This is a short nonfiction piece for my elementary science students.
|What is a food chain? It’s not something you wear around your neck. A food chain is a system of who eats whom in the animal world. It’s important to learn about because it shows that all the parts of a system depend on each other. If one is missing, it affects the others.
The start of the food chain is the sun. Plants use the sun’s energy to make food, saving up that energy inside. When an animal eats the plant, it gets that energy that was saved in the plant. Then a bigger animal eats that animal that ate the plant, and gets energy. And so on.
A really easy food chain to think about is this: Grass grows using energy from the sun. A cow eats the grass. People make the cow into a hamburger and get their energy from it! We are the top of that food chain.
Of course, we don’t just eat the meat in the burger. It probably has pickles and tomatoes and lettuce on it, too, along with some bread. People eat both plants and animals. And most food chains are really more like a food mountain. Lots of different animals eat the same kinds of plants, and lots of bigger animals eat them. Some people use the term food web instead of food chain, and that really describes it better.
Think about the food webs in the ocean. They depend on plants too. The plants that there are the most of in the ocean are tiny and float along in the water. They are plankton, which means, “drifter.” Plant plankton is called “phytoplankton,” because phyto means plant.
Most of the animals that eat phytoplankton are tiny floaters, too. They are animal plankton, called, “zooplankton.” This word is pronounced ZOEplankton, to rhyme with TOE. I know it doesn’t look that way, but that’s how scientists say it!
Lots of animals eat zooplankton. You know one already. That’s right, the great whales eat plankton. The largest animals in the world eat some of the smallest! Gray whales, blue whales and humpback whales are some of the plankton eaters. Hardly anything eats them (although sometimes killer whales will hunt gray whales, in a pack like wolves). That means that their food chain is very short: phytoplankton, zooplankton, whale. But most food systems are more complicated.
Lots of fish eat zooplankton, and other fish eat them. A still bigger fish eats those, and then a seal may eat the bigger fish (perhaps a salmon). Killer whales and sharks eat seals. Those two are at the top of their chain.
Right now in Seattle’s Woodland Park, there is a food chain problem. A terrible animal is multiplying too fast, because people have destroyed its natural predator. It digs holes for park visitors to fall into, and it chews up the plants all over the park. What is this horrible monster? It’s . . . the rabbit!
That’s right, the rabbit. A rabbit eats plants, grass and leaves. Lots of things eat rabbits, but people don’t usually like those things living in their backyards, or their city parks. Coyotes and wolves and mountain lions eat rabbits, and they just aren’t welcome in the city. People get rid of the rabbits’ predators, and so fewer rabbits die. And they have lots of babies, fast! Soon an area with too many rabbits looks like Camp Green Lake; holes all over the place. Seattle Parks now has to figure out what to do with all those rabbits.
Food chains are important. Next time you eat lunch, think about how your meal got to you. You are the end of a chain that started with the sun!
See this link for the article on the rabbits at Woodland Park, Seattle.