• A biome is an area of the planet that can be classified according to the plants and animals that live in it. Temperature, soil, and the amount of light and water help determine what life exists in a biome.

    A biome is different from an ecosystem. An ecosystem is the interaction of living and nonliving things in an environment. A biome is a specific geographic area notable for the species living there. A biome can be made up of many ecosystems. For example, an aquatic biome can contain ecosystems such as coral reefs and kelp forests.

    Not all scientists classify biomes in the same way. Some use broad classifications and count as few as six biomes. These are forest, grassland, freshwater, marine, desert, and tundra.

    Other scientists use more precise classifications and list dozens of different biomes. For example, they consider different kinds of forests to be different biomes. Tropical rain forests that are warm and wet year-round are one biome. Temperate deciduous forests—those that have cold winters, warm summers, and are dominated by trees that lose their leaves—are a different biome. Taiga forests, which are in cold regions and are dominated by cone-bearing firs and spruces, are yet another biome.

    Boundaries between biomes are not always sharply defined. For instance, there are sometimes transition zones between grassland and forest biomes. Coasts and wetlands are transition zones between terrestrial and aquatic biomes.

    Biomes move as the climate changes. Ten thousand years ago, parts of North Africa were lush landscapes cut by flowing rivers. Hippopotamuses, giraffes, and crocodiles lived amid abundant trees. Gradually, the climate dried out. Today, this region is part of the Sahara Desert, the world's largest desert.

    This marine biome is dominated by kelp, a kind of seaweed.

    Bountiful Biomes
    There are more than a dozen ways to classify biomes. Climatologists, botanists, ecologists, biologists, and anthropologists have different criteria for deciding what constitutes a biome. One of the simplest classification systems has only two biomes: terrestrial (land) and aquatic (water). One of the most complex has more than a dozen.

  • Term Part of Speech Definition Encyclopedic Entry
    abundant Adjective

    in large amounts.

    amid Preposition

    in the middle of.

    aquatic Adjective

    having to do with water.

    biome Noun

    area of the planet which can be classified according to the plant and animal life in it.

    Encyclopedic Entry: biome
    broad Adjective

    wide or expansive.

    classify Verb

    to identify or arrange by specific type or characteristic.

    climate Noun

    all weather conditions for a given location over a period of time.

    Encyclopedic Entry: climate
    coast Noun

    edge of land along the sea or other large body of water.

    Encyclopedic Entry: coast
    coral reef Noun

    rocky ocean features made up of millions of coral skeletons.

    deciduous Adjective

    type of plant that sheds its leaves once a year.

    desert Noun

    area of land that receives no more than 25 centimeters (10 inches) of precipitation a year.

    Encyclopedic Entry: desert
    ecosystem Noun

    community and interactions of living and nonliving things in an area.

    Encyclopedic Entry: ecosystem
    environment Noun

    conditions that surround and influence an organism or community.

    fir Noun

    variety of pine tree.

    forest Noun

    ecosystem filled with trees and underbrush.

    freshwater Noun

    water that is not salty.

    grassland Noun

    ecosystem with large, flat areas of grasses.

    kelp forest Noun

    underwater habitat filled with tall seaweeds known as kelp.

    lush Adjective

    abundant and rich.

    marine Adjective

    having to do with the ocean.

    network Noun

    series of links along which movement or communication can take place.

    precise Adjective


    rain forest Noun

    area of tall, mostly evergreen trees and a high amount of rainfall.

    Encyclopedic Entry: Rain forest
    Sahara Desert Noun

    world's largest desert, in north Africa.

    soil Noun

    top layer of the Earth's surface where plants can grow.

    spruce Noun

    coniferous, or cone-bearing, tree.

    taiga Noun

    evergreen forest in cool, northern latitudes. Also called boreal forest.

    Encyclopedic Entry: taiga
    temperature Noun

    degree of hotness or coldness measured by a thermometer with a numerical scale.

    Encyclopedic Entry: temperature
    terrestrial Adjective

    having to do with the Earth or dry land.

    transition zone Noun

    area between two natural or artificial regions.

    tropical Adjective

    existing in the tropics, the latitudes between the Tropic of Cancer in the north and the Tropic of Capricorn in the south.

    tundra Noun

    cold, treeless region in Arctic and Antarctic climates.

    wetland Noun

    area of land covered by shallow water or saturated by water.

    Encyclopedic Entry: wetland