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KEY CONCEPT Food chains and food webs model the flow of energy in an ecosystem. Is this a food chain or food web? What can we infer from this diagram?. GRAMA GRASS. DESERT COTTONTAIL. HARRIS ’ S HAWK. A food chain is a model that shows a sequence of feeding relationships.
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KEY CONCEPT Food chains and food webs model the flow of energy in an ecosystem. Is this a food chain or food web? What can we infer from this diagram?
GRAMA GRASS DESERT COTTONTAIL HARRIS’S HAWK A food chain is a model that shows a sequence of feedingrelationships. • A food chain links species by their feeding relationships. • A food chain follows the connection between one producer and a single chain of consumers within an ecosystem. What do you notice about the arrows? Which organism is at the top of this food chain?
carnivore Decomposer Detritivore • Herbivores eat onlyplants. Ex. Rabbit • Carnivores eat only animals. Ex. Lion • Omnivores eat both plants and animals. Ex. Bear • Detritivores eat dead organic matter. Ex. earthworm • Decomposers are detritivores that break down organic matter into simpler compounds. Ex. Bacteria, fungi • Consumersare not all alike.
Specialists are consumers that primarily eat one specific organism or a very small number of organisms. • Changes in food web can cause extinctions • Ex. Florida snail kites feed mainly on apple snails. Water quality in the FL Everglades has declined and with it, Everglade Snail Kite populations have as well. Why? • Generalists are consumers that have a varying diet. • Changes in the environment/food web are easier to handle since they have alternative means for food
Primary consumers are herbivores that eat producers. • Secondary consumers are carnivores that eat herbivores. • Tertiary consumers are carnivores that eat secondary consumers. • Omnivores, such as humans that eat both plants and animals, may be listed at different trophic levels in different food chains. • Trophic levels are the nourishment levels in a food chain.
Food web or food chain? Justify your answer.
A food web shows a complex network of feeding relationships. • An organism may have multiple feeding relationships in an ecosystem. • A food web emphasizes complicated feeding relationships and energy flow in an ecosystem. Which creature consumes the most in this web? The least? Do any have no predator in this web?