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Friday, November 21, 2008

Decomposer

Decomposers (or saprotrophs) are organisms that consume dead organisms, and, in doing so, carry out the natural process of decomposition. Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substrates to get their energy, carbon and nutrients for growth and development. Decomposers use deceased organisms and non-living organic compounds as their food source. The primary decomposers are bacteria and fungi.

Importance of decomposers in the ecosystem

this is so wrong and didn't help me at all!!!!!!When a plant or animal dies, it leaves behind nutrients and energy in the organic material that comprised its body. Scavengers and detritivores can feed on the carcasses, but they will inevitably leave behind a considerable amount of unused energy and nutrients. Unused energy and nutrients will be present both in the unconsumed portions (bones, feathers or fur in the case of animals, wood and other indigestable litter in the case of plants) and in the feces of the scavengers and detritivores. Decomposers eat things by breaking down this remaining organic matter by breaking it into pieces. Decomposers eventually convert all organic matter into carbon dioxide (which they respire) and nutrients. This releases raw nutrients (such as nitrogen, phosphorus, and magnesium) in a a form usable to plants and algae, which incorporate the chemicals into their own cells. This process resupplies nutrients to the ecosystem, in turn allowing for greater primary production.

Although decomposers are generally located on the bottom of ecosystem diagrams such as food chains, food webs, and energy pyramids, decomposers in the biosphere are crucial to the environment. By breaking down dead material, they provide the nutrients that other organisms need to survive. As decomposers feed on dead organisms, they leave behind nutrients. These nutrients then become part of the soil. Therefore, more plants can grow and thrive.

Bacteria

Bacteria are the primary decomposers of dead animals (carrion) and are the primary decomposers of dead plant matter (litter) in some ecosystems. In soils, where decomposition occurs in terrestrial ecosystems, bacteria are capable of rapid growth and reproduction. This allows bacteria to rapidly utilize and decompose available organic matter, especially if the organic matter has relatively simple chemical bonds. Bacteria were traditionally believed to be less abundant in soils than fungi, and therefore less important as decomposers. In some grasslands, however, active bacteria can be more abundant than active fungal hyphae, and bacteria in such ecosystems are much more important in the recycling of nutrients. Bacteria can also be very important in agricultural fields, because tillage usually increases the abundance of bacteria relative to fungi.

Fungi

Fungi are the primary decomposers of litter in many ecosystems. Unlike bacteria, which are unicellular, most saprotrophic fungi grow as a branching network of hyphae. While bacteria are restricted to growing and feeding on the exposed surfaces of organic matter, fungi can use their hyphae to penetrate larger pieces of organic matter. Additionally, only fungi have evolved the enzymes necessary to decompose lignin, a chemically complex substance found in wood. These two factors make fungi the primary decomposers in forests, where litter has high concentrations of lignin and is often in large pieces.Also, If manufunctured with other organismes, may grow elsewhere from its chemical persuit, leaving behind the same type of bacteria left on the plant,tree organism, Etc.

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