Flow of Energy through Living Systems

Discover how energy moves through ecosystems with food chains, webs, and pyramids!

Energy from Food When food is eaten, energy passes through an ecosystem, but some of the energy is changed to heat and is not passed on. In other words, some of the energy is lost because it is changed to heat. So we don't actually get ALL the energy that is in the food we eat. Energy moving in an ecosystem can be described in 3 different ways:1. As a food chain2. As an energy chain3. As a food webThese are just 3 different ways that scientist use to look at and discuss how energy moves through an ecosystem. As energy moves through an ecosystem some of the energy is changed to heat and lost. True False The sun and photosynthesis form the foundation of all food webs. true false There is more energy available at the top of an energy pyramid than at the bottom true false Food Chains and Food Webs Food chains can be very long or very short, but basically food chains are a simple way to show how energy moves in an ecosystem. However, in order to see what is really going on, you need to think about combining many food chains into a food web. A food web is a more complete picture of what is going on in the real world. Plantsand protistsare producers which means that they make their own food through the process of photosynthesis. Producers make their own food and that is how they get their energy. Producers use the sun's energy, along with water and carbon dioxide to make their own food. The food they produce is a type of sugar called glucose. The simple story of photosynthesis and food What is the process of photosynthesis all about (OPTIONAL)? Type of Consumers Consumers can't make their own food so they eat other organisms to get their energy. All animals are consumers. There are 5 types of consumers:1. Herbivores are consumers that eat other plants A rabbit is a good example of an herbivore. Herbivores would order a pizza with brocoli, tomatoes, spinach, etc . . .2. Carnivores are consumer that eat other animals. They are what we call predators and they are the meat-eaters. A lion is a good example of a carnivore. The word "carnivore" comes from the Spanish work "carne" which means "meat." A carnivore would order a pizza loaded with pepperoni, sausage, bacon, etc . . . you get the idea.3. Omnivores are consumers that eat both plants and animals. For the most part, people are omnivores. An omnivore would order a pizza loaded with brocoli, pepperoni, fresh tomatoes, sausage, onions, bacon, etc . . . you get the idea.4. Scavengers are consumers that eat dead animals. They are the garbage collectors of the animal world. If it weren't for them, dead animals would lie around much longer than they do. Their job is to eat as much of the dead animal as possible. A scavenger would be found behind the pizza shop eating all the rubbish in the dumpster. 5. Decomposers are basically fungi and bacteria that break down dead matter into it basic parts (molecules of vitamins, minerals and nutrients) and return them to the soil so that plants can use them to grow big and strong. A scientist would find a decomposer by looking under a microscope where the decomposer would be breaking down any pizza scraps that the scavenger left behind. Match the consumer with its description. carnivore a consumer that eats meat. Also known as (aka) a predator. omnivore this consumer eats both plants and other animals. Most people are this type of consumer. herbivore this consumer only eat plants An example would be a cow or a rabbit. scavenger this consumer comes along after the animal is dead and eats the dead flesh. It is nature's garbage collector. decomposers these consumers are mainly fungi and bacteria and they break down small bits of dead matter into molecules of nutrients that can be returned to the ground and used by plants to grow big and strong. Food Chains and Food Webs On land, the food of an animal can be traced back to plants. In the ocean, food chains often begin with plant-like organisms called plankton. Food chains at deep sea vents begin with bacteria. Explain what producers are and why they are at the beginning of every terrestrial (land) and aquatic (water) ecosystem. Energy Pyramids In an ecosystem all energy comes from the sun. At the beginning of any ecosystem, the sun's energy is transferred to the producers, plants and plankton, and then on to the herbivores, carnivores, omnivores, scavengers and decomposers. However, as we move up the food chain, less and less of that energy is available. The best way to look at this is from a diagram called an energy pyramid. As with all pyramids it is widest at the base which tells us that is where the greatest amount of energy is. The producers are always at the bottom of the pyramid and always have the greatest amount of energy in an ecosystem.As animals use the energy, a lot of it is used as body heat which is given off. This means that this energy can't be passed on to the next consumer because it has been changed to heat energy and has been given off. In other words, only a small amount of the energy you eat is actually stored in your body. Most of it is used to keep your body warm, to keep your body moving and your organs working. So if you were eaten (and let's hope this doesn't happen!) the "thing" eating you would only get a small amount of the energy that you ate. You would have already used most of this energy to move and keep yourself warm. Energy Pyramids Show the Flow of Energy Through an Ecosystem Use the words in the Word Bank to correctly fill in the blanks.Word Bank: energy pyramid, producers(2), base, top, herbivore, photosynthesis, sun Plants and plankton are the main producers in an ecosystem. They are called producers because they make their own food through a process called photosynthesis. The energy that plants use to make their own food comes from the sun. However, once a plant gets eaten it only passes on 10% of its energy to the herbivore that is eating it. This transfer of energy from level to another is best pictured using an energy pyramid. Most of the energy in an energy pyramid is found at the base and the least amount of energy is found at the top of the pyramid. The sun and photosynthesis form the foundation of all food webs. true false The sun and photosynthesis form the foundation of all food webs. true false The sun and photosynthesis form the foundation of all food webs. true false