Energy Flow B4e

OBJECTIVES Key Objective Explain the flow of energy in the environment Construct pyramids of numbers from given information and explain what they show (C/D) Construct pyramids of biomass from given information and explain what they show (C/D) Distinguish between pyramids of numbers and pyramids of biomass. (B/A) Explain how the efficiency of energy transfer explains the shape of pyramids of biomass. (B/A) Explain how the efficiency of energy transfer explains the limited length of food chains. (B/A) Calculate the efficiency of energy transfer. (A*)

Look at the picture of the freshwater aquarium above and answer the following questions. 1.Using the organisms in the tank, draw as many food chains as you can. Remember that the direction of the arrows shows the flow of energy (from plants). 2.Combine your food chains to form a food web. 3.Name two producers. 4.Name two consumers. STARTER

Food chains A food chain shows where the energy goes in a food chain (in other words, “what gets eaten by what”): Cabbage Rabbit Stoat Fox The arrows indicate where the energy is going Plants convert the sun’s energy into food Producer Herbivore (primary consumer) Secondary consumer Top carnivore (tertiary consumer)

Match these words… Tertiary consumer Herbivore Top carnivore Producer Secondary consumer Consumer Omnivore Carnivore Primary consumer Usually plants. Starts off a food chain Animals that only eat plants An animal that eats producers An animal that eats primary consumers An animal that eats secondary consumers A general word for “an eater” Eats only animals Not eaten by anything else Eats both animals and plants

Pyramids of number In this food chain we can see that the number of organisms in each stage is less than in the previous stage: CabbageRabbitStoatFox We can draw a “Pyramid of Numbers” to show this pattern: Lots of cabbages Some rabbits A few stoats One fox

“Funny looking” pyramids Consider this food chain instead: TreeGreenflyLadybirdBird ONE tree Many greenfly Some ladybirds One bird

Pyramids of biomass In this food chain we can see that the mass of organisms in each stage is less than in the previous stage: CabbageRabbitStoatFox We can draw a “Pyramid of Biomass” to show this pattern: Mass of cabbages Mass of rabbits Mass of stoats Mass of foxes

Energy flow in a food chain Consider the energy flow in this food chain: CabbageRabbitStoatFox 100%10%1%0.1% Clearly, not all of the ___’s energy that becomes stored in the _______ will end up in the fox. Only around ______ is passed on to the next stage in each food chain. Energy is lost at each stage because of a number of reasons: 1)Each organism has to ____, keep warm etc 2)Energy is lost through faeces (______) Words – 10%, move, sun, waste, cabbage

Your Task… Research the meaning of the terms biomass and biofuels. Then find out; –The different methods of transferring energy from biomass –Biofuels (how they are manufactured & uses) –Pros (reasons for development) and cons