Earth's Features

1. Land and Its Biomes

Biomes are areas of the earth with similar climatic conditions, plant life, and animal life.

Land is made up of seven major, unbroken landmasses surrounded by water, called continents. They're named Africa, Europe, Asia, Australia, North America, South America, and Antarctica.

Across these seven main landmasses are different regions with various ranges of temperature and precipitation. These different regions have been categorized into eight major biomes (see map below), which are largely determined by those two factors. They include tundra, taiga, temperate forest, tropical rainforest, temperate grassland, savanna, steppes, and desert.

term to know

Biome

Areas of the earth with similar climatic conditions, plant life, and animal life.

2. Water

Oceans are the largest bodies of water in the world, holding 97% of the earth's water, all of it saltwater. There are four major oceans, the Atlantic, the Pacific, the Indian Ocean, and the Arctic Ocean, shown below. The earth's oceans regulate our atmosphere by absorbing and storing the sun's energy.

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Oceans also cover 70% of the Earth's surface.

The remaining 3% of the water on Earth is freshwater, which is held in the following:

• Ice caps frozen at the Arctic and Antarctic poles
• Glaciers, which are snow that has been compressed into ice on mountains and ice caps
• Rivers, streams, and lakes on land, as well as groundwater that has collected on land under its surface.

3. Atmosphere

Our atmosphere is made up of five layers: the troposphere, the stratosphere, the mesosphere, the thermosphere, and the exosphere (see diagram below).

Each layer is made up of a different combination of gases. The lowest layer, the troposphere, is the layer we breathe. The stratosphere contains our ozone layer, which protects the earth from receiving too much UV radiation that would cause health problems and damage vegetation.

4. Weather and Climate

Weather includes precipitation — or rain, snow, and sleet — as well as wind and temperature. Climate is the weather that an area receives over many years. Climate is determined by many factors, one of which is a region's physical features.

An important factor to remember is that as elevation increases, temperatures drop.

EXAMPLE

You might travel to the rain forest near a mountain range. In the lowlands, temperatures will be high. However, if you were to climb a nearby mountain that was tall enough, there would be snow and temperatures would drop.

Another factor to remember is that the farther one gets from the equator, the colder it generally is.

IN CONTEXT

Consider these factors in relation to Africa, shown in the map below.

Northern Africa is directly on the equator and experiences high temperatures in an extreme desert biome. As you move downward in latitude, it shifts to colder biomes and climates. The farther you are from a significant body of water, such as the ocean, the drier it is. As you can see, the northern portion of Africa is driest in the middle, where there is an extreme desert, but has wetter biomes as you get closer to the oceans.