All food chains and networks have at least two or three trophic levels. In general, there are a maximum of four trophic levels. Many consumers eat at more than one trophic level. Humans, for example, are the main consumers when they eat plants such as vegetables.
Trophic level, passage of a nutritional series or food chain in an ecosystem. Organisms in a chain are classified at these levels based on their eating behavior. The first and lowest level contains the producers, the green plants. Plants or their products are consumed by second-level organisms, herbivores or herbivores.
On the third level, primary carnivores or carnivores eat herbivores; and on the fourth level, secondary carnivores eat primary carnivores. These categories are not strictly defined, since many organisms feed on various trophic levels; for example, some carnivores also consume plant materials or carrion and are called omnivores, and some herbivores occasionally consume animal matter. A separate trophic level, the decomposers or transformers, consists of organisms such as bacteria and fungi that break down dead organisms and waste materials into nutrients that can be used by producers. A trophic level is the group of organisms within an ecosystem that occupy the same level in a food chain.
There are five main trophic levels within a food chain, each of which differs in their nutritional relationship with the primary energy source. The main source of energy in any ecosystem is the Sun (although there are exceptions in deepwater ecosystems). The dietary traits and habits of different organisms can affect the ecosystem and change the dynamism of the food web. The number of species and their interactions with each other can cause an effective change in the structure of the food web.
They use solar energy through photosynthesis and do not rely on other animals to meet their nutritional needs. The rest of the trophic levels are made up of consumers, also known as heterotrophs; heterotrophs cannot produce their own food, so they must consume other organisms in order to be nourished. About 50% of the energy (possibly up to 90%) in food is lost at each trophic level when an organism is ingested, making it less efficient to be a higher-order consumer than a primary consumer. The secondary consumers, at trophic level three, are carnivores and omnivores, which obtain at least part of their nutrients from herbivorous tissue.
The primary producers are usually plants and algae, which photosynthesize to make their own food source. As you probably know, the organisms at the base of the food chain are photosynthetic: terrestrial plants and the phytoplankton (algae) of the oceans. They rely on autotrophs to meet their food needs and include organisms such as insects, cows and pigs. Trophic levels represent a hierarchical situation in which several species are classified according to their dietary needs.
Trophic level four contains carnivores and omnivores that feed on secondary consumers and are known as tertiary consumers. The other one below the trophic level is known as heterotrophs that cannot manufacture their food, so they have to rely on autotrophs to meet their food needs. Because of this inefficiency, there is only enough food for a few high-level consumers, but there are plenty of foods for herbivores that are further down the food chain.