Spotted hyenas with a stolen kill containing an Impala. Hyenas are one example of a tertiary consumer that rely on the feeding of other organisms for survival.

Consumers are organisms of an ecological food chain that relies upon the feeding of other organisms for survival. These organisms are formally refered to as heterotrophs, which are represented by all species of animals and a few species from the moneran and fungus kingdoms. Certain species of plants, such as the venus-flytrap, also obtain their nutrition through digesting arthropods, but are still considered autotrophs as they do incorporate photosynthesis for survival.

Within an ecological food chain, consumers are categorized into three groups of: primary consumers, secondary consumers, and the tertiary consumers.^[1] Primary consumers are mainly defined by developing herbivore diets, feeding upon species of plants, while secondary consumers develop carnivorous and omnivorous diets, capable of preying upon both plants and other animals respectively. Tertiary consumers can be considered as an apex predator of a food chain, characterized by being categorized at the top of food chains and have no natural predators that can prey upon them. Humans are one example of a tertiary consumer. Both parasitic organisms that form symbiosis relationships with other organisms and pathogens capable of inflicting diseases can also be considered a consumer.

Consumers make up the majority of the trophic levels of a food chain and play essential ecological roles within their habitats by controlling the population of certain organisms to prevent them from overpopulating that would otherwise damage the health and the biodiversity of an ecosystem. Invasive species introduced by human activities are often classified as tertiary consumers and are one of the main contributions to damaging ecosystems, due their situation of not having any natural predators within their introduced habitats. This would result in competition of resources, space, the overconsumption of other organisms, and the spread of diseases to native biodiversity.

[edit] See also

• Ecosystem
• Food chain
• Primary producers

[edit] References

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