The food chain or trophic chain indicates the nutritional relationships between producers, consumers and decomposers. In other words, the chain reflects who eats whom (a living being feeds on the one that precedes it in the chain and, at the same time, is eaten by the one who follows it).
It is, in short, a stream of energy that begins with photosynthesis and is then transferred from one organism to another through nutrition. The food chain, therefore, begins with photosynthetic plants, which have the ability to create living matter from the inert. Therefore, they are called producers.
Autotrophs is how these aforementioned producers are also called, among which we can emphasize that there are plants.
In the next link in the chain we find the animals that feed on the producers and are called primary consumers or phytophagous. The herbivorous beings are those that consider that they are primary consumers since they are the ones that feed on the producers, the plants. Among them we could highlight, for example, insects. These animals serve as food for others that are known as secondary consumers or carnivores.
And then we could also talk about tertiary consumers, which are those that basically feed on secondary ones. Among those we could highlight that there are all those animals and beings of the ecosystem that exert superiority over the rest, as would be the case of super predators such as the crocodile, the shark, the jaguar, the polar bear, the wolf or the lion.
According to abbreviationfinder, to close the chain, bacteria and fungi appear that decompose the waste of plants and animals. With this decomposition, simple elements reappear that are used as food by plants.
However, to all the above it must be added that up to seven levels can be established in this food chain if actions or phenomena such as commensalism or decomposition are taken into account.
In order to fully understand how the food chain works and to be able to work with it in a much easier way, it is common to represent it through the so-called trophic pyramid. It is an element, in the shape of said geometric object, where each of the aforementioned levels is ordered according to a criterion from highest to lowest. That is, at the top of it, the upper level will appear, that of the super predators, and thus it will continue to descend until it reaches the base of the pyramid where the beings called producers are found.
In a food chain, all beings have great importance. With the disappearance of a link, the beings that follow it will run out of food. On the other hand, living beings that are in the level immediately before the missing link will begin to experience an overpopulation, since they will not have their predator. That is why the protection of ecosystems and all their components is of vital importance.