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.