Life under Extreme Conditions: and Polar Regions Note: These links do not work. Use the links within the outline to access the images in the popup windows. This text is the same as the scrolling text in the popup windows.

I. Introduction (Page 1)

II. What is a ? (Page 2)

Vacinity of Plants: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/vicinity_of_plants.html

This diagram illustrates the effect of plants on the distribution and abundance of soil invertebrates. The size of the black circles is in proportion to the number of invertebrate individuals. The greatest concentration of invertebrates is near the surface of soil under plants. Numbers decrease both with increasing depth in the soil and with increasing lateral distance from the shade of the plant.

III. How do deserts form? (Page 3)

Formation of a Subtropical Desert: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_bigimages/hadley_cell.html

Hot, moist air in the tropics rises and as it cools, it loses its moisture as rain. The now dry air moves to the subtropics where it descends, heats again and blows back to the tropics, drying up the land and causing a desert.

IV. Deserts of the world (Page 4)

Distribution: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/distribution.html

This map shows the distribution of deserts around the world. In the western United States and Mexico lies a complex of deserts that are mainly deserts. These include the Great Basin, Mojave, Sonoran and Chihuahuan deserts. In , the Monte Desert is also a rain shadow one but the Atacama and Patagonian deserts are formed by cold currents. The Australian Deserts are subtropical ones. In southern Africa, the Kalahari is subtropical while the is a combination of subtropical and cold current. The great expanse of deserts from Northern Africa to Central Asia are mainly subtropical in the west and include the , Arabian, Iranian, and Thar deserts. In the east the Turkestan, Taklamakan and Gobi deserts have more the character of continental deserts.

V. Desert adaptations (Page 5)

VI. (Page 6)

VII. The Antarctic environment (Page 7)

Sea: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/sea.html Here a large glacier has reached the sea. The steep cliffs are where ice has floated out on the water, broken off and floated away as icebergs.

Nunataks: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/nunataks.html These nunataks are in the Prince Charles Mountains, .

Oases: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/oases.html

An Antarctic “oasis” is a small coastal area that is free of ice and snow in the southern summer. Such oases are isolated from other oases by long stretches of ice where the ice cap or glaciers come down to meet the sea. This particular oasis is Mawson Oasis. There is a year-round Australian Antarctic base located on it. In the photograph you can see the annual supply ship at anchor just off the base.

Dry Valleys: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/dry_valleys.html

This photograph shows a research campsite in an area of Antarctica that is free of ice and snow.

Soils: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/soils.html

The soil you see here is typical of Antarctic soils. It has very little organic matter and consists mainly of fine chips of physically weathered parent rock. The knife is for scale.

Year-round: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/year- round.html

These maps show the distribution of temperatures on the Antarctic continent. In January, which is summer in the southern hemisphere, average temperatures are below

-30°C over most of Antarctica and the only parts of the continent that ever get above freezing are the extreme edges and parts of the Antarctic Peninsula.

In July, which is winter, the temperatures are always well below freezing and in the interior plummet to values below -70°C.

Drains Peripherally: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/drains_peripherally.html

The upper diagram shows the high-altitude winds dropping down into the low pressure area over the south pole, and then flowing down over the ice cap toward the periphery of the continent.

The lower picture shows the pattern of lateral wind flow as influenced by topography and the rotation of the earch.

Drifting Snow: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/drifting_snow.html

The Antarctic winds continually shift snow around, especially during blizzards. Bare areas can become covered in just a few minues.

VIII. Terrestrial Antarctic biota (Page 8)

Fly: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/fly.html This insect is a midge, a type of fly. Unlike most flies it is wingless. It lives on the Antarctic Peninsula.

Springtails: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/springtails.html

Springtails occur many places in the world but they are the only insects that inhabit Antarctica other than the Antarctic Peninsula. They have no wings and are very primitive insects. They are capable of anhydrobiosis.

IX. Antarctic ecosystems (Page 9)

Moss-lichen: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/moss- lichen.html

The mosses you see here represent the most lush vegetation cover that one finds in Antarctica.

Elephant Seals: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/elephant_seals.html

The upper photograph shows a colony of elephant seals on an Antarctic beach. Elephant seals are social and usually form large colonies. The lower picture is of a male bellowing. His roar is enhanced by the resonating chamber of the large proboscis on his nose. Large males weigh several tons.

Giant Petrels: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/giant_petrels.html

Here are giant petrels resting on a beach. They are scavengers on dead penguins and seals and occasionally will take live penguins.

Skua: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/skua.html

The skua is a large brown sea gull that is a voracious predator on other birds. It also scavenges on dead penguins and seals.

Eating Species: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/deserts/deserts_popups/eating_species.html

The Antarctic leopard seal is a voraacious predator. This one has just caught a penguin at the surface of the water.