The tundra biome is an ecosystem situated near the North Pole in the Arctic Circle. There are three types of tundra: arctic tundra, alpine tundra and Antarctic tundra. It is noted for its frost-molded landscapes, extremely low temperatures, little precipitation, poor nutrients, and short growing seasons.
The winters are extremely cold with temperatures typically below -34° C. The summers last only about two months and the temperatures are still very cold ranging from 3° to 12° C.
Only a thin layer of soil, called the active layer, thaws and refreezes each year. This makes shallow root systems a necessity and prevents larger plants such as trees from growing in the Arctic. (The cold climate and short growing season also prevent tree growth. Trees need a certain amount of days above 50 degrees F, 10 degrees C, to complete their annual growth cycle.)
• Most of the plants are small, grow close together and close to the ground. This protects them from the cold temperatures and the strong winds.
• Some flowering plants have fuzzy coverings on the stems, leaves and buds to provide protection from the wind. Some have woolly seed covers.
• Lichens grow in mats on the ground and on rocks across the Arctic. Lichens provide an important food source for caribou in the winter.
• Many Arctic species can grow under a layer of snow, and virtually all polar plants are able to photosynthesize in extremely cold temperatures.
• During the short polar summer, plants use the long hours of sunlight to quickly develop and produce flowers and seeds.
• Flowers of some plants are cup-shaped and direct the sun’s rays toward the center of the flower. Dark-colored plants absorb more of the sun’s energy.
• In addition, many species are perennials, growing and blooming during the summer, dying back in the winter, and returning the following spring from their root-stock. This allows the plants to direct less energy into seed production. Some species do not produce seeds at all, reproducing asexually through root growth.
• Small leaves help the plants retain moisture.
• The animals in these regions are usually white or light colored, e.g., polar bear, penguin. This adaptation helps them in maintaining their body temperature, and in camouflaging.
• These animals can store fat in their body as they eat a lot during the summer.
• The stored fat can be consumed during the winter months because the animals hibernate for months, i.e., go into a state of inactivity, during severe winters.
• In hibernation, their metabolic activity is reduced to a great extent. In this state, their heartbeat, breathing rate and temperature become very low.
• Furred soles of the feet of polar bears protect them from cold and prevent them from slipping.
• The small animals burrow down into the snow. The snow traps the air, and it becomes an excellent insulator.