A Trophic level is defined by google as being: Each of several hierarchical levels in an ecosystem, consisting of organisms sharing the same function in the food chain and the same nutritional relationship to the primary sources of energy.
In other words it is certain level in an ecosystem of a food chain.
For example say there is a photosynthesizing (sunlight eating) plankton in a pond. That would be the primary level of the ponds trophic structure. The next level would be the animal that ate the plankton, and then the next level would be the animal that ate that animal... and so on.
This goes on but Trophic levels do not usually exceed the 5th level just because of the percentage of energy that is transferred between each trophic level. I am pretty sure that the percentage of the original energy from the energy source (the sun) passed between levels is only 10%.
An interesting thing about trophic structure is that there is a connection between the levels, so much so that one level can control the amount of the other levels.
Say that people know that a certain first level plankton are doing good for a pond by keeping a certain harmful bacteria away. But then they find that for one reason or another they find that there are not as many plankton as there should be, and the bacteria levels are increasing. What the people can do is to add more of a third level species, who prey on the second level which in turn preys on the plankton. The second level will then be decreased so much as to allow more plankton to exist, thus cutting down on the harmful bacteria levels.
So here is a good example of how knowing trophic levels can be useful.
In other words it is certain level in an ecosystem of a food chain.
For example say there is a photosynthesizing (sunlight eating) plankton in a pond. That would be the primary level of the ponds trophic structure. The next level would be the animal that ate the plankton, and then the next level would be the animal that ate that animal... and so on.
This goes on but Trophic levels do not usually exceed the 5th level just because of the percentage of energy that is transferred between each trophic level. I am pretty sure that the percentage of the original energy from the energy source (the sun) passed between levels is only 10%.
An interesting thing about trophic structure is that there is a connection between the levels, so much so that one level can control the amount of the other levels.
Say that people know that a certain first level plankton are doing good for a pond by keeping a certain harmful bacteria away. But then they find that for one reason or another they find that there are not as many plankton as there should be, and the bacteria levels are increasing. What the people can do is to add more of a third level species, who prey on the second level which in turn preys on the plankton. The second level will then be decreased so much as to allow more plankton to exist, thus cutting down on the harmful bacteria levels.
So here is a good example of how knowing trophic levels can be useful.