Why didn't we evolve to use Nitrogen?

vodkafan

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This is something I always wondered about. Nature doesn't usually waste resources. There is more nitrogen in air than there is O2. When we eat protein , it ultimately breaks down in our muscles into nitrogen. But we are breathing nitrogen in all the time along with our oxygen ! Our bodies just breathe it back out again. I just think evolution missed a neat trick there...
 
I just read my first post again and realised it might be misinterpreted. I didn't mean breathe nitrogen instead of oxygen. I meant why didn't we develop a parallel system in our bodies to absorb the nitrogen as well at the same time, to use as food.
 
This is something I always wondered about. Nature doesn't usually waste resources. There is more nitrogen in air than there is O2. When we eat protein , it ultimately breaks down in our muscles into nitrogen. But we are breathing nitrogen in all the time along with our oxygen ! Our bodies just breathe it back out again. I just think evolution missed a neat trick there...

An answer to your question can be deduced from the following:
Is Nitrogen Combustible?

By Vincent Summers, eHow Contributor
 
We evolved second to plants, which require nitrogen.
What's more, it is a component of both
-amino acids,
the building blocks of proteins
and
- nucleic acids,
DNA & RNA
So, in fact, we did evolve to use nitrogen.
 
The reason we use oxygen and not nitrogen is a matter of chemistry not evolution. It is oxygen's ability to oxidize (the term oxidation is taken from oxygen's affinity to react) that sets it apart from nitrogen. Nitrogen is perfectly content to remain as it is. It takes an external effort to cause it to do otherwise. Oxygen, on the other hand, actively seeks to react with nearly everything it encounters. Nitrogen's abundance assures oxygen's dilution, otherwise the atmosphere would burn away. That is the simple explanation. I could go on but, I don't want to be boring or bumptious.:)
 
Yes nitrogen is pretty inert stuff. Still, I think people didn't really get the thrust of what I was getting at. Never mind!
 
vodkafan said:
Still, I think people didn't really get the thrust of what I was getting at. Never mind!
That's too bad. I like these types of questions. If you'd like to elaborate on your question a little perhaps we can expand on the answer.
 
Well, protein breaks down in our bodies to nitrogen. So we need nitrogen. We have to go through the process of eating protein to get the nitrogen. I am just surprised that evolution didn't find a way to liberate nitrogen directly into our blood from the air we breathe. Maybe a different type of blood corpuscle or something. So you would have some corpuscles carrying nitrogen through the blood at the same time as red corpuscles are carrying oxygen side by side.
All you would need to ingest food wise is carbohydrates for energy, vitamins and minerals. Anyway, it didn't happen. The nitrogen in the air just goes in our bodies and back out uselessly. I just wondered why nature missed that trick. Maybe nitrogen is just too stable and inert.
 
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