BY5.7 Energy

Energy Source

• the ultimate source of energy is the sun
• the sun releases energy in the form of electromagnetic waves
• most of the solar energy is reflected, absorbed or radiated back by the ozone layer, dust particles and clouds
• 90% of the energy that penetrates the Earth's atmosphere and reaches the surrface is reflected by vegetation, sil and water or absrobed and radiated to atmosphere as heat
• only 10% is available for producers to use
• of the energy entering the plant between 15 and 5% is utilised by it
• the rest is lost partly by reflection and by the evaportation of water

Trophic efficiency:

• percentage of energy at one trophic level that is incorporated into the next one
• rate at which energy passes into each trophic evel is about 10% of the energy at previous evels
• known as the gross ecological efficiency
• values differ between ecosystems

Energy flow through producers:

• a large amount of energy that falls onto a plant is not absorbed
• it is lost in 3 ways:
  • wavelength is wrong and so it is not absrobed
  • some light is refelcted
  • some light passes straight through wihtout hitting any chlorophylls

Photosynthetic…