A Douglas fir Cone being decomposed by Saprophytic Fungi.By Sophie Wilderdijk and Eiche Bullesbach
SECOND VERSION by Ollga Maliko and Ethel Chan
A Douglas fir Cone being decomposed by Saprophytic Fungi.Since one of the characteristics of fungi is that they are unable to produce their own food by photosynthesis, due to the lack of choloroplasts, they obtain their food from other organisms. They also do not have mouths to take in food as animals do, therefore they absorb food through their plasma membranes and cell walls. One of the types of such heterotrophic food intake methods is saprophytism. Fungal saprophytes are fungi that live on dead organic matter and obtain their nutritional supplements by participating in the decay process.
Fungal saprophytism plays a very significant role in the maintenance of the equilibrium of ecosystems. They break down wastes from dead organic matter and thereby enabling the constituent materials to be available for reuse by other organisms within the ecosystem. However, this breakdown can be both positive and negative, depending on the consequences. For example, saprophytic fungi cause food spoilage, ruin fabrics due to mildew caused by the fungi, as well as causing the destruction of timber, which can be shown with several examples.
Aboriginal people of the Pacific North West Coast of Canada carved Totem poles which are exposed to weathering and saprophytes in nature. Artifacts such as these are considered very important to the heritage of North America. However, due to fungal saprophytism as well as other factors of decay, great damage has resulted to these artifacts. In this context, it is interesting to notice that in the philosophy of the Native people, Totem poles were supposed to decay. It is therefore seen by the Natives that saprophytes are good; they are part of the natural environment. Western people, however, want to preserve such artifacts by the use of chemicals that will prevent saprophytes from breaking down the Totem poles. From this point of view, saprophytes are considered a nuisance.
Yet another example of the negative consequences of saprophytism, is dry rot, which occurs in wooden houses, and other wooden structures, causing the wood to deteriorate and the structure to fall apart. Especially in very humid areas such as the Tropics, this problem is very common, because fungi grow particularly well in humid surroundings.
Wood is a very common material for building. In the use of wood for railway ties, as well as electricity poles, the wood must not decompose, as the replacement of these would be very inconvenient. Therefore, chemicals such as fungicides like creosote are used to prevent degradation. It is important to note that such chemical treatment can have a major impact on the polluting of the nature around it (such as the soil around the ties or poles), resulting in interference of the ecological balance.
Alternatives to the chemical treatment of wood by fungicides, are the technique of pressurizing the wood, as well as the use of plastic wood. Plastic wood is a new substitute for wood that is made out of recycled plastic. When this "wood" is no longer useful, it can be melted down into another shape or form. However, when chemically treated or pressurized wood is no longer useful, it is very difficult for it to decompose, and therefore piles up as waste.
One can see that the fight against the negative consequences of saprophytism leads to new problems. However, after having pointed out the negative and destructive aspects of fungal saprophytism, it is important to take into account that its role as a decomposer is crucial to prevent the buildup of waste material and replenish nutrients so that they can re enter into the cycles of life. If organic matter was not broken down, it would pile up to such an extent that life would eventually cease to exist.
The most important role of saprophytes is the decomposition of organic matter. However, in every day life, saprophytes are important in other ways. For example, in the production of blue-veined cheese, spores of Penicillium roqueforti or Penicillium glaucum (two kinds of molds) are used to create the specific flavor, texture, and appearance.
Saprophytes are very significant in that they can have positive and negative impacts. The fore mentioned impacts are only a few of the great range of effects that saprophytes can have. One tends to see saprophytes as more negative than positive, especially since they often spoil food, or create damage or inconvenience. Yet one should keep in mind the significance they have in the decomposition of organic matter, where they return nutrients of dead organic matter to the system, so that they are available for new growth.
By Ollga Maliko and Ethel Chan
All organisms require a fairly steadily supply of materials and energy from the environment to stay alive. Nutrition which involves dependence upon preformed organic molecules is called heterotrophic nutrution. The organisms using it are called heterotrophic. Saprophytism is a kind of extracellular digestion. The digestive enzymes are secreted from the cell and the food is digested outside the cell. As the food is digested, it diffuses through the cell wall. A saprophytic food chain goes from dead organic matter of decaying animal or plant bodies to micro-organisms.
Rhizopus secretes starch- digesting enzymes or amylase onto bread and absorbs the products of digestion. Bacterial saprophytes and saprophytic fungi are essential to the recycling of nutrients in natural ecosystem. They cause the decay of dead animal and plant material as they convert complex organic compounds to simpler ones. Saprophytism provides a means for saprophytes to obtain nutrients to build material and to be able to reproduce. Also, saprophytism helps the non-green plants (those that cannot produce food by photosynthesis) to survive. Humans use bacteria and molds for ripening cheese. The natural flavours of butter milk and cream are due in part to the saprophytic bacteria that grow in them. If saprophytism did not exist,the transformation of energy in the food web would be interupted. The dead organisms would not decay and the energy stored in them would not be reused therefore the exhaustion of energy resource would be speeded up. The whole food web would be affected and because the ecosystem is made up of many food webs, the whole ecosystem would be affected eventually. The decay of dead organisms would take a much longer time and the recycling of energy would not be as efficient as it is now.
REFERENCE
Kirk, David . 1975 Biology Today . Random House , P.105
Roberts, M.B.V . 1986 Biological for life . Nelson , P.184
Stauffer, Andrew . 1966 General Biology . D.Van Nostrad Company,Inc., P.445
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