What Makes A Biome?

What Makes A Biome?

Biomes are typically characterized by the resident biota within them. Currently, there is a disagreement in the scientific community about what exactly makes a biome.


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Biology, Ecology, Conservation, Earth Science


Deciduous Forest Fall

Trees in a deciduous forest during the fall.

Photograph by Clarita Berger/National Geographic Creative
Trees in a deciduous forest during the fall.
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A biome is a community of plants and animals in a given climate, and each biome has life-forms that are characteristic to that place. For instance, the plants and animals that inhabit the Amazon rainforest are completely distinct from those in the Arctic tundra. However, not everyone agrees on exactly what constitutes a biome, and defining them presents a challenge.

Biomes are sometimes confused with habitats and ecosystems, but there are differences between them. Ecosystems focus on the way plants and animals, called biota, interact with the environment. The way nutrients and energy flow helps define ecosystems. A single biome can have multiple ecosystems within it. A habitat is specific to the area a population or species lives in. Biomes describe life on a much larger scale than either habitats or ecosystems.

Defining Biomes

Frederic E. Clements was an ecologist who studied the relationship between living things and their surroundings. He first used the term biome in 1916 and later worked with another ecologist, named Victor Shelford, to expand the definition of biome. By 1963, they were able to define the tundra, coniferous forest, deciduous forest, grassland, and desert as different biomes.

Biomes are different because of the organisms that live there and the climate of the area. The organisms within a biome also share adaptations for that particular environment. Adaptation is the process of change that a species goes through to become better suited to its environment. Climate is also a major factor in determining the types of life that reside in a particular biome. Several factors influence climate, such as latitude, geographic features, and how atmospheric conditions affect heat and moisture.

Not all scientists agree about the number of defined biomes. Most agree that climate and the organisms that live there are important. But some do not think factors like human activity and biodiversity, which is the variety of life forms that exist in a place, should be included in biome definitions. The main types of biomes that come out of the different definitions are tundra, desert, grassland, coniferous forest, deciduous forest, tropical rainforest, and aquatic biomes.

Tundra Biomes

The tundra is located at the northernmost parts of the globe. It is defined by long, cold winters and cool summers. The animals and plants that reside here have evolved adaptations, such as thick fur and the ability to hibernate, which allow them to survive in the frigid environment.

Desert Biomes

Deserts are defined by dryness, and can be located in both cold and warm climates. Life in these areas is adapted to a lack of water and nutrients.

Grassland Biomes

The grassland biome is found on every continent except Antarctica. It is characterized as being flat and grassy, with very little tree cover. Large mammals that graze, such as elephants or bison, inhabit these areas, along with small mammals, birds, and predators.

Coniferous Forest Biomes

Coniferous forests are also known as taigas or boreal forests. These areas experience long, cold winters, short summers, and heavy precipitation. The primary vegetation types are conifers and evergreen trees. Sometimes this category is split into another category known as the temperate forest, where temperatures are not as cold. One example of this warmer forest would be the western coast of North America, a humid forest system home to redwoods and cedars.

Deciduous Forest Biomes

Deciduous forests are located in eastern North America, Western Europe, and northeastern Asia. This biome is marked by broad-leafed trees, such as maple and oak, that lose their leaves seasonally as the temperatures begin to drop. Overall, these regions are temperate, that is, they have mild temperatures, but still have a distinct winter season.

Tropical Rainforest Biomes

Tropical rainforests in equatorial regions are warm and wet with diverse vegetation that forms a canopy. The uppermost trees and branches in a forest form a kind of roof—this is a canopy. Leaf litter on the ground and the humid conditions create a layer of nutrients above the low-quality soil, which allows for the growth of a wide variety of vegetation. Tropical rainforests are famous for hosting vast amounts of biodiversity.

Aquatic Biomes

There are numerous ways to classify aquatic biomes. Often freshwater and saltwater biomes are defined separately using factors, such as water depth, temperature, and salinity. Terrestrial biomes, or land biomes, are typically classified by vegetation types, but this method can be difficult to apply to aquatic environments. They do not have as much visible plant life.

Although biomes are often thought of as distinctly separate regions, in reality, they are not isolated from one another. Biomes do not typically have exact boundaries, but instead, there are frequently transition zones between biomes. These zones are referred to as ecotones, and they can be naturally occurring or created by humans.

Many biome definitions exclude humans. However, some scientists believe that human presence is an important part in defining biomes. They are of the opinion that most biomes are actually primarily influenced by humans. Scientists are also beginning to recognize how the results of human activities, such as habitat destruction and climate change, will change how biomes are defined in the future.

Media Credits

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Tyson Brown, National Geographic Society
National Geographic Society
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Gina Borgia, National Geographic Society
Jeanna Sullivan, National Geographic Society
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Sarah Appleton, National Geographic Society, National Geographic Society
Margot Willis, National Geographic Society
Clint Parks
Roza Kavak
Last Updated

October 19, 2023

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