5.9B Food Webs Student Expectation
The student is expected to describe how the flow of energy derived from the Sun, used by producers to create
their own food, is transferred through a food chain and food web to consumers and decomposers.
Key Concepts
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All energy transferred through food chains and webs is derived from the Sun.
Producers use the Sun’s energy to create their own food through photosynthesis.
Consumers and decomposers get their energy from producers or other consumers.
The different parts of a food web are producers, consumers, and decomposers.
Fundamental Questions
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From what source do all food chains and food webs get their energy?
What are the different parts of a food web?
How does the energy flow from one organism to the next in a food chain or web?
Pre-Assessment: Assigned February 9th Due February 13th, 2015
Vocabulary: Due February 19th
Food Chain
Food Web
Predator
Prey
Questions: February 18th, 2015
1. What is a producer?
2. Give an examples of producers
3. What is a consumer?
4. Give examples of consumers.
5. What is a decomposer
6. Give examples of decomposers.
7. How do plants produce their own food?
8. What role does a decomposer play in a food web?
9. Compare the producers, consumers and decomposers found in different habitats.
10. How do the nonliving elements of a habitat affect a food chain?
11. Why is the Sun important to a food web?
12. How does the removal of an organism affect a food web?
13. What part of a food web do you feel is most important? (Producers, consumers, or decomposers)
14. If you were to create a new habitat, what producers, consumers and
decomposers would you include?
15. What would happen if you added a new consumer to a food web?
Web Assignments: Due February 19th, 2015
Post Assessment: Given on February 19th, 2015
Teacher Background
Standards (4)
5.9B(i)5.9B(ii)5.9B(iii)5.9B(iv)Explanation:
Understanding the transfer of energy in food chains and food webs provides a foundation for more advanced
topics in biology in high school and college.
Key Concept 1: All energy transferred through food chains and webs is derived from the Sun.
The source of all energy on Earth is the Sun. However sunlight is not usable food for animals. It must first be
changed to a usable form by plants. Animals, not able to produce their own food, are required to eat plants or
other animals to gain energy. An example is grass which absorbs sunlight and is eaten by a grasshopper, which
is eaten by a toad, which gets eaten by a snake, which finally gets eaten by a hawk. In time the hawk dies,
decays, and is broken down by the decomposers which return the nutrients back to the soil which is used again
by nearby plants. A food chain shows the transfer of this energy.
Sometimes more than one animal will eat a mouse, for example, and a complex set of energy transfers occur.
The interconnected food chains are called a food web. Regardless of how simple a food chain may be, or how
complicated a food web becomes, the Sun is still the original source of energy for all living things.
Key Concept 2: Producers use the Sun’s energy to create their own food through
photosynthesis.
Plants use sunlight, water, and carbon dioxide to make glucose, a type of sugar the plant uses for food. When
animals eat plants, the energy stored in the plant is transferred to the animal. Only plants produce their own
food, so they are called producers. From the smallest green algae in a pond to the largest tree on earth, all
plants produce their own food through photosynthesis.
Key Concept 3: Consumers and decomposers get their energy from producers or other
consumers.
Some animal consumers get their energy by eating plant producers. Other animal consumers get their energy by
eating other consumers (animals). Some animals eat both plants and other animals to obtain energy.
(Decomposers such as bacteria and fungi, are organisms that break down dead organisms and their wastes to get
energy.)
Key Concept 4: The different parts of a food web are producers, consumers, and
decomposers.
In order to ensure a successful interactive ecosystem, there must be a proper balance in the populations of
organisms within a food web. Any change in the population of any organism in the food web or food chain will
affect other organisms. If all the grass in an area was killed in a wildfire, there would be less grass for the deer
to eat and they could die off. If there were not enough deer to eat, then the predators (coyotes) would die off. If
any population of organisms changes in some way, either increasing or decreasing, it will affect other organisms
in the food web. Ultimately decomposers, through their chemical breakdown of the remains of dead plants and
animals, return the nutrients in those decaying bodies back to the soil. This decaying material becomes soil
“humus”, a rich organic material that supports plant growth and the food web continues.
Question Prompts
Remember/Recall
What is a consumer?
A consumer is an organism that eats other organisms for survival; an animal.
What is a producer?
A producer is an organism that makes its own food; a plant.
Understand/Skill and Concept
Give examples of producers.
Answers will vary. Plants are producers.
Give examples of consumers.
Answers will vary. Animals are consumers.
Give examples of decomposers.
Answers will vary. Bacteria, fungi, and earthworms are decomposers.
Apply/Skill and Concept
How do plants produce their own food?
Plants produce their own food through the process of photosynthesis.
What role does a decomposer play in a food web?
A decomposer breaks down dead organisms returning the nutrients to the soil.
Analyze/Strategic Thinking
Compare the producers, consumers and decomposers found in different habitats.
Answers will vary. All habitats have producers, consumers, and decomposers.
How do the nonliving elements of a habitat affect a food chain?
Answers will vary. Possible answers include the lack of water can lead to a decrease in plant growth causing a
shortage of food for herbivores. This then affects the secondary consumers.
Why is the Sun important to a food web?
The Sun is the source of all energy transferred in a food web.
Evaluate/Extended Thinking
How does the removal of an organism affect a food web?
The removal of one organism can shift the balance of a food web. It causes organisms to depend on other food
sources and creates additional competition.
What part of a food web do you feel is most important? (Producers, consumers, or decomposers)
Answers will vary.
Create/Extended Thinking
If you were to create a new habitat, what producers, consumers and
decomposers would you include?
Answers will vary.
What would happen if you added a new consumer to a food web?
There would probably be increased competition for producers and/or herbivores.