Life at the Top of a Food Chain

In this example, plankton are at the bottom of a food chain. Shellfish eat the plankton, bigger fish eat the shellfish, seals eat the bigger fish and killer whales eat the seal. Since nothing eats the killer whale, it sits at the top of the food chain. That may sound like good news for the killer whale, but it isn't. Due to biological magnification and being at the top of the food chain, it suffers most from poisons. By the time the killer whale eats the contaminated seal, it's also eating the pesticides from thousands of contaminated fish, shellfish and plankton that were part of the seal's food chain. This is how biological magnification happens. The presence of toxins in fatty tissue increases or magnifies as it goes up the food chain. Sadly, when baby killer whales nurse from their mothers that are poisoned with chemicals, they can get very sick and die.