Food chain
organisms are divided into auto- and heterotrophic;
plants change light energy into the energy of chemical bonds, and heterotrophic organisms use energy stored in the food they consume.
to categorize organisms in the food chains.
Food chain
Organisms in ecosystems are interrelated with food dependencies in such a way that they form food chainsfood chains. In the food chain, the species that is one link in the chain becomes the food of the species being next link in the chain.
The food chain (also referred to as trophic) begins with the producer. The next link in the chain is the first level consumer eating the producer, i.e. herbivore. The next link is a carnivore, i.e. a second level consumer, followed by a third level consumer and possibly other consumers. The place that a given organism has in the food chain depends on what it feeds itself and for what organisms it becomes food. We call this a trophic level.
The arrows used in the food chain illustrate the flow of matter and energy through the trophic levels. These arrows run from producers who create organic compounds from inorganic compounds to consumers. Species, especially omnivorous, may take different trophic levels in different food chains, depending on what is their primary source of food.
In the first food chain, the producer is a potato, a first level consumer Colorado beetles, a second level consumer is a pheasant, and, finally, a fox is the third level consumer. This chain is longer than the next one, in which the last link – fox – is the second level consumer. This is due to the fact that the pheasant is an omnivorous bird – it may appear in the food chain both as a herbivore (when feeding on wheat) or as a carnivore (when feeding on a herbivorous Colorado beetles). Potatoes can be food for mice that are eaten by foxes, buzzards or kestrels. On the other hand, not only the pheasant, but also partridge and robin feed on the Colorado beetles. The same organisms often occur simultaneously in several food chains that are all connected and form trophic networks. The richer and more diverse the ecosystem, the more complex the food chains are.
Place a man and a hen in the food chain in Figure 4. Connect these organisms with others using the arrows which symbolize food dependencies. Determine on which trophic levels the human and the hen are in this food chain.
Some food chains are very short while other are long. An example of a very short food chain is that of an elephant. Elephant is the consumer of the first level and also of the last one. Due to its size, it rarely becomes prey.
Examples of extremely long food chains are found in some aquatic ecosystems, inhabited by many species.
In a certain food chain, the butterfly caterpillar feeds on crop plants and is eaten by a small songbird. This bird, in turn, very often falls victim to a large bird of prey. Match the organisms with the roles they play in a food chain.
third-line consumer, first-line consumer, second-line consumer, producers
| crop plants | |
| caterpillar | |
| songbird | |
| bird of prey |
Summary
All organisms in the ecosystem are connected by complex food dependencies – they form chains and trophic networks.
The trophic levels are distinguished in the ecosystem: producers, consumers of the first, second and subsequent levels and decomposers.
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Keywords
food chain, producer, first level consumer, herbivore, carnivore
Glossary
konsumenci – organizmy cudzożywne odżywiające się pokarmem roślinnym (roślinożercy – konsumenci I rzędu) lub pokarmem mięsnym (mięsożercy – konsumenci dalszych rzędów)
łańcuch pokarmowy – szereg organizmów, z których każdy stanowi pożywienie następnego
poziomy troficzne – grupy organizmów pełniących podobną funkcję w łańcuchu pokarmowym; producenci, konsumenci i destruenci