Our planet can be subdivided into nine major terrestrial biomes. These are polar ice, tundra, taiga, temperate deciduous forest, temperate grassland, chaparral, desert, savanna, and tropical forest.

As you can see, the biomes are distributed partially by latitude, and partially by distance from the oceans.

Let’s briefly consider the characteristics of each of these biomes.

Polar biomes have very low temperatures throughout the year and are permanently covered in snow and ice.

This means that plants can’t grow here, although microscopic algae can develop temporarily on the ice or snow.

Because there isn’t any real vegetation, the diversity of life is very low. In the north polar biome, some animals like polar bears and seals can live off the fish in the water under the ice.

The region of permanent snow and ice at the top of very high mountains is equivalent to the polar ice biome.

Moving down toward the equator, we encounter the flat open landscape of the arctic tundra. This cold region is characterized by permanently frozen subsoil, called permafrost, chilling winds, and little rainfall. These climate conditions prevent trees from growing. Plant life consists of low shrubs, sedges, grasses, mosses, and lichens.

Alpine tundra, found close to the tops of high mountains, has similar plant communities..

Taiga, the northern or boreal forest, is the most extensive of all the terrestrial biomes. This region of cone-producing trees, called conifers, is located south of the arctic tundra.

Taiga is also found at cool, high elevations in more temperate latitudes, such as the mountainous western regions of the United States and Canada.

Long, cold winters, and short, occasionally warm, wet summers are typical of this region. The soil is thin, nutrient poor, and acidic. 

Temperate deciduous forests are found in the middle latitudes.

Deciduous forests receive fairly constant rainfall all year round, but before the cool winter comes, deciduous trees lose their leaves. The carpet of fallen leaves adds organic matter to the soil, making the soil more fertile.

The loss of leaves also helps the trees conserve energy during the months when there is less sunlight and lower temperatures, reducing the amount of photosynthesis that could take place.

Much of this biome has been lost because of urbanization and farming.

Grasslands occur in places that have similar climates to temperate deciduous forests. However, these regions experience seasonal droughts that prevent many trees from becoming established. Cold winters and the lack of natural windbreaks favor hardier plant species, such as grasses and annual plants.

Grassland soil is deep and rich in nutrients, making it fertile land for agriculture. Most of the grassland in developed countries has now become farmland.

Chaparral, or Mediterranean vegetation, is characterized by hot dry summers and mild rainy winters. This biome occurs close to oceans in California, South Africa, parts of Australia, and around the Mediterranean Sea. The dense evergreen shrubs of chaparral vegetation are adapted to long, dry summers with little or no rain, and a short growing season each spring.

Deserts are regions that receive less than 12 inches of rainfall yearly. Some deserts are very hot, like the Sahara desert in Africa. Others are cold, like the coastal deserts of Patagonia in South America.

Because desert climates are arid and harsh, the animals and plants that live in deserts must be adapted to a life without water. Plants are thick-skinned and have few stomata, thereby preventing water loss. Animals burrow underground or find shelter from the sun, coming out at night to hunt and feed.

Savannas are related to temperate grasslands, but are found in warmer parts of Africa, South America, and Australia, on either side of the belt of tropical forests near the equator.

Characterized by grasses and scattered trees, savannas don’t experience cold winters, but have cool, dry winters; hot, dry summers; and a rainy season that provides most of the moisture for the whole year.

The world’s tropical forests include the rainforests that encircle Earth around the equator.

Temperatures in tropical rainforests are almost constant throughout the year, and even throughout the day and night. Precipitation ranges between 60 and 160 inches each year, and rain often falls at the same time each day.

There is more biodiversity in the world’s rainforests than in any other biome. However, tropical forests are being destroyed by humans at an alarming rate. More than an acre of land is destroyed every minute by people burning the trees to clear space for farming, and chopping them down for lumber.

See how well you understand the relationship between biomes and climate.

The three sets of climate data show the yearly range of temperature and rainfall in three different biomes. Drag the climate data over the biome that you think it accurately represents.

Correct: That’s right!

All Others: Sorry, that’s not quite right.

All: A. These data are for the Sahara desert in Africa. There is almost no rainfall throughout the year, except for a very short rainy season during the spring.

B. These data are for Luxembourg, in Europe—a temperate deciduous area that has steady rainfall with cool winters and warm summers.

C. These data are for the Brazilian rainforest in South America. The temperature and rainfall ranges stay pretty much the same throughout the year.

Now that we’ve looked at the variety of terrestrial biomes, let’s continue by looking at the aquatic biomes.

Copyright 2006 The Regents of the University of California and Monterey Institute for Technology and Education