Energy Flows Aim : To be to explain energy flows in food chains trophic levels

1. Quick test: • What is a biome? • What is an ecosystem? • What is biomass? • What is the difference between abiotic and biotic? • Which factors lead to different biomes? Energy Flows Aim: To be to explain energy flows in food chains trophic levels Energy = Insolation

2. Insolation = Photosynthesis= More biomass Question: What is missing that plants require to grow? (as well as starch?)

3. Energy Flows- Food chain Stages in food chain. Once food/photosynthesis has been used to build the plant, that plant then becomes available to other organisms, which in turn will become available to other organisms. This flow of energy through plants and animals, then back into the soil, is called a FOOD CHAIN.

4. Trophic levels • This diagram shows a simple food chain/trophic levels. • TASK: think of suitable organisms for each level. • As you can see from the arrows there is a loss of energy at each stage (respiration, excretion, heat into atmosphere). Also, you can see that as levels go up there are less organisms, this is due to organisms becoming more complex and thus more lower level organisms are required to support each level as they go up.

5. The fall in biomass • As you climb the trophic levels the amount of biomass decreases due to the reduction in organisms. • Energy found within any plant and animal material is known as biomass, and it can be measured in a variety of ways: • Calories. • Dry weight. • Ash weight (weight after burning).

6. Food chains, Trophic levels & Energy • Plants represent the first trophic/energy level in the chain. They are called producer organisms (self feeding autotrophs) as they produce their own food via photosynthesis. All other trophic/energy levels are filled with consumers (heterotrophs- these are unable to ‘fix’ their own carbon so take it to grow from other organisms) • Primary and secondary consumers differ due to their diets- primary are vegetarians or herbivores and secondary consumers are meat eaters or carnivores. The final trophic/energy level sees the top predators known as omnivores as they eat both plants and other animals. • The transfer of energy is not 100% efficient, as energy is lost via respiration, dead organisms, decay, excreta, and heat given off. The result is that fewer organisms are supported at each level, but the individual size of each organism increases at each trophic level.

7. Reducer Organisms First 21 secs Meet EarthWorm Jim- a gang of detritivores. His team of friends include lice and vultures. This gang are experts at eating dead and decaying organisms. His arch enemies in returning any remaining nutrients to the soil are the decomposer crew Brenda the bacteria and fungi. This crew are experts at the breakdown of dead plants, animals and even excrement, aka poo poo!

8. Study- Page 112- read and make notes- marine food web & 113-Activities 1 & 2 (not 3)