Energy Flow in Food Chains, Food Webs, & Energy Pyramids
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.
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?
Awesome Web Site! http: //science-class. net/Ecology/energy_transfer. htm • Let’s take a look at the above web site relating to ecology and energy transfer.
Another Cool Site http: //www. harcourtschool. com/activity/food_menu. html After we look at the above web site, we’ll go on to view the Brain. Pop video entitled FOOD CHAINS. The Brain. Pop videos provide further enrichment of topics discussed in class and are interesting as well as easy to understand! www. brainpop. com
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.