7.3 Tundra Cold, windy, dry region Located in Northern Hemisphere, south of polar ice caps in Alaska, Canada, Greenland, Iceland, Scandinavia and Russia One of the largest biomes Makes up 10 % of earth Fewer organisms live here than any other biome Lack of biodiversity makes tundras very fragile and unstable

Tundras

Tundra Climate · Little precipitation · Less than 25 cm ·  Air temperature rarely reaches above 100 C (about 50 F.) ·  Temps usually are below freezing ·  Most precipitation is snow or ice Temperature is the limiting factor · Summer days long and cool · Only top layer of soil thaws during the summer. This is called the active zone. ·  A dense mat of mosses, grasses and other plant life cover the active zone during the summer ·  Beneath the active zone, the soil never thaws and this is called permafrost.

Tundra Climate · The little bit of rain that does fall cannot be absorbed through the permafrost. This causes the water to collect as surface water forming bogs, marshes, ponds and small streams. These areas serve as breeding grounds for insects such as mosquitoes and black flies, which provide an important link in the food web.

Tundra Organisms · Growing season is only 60 days · Most common plants are mosses, shrubs, grasses, and small wildflowers. Lichens are also common. They are composed of fungi and algae. Most common animals are seasonal

Tundra Plants · Ground is warmed by radiant energy from sun ·  Plants grow close to ground for heat and because of small, short root systems · Small roots because they cannot penetrate permafrost Destruction of plants by humans is dangerous because plants grow back slowly in the tundra.

Tundra Animals · Most animals are those that are migrating through ·   Migratory animals are those that travel seasonally ·   Migratory behaviors are said to be instinctive ·   Many birds come here to breed because there are less predators ·   These birds feed off the tundra insects ·   The birds in turn provide food for the migrating Arctic fox  

Tundra Animals ·   Caribou (relative of reindeer) is also a migratory animal. They feed on lichens. Pollution has destroyed a lot of the lichens, so this is bad for the caribou. ·   Animals have thick coats which allows air to be trapped in between to insulate against the cold ·   They also have wide hooves to help walk on ice or snow. ·   Some animals are year round residents. These include the following: Arctic fox, musk ox, polar bears, and wolverines.