Define nutrition. What are the Different Modes of Nutrition?

Nutrition is the process by which living organisms obtain and utilize nutrients from food to support their growth, development, and maintenance of body functions. Nutrients are substances that the body needs to carry out its various functions, such as energy production, tissue repair, and immune system function.

There are two main modes of nutrition: autotrophic and heterotrophic.

  1. Autotrophic nutrition: In autotrophic nutrition, organisms can produce their own food using simple inorganic substances such as carbon dioxide and water. They use energy from sunlight or chemical reactions to convert these substances into organic compounds such as sugars and amino acids. Autotrophic nutrition is seen in plants, algae, and some bacteria.
  2. Heterotrophic nutrition: In heterotrophic nutrition, organisms obtain their food by consuming other organisms or organic substances produced by other organisms. Heterotrophic nutrition can be further classified into:
    • Holozoic nutrition: In holozoic nutrition, organisms ingest solid or liquid food and digest it internally. This type of nutrition is seen in animals and some protists.
    • Saprophytic nutrition: In saprophytic nutrition, organisms obtain nutrients from dead or decaying organic matter. This type of nutrition is seen in fungi and some bacteria.
    • Parasitic nutrition: In parasitic nutrition, organisms live in or on other living organisms (hosts) and obtain nutrients from them. This type of nutrition is seen in parasites such as tapeworms, ticks, and lice.

In summary, autotrophic organisms produce their own food using inorganic substances, while heterotrophic organisms obtain their food from other organisms or organic matter. Heterotrophic nutrition can be further classified into holozoic, saprophytic, and parasitic nutrition.