In this topic you will learn about how climate and soil affect where different populations live.

The land on Earth is divided into six major kinds of large ecosystems called biomes. Each biome has its own kind of climate, soil, plants, and animals. Each biome can be found in different parts of the world.

Grasslands are biomes where grasses are the main plant life. They are areas where rainfall is irregular and not usually plentiful. Prairies are one kind of grassland. Today many grasslands are covered with crops such as wheat, corn, and oats.

A taiga is a cool, forest biome of conifers in the upper Northern Hemisphere in Alaska, Canada, Norway, Sweden, Finland, and Russia. The taiga is a major source of lumber and pulpwood. Much of the lumber is used for making houses. The pulpwood is turned into paper products.

The cold, treeless biome of the far north, marked by spongy topsoil, is the tundra. Tundras are located in northern Alaska, northern Canada, Greenland, and the frigid parts of Europe and Asia. It is so cold in the tundra because the Sun's rays strike the tundra at a low angle. Most tundra plants are wildflowers and grasses.

A desert is a sandy or rocky biome, with little precipitation and little plant life. Every continent has at least one desert. Few animals and plants live in deserts. Those that do are hardy. They are adapted to living in the desert.

A forest biome with many kinds of trees that lose their leaves each autumn is called a deciduous forest. This is where broad-leaved trees grow. Each autumn the leaves turn orange, yellow, and red. Then the leaves fall to the ground and decay. The dead leaves help make the soil rich and fertile. Animals such as squirrels, deer, chipmunks, raccoons, and skunks are natives of this biome. Birds such as cardinals, robins, crows, and hawks, and insects such as bees live in deciduous forests.

The tropical rain forest is a hot, humid biome near the equator, with much rainfall and a wide variety of life. The canopy of a tropical rain forest spreads like a huge umbrella. It is so thick that little sunlight ever reaches the ground. Most of the life is up high in the branches where howling monkeys and purple orchids cling. There are no tropical rain forests in North America or Europe. However, Central America, South America, India, Africa, Southeast Asia, Australia, and many Pacific Islands have rain forests.

The two types of watery ecosystems are saltwater and freshwater. Lakes, streams, rivers, ponds, and certain marshes, swamps, and bogs are all freshwater ecosystems. Oceans and seas are saltwater ecosystems.