Food Chains & Food Webs

Science 10Ms. Lowrie

Food Chains

Show the flow of energy through an ecosystem

Linear pictures of how energy moves (is transferred) from one organism to the next

Food Chains

Notes:All food chains start with a producer (a plant)

Arrows point in the direction of energy flow Not who eats who

Ex: algae fish bear

Examples of food chains:1. Lichen Snail Toad Bird

2. Wild Berries Field Mouse Fox

3. Phytoplankton Zooplankton Salmon Eagle

Activity – You & Food Chains

Think about what you last ate. Whatever it was, its main ingredients

were once part of living organisms Plant matter in was made by plants, using

sunlight, carbon dioxide, water, nutrients in soil Animal matter was made from items the animal

ate (plants, animals, or both) By eating, you become another link in this chain

of life!

You In a Food Web

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Activity – You & Food Chains

1. List all food eaten in your last 2 meals For processed foods, list all ingredients that

come from living things

2. Organize the items from #1 into a t-chartPlant Matter Animal Matter

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-(includes eggs, milk, butter & cheese)

Activity – You & Food Chains

3. Identify all items under the ‘Animal Matter’ column as either a(n):

Herbivore Omnivore Carnivore

Activity – You & Food Chains

4. Create three food chains to which you are linked.

Use ideas from the data in your chart. Food Chain 1:

Food Chain 2:

Food Chain 3:

Activity – You & Food Chains

Answer the following questions: Brainstorm answers with your table

1. What kinds of organisms are at the start of every food chain?

2. Do any of your food chains have more than three links? Suggest a reason why or why not.

3. For what species might you become a source of food? When or why might this happen?

You In a Food Web

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Food Web

Show interactions among food chains

Most animals:eat more than one

type of foodare eaten by more

than one predatorare part of more than one food chain

Activity – Creating Food Chains

Task: Create 3

different food chains from the food web

Trophic Levels

Positions in a food chain Depends on number of organisms

1st trophic level = producer 2nd trophic level = primary (1º) consumer 3rd trophic level = secondary (2º) consumer

Etc …

Last tropic level = largest omnivore / top carnivore

Trophic Levels:

Example

Trophic Levels:

Examples

Example (please copy)

Energy Flow Less energy

available to pass to next trophic levelMore ‘links’

= less energyUsually 10%

available

The 10% Rule

About 10% of energy:Stored in tissuesAvailable to be transferred when eaten

Other 90% is used for growth, reproduction or released to environment

Energy Loss (please copy)

Any questions?