Consumer (food chain)

Consumers are organisms of an ecological food chain that receive energy by consuming other organisms. These organisms are formally referred to as heterotrophs, which include animals, bacteria and fungus. Such organisms may consume by various means, including predation, parasitization, and biodegradation.

Classification

Consumers are typically viewed as predatory animals such as the wolf and hyena. However, herbivorous animals and parasitic fungi are also consumers. Some carnivorous plants, like the Venus flytrap, are classified as both.

Levels

Food web showing the organisms and their trophic levels.

Main article: Trophic level

Within an ecological food chain, consumers are categorized into three groups: primary consumers, secondary consumers, and the tertiary consumers. Primary consumers are usually herbivores, feeding on plants and fungus. Secondary consumers, on the other hand, are mainly carnivores, and prey on other animals. Omnivores, who feed on both plants and animals, can also be considered a secondary consumer. Tertiary consumers, sometimes also known as apex predators, are usually at the top of food chains, capable of feeding on secondary consumers and primary consumers. Tertiary consumers can be either fully carnivorous or omnivorous. Humans are one such example of a tertiary consumer.

Importance to the ecosystem

Consumers dominate most of a food chain. Consumers have important roles to play within an ecosystem such as balancing the food chain by keeping animal populations at a reasonable number. Without proper balance, an ecosystem can collapse and cause the decline of all affected species. This will lead to a severely disrupted ecosystem and a nonfunctional consumer web.

See also

• Food web
• Primary producers
• Autotroph