According to the heterotroph hypothesis, which event had to occur before oxygen filled the atmosphere?
Heterotrophs had to remove carbon dioxide from the air.
Autotrophs, which make their own food, had to evolve.
Heterotrophs had to evolve.
Autotrophs had to convert atmospheric nitrogen to nitrate
Heterotrophs had to carry out their metabolic activity in the presence of oxygen.
I think it's b but i'm not sure...
Heterotrophs had to remove carbon dioxide from the air.
Autotrophs, which make their own food, had to evolve.
Heterotrophs had to evolve.
Autotrophs had to convert atmospheric nitrogen to nitrate
Heterotrophs had to carry out their metabolic activity in the presence of oxygen.
I think it's b but i'm not sure...
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You got it, honey. Before we got a breathable atmosphere, autotrophs had to evolve to perform photosynthesis, which releases oxygen as a waste product. We needed green plants, including and especially algae in the oceans, to chug away producing glucose and releasing oxygen before there was a breathable atmosphere for us heterotrophs!
Now, we help a bit by putting carbon dioxide back into the atmosphere (which is needed for photosynthesis), but early autotrophs had plenty of CO2 in the primordial atmosphere to perform photosynthesis before animals evolved.
I used to kid my classes when we were studying ecology and the cycles of photosynthesis and cellular respiration and how they are exact chemical opposites made possible by photosynthesis by asking them, "Have you thanked a green plant today??" Of course, they would groan at me, but everything we eat and the oxygen we breathe can all be traced back to photosynthesis.
Now, we help a bit by putting carbon dioxide back into the atmosphere (which is needed for photosynthesis), but early autotrophs had plenty of CO2 in the primordial atmosphere to perform photosynthesis before animals evolved.
I used to kid my classes when we were studying ecology and the cycles of photosynthesis and cellular respiration and how they are exact chemical opposites made possible by photosynthesis by asking them, "Have you thanked a green plant today??" Of course, they would groan at me, but everything we eat and the oxygen we breathe can all be traced back to photosynthesis.