Detritivores vs Saprotrophs
The famous law of physics that energy can be neither created nor destructed perfectly applies into the biological world where the energy has to be flowing through ecosystems continuously. Detritivores and saprotrophs are important parts of food chains that ensure the energy flow through ecosystems and constitute the continuance of life. Detritivores and saprotrophs are both involved in decomposing the dead biological matter yet there are interesting but slight differences between their methods.
Detritivores are a type of heterotrophs that feed on the dead or organic biomass including animals, plants, and faeces. Detritivores are essentially able to digest lumps of biomass separately; hence, most of the unicellular organisms (bacteria and protozoa) and fungi may not fall into the category of detritivores. However, detritivores should not be confused with decomposers and scavengers. Detritivores in aquatic environments are usually called the bottom feeders; polychaetes, fiddler crabs, sea star, sea cucumber, and some Terebellids are common examples. Earthworm is a classic example of terrestrial detritivores, but slugs, woodlice, dung flies, millipedes, and most of the worms are some of the other examples.
Detritivores are recyclers of energy as they are being the food sources for the consumers such as carnivores. They recycle the energy mainly in forms of carbon, nitrogen, and oxygen. The decomposing biological matter is ingested into detritivores, digest inside their digestive system, and shed in simple forms. Therefore, the plants can easily absorb the nutrients from the soil. Therefore, it is clear that detritivores both consume and contribute essential nutrients for both animals and plants.
Saprotrophs are heterotrophic organisms that feed on decaying or dead plant matter in the presence of adequate levels of water, oxygen, pH, and temperature. Fungi species predominate among saprotrophs due to their ability to digest lignin in the xylem tissues of plants. There is an interesting instance where most of the dead plants during the carboniferous period did not undergo decomposition because the saprotrophs had not developed the lignin digesting enzymes by then; hence, those large plant deposits became available for the present day consumption as fossil fuels.
Saprotrophic organisms secrete digesting enzymes such as proteases, lipases, or amylases onto the substrates. The extracellular digestion transforms lipids into fatty acids and glycerol; proteins into amino acids, and polysaccharides (e.g. lignin, starch) into glucose and fructose. The simplified materials are absorbed into the fungi tissues through active transport mean called Endocytosis. Saprotrophs gain nutrition through this method, and it is vital for their growth, repair, and reproduction. Saprotrophs mainly feed on wood, dead leaves, dung, and marine wrack. The ecological role of the saprotrophs is vital for the nutrient cycles or the energy flow of the ecosystems as they consume the matter that is difficult for others.
What is the difference between Detritivores and Saprotrophs?
• Detritivores are mostly animals while saprotrophs are mostly fungi.
• Detritivores consume lumps of dead organic matter separately, while saprotrophs absorb chemically digested food.
• Saprotrophs digest their food externally, whereas detritivores do it internally in the digestive system.
• Detritivores shed most of the digested matter unabsorbed, whereas saprotrophs absorb the entire digested matter into them for their growth, repair, and reproduction.