Ecosystems
Georgia Performance Standards
S4L1: Students will describe the roles of organisms
and the flow of energy within an ecosystem.
a. Identify roles of producers, consumers, and
decomposers in a community.
b. Demonstrate the flow of energy through a food
web/food chain beginning with sunlight and including
producers, consumers, and decomposers.
c. Predict how changes in the environment would affect a
community (ecosystem) of organisms.
d. Predict effects on a population if some of the plants or
animals in the community are scarce or of there are
too many.
Essential Questions
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What is necessary for life?
Are all organisms important?
Why is a food web called a food web?
Why do organisms become extinct?
What are the roles of producers, consumers, and
decomposers in the community?
• How does the flow of energy go through the food chain?
Where does the energy come from?
• How will changes in the environment affect a community
of organisms?
• How does population affect the number of plants and
animals in the community?
ECOSYSTEM
• An ECOSYSTEM is made up of all the
living and nonliving things that interact in
an area.
• Nonliving things in a ecosystem can
include water, air, soil, and light. Nonliving
things help the living things meet their
needs.
Using nonliving things to survive.
• Soil is the loose material that covers much
of the Earth’s surface. It is made up of tiny
pieces of rock, minerals, and organic
matter.
• Organic matter is the remains of decaying
plants and animals.
• Most plants grow best in this type of soil.
Using nonliving things to survive
• Sunlight is needed by both plants and animals.
• Plants need sunlight to make food. Some plants
and animals can only survive in warm
temperatures.
• Some plants grow better in the shade. Shade
protects living things from direct sunlight and
high temperatures.
Using nonliving things to survive
• Water is a nonliving thing that all plants
and animals need in order to survive.
• A stream provides needed water for some
of the animals and plants in the forest.
• Other plants and animals get their water
from the rain.
Using nonliving things to survive
• Air is a nonliving thing that all
plants and animals must have in
order to survive in an ecosystem.
Different Ecosystems
• Each ecosystem has its own amounts of light
and water, range of temperatures, and soil
types.
• These conditions helps determine the kinds of
living things that are able to survive there.
• A living thing can only survive in an ecosystem
where its needs are met.
Relationships in an ECOSYSTEM
• Every living thing has a role to play within
its ecosystem. Every organism, plant, and
animal has a particular job in its
environment.
• Plants play the role of a PRODUCER. A
producer is an organism that makes its
own food.
• The food that plants make is used for
energy by the organisms that eat the
plants.
• All organisms need energy.
• Remember that plants use energy from
the sunlight to make food.
• The plants use this food to grow and
produce offspring (other plants).
• Some of the food is stored in the leaves,
stems, and roots of the plant.
• When an animal eats the plant, the energy
from the plant is transferred to the animal.
• All animals are CONSUMERS. A
consumer gets energy by eating plants, or
by eating other animals that eat plants.
• Consumers use this energy to live.
• ALL consumers in an ecosystem depend
on producers for food.
• Without producers, the other organisms in
an ecosystem could not survive.
PHOTOSYNTHESIS
• Remember that plants make their own
food by using energy from sunlight.
• The process by which plants make their
own food is called PHOTOSYNTHESIS.
• This takes place in the plants leaves.
• An animal that hunts other animals for
food is called a PREDATOR.
• A PREY is an animal that is hunted for
food by another animal.
• For example: an owl is one kind of
predator that and snake is one kind of prey
that they owl hunts for food.
• When a frog eats a plant, the frog gets energy
from the plant.
• When the snake eats the frog, the snake gets
energy from the frog and a smaller amount of
energy from the plant.
• When the owl eats the snake, it also receives a
small amount of energy from the plant and it also
receives energy from the snake
FOOD CHAIN
• A food chain shows the path of food
energy in an ecosystem from plants to
animals.
• Food chains are different in different
ecosystems.
FOREST FOOD CHAIN
• The FIRST link in any food chain is always
the PRODUCER.
