What Is the Biosphere?
Life has existed on planet Earth for billions of years. In that time, the many different species of plants, animals, fungi, and single-celled organisms that call our planet home have evolved alongside each other. The result is that life on Earth is linked in a complex web of connections. Scientists call this web the biosphere. This word is used to describe all the parts of our planet that support life. From the deepest oceans to the tallest mountains, everywhere there is life, there are interconnections between living organisms and our planet.
Understanding the biosphere means understanding Earth’s different layers—land, water, and air—and exploring the variety of life found in each. These connections reveal the increasing complexity—and fragility—that Threshold 5 added to the Universe and to our own lives.
The biosphere, atmosphere, hydrosphere, and geosphere are all interconnected parts of planet Earth. Organisms live in the air, water, and under the ground, as well as on the surface of our planet.
The biosphere: Network of life
The word biosphere was first used by a geologist named Eduard Suess (1831–1914). He wrote about it in a book called The Face of the Earth. Suess combined the prefix bio, meaning “life,” and sphere, referring to the Earth’s rounded surface, to talk about the parts of the Earth that support life. He invented the word because he believed we should think about all life on Earth as part of an interconnected system.
The biosphere is the entire network of life on Earth. Thinking of a single, connected, global network of life requires us to understand the layers that make up the Earth, its water, and its atmosphere, and to develop an awareness of the biodiversity (the many different forms of life) surrounding us. This helps us understand the biosphere as the complex network connecting all life on our planet. It helps us remember how incredible—and how fragile—the complexity of life on Earth truly is.
Worlds within worlds
On a cosmic scale (in other words, compared to the Universe), the biosphere is small—just a thin layer of livable space wrapped around a medium-size planet. But on a human scale, the biosphere feels huge. There are billions of different species living on our planet’s vast expanses of water, air, and land. One way to understand this large, complex system is to break it down into smaller units. The biosphere is divided into smaller areas called biomes and ecosystems.
Biomes are large geographic regions with similar climate, plant, and animal life. For example, rainforest, desert, tundra, fresh water, and coral reefs are types of biomes on Earth.
Ecosystems are smaller habitats within biomes. They vary in size and complexity. An ecosystem can be as small as a pond or as large as a whole forest. Geography, climate, water, soils, and landscape can all contribute to the distinct features that make up an ecosystem. Within these ecosystems, all the plants, animals, rocks, water, and atmospheric conditions work together to sustain life and—ideally—keep the ecosystem in balance. Big jungles, oceans, or mountain ranges can be ecosystems, but even more specific places can be their own ecosystems. Think of a cave, a pond, a coral reef, or a city.
All organisms—from baboons to bacteria—have specialized ways to ensure survival as they search for resources in their ecosystem. Examining these individual ecosystems reveals the many complex relationships connecting all life on the planet we share.
A NASA map of land biomes on Earth. You can click here to see an interactive version of this map.
Ecologists organize their study into different levels, from the whole biosphere down to individual organisms. Within every biome, there are many different types of ecosystems of all different sizes. Ecosystems contain different communities of different species that interact with each other.
About the authors
Bennett Sherry is one of the historians working on OER Project. He received his PhD in world history from the University of Pittsburgh and has taught courses in world history, human rights, and the modern Middle East. Bennett is a recipient of the Pioneer in World History award from the World History Association, and is coauthor of The Long Nineteenth Century, 1750–1914: Crucible of Modernity (2nd ed).
Image credits
This work is licensed under CC BY 4.0 except for the following:
The biosphere, atmosphere, hydrosphere, and geosphere are all interconnected parts of planet Earth. Organisms live in the air, water, and under the ground, as well as on the surface of our planet. By Argha Manna and OER Project, CC BY 4.0.
Some organisms live high in the atmosphere, and others survive deep in the crust or the oceans. But most life on Earth happens in a thin layer (green on the diagram) near the surface of the planet.
A NASA map of land biomes on Earth. You can click here to see an interactive version of this map. By NASA Earth Observatory, public domain. https://earthobservatory.nasa.gov/biome
Ecologists organize their study into different levels, from the whole biosphere down to individual organisms. Within every biome, there are many different types of ecosystems of all different sizes. Ecosystems contain different communities of different species that interact with each other. By Argha Manna and OER Project, CC BY 4.0.