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Food Web & Food Chain

The link between organisms in an ecosystem

Food Web & Food Chain

The link between organisms

Definitions

Producers

Producers are by definition autotrophs, which means they are self-feeding. This group of organisms uses solar energy (photosynthesis) – or more rarely inorganic chemical reactions (chemosynthesis) – to create food in the form of energy-rich molecules such as carbohydrates. This process, the synthesis of carbon dioxide into organic compounds, is called primary production and is indirectly or directly connected to the survival of all life on Earth.

 

Producers are the foundation of every food chain and food web, as they provide energy for the rest of the organisms to survive.

Consumers

Consumers consist of three categories:

Primary Consumers: these animals and insects eat primary producers, they are also called Herbivores they feed on plants and fungi, organisms who receive their food and energy through the process of photosynthesis.  

Secondary Consumers: these organisms eat Primary consumers, there are two types: Carnivores and Omnivores.

Tertiary Consumers: they eat secondary consumers, sometimes both secondary and primary consumers. They are also known as the apex predator because it is at the top of the food chain. They consume energy from all other levels.

Trophic Level

Trophic level: The organisms of a chain are classified into trophic levels on the basis of their feeding behaviour.

  • The first and lowest level contains the producers, green plants.
  • The plants or their products are consumed by the second-level organisms—the herbivores, or plant eaters.
  • At the third level, primary carnivores, or meat eaters, eat the herbivores.
  • At the fourth level, secondary carnivores eat the primary carnivores.

These categories are not strictly defined, as many organisms feed on several trophic levels. (e.g. 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, consists of organisms such as bacteria and fungi that break down dead organisms and waste materials into nutrients usable by the producers.

Food chain

Food Chain: A food chain is a linear network of links in a food web starting from producer organisms and ending at apex predator species, detritivores, or decomposer species.

Food Web

A food web is a system of interlocking and interdependent food chains. (Brook Romero, September 2016)

The Constituents Of A Food Chain

Producers

 All plants, such as grass and trees, are producers. These organisms absorb the sun’s energy and convert the energy into food for themselves, allowing them to grow larger, make flowers and seeds, etc.

  • E.g. Phytoplankton, Algae

Consumers

These organisms, mostly animals, eat producers and/or other animals. They may also eat decomposers. Two examples of consumers are deer (eat plants) and wolves (eat animals). Consumers that only eat plants (herbivores) are often known as primary consumers.

  • E.g. Blue Striped Snappers, Jackfish, Sea Sponge, Stingray, Sea Snake

Decomposers

 These organisms break down dead material (such as a fallen tree) into soil and return nutrients to the soil so they can be re-used by producers to create food. An example of a decomposer is a mushroom.

  • Detritivores. A special type of decomposer, these refer to the class of organisms that feeds on detritus or organic waste. (Detritus is organic matter composed of dead trees, plants and animals.)
  • E.g. bacteria, fungus, marine worms, sea slugs, sea worms, and brittle stars.