Question

What are the different modes of nutrition? Explain with one example of each mode of nutrition.

Answer 1

The two main modes of nutrition are autotrophic and heterotrophic.

1. Autotrophic nutrition: In this mode, organisms manufacture their own food from simple inorganic raw materials like carbon dioxide and water, using light or chemical energy. 

2. Heterotrophic nutrition: In this mode, organisms cannot manufacture their own food and must depend on other plants or animals for their nutritional requirements. All animals are heterotrophs.

Heterotrophic nutrition is further divided into three distinct types:

1. Saprophytic Nutrition: Organisms feed on dead and decaying organic matter by breaking it down outside their bodies and absorbing the nutrients. Bread mould (Fungi) grows on stale, moist bread to absorb nutrients.
2. Parasitic Nutrition: Organisms live on or inside another living organism (the host) and derive nutrition directly from it, often causing harm. Cuscuta (Amarbel) is a parasitic plant that climbs on other trees to absorb their prepared food.
3. Holozoic Nutrition: Organisms ingest solid or liquid organic food material, digest it inside their bodies, and absorb the nutrients. Humans (or Amoeba) ingest complex food, digest it internally, and eliminate the waste.