A mode of nutrition in which organisms obtain nutrition from dead and decaying matters is called the Saprotrophic Nutrition. Parasitic Nutrition refers to heterotrophic nutrition, in which parasites depend on other living organisms for their food.

Parasitic nutrition is a type of nutrition in which an organism lives on or inside another organism (host) and derives its nutrients from the host. The parasite benefits from this relationship, while the host is harmed.
- Parasites can be classified as ectoparasites (living on the host's body) or endoparasites (living inside the host's body).
- Examples of parasitic nutrition include tapeworms, fleas, and ticks.
- Parasites often have specialized structures such as hooks, suckers, or modified mouthparts to attach themselves to the host and obtain nutrients.

Saprotrophic nutrition is a type of nutrition in which an organism feeds on dead or decaying organic matter. These organisms are known as saprotrophs or decomposers.
- Saprotrophs secrete enzymes onto the dead organic matter to break it down into simpler substances.
- They then absorb the nutrients released from the breakdown process.
- Examples of organisms that exhibit saprotrophic nutrition include fungi like mushrooms and bacteria.

Differences between Parasitic and Saprotrophic Nutrition:
1. Source of nutrients:
- Parasites obtain nutrients from living hosts, while saprotrophs obtain nutrients from dead organic matter.
2. Relationship with host:
- Parasites harm their hosts, while saprotrophs help in the decomposition process.
3. Structures and adaptations:
- Parasites often have specialized structures for attachment to hosts, while saprotrophs secrete enzymes for decomposition.
In conclusion, parasitic nutrition involves one organism living off another, while saprotrophic nutrition involves feeding on dead organic matter. Both types of nutrition play important roles in ecosystems.