1. Ecosystems
and
How They Work
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2. Ecosystems
a system formed by the interaction of a community of organisms with their physical environment

3. Energy to Live BACK NEXT In order to live animals need energy.
Some animals get the energy they need to live from eating plants and other vegetation.
Some animals get their energy from eating other animals.
Some animals eat both plants and other animals.
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4. Producers BACK NEXT Nearly all food webs start with a green plant.
Green plants are called producers because they produce their own food.
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5. Consumers BACK NEXT Animals are consumers.
Some consume plants to get the energy they need to live.
Others consume other animals.
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6. Bacteria and Fungi are examples of decomposers.
Decomposers are organisms that break down dead animals and plant matter. Without decomposers, think of all of the litter that would be left lying all over the Earth’s surface!
Bacteria and Fungi are examples of decomposers.

7. Prey
Animals that are eaten by other animals are called prey.
Some prey animals are herbivores.
Some omnivores and carnivores are also prey to other animals.
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8. Predators
Animals that eat other animals are called predators.
Some animals are predators and prey.
This means they eat some animals but are eaten by others.
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9. Herbivores BACK NEXT Animals that eat plants are called Herbivores.
Herbivores have evolved to eat plants.
They have specialized teeth and stomachs to enable them to get the energy they need from plants.
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10. Carnivore BACK NEXT Animals that eat plants are called Carnivores.
Carnivores have evolved to eat meat.
They have specialized teeth and stomachs to enable them to get the energy they need from the bodies of other animals.
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11. Animals that eat plants and meat are called Omnivores.
Humans are omnivores.
Omnivores have teeth and stomachs that enable them to eat and digest both plants and meat.
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12. Food chains use arrows to show who passes energy to who.
Food Chains show what eats what in order to gain the energy it needs to live.
Food chains use arrows to show who passes energy to who.
Eaten by:
Eaten by:
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13. Looking at this food chain, what do you think would happen if there were:
no plants
no snakes
no owls
If an ecosystem looses an organism, the other organisms will be affected. This is why it is important to have producers, consumers, and decomposers in an ecosystem. Balance in the ecosystem is very important!

14. Food Webs
Food Webs are more complicated that Food Chains. Food Webs are actually just food chains that run together because more than one organism may feed on another organism.

15. Let's Practice! Food Chain Practice
Food Web Practice