Chapter 9.3: Matter and Energy in Ecosystems

Section 3 Matter and Energy in Ecosystems

Energy Flow Through Ecosystems
Food contains nutrients and energy needed for survival.
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When one organism is food for another
organism, some of the energy in the first organism (the food) is transferred to the second organism (the eater).

Energy Flow Through Ecosystems
Producers are organisms that take in and use energy from the Sun or some other source to produce food.
Consumers are organisms that take in energy when they feed on producers or other consumers.
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When organisms die, other organisms called decomposers take in energy as they break down the remains of organisms.

Food Chains
A food chain is a model, a simple way of showing how energy, in the form of food, passes from one organism to another.
When drawing a food chain, arrows between organisms indicate the direction of energy transfer.
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Food Chains
Food chains usually have only three or four links. This is because the available energy decreases from one link to the next link.
In a food chain, the amount of energy left for the last link is only a small portion of the energy in the first link.
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Food Webs
A food web is a series of overlapping food chains that exist in an ecosystem.
A food web provides a more complete model of the way energy moves through an ecosystem.
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Food Webs Matter and Energy 3

Topic: Energy Transfer
Food chains are models that represent energy moving through an environment.
As food moves through a food chain very little energy is passed from one level to the next.
Food webs are models of several overlapping food chains.

Ecological Pyramids
Most of the energy in the biosphere comes from the Sun.
Producers take in and transform only a small part of the energy that reaches Earth’s surface.
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Ecological Pyramids
An ecological pyramid models the number of organisms at each level of a food chain.
The bottom of an ecological pyramid represents the producers of an ecosystem.
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The rest of the levels represent successive consumers.

Energy Pyramid
An energy pyramid compares the energy available at each level of the food chain in an ecosystem.
A pyramid of energy usually has three or four levels.
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Only about ten percent of the energy at each level of the pyramid is available to the next level.

Topic: Energy Pyramids
Most of the energy in an environment comes from the sun.
An ecological pyramid models the number of organisms at each level of a food chain
Only about ten percent of the energy at each level of the pyramid is available to the next level

The Cycles of Matter
The law of conservation of mass states that matter on Earth is never lost or gained. It is used over and over again.
The carbon atoms in your body might have been on Earth since the planet formed billions of years ago. They have been recycled billions of times.
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Other Cycles in Nature Matter and Energy 3
The movement of carbon through Earth’s
biosphere is called the carbon cycle.

Other Cycles in Nature
The nitrogen cycle begins with the transfer of nitrogen from the atmosphere to producers then to consumers.
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The nitrogen then moves back to the atmosphere or directly into producers again.
Phosphorus, sulfur, and other elements needed by living organisms also are used and returned to the environment.

Topic: Matter and Cycles
Matter cannot be created or destroyed.
The three main cycles that affect living things are the water cycle, the carbon cycle, and the nitrogen cycle.
Carbon is cycled through photosynthesis and respiration. (pg. 216, 275)
Nitrogen is mainly cycled from producers to consumers and back to the atmosphere. (pg. 216)

What Have You Learned?
Why will most habitats never reach biotic potential?
What is the difference in food chains and food webs?
What does an energy pyramid show?
What cycles mainly effect living things?

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Chapter 9.3: Matter and Energy in Ecosystems

by Dwayne Squires on Feb 09, 2009

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Chapter 9.3: Matter and Energy in Ecosystems Presentation Transcript