Understanding Natural Ecosystems and Their Importance

Nature is a chemical element of life, such as oxygen, carbon, and nitrogen. They are recycled. On land, they move from the soil into plants. Minerals and nutrients return to the soil. Microorganisms in the soil, such as bacteria, play an important part in releasing the nutrients and minerals from decaying matter.

The North Pole is surrounded by the permanently icy Arctic Ocean. The South Pole is on the continent of Antarctica. Because the poles never come close to the Sun, this means that ice and snow cover the poles all year round. Polar animals have thick fur and layers of fat on their bodies. Human beings hunt polar animals for food and clothing.

Worlds with a temperate climate are covered by woodlands. Coniferous trees can survive in lower temperatures than deciduous trees. Woodlands are found in northern regions or mountains. Many of the animals in these areas are nocturnal.

The name given to large areas of wild grass with small plants is grasslands. They are found where there is enough rainfall. During the wet season in Africa, they are green and rich with fresh new grass and plants. There are many types of food available.

Deserts are areas of land that have very little or no rainfall. They can be found in hot places and rocky areas, and there are also cold deserts. In hot deserts, the temperature can reach up to 50°C. Only a few animals and plants are able to live there.

All of the plant and animal species live in tropical rainforests. Tall trees form a thick roof of branches called the canopy. The forest floor is dark.

Plates of the Earth push against one another, which takes millions of years to happen. Some mountains are so high that they are covered with ice and snow, and they have less oxygen.

Rivers are natural channels of water, and they have a water cycle. A river starts as a spring melting from glaciers. Streams eventually join together to form a larger lake.

The seashore is a place where land meets the sea. It can be rocky cliffs, sandy beaches, or pebble beaches. The sea carries sand and other materials and also brings tiny particles of food. Seashore plants grow like other plants, providing moisture for small animals.

Two-thirds of the Earth's surface is covered by vast expanses of salty water called oceans. Some volcanoes are found underwater. The movements of the water are called currents. You can find microscopic plants to giant whales in the oceans. Phytoplankton are eaten by tiny animals.

Coral reefs are found in tropical shallow waters around volcanic islands. They are made from layers of the skeletons of tiny animals called polyps. Colonies of polyps can build up great banks of coral. There are different types of coral reefs.