Heterotrophic Nutrition

Every non-autotrophic organism which depends on others for its food is called a heterotroph. Heterotrophs include every animal and non-photosynthetic plants which are unable to prepare organic molecules on their own.

Heterotrophs break down the complex food into simpler forms. Heterotrophic nutrition can be classified into three types, based on the ways in which organisms obtain their food.

Heterotrophic Nutrition

The diagram representing the Holozoic Nutrition in Amoeba

Types of Heterotrophic Nutrition

Heterotrophic nutrition can be divided into the following types:

Holozoic Nutrition

Holozoic nutrition means the feeding of solid and liquid food by animals. This involves the steps of ingestion, digestion, absorption, assimilation, and excretion.

Ingestion is the intake of food, which is broken down into simpler organic matters by a process called digestion. After extraction of useful components, every other unwanted and indigested particle is excreted out.

Other holozoic organisms are animals like cat, deer, dog etc. and also amoeba.

What is Holozoic Nutrition in Amoeba?

The holozoic nutrition in amoeba takes place in the following steps:

  • Amoeba feeds through the process of holozoic nutrition. The amoeba projects its pseudopodia and encircles the food. It then engulfs the food by the process of phagocytosis.
  • The food vacuoles of amoeba are rich in digestive enzymes which break the food into simpler substances. This process is known as digestion.
  • The digested food is absorbed into the cytoplasm leaving behind the undigested materials. This absorbed food is utilized to produce energy for the growth and development of the cell.
  • The undigested food material is ejected out by the rupturing of the cell membrane.

Types of Holozoic Organisms

Holozoic organisms can be divided into three types:

  • Herbivores- These organisms depend upon plants for their food. For eg., cows, buffaloes. deer, elephants, etc.
  • Carnivores- These animals feed on other animals for their food. For eg., lion, tiger, leopard, etc.
  • Omnivores- These animals depend upon both plants and animals for their food. For eg., cockroach, pig, crow, ant.

Saprophytic Nutrition

Saprophytes (animals which follow saprophytic nutrition) feed on dead and decayed organisms for energy. They consume dead and decayed remains of animals and plants. In this way, they help clean the environment.

Some examples of saprophytes are fungi and certain types of bacteria. These are also responsible for the staling of bread, cakes etc.

Saprophytes release certain enzymes to act on the complex organic matter and break it into simpler substances which can be easily consumed by them.

Parasitic Nutrition

Organisms which feed on other organisms by deriving out nutrients from other animals (hosts) are called parasites. Parasites extract the nutrients from the host and are harmful to their health, sometimes they even kill the host. Both animals and plants may serve as host.

In the case of a parasite, the host is never in benefit. Few examples of parasites are louse on a human head, Cuscuta plant, and tapeworms.

Based on feeding habits heterotrophs are classified as herbivores, carnivores, and omnivores.

Also Read: Autotrophic Nutrition

To know more about what is holozoic nutrition, saprophytic nutrition, parasitic nutrition, and other concepts related to heterotrophic nutrition, keep visiting BYJU’S website, or download BYJU’S app for further reference.

Frequently Asked Questions

What do you understand by heterotrophic mode of nutrition?

Heterotrophic nutrition is the mode of nutrition where the organism is unable to prepare its own food and depends upon plants or other organisms for nutrition.

What are the different types of heterotrophic nutrition?

Heterotrophic nutrition can be holozoic which can be seen in cat, deer, amoeba, etc; saprophytic where the organisms feed on dead and decaying organisms, for eg., bacteria and fungi; and parasitic where the organism depends upon the host for nutrition, for eg., lice, tapeworms, etc.

What are the different types of heterotrophs?

There are four different types of heterotrophs which include herbivores, carnivores, omnivores, and decomposers. herbivores, carnivores and omnivores undergo holozoic type of heterotrophic nutrition.

What is holozoic nutrition?

Holozoic nutrition involves the consumption of solid and liquid food materials by the organisms. It is carried out in certain steps that include ingestion, digestion, absorption, assimilation and excretion. It is exhibited by amoeba, cows, dogs, etc.

What do you mean by chemosynthetic heterotrophs?

Chemosynthetic heterotrophs obtain energy by chemical reactions, i.e., oxidation of organic compounds. For eg., the organisms that obtain energy by the oxidation of glucose during the process of respiration are chemosynthetic heterotrophs.

How is heterotrophic nutrition different from autotrophic nutrition?

In autotrophic nutrition, the organisms prepare their own food. This type of nutrition is seen in plants where they prepare their food by the process of photosynthesis. On the contrary, in heterotrophic nutrition, the organisms depend upon plants and other animals for their food as they cannot prepare their own food. this can be seen in cows, dogs, tigers, elephants and humans.

What is nutrition?

Nutrition is the process of obtaining food required to obtain energy to carry out life processes. There are two major modes of nutrition- autotrophic nutrition and heterotrophic nutrition.

Give a few examples of heterotrophs.

Bacteria, fungi, yeast, cows, dogs, humans are all heterotrophs. They all depend on plants and other animals for their food.

Practise This Question

Rhizobium bacteria help in nitrogen fixation, but they cannot make their own food.

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