Definitions

Trophic levels of the food chains

Burgess COMMENTARY

Peter Burgess

Trophic levels of food chains

The levels of a food chain (food pyramid) is called Trophic levels. The trophic level of an organism is the level it holds in a food pyramid.

• The sun is the source of all the energy in food chains. Green plants, usually the first level of any food chain, absorb some of the Sun’s light energy to make their own food by photosynthesis. Green plants (autotrophs) are therefore known as ‘Producers’ in a food chain.

• The second level of the food chains is called the Primary Consumer. These consume the green plants. Animals in this group are usually herbivores. Examples include insects, sheep, caterpillars and even cows.

• The third in the chain are Secondary Consumers. These usually eat up the primary consumers and other animal matter. They are commonly called carnivores and examples include lions, snakes and ca.

• The fourth level is called Tertiary Consumers. These are animals that eat secondary consumers.

• Quaternary Consumers eat tertiary consumers.

• At the top of the levels are Predators. They are animals that have little or no natural enemies. They are the ‘bosses’ of their ecosystems. Predators feed on preys. A prey is an animal that predators hunt to kill and feed on. Predators include owls, snakes, wild cats, crocodiles and sharks. Humans can also be called predators.

• When any organism dies, detrivores (like vultures, worms and crabs) eat them up. The rest are broken down by decomposers (mostly bacteria and fungi), and the exchange of energy continues. Decomposers start the cycle again.