Video Transcript
What is the name given to an
organism that releases carbon dioxide into the atmosphere by breaking down dead
organic material? (A) Scavenger, (B) decomposer, (C)
composter, (D) carbon dioxider, or (E) decayer.
An organism that breaks down dead
organic material and releases carbon dioxide is part of one of the key steps in the
carbon cycle. The four main processes in the
carbon cycle are photosynthesis, respiration, decomposition, and combustion. In photosynthesis, carbon dioxide
is removed from the air. This happens in green plants,
algae, some bacteria, and phytoplankton. 6CO2 molecules react with six water
molecules, and sunlight energy is used to convert these into glucose, C6H12O6, and
six oxygen molecules.
The carbon from carbon dioxide in
the atmosphere is incorporated into organic molecules inside the plants. In the other three main processes
of the carbon cycle, carbon dioxide gas is released to the air. Their equations are very
similar. They all involve a carbon compound
reacting with oxygen to produce CO2 and water, as well as energy or molecules which
transfer energy. The question asks about the release
of carbon dioxide. So, we know the question is not
talking about photosynthesis, and we can eliminate it. The question asks about the
breaking down of dead organic material.
Let’s look at the remaining three
processes to see which one involves the breaking down of dead organic matter. Respiration is a process which
occurs in every living cell with a plant or animal. The purpose is to produce ATP
molecules from food, and ATP delivers energy to drive cellular processes. Decomposition occurs in decomposer
organisms. Decomposition is a type of
respiration where dead organic material is the food for the decomposer organism. Combustion, though it has a similar
equation to respiration and decomposition, is a human activity. Combustion is the burning of fuel,
such as fossil fuels, for example, coal, oil, and natural gas. So, we can see that an organism
that releases carbon dioxide by breaking down dead organic material is a
decomposer.