Heterotrophic Nutrition

Heterotrophic Nutrition

It is a mode of nutrition in which an organism obtains readymade food from an outside source for both body building and liberation of energy. Heterotrophic nutrition is of three main types- saprophytic, parasitic, and holozoic.

Differences between autotrophic and Heterotrophic Nutrition

Autotrophic NutritionHeterotrophic Nutrition
1. Food. The food is manufactured by the organism.

2. Energy. An external source of energy like sunlight is required.

3. Raw Materials. Inorganic raw materials are obtained from outside.

4. chlorophyll. It is required to trap the solar energy.

1. Readymade food is obtained form outside.

2. Energy is obtained from the food.

3. They are not required.

4. Chlorophyll is absent.

  1. Saprophytic Nutrition. It is obtaining nutrients from organic remains and food articles by performing external digestion. Here digestive enzymes are poured over the food particles which undergo solubilization. The solubilized materials are absorbed and assimilated. The organisms performing saprophytic nutrition are called saprophytes, e.g., fungi like bread mould, yeast, and mushrooms, several bacteria.
  2. Parasitic Nutrition. Here, a living organism called a parasite obtains food from another organism called the host. The parasite may live over the body of the host (ectoparasite, e.g., leech, ticks, lice, Cuscuta or Amar Bel) or inside the body of the host (endoparasite, e.g., Tapeworm, Ascaris). The parasites causing disease in the host are called pathogens.

Differences between Saprophytes and Parasites

Saprophytes Parasites
1. Nutrition. It is obtained from organic remains.

2. Digestion. External digestion occurs while taking of food.

3. Disease. They do not cause disease.

1. It is obtained from a living host.

2. An external digestion is absent.

3. Parasites may cause disease.