When discussing the different interactions in an ecosystem, one must identify the different types of consumers. 

         Autotrophs produce their own food (example: plants).

         Herbivore plant eaters (example: deer).

         Omnivore eats both plants and meat (example: bear).

         Carnivore eats primary meat (example: coyote).

         Decomposers breaks down dead tissue (example: bacteria).

         Producer- also known as autotrophs, produces its own food.

         Primary, secondary, tertiary consumer a consumer is any animal that does not produce its own food; it is considered a primary, secondary or tertiary consumer depending on where it may be found in a food chain or food web.  A primary consumer will feed on autotrophs, a secondary consumer will feed on primary consumers, and tertiary consumer will feed on secondary consumers.   

A food chain is a possible route for the transfer of matter and energy (food) through an ecosystem from autotrophs through heterotrophs and decomposers.

            Example of food chains:

         Producer primary consumer secondary consumer tertiary consumer decomposer

         Grass rabbit fox decomposer (upon the death of the fox)

A food web shows all possible feeding relationships in a community at each trophic level; represents a network of interconnected food chains.

            An example of a food web:



The difference between a food chain and a food web is that a chain is a single strand of the different levels of energy transfer, where as a food web will show the many strands in a particular ecosystems such as a forest.

A food pyramid, or ecological pyramid, will show population sizes (amount of energy at that level) in an ecosystem.  The pyramid most often decreases, as it gets farther up.  In the example of the food web above, a food pyramid can be created with the clover, the worm, and the raccoon.  There is a much larger abundance of clover than the other two; they will be on the bottom of the pyramid.  The worm will be the next step with a smaller number than clover, but larger number of raccoon.  The raccoon will be on the top of the pyramid with the smallest number.  The pyramid will look like this:



Text Box: Raccoon
Text Box: Worm
Text Box: Clover






Use the following food web to answer questions 1-5.



1.   What type of ecosystem would you think that this food web is diagramming?

a.   Tropical forest

b.   Grassland

c.    Coastal

d.   Swampland


  1. Which of the following would be the most complete food chain derived from this food web?

a.   Marsh Vegetation Grasshopper Salmon Harbour Seal Killer Wale

b.   Marsh Vegetation Snails Mosquito Herring Harbour Seal Killer Whale

c.    Marsh Vegetation Herring Harbour Seal

d.   Mosquito Salmon Bald Eagle Marsh Hawk


  1. The herring in this food web can be classified as two different types of consumers depending on the food chain.  They are:

a.   Autotroph; Primary Consumer

b.   Primary Consumer; Secondary Consumer

c.    Primary Consumer; Tertiary Consumer

d.   Secondary Consumer; Tertiary Consumer


  1. All of the following can be classified as a secondary consumer, EXCEPT:

a.   Rat

b.   Salmon

c.    Vole

d.   Snow Geese


  1. In a food pyramid, which of the following would make up the smallest level:

a.   Marsh Vegetation

b.   Salmon

c.    Marsh Hawk

d.   Rat


  1. Humans are an example of _____.

a.   Producers

b.   Herbivores

c.    Omnivores

d.   Carnivores


  1. All of the following would be considered carnivores, EXCEPT:

a.   Coyote

b.   Bear

c.    Fox

d.   Shark


  1. All of the following would be considered herbivores, EXCEPT:

a.   Grasshopper

b.   Giraffe

c.    Zebra

d.   Human