Food Chains, Food Webs and

Energy Flow

• A Food Chain is a model that shows how food passes (flows)

from organism to organism.

Simple Food Chain

• It starts with an energy source (the sun).

• Plants convert the sun’s energy into a form that can be

stored in food.

• Some microscopic organisms called Phyto-plankton also

trap energy from the sun and convert it into food.

More Examples of Simple Food Chains

• The plants and phytoplankton in food chains are producers.

• Photosynthesis occurs when producers use Chlorophyll (a green

chemical) to trap energy from the sun and create food.

• The trapped energy is used to convert carbon dioxide gas and water into

sugar and starch. As a result, oxygen is released back into the air.

• A Food Web shows interconnected Food Chains in an ecosystem.

Phytoplankton

• A Food Web is more realistic because it shows feeding

relationships in ecosystems.

• Producers are usually eaten by many different consumers and

consumers are eaten by more than one kind of predator.

• A Pyramid of Numbers shows how many organisms are at each level in a food chain.

• There are always a large number of producers at the bottom and fewer consumers at the top.

• Animals high on a food chain must eat many organisms on lower

levels.

• Energy Flow is the transfer of energy that begins with the Sun and

passes from one organism to the next in a food chain.