Producers, Consumers
and
Decomposers 
Introduction:
Every
organism has one or two functional roles in the ecosystem depending on whether
they are autotrophs or heterotrophs.
Plants and other photosynthetic organisms are known as Producers.
This is because they use the sun.s energy to produce their own food.
The extensive collection of plant pictures on the Internet and in books
affords us the opportunity to observe many representatives of the stages of
plant evolution.
Consumers fall into categories based on their feeding strategies.
The main groups consist of herbivores, carnivores and omnivores. Herbivores
consume the primary producers, which are mainly plants, and chlorophyll
containing bacteria. These are the
.vegetarians. of the world. Carnivores
eat flesh or meat, which usually means the other consumer species.
Omnivores are not specialized
and eat both plants and animals.
When organisms die what happens to
their bodies? Decomposers take care
of them. Decomposers
are organisms that feed off of dead and decaying matter called detritus.
For this reason they are also know as Detrivores. Like the worms, decomposers help to make healthy soil and put
nutrients and chemicals into the soils. They
play an important role in cycling nutrients such as Carbon, Nitrogen, and
Phosphorus back into the environment for producers to use all over again.
National Standards Addressed:
The
life science standards covering Diversity
and Adaptations of Organisms and Regulation and Behavior are both covered by
talking about how many plants have adapted and evolved to meet the demands of
their environment. Also many
animals have behaviors that are suited to the world they live in.
With these real life examples students will be able to more closely
identify this standard with the world around them.
The
Unifying Concepts and Processes standard of Evolution and Equilibrium
is applied when you discuss the evolution of the many plant and animals over
thousands of years. You can also
discuss how the things in nature all exist in equilibrium because things in
nature tend to balance each other out.
The
Physical Science standard Transfer of Energy can be integrated when
talking about energy flow through the system of food webs.
Much of a plants available energy is lost when it is eaten that is why an
herbivore must eat large volumes of plants.
Also, when larger carnivores eat smaller animals much of the energy is
lost so they must also eat many smaller animals.
Only about 10% of the total energy is passed from one organism to the
next.
The
Teaching standards, Modifying the
classroom and Inquiry involve the students making posters and becoming more
involved in their learning. This is
also an activity that can be taken outdoors or into other settings to give the
students a change of scenery.
Objectives and Benchmarks:
This
activity will allow students to observe the various types of organisms in our
world. They will observe the levels
of plant evolution from cyanobacteria, algae, moss, ferns, conifers and
flowering plants. Students will
also observe the three levels of consumers.
Herbivores, Carnivores and Omnivores will be discussed as part of the
lesson. Decomposers are a valuable
part of our world and students will explore them and learn about their role in
nature.
Materials:
Paper
& Pencils
Magazines Glue
Markers
Crayons Colored
Pencils
Scissors
Text books Large Posterboard
Optional
Materials- Lab Specimens, Internet Access
Procedure:
Discuss
with students the various stages of plant evolution and show some examples of
them. Then teach them three levels
of consumers and their importance in nature.
Finally relate the decomposers to things that they can see in their
lives. Talk about bread mold and
mushrooms.
Have
the students go through old magazines and cut out examples of the various
organisms that they have seen. They
can make collages of the different levels of life by pasting in pictures or
drawing them.
Things to Consider:
Think
about the process of plant evolution and the steps they went through.
Which of these categories shows the
greatest diversity of life?
What is the importance of consumers
and their role in our world?
Where
does each of the decomposers live? What
type of food do they consume? What
would the world be like with no decomposers?
Possible
Integration:
This
activity could also be used as an art lesson by drawing the various producers,
consumers and decomposers for the posters.
For
an ecology lesson you could discuss habitats of the different organisms.
Critical Concepts:
