4 Conditions For Life On Earth


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4 Conditions For Life On Earth

  1. 1. The 4 Conditions for Life on Earth
  2. 2. 1. A Constant and Relatively Mild Temperature <ul><li>-50 to about +50 degrees Celsius </li></ul><ul><li>Average temp. has been between 10-20 degrees C for 3.5 billion years </li></ul><ul><li>The Greenhouse effect allows for heat in the atmosphere (carbon and water vapor) </li></ul><ul><li>Without proper water and carbon, the earth would be -73 degrees C. </li></ul>
  3. 3. The Greenhouse Effect <ul><li>Plants play a significant role in creating a stable </li></ul><ul><li>temperature </li></ul><ul><li>through releasing </li></ul><ul><li>water vapor and oxygen </li></ul><ul><li>by the processes of </li></ul><ul><li>photosynthesis and </li></ul><ul><li>transpiration </li></ul><ul><li>They also absorb </li></ul><ul><li>heat from the sun’s </li></ul><ul><li>rays and limit the </li></ul><ul><li>albedo effect </li></ul>
  4. 4. The Real Greenhouse Effect
  5. 5. 2.The Importance of Water <ul><li>First water likely came from volcanic activity and the vapors released </li></ul><ul><li>Biologists believe earth first began in the oceans – blue-green algae </li></ul><ul><li>Oceans trap heat and distribute it around the world (2/3 of the earth) </li></ul><ul><li>No living thing consists of less than 50% water </li></ul><ul><li>Water is the metabolizing agent that allows plants and animals to dissolve minerals and nutrients to create energy </li></ul>
  6. 6. Photosynthesis
  7. 7. 3. The Importance of Gases <ul><li>78% nitrogen, 21% oxygen, carbon dioxide 0.03% </li></ul><ul><li>The plants have removed most of the carbon dioxide that originally existed and produced lots of oxygen </li></ul><ul><li>Without life on earth, carbon dioxide would increase </li></ul><ul><li>The production of carbohydrates, fats, and proteins require oxygen, carbon, and nitrogen atoms from the atmosphere, and hydrogen from water </li></ul>
  8. 8. 4. The Role of the Atmosphere <ul><li>Layer of gases about 80-100kms thick </li></ul><ul><li>Helps maintain a consistent temp. </li></ul><ul><li>Shields earth from collisions with cosmic particles (meteors) </li></ul><ul><li>Oxygen levels at 21% allow for life, if they drop, animal life would not be possible, if it exceeds 25% most plants would be consumed by fire </li></ul><ul><li>Oxygen is produced by plants and consumed by animals and the burning of plants and fossil fuels </li></ul>
  9. 9. The 4 Spheres <ul><li>Lithosphere – earth’s crust (soil, rocks, and minerals) </li></ul><ul><li>Hydrosphere – earth’s water </li></ul><ul><li>Atmosphere – the gases in the air </li></ul><ul><li>Biosphere – all living things (plants, bacteria, animals) </li></ul>
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