Week 2 Ecosystems and Energy Part 2

Week 2 Ecosystems and Energy Part 2

by Kate Polivka

Food Chains- The Path of Energy Flow (Who Eats Whom)​

​Energy from food passes from one organism to another based on their Trophic Level

Trophic Level: An organism’s position in a food chain, which is determined by its feeding relationships

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•First Trophic Level: Producers

•Second Trophic Level: Primary Consumers

•Third Trophic Level: Secondary Consumers

•Decomposers present at all levels

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​Let's look at each one individually

​Producers

​ Autotrophs= Producers

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Auto means “self” and tropho means “nourishment”

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So autotrophs produce their own food from inorganic material

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oEx: plants via photosynthesis and hydrothermal vent bacteria via chemosynthesis

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​Consumers

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•Heterotrophs = Consumers

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​Consumers have to eat other things to survive. They cannot make their own food

oPrimary consumers eat plants

oSecondary consumers eat primary consumers

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Draw

Circle the autotroph

Multiple Choice

Bears are _______

• Autotrophs

• Heterotrophs

• Furotrophs

• Producers

​Detrivores

​•Consumers of detritus

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​Detrivores eat decaying material.

This could be dead leaves or animals.

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Some detrivores include: Worms, crabs, and many other bugs.

​Decomposers

•Break down dead organic material

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•Release inorganic molecules (CO2 and nutrients) that producers can use

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•Ex: fungus, bacteria

Multiple Choice

A crab eats decayed materials including detritus. A crab is a(n) ______.

• Producer

• Consumer

• Detrivore

• Decomposer

​Food Chain vs. Food Web

The food chain model shows how energy from food passes from one organism to another based on their Trophic Level

oTrophic level: An organism’s position in a food chain, which is determined by its feeding relationships. Ex. Producers, Consumers, Detrivores, and Decomposers.

​ ***The food chain explains WHO EATS WHO***

​Food Web

•Food web visualizes feeding relationships within a community

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​Food web is more complex than food chain model

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Open Ended

Do you think a food web model or a food chain model better represents what happens in nature? Why?