Heterotrophs or consumers

Lesson 9: Producers, consumers and decomposers

Heterotrophs or consumers

These organisms are dependent upon other organisms for food. Eg: man and all the animals. They are of three types viz. primary consumers, secondary consumers and tertiary consumers.

  • Primary consumers or Herbivores: These animals get their food by eating the producers directly. Eg: In a forest, insects, amphibians, reptiles, birds and mammals, animals - hare, deer and elephants, in grass lands, black buck, in semi-arid areas, chinkara, in sea, small fish are the herbivores.

  • Secondary consumers or carnivores: These animals feed on herbivores. Eg: tigers, leopards, jackals, foxes, wild cats in forest, large fish & whale in sea. These may be predators or parasites.

  • Tertiary consumers or Omnivores: Organisms which consume plants as well as animals, like humans, cockroach and fox.

All three types of consumers are called macro consumers or Phagotrophs.

A consumer is an organism that obtains nutrients from other organisms. This is also a heterotroph. A heterotroph is an organism that cannot synthesize their own food and must obtain it ready made.

There are several groups of heterotrophs. Heterotrophs are all organisms that obtain their food from the environment. All animals and certain types of micro-organisms are heterotrophs. These organisms must take in, or ingest, food containing already made organic nutrients from other plants or animals. It all depends on what they eat and how they obtain it. Heterotrophs include herbivores, carnivores, omnivores and saprobes.

  • Herbivores are animals that feed only on plants. Rabbits, cattle, horses, sheep and deer are all herbivores.
  • Carnivores are animals that feed on other animals. Some carnivores may be predators (such as lions, hawks, and wolves who attack and kill their prey and feed on their bodies) and some may be scavengers (they feed on dead animals that they find).

A carnivore is a type of heterotroph that feeds only on other animals. There are two different ways to classify carnivores. The first group is known as predators. Predators hunt and kill other animals for food. Animals like lions, wolves, snakes, and sharks are all classified as predators. Another group of animals that are considered carnivores are scavengers. Scavengers are animals that feed on the dead bodies of other organisms. Animals such as vultures, hyenas, and griffins and all classified as scavengers. Scavengers eat the food that has been killed and left behind by predators. Scavengers are a very important group because they dispose of the carcus's of animals that have been left to decompose.

  • Omnivores are animals that feed on both plants and animals. Examples of omnivores are humans and bears.
  • Saprobes are organisms that get nutrients by breaking down the remains of dead plants and animals. Examples of saprobes are bacteria and fungi.
Last modified: Thursday, 29 December 2011, 7:18 AM