Earth's Spheres: Atmosphere and Biosphere

• The Earth consists of four spheres: the atmosphere, biosphere, geosphere, and hydrosphere.

Atmosphere

• The atmosphere refers to all the air on Earth.
• Its name originates from the Greek word "atmos," meaning "vapor."
• It is abiotic, containing no living organisms.
• The atmosphere extends up to 10,000 kilometers above Earth's surface.
• It is the outermost layer composed of physical matter.
• The atmosphere is primarily composed of 78% nitrogen, 21% oxygen, 0.9% argon, and 0.1% other gases.
• There are five layers within the atmosphere: troposphere, stratosphere, mesosphere, thermosphere, and exosphere.
• The troposphere is the densest layer.
• Layers increase in temperature as they get further from Earth.
• The ozone layer, located in the stratosphere, blocks ultraviolet radiation.

Biosphere

• The biosphere encompasses all living things on Earth, including plants, animals, and microorganisms.
• Its name originates from the Greek word "bio," meaning "life."
• It is the only biotic sphere.
• Life is abundant on Earth, from microscopic organisms to large animals.
• It depends on the other three spheres for survival, needing water from the hydrosphere, oxygen from the atmosphere, and shelter from the geosphere.
• Most life is found on Earth's surface, but the biosphere extends 500 meters below the surface and 6 kilometers above sea level.

Geosphere

• The geosphere includes all solid land in Earth's crust.
• Its name originates from the Greek word "geo," meaning "earth."
• It is abiotic, and does not contain living organisms.
• It contains all solid rock and liquid molten rock.
• Rocks change states of matter due to extreme pressure closer to the center of Earth.
• The geosphere consists of four layers: the inner core, outer core, mantle, and crust.
• The inner core is the hottest layer, reaching about 6,000 degrees Celsius.
• The outer core is composed of liquid iron and nickel at 5,000 degrees Celsius.
• The mantle is made of rock, magnesium, and iron, with temperatures ranging from 871 to 4,000 degrees Celsius.
• The crust is the outermost layer, with a maximum temperature of 871 degrees Celsius.

Hydrosphere

• The hydrosphere contains all water on Earth.
• Its name originates from the Greek word "hydro," meaning "water."
• It is considered abiotic.
• Water is composed of two hydrogen atoms and one oxygen atom.
• Water exists in liquid, solid (glaciers, ice), and gaseous (water vapor) forms.
• Over 97.5% of Earth's water is in the oceans.

Interaction of Spheres

• The spheres interconnect and interact in many ways.
• Rain from the hydrosphere falls through the atmosphere and lands on the geosphere.
• This water can then be used by animals from the biosphere.
• Human actions, such as cutting down trees, can negatively impact the geosphere and biosphere.

Explore the atmosphere and biosphere, two of Earth's four spheres. The atmosphere contains all the air on Earth. The biosphere includes all living things. Learn about their composition, layers, and importance.