Food webs are, by definition, consisting of all food chains in a single ecosystem. A food chain is a group of organisms linked in order of the food they eat. The organisms in these food webs are separated into different trophic levels. A trophic level is one of three positions on the food chain including producers, consumers, and decomposers. Producers are also known as autotrophs. They make their own food and do not need to depend on any other organisms for nutrients to survive. Producers use photosynthesis to provide themselves with the appropriate nutrients. Examples of producers are seaweed and some types of bacteria. The next level is the primary consumer level. Primary consumers are herbivores, which means that primary consumers eat plants, algae, and other producers. A mouse is considered a primary consumer. Next, there are secondary consumers. Secondary consumers are carnivores, which means that they eat herbivores. An example of a secondary consumer would be a snake that would eat a mouse. Further up the ladder, there are the tertiary consumers. Tertiary consumers eat secondary consumers. Examples of tertiary consumers include owls or eagles that would eat the snake (secondary consumer) that ate the mouse (primary consumer). Finally, there are the decomposers and detritivores. Decomposers eat organic wastes and turn them into inorganic materials, such as nutrient-rich soil. Detritivores, on the other hand, are organisms that eat nonliving plant and animal remains. (Dunn)
In this activity, I learned a lot about the food webs and energy pyramids in an aquatic ecosystem. We were charged with placing the organisms that we had collected in our cards into the proper order based on the trophic levels that the organisms are placed in. My group's ecosystem was an aquatic ecosystem. The way that my group organized our web was (from bottom to top) producers, primary consumers, secondary consumers, tertiary consumers, and then, decomposers. One example for each of these levels would be plankton for primary consumers. For secondary consumers, we have the example of small fish. Tertiary consumer of our food web would be the shark. At the top, for our decomposer, we have the sea urchin.
The biome that my group's food web represents is the aquatic biome. A biome is an area of the planet that can be classified according to the plants and animals that live in it. (Dunn) We know that the biome of our food web is the aquatic (or marine) biome because the animals and plants in our food web are those that we would find in the oceans of Earth. In conclusion, the food web that my group was assigned, was the aquatic biome food web.
Dunn, Margery G. (Editor). (1989, 1993). "Exploring Your World: The Adventure of Geography." Washington, D.C.: National Geographic Society.
