2 Principles of Ecology
2 Flow of Energy in an Ecosystem
12(A), 12(C)
MAINIDEA
Write the Main Idea for this lesson.
NEW VOCABULARY
autotroph
biomass
Use your book to fill in vocabulary terms in this paragraph about food
chains.
In a
carnivore
, matter and energy move from
to
to
. A food chain is made of many
decomposer
detritivore
steps; each organism in the food chain represents a step called a
. An
food chain
food web
whereas a
is a heterotroph that eats only plants,
preys on other heterotrophs. An
herbivore
eats both plants and animals. Nutrients are returned to
heterotroph
the soil, air, and water by
trophic level
possible feeding relationships at each trophic level is called a
. A model that shows all the
.
If you were a scientist and you wanted to determine the weight of living
matter at a certain trophic level, you would measure the
ACADEMIC VOCABULARY
Use foundation in a sentence which shows its scientific meaning.
foundation
foundation
Science Notebook • Principles of Ecology
18
.
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omnivore
2 Flow of Energy in an Ecosystem (continued)
Student Edition, pp. 41–44
Reading Essentials,
pp. 16–18
Summarize three ways that organisms get energy, by completing
the table.
Type of
Energy in an Ecosystem
Organism
Other
name(s) for
this type
Autotrophs
Food
comes from
Copyright © McGraw-Hill Education. Permission is granted to reproduce for classroom use.
Chemical
reactions
that occur
consumers, herbivores,
carnivores, scavengers,
omnivores
no other name
1.
2.
3.
The organisms that are
eaten release energy
and molecules for the
consumer’s body.
The organisms
that are
decomposed
release energy
and molecules
for the
decomposer’s
body.
Examples
GET IT? Compare and contrast the four different types of
heterotrophs.
Classify each of the following organisms as an autotroph or a
heterotroph. Put an A in front of those that are autotrophs and an H in
front of those that are heterotrophs.
1. Alligator
5. Moss
2. Squirrel
6. Siberian tiger
10. Rabbit
3. Maple tree
7. Daffodil
11. Tomato
4. Whale
8. Rhinoceros
12. Cockroach
Science Notebook • Principles of Ecology
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9. Dandelion
2 Flow of Energy in an Ecosystem (continued)
Models of Energy Flow
Contrast a food chain with a food web.
State three things that an ecological pyramid shows that food webs and
food chains do not show.
Create a food web and name the organisms you include. Indicate each
organism’s trophic level.
Analyze the place in the food chain in which you participate. Use the vocabulary terms from this
section that apply to you.
Science Notebook • Principles of Ecology
20
Copyright © McGraw-Hill Education. Permission is granted to reproduce for classroom use.
SUMMARIZE
2 Flow of Energy in an Ecosystem (continued)
REVIEW IT !
1. MAINIDEA Compare and contrast autotrophs and heterotrophs.
2. Illustrate the flow of energy through a simple food chain that ends with a lion as the
final consumer.
3. Classify a pet dog as an autotroph or heterotroph and as an herbivore, carnivore, or
omnivore. Explain.
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4. Evaluate the impact on living organisms if the Sun began to produce less energy and
then finally burned out.
5. Create a simple food web of organisms in your community.
6. Draw an energy pyramid for a food chain made up of grass, a caterpillar, tiger beetle,
lizard, snake, and a roadrunner. Assume that 100 percent of the energy is available for
the grass. At each stage, show how much energy is lost and how much is available to the
next trophic level.
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