Spheres of Earth and Organization of Life

• Earth has four spheres: Atmosphere, Lithosphere, Hydrosphere, and Biosphere.

Atmosphere

• Layer of gases: 78% nitrogen, 21% oxygen, <1% argon, water vapor, etc.

• Affects temperature and blocks solar radiation.

Lithosphere

• Rocky outer shell of Earth made of rocks, minerals, and soil.

• Thickness: 50-150 km.

Hydrosphere

• All water on Earth: oceans (97%), lakes, ice, groundwater, clouds, etc.

• Circulated through the water cycle.

Biosphere

• Where life exists within other spheres.

• Organization: Biosphere -> Biomes -> Ecosystem.

Ecosystem

• Living organisms and their interactions with each other and nonliving environment. Described by abiotic and biotic factors.

Biotic factors

• Effects due to living things: competition, disease, biodiversity, predation.

Abiotic factors

• Interaction of organisms with the environment.

• Non-living components: sunlight, temperature, wind, moisture, soil conditions.