Jessica Harwood Douglas Wilkin, Ph.D.

Consumers and DecomposersJessica HarwoodDouglas Wilkin, Ph.D.Say Thanks to the AuthorsClick http://www.ck12.org/saythanks(No sign in required)

To access a customizable version of this book, as well as otherinteractive content, visit www.ck12.orgAUTHORSJessica HarwoodDouglas Wilkin, Ph.D.EDITORDouglas Wilkin, Ph.D.CK-12 Foundation is a non-profit organization with a mission toreduce the cost of textbook materials for the K-12 market bothin the U.S. and worldwide. Using an open-content, web-basedcollaborative model termed the FlexBook , CK-12 intends topioneer the generation and distribution of high-quality educationalcontent that will serve both as core text as well as provide anadaptive environment for learning, powered through the FlexBookPlatform .Copyright 2015 CK-12 Foundation, www.ck12.orgThe names “CK-12” and “CK12” and associated logos and theterms “FlexBook ” and “FlexBook Platform ” (collectively“CK-12 Marks”) are trademarks and service marks of CK-12Foundation and are protected by federal, state, and internationallaws.Any form of reproduction of this book in any format or medium,in whole or in sections must include the referral attribution linkhttp://www.ck12.org/saythanks (placed in a visible location) inaddition to the following terms.Except as otherwise noted, all CK-12 Content (including CK-12Curriculum Material) is made available to Users in accordancewith the Creative Commons Attribution-Non-Commercial 3.0Unported (CC BY-NC 3.0) License (http://creativecommons.org/licenses/by-nc/3.0/), as amended and updated by Creative Commons from time to time (the “CC License”), which is incorporatedherein by this reference.Complete terms can be found at http://www.ck12.org/terms.Printed: January 26, 2015CONTRIBUTORSDoris Kraus, Ph.D.Niamh Gray-WilsonJean Brainard, Ph.D.Sarah JohnsonJane WillanCorliss Karasov

www.ck12.orgC HAPTERChapter 1. Consumers and Decomposers1Consumers andDecomposers Explain the roles of consumers and decomposers in an ecosystem. Distinguish herbivores from carnivores and omnivores. Classify organisms on the basis of how they obtain energy and describe examples of each.What is breaking down this leaf?Notice how this leaf is slowly being broken down. This process can be carried out by fungi and bacteria on theground. Breaking down old leaves is an important process since it releases the nutrients in the dead leaves back intothe soil for living plants to use.Consumers and DecomposersRecall that producers make their own food through photosynthesis. But many organisms are not producers andcannot make their own food. So how do these organisms obtain their energy? They must get their energy fromother organisms. They must eat other organisms, or obtain their energy from these organisms some other way. Theorganisms that obtain their energy from other organisms are called consumers. All animals are consumers, andthey eat other organisms. Fungi and many protists and bacteria are also consumers. But, whereas animals eat otherorganisms, fungi, protists, and bacteria "consume" organisms through different methods.The consumers can be placed into different groups, depending on what they consume. Herbivores are animals that eat producers to get energy. For example, rabbits and deer are herbivores that eatplants. The caterpillar pictured below ( Figure 1.1) is a herbivore. Animals that eat phytoplankton in aquaticenvironments are also herbivores. Carnivores feed on animals, either herbivores or other carnivores. Snakes that eat mice are carnivores. Hawksthat eat snakes are also carnivores ( Figure 1.1).1

www.ck12.org Omnivores eat both producers and consumers. Most people are omnivores, since they eat fruits, vegetables,and grains from plants, and also meat and dairy products from animals. Dogs, bears, and raccoons are alsoomnivores.FIGURE 1.1Examples of consumers are caterpillars(herbivores) and hawks (carnivore).Decomposers and StabilityDecomposers ( Figure 1.2) get nutrients and energy by breaking down dead organisms and animal wastes. Throughthis process, decomposers release nutrients, such as carbon and nitrogen, back into the environment. These nutrientsare recycled back into the ecosystem so that the producers can use them. They are passed to other organisms whenthey are eaten or consumed. Many of these nutrients are recycled back into the soil, so they can be taken up by theroots of plants.The stability of an ecosystem depends on the actions of the decomposers. Examples of decomposers includemushrooms on a decaying log. Bacteria in the soil are also decomposers. Imagine what would happen if therewere no decomposers. Wastes and the remains of dead organisms would pile up and the nutrients within the wasteand dead organisms would not be released back into the ecosystem. Producers would not have enough nutrients. Thecarbon and nitrogen necessary to build organic compounds, and then cells, allowing an organism to grow, would beinsufficient. Other nutrients necessary for an organism to function properly would also not be sufficient. Essentially,many organisms could not exist.FIGURE 1.2Examples of decomposers are (a) bacteria and (b) fungi.2

www.ck12.orgChapter 1. Consumers and DecomposersSummary Consumers must obtain their nutrients and energy by eating other organisms. Decomposers break down animal remains and wastes to get energy. Decomposers are essential for the stability and survival of an ecosystem.Explore MoreUse the resource below to answer the questions that follow. Decomposers at http://www.youtube.com/watch?v Z6V0a 7N1Mw (3:19)MEDIAClick image to the left or use the URL below.URL: 91. What is the role of decomposers in an ecosystem? What is the source of the matter which is decomposed?2. How do the actions of earthworms improve soil quality? How does this impact the amount of biomass anecosystem can support?3. How do gastropods function as decomposers?Review1.2.3.4.What is a consumer?What’s the term for a consumer that eats both leaves and fish?What are the different types of consumers?Why are decomposers important in the ecosystem?References1. (a) Benny Mazur (Flickr: Benimoto); (b) Steve Jurvetson (Flickr: jurvetson). Both caterpillars and hawks areconsumers . CC-BY 2.02. (a) Umberto Salvagnin (Flickr: kaibara87); (b) Flickr:takomabibelot. Bacteria and fungi are often decomposers . CC BY 2.03

Feb 03, 2015 · organisms that obtain their energy from other organisms are called consumers. All animals are consumers, and they eat other organisms. Fungi and many protists and bacteria are also consumers. But, whereas animals eat other organisms, fungi, protists, and bacteria "consume" organisms through different methods.