here on this antediluvian tropical beach, how can my 37 years ever begin to compare with 200 million? I am seized with wonder for the ineffable. And in the midst of it all, I suddenly realize my toes are cold.
from "Linnaeus Terrace/The Ice Falls," by Alan Campbell
Artist's Sketchbook Journal, 1993
A Writer Roams the Dry Valleys
The Wright and half a dozen other valleys at the northeastern end of the Transantarctic Mountains are collectively referred to as the Dry Valleys. It has not rained here in two million years. No animal abides, no plant grows. A persistent, sometimes ferocious wind has stripped the country to stone and gravel, to streamers of sand. The huge valleys stand stark as empty fjords. You look in vain for any conventional sign of human history the vestige of a protective wall, a bit of charcoal, a discarded arrowhead. Nothing. There is no history, until you bore into the layers of rock or until the balls of your fingertips run the rim of a partially exposed fossil. At the height of the austral summer, in December, you smell nothing but the sun-beaten stone. In a silence dense as water your eye picks up no movement but the sloughing of sand, seeking its angle of repose.
The air here is so clear the eye can fasten effortlessly on the details, on the sharp break of shadow creases, in distant mountains, making binoculars curiously redundant. The hues of yellow and brown, the tints of orange and red that elevate the sedimentary rocks above the igneous layers of granite, take the starkness out of the land but do not alter its line, which is bold, balanced, serene. Classic....
In a week of ambling, of looking among mountain boulders hoodooed by the wind, of sitting in windless bights amid glacial debris, of lining out like a Dinka on the heels of my hands and one knee to taste the salt ponds, I found the Dry Valleys unfetchable. Whatever one might impute to this landscape, of beauty or horror, seemed hardly to take hold; my entreaties for conversation met almost always with monumental indifference. I have never felt so strongly that unsettling aloofness of the adult that a small child knows, and fears. It is hard to locate the reassurance of affection in these circumstances. And yet this land informs, some would say teaches, for all its indifference. I can easily imagine some anchorite here, meditating in his room of stone, or pausing before a seal shipwrecked in this polar desert. Over the years, one comes to measure a place, too, not just for the beauty it may give, the balminess of its breezes, the insouciance and relaxation it encourages, the sublime pleasures it offers, but for what it teaches. The way in which it alters our perception of the human. It is not so much that you want to return to indifferent or difficult places, but that you want not to forget.
If you returned it would be to pay your respects, for not being welcomed.
excerpt from "Informed by Indifference": A Walk in Antarctica by Barry Lopez, reprinted by permission of Sterling Lord Literistic, Inc.

Resources
Books
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McMillan, Bruce. Penguins at Home: Gentoos of Antarctica. Houghton Mifflin, 
1993. 32 pp., photographs (Outstanding Science Trade Books for Children).
Todd, Frank S. The Sea World Book of Penguins. Harcourt  Brace Jovanovich, 
1981.
Henshaw, Dorothy Patent. Looking at Penguins. Holiday House, 1993, 40 pp., 
color illustrations. 
Michael, George. Glaciers, Creative Education. 1991, 40 pp., illustrated, 
color photographs.
Stonehouse, Bernard. Ice. Macmillan Childrens Group, 1992 48 pp.
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Magazine Articles
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"Life in a rock," by Tom Waters, Earth magazine, July 1994, pp. 20-23.
"At the Bottom of the World," by W. E. Butterworth, Boys Life, Feb. 1994, 
pp. 20-21.
"All the right moves," by Charles Norlander, National Geographic World, 
Dec., 1993, pp. 15-19. (discusses the unique behavior of penguins )
"Penguins, Cool Moves," National Geographic World, Dec. 1993, pp. 15-19.
"Inside a Glacier," National Geographic World, June 1994, pp. 10-14. 
"Antarctic Fur Seal," National Geographic World, August 1990, pp. 20-21.
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Filmstrips and Videos
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Fossils: Traces of the Past, National Geographic Society, 1982, gr. 5-9, 
filmstrip with cassette.
The Living Earth, National Geographic Society, 1991, gr. 9-12, VHS video, 25 
minutes.
Antarctic Adventure, produced by Fenton McHugh, Bennett Marine Video, 
1989, 30 minutes.
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