Describe the three mechanisms of heterotrophy. Where on Earth might you expect to find one or the other of these three pathways to dominate?
What will be an ideal response?
a. Aerobic Respiration
The heterotrophic pathway that releases the most energy is aerobic respiration, which uses molecular oxygen to decompose organic matter through the process of oxidation, converting the organic carbon to carbon dioxide. Aerobic respiration occurs in environments in direct contact with the atmosphere.
b. Anaerobic Respiration
In environments where oxygen isn't present (e.g., in muds on the seafloor and lake bottoms, and in the guts of animals), anaerobic heterotrophs, especially bacteria, substitute other oxidized inorganic compounds in lieu of oxygen to decompose the organic matter. Bacteria use such oxidants as dissolved nitrate (through a process known as denitrification) or sulfate (sulfate reduction) or particulate metal oxides of iron and manganese.
c. Fermentation
Other heterotrophic organisms (certain fungi such as yeasts and some bacteria) perform fermentation, an important process that breaks down large, complex organic compounds into simpler ones that can be used by other heterotrophs. Fermenters do not oxidize organic matter, but they are able to utilize the energy that is released when complex organic materials are broken apart. Fermenters tend to live deeper in sediments where the alternative oxidants have themselves been depleted.
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Indicate whether the statement is true or false
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A) s B) p C) d D) f
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a. wave period b. wave velocity c. wavelength d. wave fetch