Parasite : Some organisms for theirs requirement of food nutrients which are must for their survival, growth and reproduction, depend on the food produced by other living organism called host. Such living organism which deprives the host of valuable nutrients, is called a parasite
Saprotrophs: Some organisms like fungi, have a different mode of nutrition.They secrete digestive juices on the dead and decaying matter and convert it into a solution. Then they absorb the nutrients from it. This mode of nutrition in which organisms take in nutrients in solution form from dead and decaying matter is called saprotrophic nutrition. Plants which use saprotrophic mode of nutrition are called saprotrophs.