FOOD CHAINS AND FOOD WEBS

THE CONCEPT OF A FOOD CHAIN  SHOULD  BE INTUITIVELY CLEAR. THE FROG EATS THE INSECT, THE SNAKE SWALLOWS THE FROG EATS THE INSECT, THE SNAKE SWALLOWS THE FROG, AND THE SWOOPING HAWK FINISHES OFF THE  SNAKE. WE THUS HAVE A FOOD CHAIN. IT IS JUST A SEQUENCE OF ORGANISMS, IN WHICH EACH IS THE FOOD FOR THE NEXT. ALL ORGANISMS, DEAD OR ALIVE, ARE POTENTIAL SOURCES OF FOOD FOR OTHER ORGANISMS.

FOOD CHAINS OVERLAP, SINCE MOST ORGANISMS HAVE MORE THAN ONE ITEM ON THEIR MENU. AGAIN, AN ORGANISM COULD BE FOUND ON THE MENUS OF MANY OTHER ORGANISMS. THUS, WE HAVE A COMPLEX NETWORK OF INTERCONNECTED FOOD CHAINS  CALLED A FOOD WEB.

IF EVERY ORGANISMS MUST EAT ANOTHER ORGANISM FOR SURVIVAL, WHERE DOES THE FOOD CHAINS START? OBVIOUSLY THERE MUST BE AT LEAST ONE SELF-FEEDING ORGANISM THAT PRODUCES FOOD AND EATS IT TOO! SUCH PRODUCERS ARE IN FACT ALL AROUND US-THE GREEN PLANTS.