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 à primary consumer à secondary consumer à tertiary consumer à decomposer
· Grass à rabbit à fox à 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:
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
a. Marsh Vegetation à Grasshopper à Salmon à Harbour Seal à Killer Wale
b. Marsh Vegetation à Snails à Mosquito à Herring à Harbour Seal à Killer Whale
c. Marsh Vegetation à Herring à Harbour Seal
d. Mosquito à Salmon à Bald Eagle à Marsh Hawk
a. Autotroph; Primary Consumer
b. Primary Consumer; Secondary Consumer
c. Primary Consumer; Tertiary Consumer
d. Secondary Consumer; Tertiary Consumer
d. Snow Geese
a. Marsh Vegetation
c. Marsh Hawk