Download Understanding Food Chains and Food Webs in Ecosystems and more Lecture notes Ecosystem Modelling in PDF only on Docsity! 73 74 The Difference Between Food Chains and Food Webs A food chain shows one energy path in an ecosystem. A simple food chain always contains a producer, a primary consumer and a secondary consumer and a decomposer. But most organisms are part of more than one food chain. Scientists often use a food web to show a more complete picture of the flow of energy in an ecosystem. A food web is a system of several overlapping food chains. Directions: In the food chain below draw in the arrows and add a decomposer. Consumers are classified by what they eat. Consumers that eat only plants are called herbivores. Deer, chipmunks and most insects are herbivores. Consumers that eat only animals are called carnivores. Badgers, cougars and wolves are carnivores. A consumer that eats both plant and animals is called an omnivore. Birds, goats and monkeys are omnivores. An omnivore can play more than one role in an ecosystem. For example, a large fish in in a pond will eat both little fish and algae (microscopic plants). When it eats the algae it is a primary consumer. When it eats little fish it is a secondary consumer. Directions: 1. In the food web below use a different colored pencil to draw in each simple food chain. 75 Materials: Edge of Pond Ecosystem paper, colored pencils What To Do 1. Use different colored pencils to draw the arrows for at least 3 different food chains. 2. Remember the arrows point in the direction the energy flows. 3. Draw in the ecosystems energy source. 4. Color the picture. Hints: Small green algae are plants Bacteria are found in dirt and soil. They can be drawn into the picture. Grasshoppers eat grass Each food chain ends with a decomposer Questions: 1. What does the snake eat? ___________ 2. What does the owl eat? _____________ 3. What would happen to the rabbit population if all the snakes in this ecosystem were killed? _______________________________________ 4. What would happen to the owl population if there were more rabbits? ______________________ 5. What would happen to the grass around the pond if there were more rabbits? _________________ 6. If there were a great many rabbits and they ate all the grass around the pond what would happen to the grasshopper population? ___________________ 7. What is the difference between a food chain and a food web? ________________________________ If time allows watch the Food Web video on www.missdoctorbailer.com Ed ge o f A P on d Ec os ys te m 76
