Transcript Food chains
Energy Transfer and Feeding Relationships “WHAT’S FOR DINNER?” Reminders and Take Notice! Your lab is due on Monday, March 25. You and your partner will be marked on: proper arrangement of the write up completion of the lab in its entirety Your ability to reflect upon the observations made based on the experiment you carried out You will have your first quiz on Wed. March 27 Topics include 1. The Earth’s Spheres, 2. Biotic and Abiotic features, and 3. Energy Consumption + Feeding Relationships In other words, the first three slide shows, omitting adaptation Feeding types Animals can be grouped in several ways. One way of doing this is based on how animals feed. Some organisms are producers. Producers make their own food. Plants produce their own food using light energy from the Sun. Some types of bacteria can also make their own food by using light or chemical reactions. Consumers cannot make their own food. They must consume other organisms to get the food that they need. Where does all the Energy in a food chain come from? • Major source of energy for our planet Provides energy used by green plants to make their own food in the process known as Photosynthesis Plants provide food for other organisms Also provides solar energy to generate electricity, light energy and thermal energy to warm the planet and its inhabitants How does the Energy get IN to the Food Chain? Photosynthesis Executed by plants A process by which plants take in the sun’s energy, carbon dioxide and water to produce oxygen and stored energy upon which plants grow and survive Carbon Dioxide + Water + Sunlight Sugar (energy) + Oxygen CO2 + H2O + Sunlight C6H12O2 + O2 The reason photosynthesis occurs in plants and not animals is because it requires a chemical called chlorophyll How do CONSUMERS USE this energy? Cellular Respiration Occurs in animals A process by which animals take in sugar and oxygen to fuel the body while producing water and carbon dioxide C6H12O2 + O2 CO2 + H2O + ATP Complementary Processes The product of one process equals the starting components of the other process Types of Consumers Herbivores: plant eaters (eg. Rabbit) Carnivores: meat eaters (eg. Fox) Omnivores: plant and meat eaters (eg. Bear) Food chains – what eats what? With the following groups, create a food chain, identifying each group member as a plant or animal. **REMEMBER WHAT YOU WERE AND WHERE YOU FELL IN THE CHAIN. Arctic 1 Caroline Emma Micaela Tatum Forest 1 Paul Tristan Jacob T. Luke Pond 1 Patrick Tony Stephen Arctic 1 Nathan Nick G. Hennadiy Nick R. Forest 1 Matt Kyle Alex Zach Arctic 2 Jo-Anna Holly Julie Katie Forest 2 Karly Jillian Melissa Sarah Pond 2 Jim Derek Keegan Arctic 2 David Oliver Madi Liv Forest 2 Alec Jacob M. Jacob R. Jacob B. Pond Rachel Tasha Mandy Cindy Food chains A food chain shows what is eaten by what. Each arrow means ‘eaten by’. leaf caterpillar bird cat What does this food chain show? A leaf is eaten by a caterpillar, which is eaten by a bird, which is eaten by a cat. Energy is transferred from one organism to another in the direction of the arrow Food chains – activity Green plant Goat Owl Rabbit Mouse Wild Cat Snake Eagle Lion Jackal (like a wolf) Ranking consumers A food chain can be used to rank different types of consumers. seaweed producer limpet primary consumer crayfish human secondary consumer tertiary consumer producers – make their own food; primary consumers – eat producers; secondary consumers – eat primary consumers; tertiary consumers – eat secondary consumers. Do animals only eat one species?? Food chains show simple relationships Food webs show all the feeding relationships in a habitat Which of these organisms are producers? Which ones are Herbivores? Which ones are carnivores? Which ones are omnivores? Build a food web Nuts Mice Wolf Bear Nuts Deer Wolf Bear Bark Rabbit Wolf Bear Blossoms Insects Birds Red fox Bear Blossoms Bees Bear Bark Rabbit Red fox Bear Food Pyramids We draw food webs to show how animals’ eating habits are related We draw pyramids to show how energy (biomass) is passed along from one animal to the next What shape is a pyramid? What can the shape tell us about energy at the top? What is Biomass? The total dry mass of living organisms in a group or area Example: How do we measure the biomass for field of grass? (producer level on our food chain) Dry the grass then take the mass of it = biomass of the grass Biomass tells us how much Energy is available to the next trophic level Why do we take the water out when we measure biomass??? Example: What has more energy? Watermelon Bread Two Types of Pyramids 1) Pyramid of Numbers Count number of each organism Not as accurate Example: 1 oak tree, 10 caterpillars, 2 birds Blackbird Caterpillar Oak Tree Types of Pyramids 2) Pyramid of Biomass Weigh all the organisms at each stage of the food chain (biomass of producers > consumers) More accurate to show feeding relationship Example: even if there is only one oak tree it can have many caterpillars living from it Blackbird Caterpillars Oak Tree Food Pyramids and Energy Only about 10% of the energy from one level gets passed to the next Reasons why biomass decreases as you go up the pyramid: Not all of the plant is eaten by herbivores (only eat leaves, not roots) Not everything eaten is digested (wolf eats a deer, uses meat but fur is waste) Energy is lost in the form of body heat, used for activity, to carry out life processes Example: When we eat chicken for dinner we do not get 100% of the energy from it. Why? Eating lower on the food chain wastes less energy Animals need energy to live, grow and reproduce Animals get less energy from what they eat if at the top of the food chain This can explain why there are usually fewer carnivores than herbivores, and fewer herbivores than plants Eagle Rabbit Grass Practice Calculation for Energy Transfer Calculate the units of energy in each trophic level of the food chain below. Remember that only 10% of the energy gets passed along. (Starting energy units) x (0.10) = Energy passed along (Starting energy units) x (0.10) = Energy passed along (2543) x (0.1) = 254.3 units of energy (grasshoppers) (254.3) x (0.1) = 25.43 units of energy (spotted frog) TRY THE NEXT STEP ON YOUR OWN! (Starting energy units) x (0.10) = Energy passed along (25.43) X (0.1) = 2.543 units of energy (redtailed hawk) Answer: Hint: Every trophic level you move up in the food chain, you move the decimal over one place to the left (This is 10% of the starting number) 254.3 energy units 25.43 energy units 2.543 energy units