Food web
From Palaeos
| TROPHIC STRUCTURE |
| Guild | Food chain | Food pyramid | Food web | Nutritional group | Productivity | Trophic group | Trophic level |
Food web
A food web or food network extends the food chain concept from a simple linear pathway to a complex network of interactions. The direct steps as shown in the food chain example above seldom reflect reality. This "web" makes it possible to show much bigger animals (like a whale) eating very small organisms (like plankton). Food sources of most species in an ecosystem are much more diverse, resulting in a complex web of relationships as shown in the figure on the right. In this figure, the grouping of Phytoplankton --> Herbivorous zooplankton --> Carnivorous zooplankton --> Arctic char --> Capelin on the far right is a food chain; the whole complex network is a food web/network.
Food chains, food webs, and/or food networks describe the feeding relationships between species in a biotic community. In other words, they show the transfer of material and energy from one species to another within an ecosystem.
As usually diagrammed, an organism is connected to another organism for which it is a source of food energy and material by an arrow representing the direction of biomass transfer. Organisms are grouped into trophic levels—from the Greek word for nourishment, trophikos—based on how many links they are removed from the primary producers. Primary producers, or autotrophs, are species capable of producing complex organic substances (essentially "food") from an energy source and inorganic materials. These organisms are typically photosynthetic plants, bacteria or algae, but in rares cases, like those organisms forming the base of deep-sea vent food webs, can be chemotrophic. All organisms that eat the autotrophs are called heterotrophs. They get their energy by eating the producers.
