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Tropic Levels: An Introduction
Tropic Levels: An Introduction
Trophic levels make up a food chain. Every organism can be described using a trophic level, which depends on how they obtain their energy.
When we say trophic level we talk about the position that an organism occupies within the food chain. For example
What process does grass get its energy from?
Plants and algae are known as autotrophic organisms. This means that they can make their own food from light and simple inorganic minerals from the soil. For that reason, they are the first trophic level: Producers.
What do you think the word trophic means?
Which of these organisms would be classed as a level 1 trophic species?
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Trophic level 2 organisms are any species that consumes level 1 species. Which of these belong to trophic level 2?
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Carnivorous species occupy which trophic levels?
Level 3 carnivores are animals that feed off herbivorous prey (a snake that eats a rabbit). Level 4 carnivores are those that feed off prey that are carnivores too (the eagle that eats the snake).
In summary...
These are the different trophic levels and their occupants.
Very few food chains reach beyond level 4 (tertiary consumers), but the carnivores that do reach level 4 are called apex carnivores. What do you think that means?
Trophic levels show how nutrition and energy move "up" the food chain from one species to another. There is an additional trophic level that feeds off all of these levels when individuals die. Which of these organisms gain their nutrients from dead organic material?
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This shows again the different trophic levels and their occupants.
Decomposers are the organisms that feed off dead individuals from all trophic levels. Bacteria and fungi digest their food by secreting enzymes onto the dead material and then absorbing the products. Worms and insects digest the material in the same way as other animals.
