Answer:
D. Makes food molecules using chemical energy
Explanation:
Like all autotrophs, chemoautotrophs are able to “fix” carbon. They take atoms of carbon from inorganic compounds, such as carbon dioxide, and using it to make organic compounds such as sugars, proteins, and lipids.
Chemoautotrophs are commonly found in environments where plants cannot survive, such as at the bottom of the ocean, or in acidic hot springs.
Some types of chemoautotrophs also play critical roles in plant-based ecosystems. Although plants perform carbon fixation in these ecosystems, many plants rely on chemoautotroph bacteria to fix nitrogen, which is necessary to make amino acids and proteins.
Function of Chemoautotroph
Basis of Ecosystems Without Sunlight
Chemoautotrophs form the basis of the energy pyramid for ecosystems where photosynthesizers can’t survive. Without chemoautotrophs, life would only be able to exist where energy could be derived from sunlight.
They are the basis of some deep sea ecosystems, such as those existing around deep sea hydrothermal vents.
Scientists have speculated that chemoautotrophs could form the basis of life on planets which receive less sunlight than earth.
Nitrogen Fixation
One type of chemoautotroph, Nitrosomonas, plays the crucially important role of fixing nitrogen in the soil of some ecosystems. Like most chemoautotrophs, Nitrosomonas can take toxic chemicals – in this case ammonia – and turn it into materials for life.
Nitrosomonas harvests nitrogen from ammonia, and fixes it into organic compounds which can then be used to produce amino acids, proteins, and other crucial materials for life.
Possible Origin of Life
We have no fossils of the first cells on Earth, so we are not able to say at this time what they were like. We know that they had to be autotrophs, since they would have had to produce all of their own organic materials.
Some scientists think that the first cells were likely photoautotrophs, deriving energy form sunlight – but other scientists think the first cells may have been chemoautotrophs, and that photosynthesis may have evolved later.
If true, this would make all of us descendants of chemoautotrophs!
