Illustrate energy flow in food chains food webs

Illustrate energy flow in food chains, food webs, and energy pyramids.

Essential Question What does a food chain show us?

Essential Question How is a food web different from a food chain?

Essential Question How does energy flow through an ecosystem?

Essential Question How does the amount of energy change as it moves through an energy pyramid?

Food Chains • Food chains use pictures or words and arrows to show the movement of energy through the trophic levels of organisms. • The trophic level of an organism indicates the position that the organism occupies in the food chain. • It shows what it eats and what eats it.

Producers & Consumers The levels are numbered according to how far the particular organism is along the chain. • Producers are at level 1. (Plants are producers because they produce their own food. ) • Herbivores are at level 2. (consumer) • Predators are at level 3. (consumer) And so on…

Anything that cannot make its own food must eat to survive. It must “consume” its food! It is a consumer.

The owl eats the snake that ate the frog that ate the caterpillar that ate the flower.

Note: There’s something wrong. What is it?

Why does this look more like a “cycle” than a chain? Let’s discuss this one in detail.

Why is the SUN in this picture?

q In this food chain, what is the producer? q What is the first level consumer? q What is the second level consumer? q Is the polar bear the 3 rd level consumer? Explain.

Trophic Levels

Food Webs • Food webs describe the organisms found in interconnecting food chains using pictures or words and arrows. • In other words, food webs are a bunch of food chains all together! • They describe the complex patterns of energy flow in an ecosystem by modeling who consumes whom or what.

Let’s follow a few food chains found in this food web.

There a lot of arrows here, but they’re easy to follow. Try it.

Food Webs are EASY!

Energy Pyramids • An energy pyramid shows the amount of energy that moves from one trophic level to another in a food chain. • The most energy is available at the producer level of the pyramid. • The availability of energy decreases as it moves up the energy pyramid.

The most energy is at the producer level – the base of the pyramid.

The Energy Pyramid

Who needs the most energy to survive?

Making a Model v Let’s make a model of an energy pyramid. v The model you will construct will be simple. It will show pictures of the producers and consumers at each level, the names in words, and the trophic levels. v The good news is that this model really is perfect for meeting our objectives relating to energy pyramids. v Make sure you follow all instructions for proper completion of the model.

Acknowledgements • All pictures were obtained from various sources on Google Images. • None of the pictures/illustrations are mine. • Credit is given to all artists/photographers for their work.