1. 4.2: Energy flow

2. Sunlight & ecosystems Producers utilize energy from the sun via photosynthesis e.g. plants, eukaryotic algae and cyanobacteria. All are autotrophs. Heterotrophs are indirectly dependent on the energy from the sun. e.g. consumers, saprotrophs and detritivores. All are dependent on carbon compounds as their source of energy. The amount of energy harvested from the sun varies depending on location.

3. Energy conversion Energy flows through a food chain by organisms feeding. Draw a simple food chain with 5 parts. What does the arrow represent? Which are producers? Which are consumers?

4. Respiration? Typically, the energy produced from respiration is released into the environment as heat. Living organisms cannot convert heat into other forms of energy. Eventually, all the heat produced by a living organisms will be lost to the environment.

5. Make a food web using these organisms. 4.2: food web activity

6. Trophic levels What is a trophic level? Energy losses between trophic levels limits the length of many food chains. Energy is lost for many reasons, including: - energy lost as heat (eventually, due to respiration) - organism only partially consumed at each trophic level - organism consumed is not fully digested/absorbed. ONLY A SMALL PORTION OF THE ENERGY IN THE BIOMASS OF AN ORGANISM IS PASSED ONTO THE NEXT TROPHIC LEVEL

7. Pyramids of energy A graphical representation of energy converted to new biomass at each trophic level. Units = kilojoules per metre squared per year (KJ m -2 y -1 ) Bars should be scaled to represent to energy at each trophic level

8. 10 % Law of energy flow Of the total energy entering a particular trophic level, only 10% is available for the next higher trophic level. ◦Grass → Goat → Tiger ◦200 KJ/ m 2 /yr → 20 KJ/ m 2 /yr → 2 KJ/ m 2 /yr ◦NOTE : KJ/ m 2 /yr - these are the units used to measure energy in an ecosystem...Kilojoules per meters squared per year 8 AMIT MISHRA - NES INTERNATIONAL SCHOOL MUMBAI