16.2 Living Things Need Energy

List some foods you had for dinner last night. What is the organism that was the source for the food.

Producers Organisms that change the energy in sunlight into chemical energy or food (photosynthesis). Green plants, algae, bacteria

Consumers Organisms that eat other organisms to obtain energy and nutrients.

Why is sunlight important to producers? Sunlight is important to producers because most producers use sunlight to make chemical energy or food.

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Herbivore A consumer that eats only plants. Grasshopper, bison

Carnivore A consumer that eats other animals. Badger, owl

Omnivores Consumers that eat both plants and animals. Grasshopper mouse

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Scavengers Omnivores that eat animals and plants that have died. vulture

Decomposers Organisms that get energy and nutrients by breaking down dead organisms. Fungi

Food Chains A diagram that shows how energy and nutrients are transferred from one organism to another.

Food Chains Producers (plants) form the base.

Food Chain Primary consumers - Herbivores (prairie dogs) first consumers on the food chain

Food Chain Secondary consumers – (coyotes) eat primary consumers

Food Chain Tertiary consumer – Organisms that eat secondary consumers (turkey vulture) Energy Producer Primary Consumer Secondary Consumer Tertiary Consumer

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Food Webs A diagram that shows the feeding relationships between organisms in an ecosystem.

Food Chains and Webs

Energy Pyramids A diagram that shows an ecosystem’s loss of energy. 10% of the energy in each level of the energy pyramid is transferred to the next level. Less energy at the higher levels of the pyramid.

Energy Pyramid

Why are only a few animals at the top of an energy pyramid? There are only a few animals at the top of the energy pyramid because most of the energy is used up in the lower levels of the energy pyramid.

Wolves and the Energy Pyramid Gray wolves are consumers, predators. They were almost wiped out as the wilderness settled. Without the wolves there are more of a population of elks.

Wolves Then there is overgrazing which will leave little grass. This leads to a decline in elks which leads to a decline in predators due to lack of food.

Balance in Ecosystems Gray wolves were brought to Yellowstone Park in After breeding they were put back into the wild. There was a decline in elks which allowed for more grass to grow. All organisms are important for the health and balance of the food web.

Review Questions 1.Explain the importance of decomposers. Decomposers obtain energy as they break down dead organisms and produce materials that can be used by other organisms. Decomposers are nature’s recyclers.

3.Explain how food chains and food webs are related. Food chains shows how energy is transferred from one organism to another. Food webs show many possible ways in which energy might be transferred between organisms.

2.Explain how producers, consumers, and decomposers are linked in a food chain. Consumers feed on producers and other consumers. Decomposers feed on producers and other consumers after they are dead.