Biosphere facts for kids

The biosphere is like a giant bubble around Earth where all life exists. Think of it as the "life sphere." It includes every ecosystem on our planet. From the highest mountains to the deepest oceans, if something is alive, it's part of the biosphere!

The biosphere is mostly a closed system for matter. This means that very little new material comes in or leaves. However, it's an open system for energy. Plants use photosynthesis to capture a huge amount of solar energy from the Sun. This energy powers almost all life on Earth.

Scientists believe the biosphere started to form at least 3.5 billion years ago. This was when the first simple life forms began to appear on Earth.

Sometimes, the word "biosphere" can also mean a closed system that contains ecosystems, even if it's not Earth. For example, scientists have built artificial biospheres like Biosphere 2 to study how life can survive in isolated environments. They also wonder if other planets or moons might have their own biospheres.

What Does "Biosphere" Mean?

This beach scene shows three parts of Earth's system working together: the land (lithosphere), the ocean (hydrosphere), and the air (atmosphere).

The word "biosphere" was first used in 1875 by a geologist named Eduard Suess. He described it as the part of Earth's surface where living things can be found.

Later, in the 1920s, a scientist named Vladimir I. Vernadsky helped us understand the biosphere in an ecological way. He saw it as the science of how all living things interact with each other and with Earth's different parts. This idea combines many sciences, like astronomy, geology, meteorology, and biology.

Different Ways to Define the Biosphere

Some scientists, like geochemists, define the biosphere more narrowly. For them, it's just the total amount of all living organisms on Earth. This is also called the "biomass" or "biota."

In this view, the biosphere is one of four main parts of Earth's system:

• The geosphere (all the rocks and land)
• The hydrosphere (all the water)
• The atmosphere (all the air)
• The biosphere (all the living things)

When you combine all these four parts into one big system, it's called the ecosphere. This term helps us talk about both the living and non-living parts of our planet as one whole.

Scientists also study "biospherics." This is the science of creating and understanding artificial, Earth-like biospheres. It helps us learn how to support life in closed systems, perhaps for future space travel.

Earth's Amazing Biosphere

How Much Life is There?

Our planet is teeming with life! Scientists estimate there are about 10³⁰ (that's a 1 followed by 30 zeros!) living cells on Earth right now. This shows just how incredibly full of life our world is.

When Did Life Begin on Earth?

This is a fossil of a stromatolite, which is one of the oldest signs of life on Earth. It's estimated to be between 3.2 and 3.6 billion years old!

The earliest signs of life on Earth are truly ancient. Scientists have found evidence of life in rocks that are 3.7 billion years old in Greenland. They've also found microbial mat fossils in Australia from 3.48 billion years ago.

Even more amazing, in 2017, scientists announced they found tiny fossilized microorganisms in Canada. These microfossils could be as old as 4.28 billion years! This suggests that life might have appeared on Earth very quickly after our oceans formed, which was about 4.4 billion years ago. Earth itself formed about 4.54 billion years ago. This quick start makes scientists wonder if life might be common in the universe.

Where Can Life Be Found?

Rüppell's vultures can fly incredibly high, showing how far up life can exist in the atmosphere.

This strange creature, a Xenophyophore, lives in the deep ocean, showing how life thrives even under extreme pressure.

Life is everywhere on Earth! From the freezing polar caps to the warm equator, you'll find living things. Even deep underground, microbes live in places we once thought were empty. The total amount of these underground microbes might even be more than all the animals and plants on the surface!

The biosphere stretches far and wide:

• Birds like Rüppell's vulture can fly as high as 11,300 meters (about 7 miles).
• Fish live deep underwater, sometimes more than 8,000 meters (5 miles) down in places like the Puerto Rico Trench.
• Yaks live high in the mountains, up to 5,400 meters (3.3 miles) above sea level.
• Tiny microorganisms can survive in the vacuum of outer space under certain conditions.
• Scientists have found microbes living inside rocks 12 kilometers (about 7.5 miles) deep underground!
• Even in the deepest part of the ocean, the Mariana Trench, single-celled life forms have been discovered at depths of over 11,000 meters (nearly 7 miles).

These discoveries show how tough and adaptable life is. The deepest life forms are often limited by temperature, as it gets hotter the deeper you go into Earth's crust. For example, microbes have been found living in rocks at 122°C (252°F)! In 2014, scientists even confirmed microbes living 800 meters (half a mile) below the ice in Antarctica.

Earth's biosphere is divided into different biomes. These are large areas with similar climates, plants, and animals. On land, biomes are often separated by how far they are from the equator. For example, areas near the equator usually have more diverse life than the cold regions near the North and South Poles.

How Life Changes Through the Year

The amount of plant life on Earth changes with the seasons. You can see this in how green the land becomes in spring and summer, and how it changes in autumn and winter. In the oceans, tiny plant-like organisms called phytoplankton also grow and shrink in number throughout the year. Satellites help us track these amazing changes from space.

Building Artificial Biospheres

Scientists have created special closed environments called artificial biospheres. These are like mini-Earths built by humans. They help us study how ecosystems work and how we might be able to support life in space or on other planets someday.

Some famous examples include:

• Biosphere 2 in Arizona, United States. It's a large, sealed structure that once housed people and many different ecosystems.
• BIOS-1, BIOS-2, and BIOS-3 in Siberia, Russia. These were also used to study closed ecological systems.
• Biosphere J (CEEF) in Japan, another experiment in closed ecology.
• Micro-Ecological Life Support System Alternative (MELiSSA) in Spain, which focuses on developing life support for long-duration space missions.

Looking for Life Beyond Earth

So far, we haven't found any other biospheres beyond Earth. But scientists are always looking! The idea of life on other planets or moons is very exciting.

Some scientists believe that complex life, like animals and plants, might be very rare in the universe. This is called the rare Earth hypothesis. However, simple microbial life might be much more common.

The Kepler Space Telescope has found many planets outside our solar system. Based on these discoveries, some scientists think that if life can start fairly easily, the closest alien biosphere could be within 100 light-years of Earth.

It's also possible that humans might create new biospheres in the future. Imagine terraforming Mars, which means changing its environment to make it suitable for Earth-like life!

See also

In Spanish: Biósfera para niños