FOREST FOOD CHAIN
• The SECOND link in a food chain is the
VOLE. A vole is an herbivore or animal
that eats only plants.
• The vole get energy from the plant.
FOREST FOOD CHAIN
• The THIRD AND FOURTH links in a food
chain are either carnivores or omnivores.
• A carnivore eats only other animals and an
omnivore eats both plants and animals.
FOOD WEB
• When TWO OR MORE food chains
overlap, they form a FOOD WEB.
• In a food web, at least one plant or animal
from each food chain is part of another
food chain.
FOOD WEB
Helpful Organisms in an
ecosystem.
• A helpful organism in an ecosystem is
called a DECOMPOSER.
• A decomposer is a living thing that breaks
down the remains of dead organisms.
• All food chains end with DECOMPOSERS
• Decomposers help the environment. They
keep it from becoming crowded with the
remains of dead plants and animals.
MICROORGANISM
• A microorganism is a tiny living thing that can
only be seen with the aid of a microscope.
• Bacteria are one type of microorganism.
• Fungi is another type
of microorganism.
Why are decomposers important to
an ecosystem?
• They release nutrients that plants and animals
need to survive.
• The nutrients are released into the soil and
water. This helps the plants and animals stay
healthy.
• Decomposers also keep the environment clean
and remove dead and decaying plants and
animals so other living things can use the space.
COMPOST
• People can create an ideal environment for decomposers
by making a COMPOST.
• A compost pile or compost bin is a place that is set aside
for the decay of materials that were part of once-living
things.
What type of things can go in a
compost?
• You can put grass clippings, leaves,
kitchen scraps, and many kinds of paper.
• These materials will be recycled by the
fungi and bacteria in the compost.
• The decayed material can then be mixed
with soil that can be used to grow plants
for food.
How do organisms change the
environment?
• Whether it is an ant, a plant, an animal, or
a human, every living thing causes
changes to its environment.
• Sometimes the change to the environment
is harmful to one organism but is helpful to
another.
• Think about a maple tree growing near a
garden. As it grows, the tree provides a
home to animals such as squirrels, birds,
and other animals. Yet, the tree blocks
sunlight and over time, only plants that
require little light will be able to survive
beneath the tree.
How do humans change the
environment?
• Humans change the environment in many
ways.
• People have changed forests into cities,
rivers into lakes, and hillsides into rubble.
• Some of these changes are good and
some are bad.
• For example, a DAM is used to hold back flood
waters. It helps control the flow of the water
which can improve river travel and it can provide
electricity.
• The DAM can also cause harm because the
flood waters used to deposit SILT along the
river’s bank. The silt helped enrich the soil. Now
farmers must use chemical fertilizers to help
their plants grow.
• Humans can be the biggest threats to the
survival of a species.
• A SPECIES is a group of living things that
produces living things of the same kind.
• At one time, passenger pigeons numbered
in the millions. Since humans killed so
many of this species, it became EXTINCT.
• EXTINCT means that the species is no
longer around.
POPULATION
• What would happen to an ecosystem if
there were not enough plants or animals?
• We have learned about the food chain. If
there were not enough plants and animals
in an ecosystem, the animals could not
survive and would have to move or
MIGRATE to another area in order to meet
their needs and be able to survive.
POPULATION
• What would happen if there were TOO many
plants and animals in an ecosystem?
• All plants need sunlight. The more plants and
trees, the less sunlight plants on the forest floor
can get. Without this sunlight, the plants will die.
• If an ecosystem has too many animals and not
enough food sources, the animals will have to
migrate in order to meet their needs and be able
to survive.
Essential Questions
•
•
•
•
•
What is necessary for life?
Are all organisms important?
Why is a food web called a food web?
Why do organisms become extinct?
What are the roles of producers, consumers, and
decomposers in the community?
• How does the flow of energy go through the food chain?
Where does the energy come from?
• How will changes in the environment affect a community
of organisms?
• How does population affect the number of plants and
animals in the community?