Cycling of Matter Study Notes

Cycling of Matter and Earth's Space

• Earth can sustain life due to:

  • An atmosphere
    defining a protective shield of gases

  • Being primarily made up of water The provided notes state that Earth is "primarily made up of water," which is a key factor in sustaining life. However, they do not specify an exact percentage. Generally, Earth's surface is about 71% water.

• The Earth comprises multiple layers that allow nutrients to cycle freely through:

  1. Atmosphere

  2. Lithosphere

  3. Hydrosphere

Earth's Biosphere

• Biosphere Definition: The regions of the Earth where living organisms exist, referred to as the biotic sphere because it harbors living things.

• Comparison with Other Planets:

  • The atmosphere, lithosphere, and hydrosphere are abiotic layers found on other planets.

  • However, Earth possesses:

  • Water

  • Reasonable temperatures

  • No other planet known to sustain a biosphere that supports life.

Nutrient Cycles

1. The Water Cycle

• Importance: This is the most vital nutrient cycle.

• Cycle Process:

  • Liquid water evaporates due to solar energy, creating water vapor.

  • Water vapor rises into the atmosphere and condenses into liquid droplets, forming clouds.

  • Once clouds reach saturation, water precipitates back to Earth as rain.

  • Post-precipitation, water undergoes the following:

  • Runs off into hydrosphere (ponds, streams, lakes, oceans).

  • Percolates through soil, replenishing aquifers.

  • This cycle repeats continuously.

2. The Carbon Cycle

• Significance: Carbon is essential for survival.

• The carbon cycle interacts with all Earth's spheres, similarly to the water cycle.

• Process:

  • Carbon dioxide in a gaseous form ( ext{CO}_2(g)) moves through the atmosphere and into the biosphere via photosynthesis.

  • Photosynthesis Process: Plants convert carbon dioxide and water into usable energy in the form of glucose and release oxygen as a byproduct.

  • Word Equation: Carbon Dioxide + Water → Glucose + Oxygen

  • Skeleton Equation:
    $ext{CO}<em>2 + ext{H}</em>2 ext{O} <br>ightarrow ext{C}<em>6 ext{H}</em>{12} ext{O}<em>6 + ext{O}</em>2$ (unbalanced)

  • Balanced Chemical Equation:
    $6 ext{CO}<em>2 + 6 ext{H}</em>2 ext{O} <br>ightarrow ext{C}<em>6 ext{H}</em>{12} ext{O}<em>6 + 6 ext{O}</em>2$

• Decomposition: Following the death of organisms, carbon is released back into the lithosphere, reinitiating the cycle.