In this age of green, the term “ecosystem” gets tossed around quite a bit–from technology to tide pools. But it’s an important concept to grasp, as in really understand, when talking about creating a sustainable food system.

Traditionally, we’ve talked of the food chain. But an ecosystem is more like thousands of threads braided together than it is a neat series of links (plankton, small fish, big fish). Whether you’re talking about agriculture or aquaculture, wide open ocean or wild prairie plains, each has a unique set of environmental and biological factors that make it home to a specific mix of plants and animals that, when in balance, all thrive together.

Why is this important? Because trying to alter an end result—be it saving a vanishing species of fish or curtailing greenhouse gas—while ignoring the native ecosystem is like trying to light a candle while it’s underwater. Julie Packard of Monterey Bay Aquarium believes we need to evaluate aquatic ecosystems as a whole in order to save the oceans (and the life within them), rather than working on species-specific solutions. And many believe we need to shift toward more traditional, closed-system farming techniques (where, for instance, manure produced by cows is used to fertilize the land that grows their food) in agriculture.

It’s a little word, a big concept, and the foundation of talks to come.

This week, lock on to the meaning of ecosystem.