1. The Roles of Organisms in an Ecosystem
Grade 7 Science: Interactions in the Environment

2. The Roles of Organisms Learning Goal: Success Criteria:
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.

3. 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

4. Producers
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).

5. Producers
Definition of a producer:
An organism that makes its own food from non-living (abiotic) materials.

6. Consumers
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?

7. Types of Consumers Herbivores: Carnivores: Omnivores: Scavengers:
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 animals
What are some more examples of each?

8. Detrivores and Decomposers
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!

9. 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!

10. 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)

11. Detrivores and Decomposers
Let’s watch some detrivores and decomposers at work (get ready for close ups of creepy crawlies and slime!):
Decomposers

12. 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.