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4.7. Importance of the atmosphere for living beings

Importance of the atmosphere for living beings

The atmosphere is essential for living beings for several reasons:

  • The air in the atmosphere has the gases necessary for life:
    • OxygenThrough respiration, living things use oxygen from the air to obtain energy. Plants and animals, day and night, throughout their lives, need oxygen and give off carbon dioxide (CO2).
    • Carbon dioxide. Plants are autotrophs, and make their own organic matter through photosynthesis, using energy from the sun, carbon dioxide (CO2), water, and mineral salts from the soil. In this process, they release oxygen that they send back into the atmosphere. These processes are what have led to the atmosphere having its current chemical composition.
    • NitrogenIt is essential in the composition of proteins. Although we cannot use nitrogen from the atmosphere directly, there are bacteria that can fix it and pass it on to the rest of the food chain (nitrogen cycle).
    • WaterWater vapor is part of the water cycle, essential for living beings. It comes from the evaporation of water from the seas and continents, and from the transpiration of plantsCondensation and precipitation can occurin water vapo .
      • Water condensation. Air can hold a certain amount of water vapor, but if the temperature drops, so does the amount of water (in a gaseous state) it can hold, so the water condenses. For condensation to occur, it is necessary to come into contact with a solid surface (condensation nucleus), such as that of the small particles that are suspended in the air. Some of the atmospheric phenomena produced by condensation are:
        • Cloud formation. Hot air is less dense than cold air and rises. As it rises, the temperature drops, it can contain less water vapor, and the water condenses around a condensation nucleus forming clouds.
        • Fog. It occurs when clouds have formed very close to the ground. The water vapor condenses due to the low temperature.
        • Dew. At night temperatures drop and water condensation occurs on the surface of the plants.
        • Frost (or pink). If the dew drops freeze, being at a temperature below 0 ºC, frost is produced.
        • Cencellared. It occurs when ice forms when small droplets of fog freeze on the surface, which is at a temperature below or close to 0 ºC.
      • Water precipitationAir currents cause small condensed cloud droplets to collide with each other and form larger droplets. When they have a large enough mass, they fall by gravity and precipitation occurs:
        • Rain, if the precipitation occurs in a liquid state.
        • Snow. If the temperature of the water freezes because it is below 0 ºC, it falls in a solid state in the form of snowflakes.
        • Hail, if the droplets of the clouds rise several times, increase in size, and freeze.
  • The atmosphere regulates temperature. The sun's rays hit the earth's surface during the day and, were it not for the atmosphere , that heat would be dissipated into space, cooling the Earth a lot at night. The natural greenhouse effect that we have already talked about is essential for life on our planet.
  • The atmosphere has a protective function.
    • The ozone layer (ozonesphere) protects us from ultraviolet radiation from the sun , which is harmful to living things.
    • It also protects us from the impacts of meteorites that could reach the Earth, since with the friction when entering the atmosphere they tend to disintegrate.
  • The atmosphere is responsible for the climate of the territory in which each living being lives.
  • Wind power has been used to power windmills, wind turbines, sailing ships, or birds and plants to transport their pollen or seeds.