Understandings:
4.2.U1 Most ecosystems rely on a supply of energy from sunlight.
4.2.U2 Light energy is converted to chemical energy in carbon compounds by photosynthesis.
4.2.U3 Chemical energy in carbon compounds flows through food chains by means of feeding. [Pyramids of number and biomass are not required. Students should be clear that biomass in terrestrial ecosystems diminishes with energy along food chains due to loss of carbon dioxide, water and other waste products, such as urea.]
4.2.U4 Energy released from carbon compounds by respiration is used in living organisms and converted to heat.
4.2.U5 Living organisms cannot convert heat to other forms of energy.
4.2.U6 Heat is lost from ecosystems.
4.2.U7 Energy losses between trophic levels restrict the length of food chains and the biomass of higher trophic levels. [The distinction between energy flow in ecosystems and cycling of inorganic nutrients should be stressed. Students should understand that there is a continuous but variable supply of energy in the form of sunlight but that the supply of nutrients in an ecosystem is finite and limited.]
Skills:
4.2.S1 Quantitative representations of energy flow using pyramids of energy. [Pyramids of energy should be drawn to scale and should be stepped, not triangular. The terms producer, first consumer and second consumer and so on should be used, rather than first trophic level, second trophic level and so on.]
4.2.U1 Most ecosystems rely on a supply of energy from sunlight.
4.2.U2 Light energy is converted to chemical energy in carbon compounds by photosynthesis.
4.2.U3 Chemical energy in carbon compounds flows through food chains by means of feeding. [Pyramids of number and biomass are not required. Students should be clear that biomass in terrestrial ecosystems diminishes with energy along food chains due to loss of carbon dioxide, water and other waste products, such as urea.]
4.2.U4 Energy released from carbon compounds by respiration is used in living organisms and converted to heat.
4.2.U5 Living organisms cannot convert heat to other forms of energy.
4.2.U6 Heat is lost from ecosystems.
4.2.U7 Energy losses between trophic levels restrict the length of food chains and the biomass of higher trophic levels. [The distinction between energy flow in ecosystems and cycling of inorganic nutrients should be stressed. Students should understand that there is a continuous but variable supply of energy in the form of sunlight but that the supply of nutrients in an ecosystem is finite and limited.]
Skills:
4.2.S1 Quantitative representations of energy flow using pyramids of energy. [Pyramids of energy should be drawn to scale and should be stepped, not triangular. The terms producer, first consumer and second consumer and so on should be used, rather than first trophic level, second trophic level and so on.]
4.2.U1 Most ecosystems rely on a supply of energy from sunlight
4.2.U2 Light energy is converted to chemical energy in carbon compounds by photosynthesis.
4.2.U3 Chemical energy in carbon compounds flows through food chains by means of feeding. [Pyramids of number and biomass are not required. Students should be clear that biomass in terrestrial ecosystems diminishes with energy along food chains due to loss of carbon dioxide, water and other waste products, such as urea.]
4.2.U4 Energy released from carbon compounds by respiration is used in living organisms and converted to heat.
4.2.U5 Living organisms cannot convert heat to other forms of energy.
4.2.U6 Heat is lost from ecosystems.
4.2.U7 Energy losses between trophic levels restrict the length of food chains and the biomass of higher trophic levels. [The distinction between energy flow in ecosystems and cycling of inorganic nutrients should be stressed. Students should understand that there is a continuous but variable supply of energy in the form of sunlight but that the supply of nutrients in an ecosystem is finite and limited.]
Energy flows but nutrients cycle through an ecosystemEnergy enters and leaves ecosystems, but nutrients must be recycled. It is the presence of saprotrophic bacteria and fungi (decomposers) that recycle nutrients from the abiotic to the biotic component of the ecosystem.
Energy flows but nutrients cycle through an ecosystemEnergy enters and leaves ecosystems, but nutrients must be recycled. It is the presence of saprotrophic bacteria and fungi (decomposers) that recycle nutrients from the abiotic to the biotic component of the ecosystem.
4.2.S1 Quantitative representations of energy flow using pyramids of energy. [Pyramids of energy should be drawn to scale and should be stepped, not triangular. The terms producer, first consumer and second consumer and so on should be used, rather than first trophic level, second trophic level and so on.]
A pyramid of energy is a graphical representation of the amount of energy at each trophic level of a food chain
Pyramids of energy will never appear inverted as some of the energy stored in one source is always lost upon transfer
Pyramid of Energy
A pyramid of energy is a graphical representation of the amount of energy at each trophic level of a food chain
- They are expressed in units of energy per area per time (e.g. kJ m–2 year–1)
Pyramids of energy will never appear inverted as some of the energy stored in one source is always lost upon transfer
- Each level should be roughly one tenth of the size of the preceding level (as energy transformations are ~10% efficient)
- The bottom level will always represent the producers, with subsequent levels representing consumers (primary, secondary, etc.)
Pyramid of Energy