The biosphere is the collection of all living things found in Earth's many diverse ecosystems. The diversity of ecosystems in the biosphere is largely the result of Earth's movement around the Sun and Earth's rotation on its tilted axis. Differential exposure to the Sun's rays leads to different types of biomes. Biomes are loosely distributed based on latitude and are defined by their climate and vegetation. Biomes contribute to the cycling of matter on Earth. Nitrogen, phosphorus, and carbon are recycled between organisms and their environment. Human activity has shifted the carbon cycle by increasing atmospheric carbon, leading to an increase in average global temperature. Climate change has measurable negative consequences for nature and humans alike.
At A Glance
- The biosphere is the sum of all ecosystems on Earth, including all organisms and the environmental factors affecting them.
- Both biotic and abiotic factors determine global and regional patterns in the distribution of life.
- Earth's movement around the Sun and rotation on its tilted axis lead to geographic variation in climate.
Biomes are large regions that share similar climatic, physical, and biotic characteristics.
Terrestrial biomes are usually defined by their average precipitation, average temperature, and dominant vegetation.
Aquatic biomes are often distinguished by their physical characteristics, such as temperature, availability of light, and salinity.
Some organisms have adapted to survive environments that would kill most organisms.
- Many biologically important chemicals, such as carbon, nitrogen, and phosphorus, are transferred between organisms and the environment in a cycle. Human behavior has disrupted the carbon cycle by adding great amounts of carbon dioxide to the atmosphere, leading to an increase in the average global temperature.
Nitrogen from the air is "fixed" by bacteria into forms organisms can use. These organisms later release the nitrogen into the soil as waste or as the organisms decompose. Nitrogen eventually returns to the air if not taken up by other organisms.
Phosphorus is removed from rock by water and then taken up by plants along with the water. Animals eat the plants, then release phosphorus as waste or upon death and decomposition. Some phosphorus from these remains is dissolved by water, while the rest of the remains eventually solidify into rock and begin the cycle again.
Carbon is taken up from the atmosphere by organisms that undergo photosynthesis. Other organisms eat them and release carbon dioxide back into the atmosphere as waste.
- The burning of fossil fuels has released carbon into the atmosphere, where it acts as a greenhouse gas, trapping heat on Earth and causing global temperatures to rise.