Food Webs How Organisms Get Energy

Producers Plants able to use light energy from the sun to produce their own food (sugar) from carbon dioxide and water. This is the equation for photosynthesis CO2 + H2O sunlight C6H12O6 + O2

Consumers Animals that cannot make their own food. They eat plants and/or animals to obtain energy. Herbivores – animals that eat only plants Carnivores – animals that eat other animals Secondary Consumer – eat only herbivores Tertiary Consumer – eat other carnivores Omnivores – Animals (including people) that eat both animals and plants

Decomposers (Bacteria and Fungi) feed on decaying matter They are known as “Nature’s Recyclers” They return nutrients to the soil and atmosphere.

More on Food Webs…. In a food web, energy is passed from one organism to another. The arrows in a food web can be replaced by the words – “Transfers Energy To.”

Food Web Concepts continued Only about 10% of the energy an organism receives when it consumes another organism becomes new body mass. 90% is used by the organism to carry out its life process (movement, digestion, reproduction, etc.) This is why an organism must eat MANY organisms below it in the food web in order to grow! The amount of energy transferred from one organism to the next in the food web becomes less and less as you progress up the food web.

One Last Food Web slide Each energy transfer within a food web is called a trophic level If the producer (plants) at the base of the food web are adversely affected, the entire food web may crumble as a result. Sunlight is the original source of energy in almost every food web because producers require sunlight to produce energy.