- ‘Hetero’ means ‘other’ and ‘troph’ means ‘nutrition’.
- Therefore, the organisms which cannot make their own food from inorganic sources and depend on other organisms for food are known as heterotrophs .
Heterotrophs can further be divided into different types :
Saprotrophic (or Saprophytic) Nutrition:
Organisms which obtain their food from dead plants, dead and decaying animal bodies and other decaying organic matter are called saprotrophs .
Eg. Fungi (Yeast, Mushrooms, bread moulds)
- Saprophytes break down food and convert complex organic molecules into simpler substances outside their body .
- These substances are then absorbed by Saprophytes as food.
A parasite is an organism which feeds on another living organism called its host.
- A parasite gives the host nothing in return and usually harms the host.
The nutrition derived from the body of this other organism without killing it is called parasitic nutrition. Eg. Tapeworm, Lice, roundworm, plasmodium, cuscuta
The mode of nutrition in which an organism takes the complex organic food materials into its body by the process of ingestion is known as Holozoic Nutrition .
The ingested food is digested and absorbed inside the body and cells of the organism.
Eg. Amoeba, Humans, Frog