How Many Types of Nutrition

Introduction

Nutrition refers to the process by which an organism takes in food and utilises it to obtain energy, for growth, repair, maintenance and several other processes in the body. In different organisms, nutrition is fulfilled in different ways. The food that is taken in through nutrition is used to attain nutrients that play a major role in all the life processes of the body including absorption, assimilation, ingestion, catabolism, biosynthesis and excretion. It is important to maintain proper nutrition in our body with the right amount of balanced nutrients.

Types of Nutrition

There are two major types or modes of nutrition taken up by living organisms. These are:

1. Autotrophic mode of nutrition

2. Heterotrophic mode of nutrition

Autotrophic Nutrition

Autotrophic nutrition is the type of nutrition wherein organisms fulfil their nutritional requirements by producing their own food. This mode of nutrition is primarily followed by green plants and these organisms are referred to as autotrophs. Autotrophs are capable of synthesising their own food from single inorganic substances like carbon dioxide (CO2) and water. These organisms are also known as producers.

Photoautotrophs are organisms that can follow autotrophic nutrition by making their own food and using sunlight as their source of energy. These organisms include green plants, algae and photosynthetic bacteria. Chemoautotrophs are organisms that synthesise their own food with the oxidation of chemicals. Some examples of chemoautotrophs are sulphur-oxidising bacteria, cyanobacteria and iron-oxidising bacteria.

Heterotrophic Nutrition

Heterotrophic nutrition is the type of nutrition wherein organisms are not capable of producing their own food and depend on other organisms or other sources to obtain nutrients. Such organisms are also known are heterotrophs or consumers. Heterotrophic mode of nutrition can further be categorised into the following types:

1. Saprophytic Nutrition- This is the type of nutrition in which organisms depend on dead and decaying organic matter to fulfil their nutritional requirements. These organisms live and feed on such matter and break it down into simpler substances. They secrete special digestive juices and undergo extracellular digestion. The nutrients are absorbed directly into the cell membranes of these organisms.

2. Parasitic Nutrition- In this type of nutrition, organisms live on the body or inside the body of their hosts and feed on them. These organisms are known as parasites and they completely depend on the host for survival. This type of nutrition is, however, damaging to the host and can even kill the host in some cases.

3. Holozoic Nutrition- This is the type of heterotrophic nutrition in which organisms take in solid or liquid food directly inside their body. There are five steps involved which are ingestion, digestion, absorption, assimilation and egestion.

Conclusion

There are two main types of nutrition exhibited by living organisms which are the autotrophic mode of nutrition and the heterotrophic mode of nutrition. Heterotrophic nutrition is again divided into three types which are saprophytic nutrition, parasitic nutrition and holozoic mode of nutrition.