Energy Flow Within an Ecosystem Ecology Energy Flow Within an Ecosystem

Objectives Trace the flow of energy through living systems. Evaluate the efficiency of energy transfer among organisms in an ecosystem.

The following standard will be addressed: Standards Addressed The following standard will be addressed: B-3.6

KEY CONCEPT Food chains and food webs model the flow of energy in an ecosystem.

A food chain links species by their feeding relationships. A food chain is a model that shows a sequence of feeding relationships. 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. DESERT COTTONTAIL GRAMA GRASS HARRIS’S HAWK

Feeding Relationships Food Chain: a series of steps in which organisms transfer energy by eating and being eaten. Autotroph  Heterotroph  Decomposer Draw using arrows: Algae  Fish  Heron

Consumers are not all alike. Herbivores eat only plants. Carnivores eat only animals. Omnivores eat both plants and animals. Detritivores eat dead organic matter. Decomposers are detritivores that break down organic matter into simpler compounds. Scavengers feed on large, dead animals carnivore decomposer

Specialists are consumers that primarily eat one specific organism or a very small number of organisms. Generalists are consumers that have a varying diet.

Trophic levels are the nourishment levels in a food chain. 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.

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. A food chain doesn’t show all the complex feeding relationships within an ecosystem.

Feeding Relationships A trophic level is a link or step in a food chain. Each organism in the food chain represents a trophic level. Many different species can occupy one level (for example there are more than one type of autotrophs) Many different kinds of organisms eat a variety of food, so they can feed at different levels.