The Roles of Organisms in an

Ecosystem

Grade 7 Science: Interactions in the Environment

Ms. Willis

Learning Goal:

Describe the roles and interactions of producers, consumers and decomposers within an ecosystem.

Understand and use appropriate science and technology vocabulary (producer, herbivore, carnivore, omnivore, scavenger, detrivore, decomposer)

Success Criteria: I can explain how producers, consumers, and

decomposers play critical roles in an ecosystem.

The Roles of Organisms

Introduction:

You play an important role in your family and/or community.

Organisms play critical roles in ecosystems. An organism’s role within an ecosystem

depends on how it obtains its food. Organisms are divided into three categories:

1. Producers 2. Consumers 3. Detrivores and Decomposers

The Roles of Organisms

Plants produce their own food through

photosynthesis, so are called producers (def next slide).

Photosynthesis: Plants use energy from the sun, water from the soil and carbon dioxide from the air to make food in the form of sugar (glucose).

Producers

Producers

Definition of a producer:

An organism that makes its own food from non-living (abiotic) materials.

Animals cannot make their own food. They

must obtain their energy from eating other organisms.

Consumer: An organism that eats other living things for energy.

Examples?

Consumers

Herbivores:

An organism that eats only plants Carnivores:

An organism that eats other animals only Omnivores:

An organism that eats both plants and animals Scavengers:

An organism that eats already dead animalsWhat are some more examples of

each?

Types of Consumers

Have you ever wondered where all the dead

organisms go (think of fallen leaves, other dead plants, animal carcasses, etc.). If there was not some way of disposing these, Earth would soon be covered with dead things!

This is where detrivores and decomposers come in! They are very important components of every ecosystem!

Detrivores and Decomposers

Detrivore: An organism that feeds on

large parts of decaying plant and animal matter and on waste material.

Detrivores leave behind their own waste material and small pieces of decaying plants and animals. Now decomposers takeover!

Detrivores and Decomposers

Decomposer: An organism that consumes and

breaks down dead organisms or waste matter into simple substances/nutrients.

Decomposers feed on any remaining decayed matter and waste left behind by consumers and detrivores. Examples: bacteria, fungi (mould)

Detrivores and Decomposers

Let’s watch some detrivores and decomposers at work (get ready for close

ups of creepy crawlies and slime!):

Decomposers

Detrivores and Decomposers

The Roles of Organisms in an

Ecosystem

Review this lesson with a partner: Complete the given six-column chart,

describing how each type of organisms obtains food. Compare ways in which

they are the same and different.