Ecosystem Structure

Food Chain

1st level of all food chains must be the producers Producers have the ability to trap energy and

produce carbohydrates (sugars) Called Autotrophs Ex. Algae, plants, trees, grasses

Food Chain

The next levels are the Consumers Those that eat to obtain energy – heterotrophs

Primary – herbivores Secondary – small carnivores or omnivores Tertiary – large carnivores

Food Chain

It starts and ends with a very important group called the decomposers Recycle the nutrients and make it available

for the chain to use again.

Food Chain – Food Web

Each level is called a Trophic Level If there are multiple options at each

level it is called a food web.

Trophic Levels

All nutrients and energy has the potential to be passed on to the next level.

Because each level eats several of the level below there is a building effect called biological magnification. This build up could be a pollutant like DDT in

Bald Eagles. – causing an issue at the upper levels.

Biological Magnification

Ecological Pyramids

The total mass of all the organisms in an ecological community is called the biomass. Each trophic level contains stored energy representing

the potential food available to organisms at the next level. Only about 10% of the biomass from one level can

transfer to the next The number of organisms (biomass), and the amount of

energy is 1/10th of the level before. All biomass starts with producers when they trap CO2

from the atmosphere into carbohydrates.

Ecological Pyramids

Ecosystem

The ecosystem is made up of several trophic levels that rely on each other to continue to survive and develop.

The producers are the foundation. The biomass available to the upper trophic levels depends on the producer numbers.