Chapter 21 Resource: Ecology

Teacher Support & PlanningContent Outline for Teaching (continued)2. Predation is the act of one organism feeding on another.a. A bird of prey, such as a falcon, is an example of a predator.b. A facon’s prey is the organism it eats.3. When the African tickbird eats insects off a zebra’s skin, both organisms in the relationshipbenefit.4. A bird that builds its nest in a tree benefits but the tree is neither harmed nor helped.5. Insects biting a zebra’s skin harm the zebra but benefit themselves.D. Each type of organism has a different role to play in an ecosystem.1. The role of an organism in an ecosystem is called its niche.2. The place where an organism lives out its life is called its habitat.DISCUSSION QUESTION:What factors might prevent a population of dandelions from overtaking a lawn? Answers will vary.Student responses should include competition for soil nutrients, availability of water, competition fromother plant populations for space.Section 3Energy Through the EcosystemA. Energy moves through an ecosystem in the form of food.1. An organism that makes its own food, such as a plant, is called a producer.2. Consumers, like grasshoppers, eat other organisms.3. Decomposers, such as bacteria and fungi, use dead organisms and the waste material ofother organisms for food.B. A food chain models how energy from food passes from one organism to another.1. In an ecosystem, food chains often overlap.2. A food web is a series of overlapping food chains that shows all the possible feedingrelationships in an ecosystem.C. In an ecosystem, matter cycles through food chains.1. The amount of matter on Earth never changes.2. Matter in ecosystems is recycled.DISCUSSION QUESTION:Name the producers, consumers, and decomposers in the following list of organisms: a hawk, agrasshopper, a field mouse, grass, and a fungus. What are the feeding relationships among these organisms?The grass is a producer; the hawk, field mouse, and grasshopper are consumers; the fungus is a decomposer.The grasshopper eats the grass, the field mouse eats the grasshopper, the hawk eats the field mouse.Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.T4Ecology