A food chain is the sequence of who eats what or whom in a biological community (or ecosystem) in order to obtain nutrition. The food chain always starts with the primary energy source such as the sun.  Next in the chain comes organisms that make their own food by consuming the primary source.  As an example, plants make their own food from sunlight through a process called photosynthesis.  Chemosynthetic bacteria make their own food energy by consuming chemicals in hydrothermal vents.  Both plants and bacteria are autotrophs or primary producers. After the autotrophs you have the next link... Show more

A food chain is the sequence of who eats what or whom in a biological community (or ecosystem) in order to obtain nutrition.

The food chain always starts with the primary energy source such as the sun.  Next in the chain comes organisms that make their own food by consuming the primary source.  As an example, plants make their own food from sunlight through a process called photosynthesis.  Chemosynthetic bacteria make their own food energy by consuming chemicals in hydrothermal vents.  Both plants and bacteria are autotrophs or primary producers.

After the autotrophs you have the next link in the food chain and that includes herbivores.  Herbivores are the primary consumers and they include anything that eats grass or plants.  For example, a grasshopper is an herbivore as is a rabbit.

The next link in the food chain are the secondary consumers.  Secondary consumers are carnivores (i.e., they eat meat), as well as omnivores (i.e., animals that will eat both plants and animals).  Secondary consumers are those things that eat primary consumers.  For example, a mouse would eat a grasshopper making the mouse a secondary consumer.

Next comes the tertiary consumer.  A tertiary consumer eats secondary consumers.  As an example, a snake will eat a mouse.  This makes a snake higher up on the food chain.  In each consumer level there is a hierarchy of consumers, meaning that consumers on the lower level of the consumer chain can and will be eaten by consumers on the higher level of the chains.  For example, the snake is a tertiary consumer but so is an owl.  Owls eat snakes because owls are in the higher level of the tertiary consumer chain.

Next is the quaternary consumer.  Quaternary consumers eat tertiary consumers.  An example of a quaternary consumer is a hawk because a hawk will eat an owl.

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