1. Interactions in Ecosystems
Food Chains, Food Webs

2. What is an Ecosystem?
A system formed by the interaction of a community of organisms with their physical environment

3. How are Ecosystems divided up?
Ecosystems can be divided a few ways:
1) Producers and Consumers
A producer is an organism that use photosynthesis to capture energy by using sunlight, water and carbon dioxide to create carbohydrates, and then use that energy to create more complex molecules like proteins, lipids and starches that are crucial to life processes.

5. How are Ecosystems divided up?
Producers make their own food and other organisms can then eat producers.
What are 3 examples of producers you can think of?
1) __________________
2) __________________
3) __________________

6. How are Ecosystems divided up?
Consumers are organisms that get their energy from producers, by eating them.
They are not able to make their own food and therefore, must get it from elsewhere.
Consumers can also eat each other, but it always comes back to a consumer eating a producer.
What are 3 examples of consumers you can think of?
1) __________________
2) __________________
3) __________________

7. Another Name for Producers and Consumers
A producer can be called an AUTOTROPH.
Auto means ‘own’ and troph means ‘eating’.
Therefore, producers survive by ‘eating’ their ‘own’ food.
A consumer can be called a HETEROTROPH.
Hetero means ‘different’ and troph means ‘eating’.
Therefore, consumers survive by ‘eating’ ‘different’ foods made by other organisms.

8. How are Ecosystems divided up?
2) Trophic Levels
In ecosystems, organisms occupy different levels based on who eats who. These levels are known as Trophic Levels.
Plants are Producers and they occupy trophic level 1
State an example here: _______________
Animals that eat plants occupy level 2
 State an example here: ______________
Animals that eat other animals tend to occupy at least level 3 (animals tend not to occupy trophic levels higher than 5)

10. Types of Producers and Consumers
Producers: There is only 1 level of producer as only plants and some bacteria can make thier own food.
Primary (1) Consumer: Eats the producers directly
Secondary (2) Consumer: Eats the primary consumers directly
Tertiary (3) Consumer: Eats the secondary consumer
Quaternary (4) Consumer: Eats the tertiary consumer directly.

11. Types of Producers and Consumers
Some organisms can occupy more than one tertiary level depending on what they can eat.
For example: A bear will eat just about anything, however, they will eat a salmon from the river (secondary consumer) as well as blueberries (producer).
The more types of foods the animal eats, the higher the type of consumer.

12. Food Chain
This is a linear ranking system of organisms showing what niches (roles) animals in an ecosystem occupy.
A food chain is easily identified as it is one line from organism to organism.

13. Draw a food chain incorporating the following
Draw a food chain incorporating the following. Indicate what trophic level each organism would be at.
eg. wild rice(plant) , minnow (little fish), pike (big fish), eagle

14. Food Web
A food chain is too simplistic to show the true interactions that occur in an ecosystem. It is merely one branch of the larger food web that can exist in nature.
You can easily identify a food web by the many lines connecting the organisms.

15. Draw a food web incorporating the following (some organisms occupy more than one level)
Before you start, make a list of who eats who
Find your level 1 producers, primary/ secondary/ tertiary / quaternary consumers and label them
Also label the trophic levels
water lilly, pond weed, snapping turtle, minnow, northern pike, loon, wild rice, frog. moose, mosquito, dragonfly, blackbird, human, eagle

16. Organisms are also defined by what they eat:
Herbivores: Plants
Omnivores: Plants/Animals
Carnivores: Other Animals
Decomposers: an organism that gets energy by breaking down the remains of dead organisms
Example: bacteria or fungi
Label the organisms in your web with these.