Earth: The Fragile Miracle

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Earth The Fragile Miracle

• Conditions for Life

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The Goldilocks Zone

• Earths life-sustaining conditions are possible
  because of its position in the solar system
• It is not too hot and not too cold if the Earth
  was any closer or further away from the Sun, the
  planet could not support life

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Other Life Sustaining Conditions

• Earths rotation on its axis and orbit around the
  Sun helps distribute heat evenly around the
  planet
• Earths magnetic field protects the planet from
  deadly radiation and particles
• Earths gravitational field holds the atmosphere
  in place preventing oxygen, nitrogen, and carbon
  dioxide from escaping into space

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Four Conditions for Life

• Stable Temperature Range
• The Importance of Water
• The Importance of Gases
• The Role of the Atmosphere

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Stable Temperature Range

• A stable temperature range (-50 to about 50
  degrees Celsius) allows life to thrive the
  average temperature has been between 10-20
  degrees Celsius for 3.5 billion years
• The greenhouse effect allows for heat in the
  atmosphere (carbon and water vapor) to be
  re-radiated back to Earth
• Without proper water and carbon, the earth would
  be -73 degrees C.

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The Greenhouse Effect

• Plants play a significant role in creating a
  stable temperature through releasing water vapor
  and oxygen by the processes of photosynthesis and
  transpiration
• Dark areas of vegetation absorb heat from the
  suns rays and limit the albedo effect heat
  being reflected back into space

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Photosynthesis
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The Importance of Water

• First water likely came from volcanic activity
  water collected on the cooling surface and as
  vapour in the atmosphere creating the water cycle
• Biologists believe earth first began in the
  oceans blue-green algae
• Oceans cover 2/3 of the Earth absorbs heat and
  distributes it around the world and controls our
  weather patterns and climates

• Helps distributes nutrients to plants and other
  organisms
• No living this consists of less than 50 water
• Water is the metabolizing agent that allows
  plants and animals to dissolve minerals and
  nutrients to create energy

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The Importance of Gases

• 78 nitrogen, 21 oxygen, carbon dioxide 0.03 -
  quite different than other planets in the solar
  system
• The plants have removed most of the carbon
  dioxide that originally existed and produced lots
  of oxygen
• Without life on earth, carbon dioxide would
  increase
• The production of carbohydrates, fats, and
  proteins require oxygen, carbon, and nitrogen
  atoms from the atmosphere, and hydrogen from
  water

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The Role of the Atmosphere

• Layer of gases about 80-100 kms thick very thin
  compared to size of Earth
• Helps maintain a consistent temperature
• Shields earth from collisions with cosmic
  particles (meteors)
• 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
• Oxygen is produced by plants and consumed by
  animals and the burning of plants and fossil
  fuels

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The Four Spheres

• Lithosphere earths crust (soil, rocks, and
  minerals)
• Hydrosphere earths water
• Atmosphere the gases in the air
• Biosphere all living things (plants, bacteria,
  animals)

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Biosphere

• Encompasses all living organisms including humans
• Divided into separate but interdependent units
  called ecosystems well defined habitats hosting
  systems of interacting organisms
• Nutrient Cycle - Continuation of life depends on
  the constant recycling of chemical ingredients
  called nutrients (Example plants and animals die
  and decompose)

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Biosphere The Carbon Cycle

• The movement of carbon from the atmosphere into
  plants, animals, and the soil and then back again
• Plants take carbon dioxide from the atmosphere to
  produce food through photosynthesis and release
  oxygen animals breath oxygen and eat plants
• Dead animals and plants decay and return carbon
  to cycle
• Over production of carbon dioxide from factories
  and burning rainforests causes climate change

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Biosphere Nitrogen Cycle

• Most powerful element in the Earths atmosphere
• Microscopic bacteria live on the roots of certain
  plants known as legumes and converts nitrogen to
  ammonia and nitrates which the plant absorbs and
  converts to protein food production

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Biosphere Oxygen Cycle

• Oxygen produced by the respiration of plants
  90 of oxygen used is replaced by algae in oceans
• Oxygen created by photosynthesis

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Biosphere Water Cycle

• Water must be recycled through the atmosphere and
  back to the Earths surface
• Most from evaporation some from transpiration
  water drawn by plants and released through their
  leaves
• Groundwater dissolves nutrients in the soil