Chapter 1 Section 3

Energy is vital to all living things Most energy comes directly or indirectly from the sun Because energy is continuously used by living things, it must be continuously replaced in the ecosystem Energy flows through an ecosystem, getting used up as it flows This is different than the water cycle, where water is recycled and not used up

Producer – an organism that captures energy and stores it in food Most energy enters an ecosystem through photosynthesis Plants and other photosynthetic organisms take water and carbon dioxide from their environment and use energy from the Sun to produce sugar.

Consumer – organisms that get their energy by eating other organisms Consumers cannot produce their own food, they consume food Consumers are classified by their position in the feeding relationship Primary Consumer – eat plants Secondary Consumer – eat plant eaters Tertiary Consumer – eat larger plant eaters

Decomposer – organisms that break down dead plant and animal matter Decomposers are the clean up crew of an ecosystem

Under each word write the following: 1.The definition 2.3 examples 3.Explain where they get their energy from Producer, Consumer, Decomposer

Scientists use two different models to show the feeding relationships that transfer energy from organism to organism in an ecosystem The models are food chains and food webs

Food Chain – describes the feeding relationship between a producer and a single chain of consumers in an ecosystem This is model for simple feeding relationships

Food Web – is a model of the feeding relationships between many different consumers and producers in an ecosystem A food web shows many overlapping and interconnected food chains It is a better model for the complex feeding relationships in an ecosystem

Energy Pyramid – a model that shows the amount of energy available at each feeding level of an ecosystem The available energy decreases as it moves through an ecosystem

Usable energy decreases as it moves from producers to consumers making the bottom level the largest The available energy gets smaller and smaller the farther up the pyramid you go

Answer the 1.3 review questions on page 28 Use complete sentences Questions 1-3