Construct and interpret a food web showing multiple feeding connections among organisms, and explain why webs are more realistic than single chains.
A food chain shows one path of who-eats-whom: grass to rabbit to fox. Real ecosystems are messier and more connected than a single chain, since a rabbit might be eaten by a fox, a hawk, or a coyote, and a fox might eat rabbits, mice, or birds. A food web links together many food chains to show all these overlapping feeding relationships at once.
Food webs matter because they show how connected an ecosystem really is. If one population changes, say rabbits become scarce, a food web helps you predict which other organisms might be affected, since foxes, hawks, and coyotes might all need to rely more on other prey.
Mastery looks like: They can build a simple food web with multiple connections and predict how a change to one organism could ripple through it.
Common stumbles: Drawing a web as several disconnected chains instead of linking shared organisms; reversing the direction of the arrows.