Trophic level – simplified
In ecology, the trophic level is the position that an organism occupies in a food chain – what it eats and what eats it.
- Plants – produce their own food by photosynthesis, harvesting energy from the sun.
- Herbivores – eat the plants.
- Carnivores – eat the organisms that eat the plants.
- Note that there are sub-levels among carnivores. As examples, the fish that eats other fish is eaten by dolphins or whales. This can become a complex web – consider the fish that eats other fish, that fish is eaten by seals, and the seals are eaten by dolphins, such as orca.
Each layer of this system absorbs toxins from its diet, the original of toxic contamination causes a greater effect on organisms at higher levels. As an example, let’s assume the plants are contaminated with 1 degree of toxicity. The fish that eats many plants, as its sole diet, could present 3 degrees of toxicity. The fish that eats these fish, consuming many as its diet, could present 10 levels of toxicity. The seal that consumes many fish, would be possibly 20 levels of toxicity. This leads to the orca that eats the seals, at 40 levels of toxicity.
This explanation is very much over-simplified with arbitrary ‘degrees of toxicity’ and given in this way only to illustrate the concept.