Lesson 3 Energy Transfer http://karensergeant.com/your-objectives-with-learning-objectives/ Energy Transfer   4.4 explain the names given to different trophic levels to include producers, primary, secondary and tertiary consumers and decomposers. 4.5 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer. 4.6 understand the transfer of substances and of energy along a food chain. 4.7 explain why only about 10% of energy is transferred from one trophic level to the next.

Every living organism needs energy to survive – but where does it come from?

Radiation from the Sun (solar or light energy). Main source of energy for all living things. Light energy is captured and used by green plants and algae during photosynthesis, to make new biomass. Biomass is the dry mass of living material in an animal or plant.

1. How many food CHAINS can you identify from this woodland community? Dead oak leaf Live oak leaf Herb Greenfly Soil fungi Moth caterpillar Ladybird Earth worm Spider Vole Small bird starter question Owl 2. Make a food web from this information In the Antarctic Ocean plant plankton are eaten by krill, which are eaten by crab-eater seals, penguins and fish. Fish and penguins are eaten by the leopard seal. Fish are also eaten by the elephant seal. Toothed whales eat all types of seal.

Each level in a food chain is called a Trophic Level. Feeding Relationships Food chains are used to show the relationships between species in a habitat. E.g.   The Secondary Consumer (eats the primary consumer, 3rd trophic level) The Primary Consumer (eats the producer, 2nd trophic level) The Producer (all food chains start with this – 1st trophic level) RABBIT FOX GRASS pr Each level in a food chain is called a Trophic Level.

Food Webs Food chains can be built up into complex food webs. Food webs have branches, chains never do. Food webs are more stable. they don’t give us any more information about how many organisms or the biomass of organisms at each level To see this we must look at other ways of presenting this information

Ecological Pyramids Designed to represent the relative amounts of organisms at each tropic level in a food chain. There are two main types: Pyramid of Numbers Pyramid of Biomass The numbers of organisms at each trophic level in a food chain. The total mass of organisms at each trophic level in a food chain.

Fresh Water Food Chain Activity Follow the instructions on the sheet to find out: The trophic levels of each organism. The total number of organisms at each trophic level. The total biomass at each tropic level. The total energy available at each trophic level.

Total number of organisms Trophic Level Role in food chain Total number of organisms Total Mass (g) Total Energy (kJ) 1 2 3 4

Pyramids of Numbers In a pyramid of numbers, the length of each bar represents the number of organisms at each trophic level in a specified area.

Lots of grass is required to support the grasshopper population. Grass → grasshoppers → frogs → birds Birds Lots of grass is required to support the grasshopper population. Frogs Grasshopper works nicely because the numebr Grass

One elder tree can support the aphids. Elder tree → aphids → lacewings→ starling The pyramid of numbers is not triangular because it is based on the size of the elder tree, which is very large compared to the caterpillars that eat them. One elder tree can support the aphids. sometimes pyramids of numbers can look a bit strange. this is due to the large size of some producers. because so big – don’t need as many to support

Compare Numbers to Biomass In a pyramid of biomass, the length of each bar represents the total mass of organisms at each trophic level in a specified area.

Pyramids of Energy In a pyramid of energy, the length of each bar represents the total energy at each trophic level in a specified area. Only about 10% of the energy entering a trophic level is passed onto the next.

Pyramid of Numbers, Biomass & Energy So why do the pyramids have a triangular shape?

This explains why not many food chains have more than four or five trophic levels. Cabbage Rabbit Stoat Fox 100% 10% 1% 0.1% Energy is lost at each level – Some parts of organism arent eaten (e.g. roots of grass, bones) Some parts remain undigested and so are not absrobed, forming faeces Some materials absorbed form excretory products (e.g. amino acids forming urea in urine) Many materials are respired releasing energy, some lost as heat, CO2 and H2O Marine food chains can have six trophic levels due to the huge amount of light energy reaching surface waters.

Where does this energy go. 4 Where does this energy go? 4.7 explain why only about 10% of energy is transferred from one trophic level to the next. Energy is lost as heat through cellular respiration Biomass in as food Biomass lost as urine (Some materials absorbed form excretory products) Biomass lost – used to provide energy for movement, growth, etc Indigestible Biomass lost as faeces Biomass turned into new cow biomass Biomass digested Energy is lost at each level – Some parts of organism arent eaten (e.g. roots of grass, bones) Some parts remain undigested and so are not absrobed, forming faeces Some materials absorbed form excretory products (e.g. amino acids forming urea in urine) Many materials are respired releasing energy, some lost as heat, CO2 and H2O

Copy and complete: The amounts of ____________ and ___________ contained in organisms always gets less at each stage of a _______ __________ from __________ onwards. Biomass is lost as ____________ products and used to release energy in __________. This is used for __________ and to control _______ _________. Only a small amount is used for ______________. biomass body temperature energy food chain growth movement producers respiration waste

Copy and complete: The amounts of biomass and energy contained in organisms always gets less at each stage of a food chain from producers onwards. Biomass is lost as waste products and used to release energy in respiration. This is used for movement and to control body temperature. Only a small amount is used for growth. biomass body temperature energy food chain growth movement producers respiration waste