# What is the probability of evolution of Humans to breathe in some other available gas instead of oxygen? [closed]

A general Overview:

Due to heavy pollution and the rapid accumulation of greenhouse gases, fresh oxygenated air is decreasingly available in the atmosphere and carbon dioxide levels are rising. (There is plenty of nitrogen present.)

In response humans are trying to save themselves by adapting to breathe Carbon Dioxide similar to plants.

Can evolution (natural or induced) change this basic aspect of human biology?

• "Breathing Oxygenated air" to breathing a convenient air, whatever is available?

Is it possible natural evolution could adapt humans to these changes? If yes, can anyone use the appropriate science to demonstrate the probability or the positive possibility this happening? If no, could gene manipulation make it possible?

• Are you asking an hard science calculation of the probability of some event? That is topic for a master degree thesis in Mathematics, not exactly a world building question. Also, you should specify a bit more your conditions. "convenient gas" is very broad. – L.Dutch - Reinstate Monica Aug 17 '18 at 12:09
• hard-science requires answers to be based on scientific papers and back up their reasoning with calculations and precise real-world data. That's a difficult requirement for people to provide answers. Are you sure that science-based reasoning is not enough for you? And please note that the same kind of scientific rigor is expected from you as the querent as you expect from answers to your question. Please be specific and add sources for any claims/ provide links with further reading material, for example about what is a "convenient air" in this question. – Secespitus Aug 17 '18 at 12:13
• Plants do not breathe CO2. They transform CO2 and H2O into sugars, freeing up O2. For breathing plants use our same O2 (that's why it's advised to not have plants in your bedroom) – L.Dutch - Reinstate Monica Aug 17 '18 at 12:21
• "...trying to save themselves by learning to breathe Carbon Dioxide exactly like trees..." You'd better register your idea somewhere before Mic Graves turns it into a Gumball episode. – Renan Aug 17 '18 at 12:26
• "Learning to breathe Carbon Dioxide exactly like trees": trees breathe oxygen just like humans. They feed on carbon dioxide (and water and light). – AlexP Aug 17 '18 at 14:52

No, oxygen breathing creatures are unlikely to evolve to not use oxygen, unless a better or more abundant element is in the atmosphere, which is unlikely because oxygen is about the best element there is for this purpose. Also, complex organisms are built on certain building blocks and to change a building block the whole creature would need to be scrapped, so humans and complex life would fail to adapt if you tried to change them now. If you started with the base ancestors you could potentially evolve a human like creature that doesn't breath oxygen, but it would be dificult.

Edit: A bunch of stuff related to how oxygen is one of the defining factors of life on earth and why it's so good at what it does. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3258841/

• I am afraid this doesn't fit the requirement for an hard-science answer. It's not backed up by equations, empirical evidence, scientific papers, other citations, etc. – L.Dutch - Reinstate Monica Aug 17 '18 at 12:26
• @L.Dutch So I should use citations? – Clay Deitas Aug 17 '18 at 12:27
• @ClayDeitas yes. – Renan Aug 17 '18 at 12:28

Evolution is adaptation to changing environment. Humans will adapt to your world by living in domes, and using breathing masks. So no need to evolve different biology.

Wild animals can adapt to moderate changes in atmosphere composition. Earth had periods with a lot more CO2 in the atmosphere than now. But oxygen remains the foundation of most life on earth.

The only living things that can switch from oxygen-breathing to photosynthesis or even use of other elements (chemosynthesis) are the primitive single-cell organisms (like algae, bacteria in hydrothermal vents). Once you start evolving into multi-cell organisms, your basic metabolism cannot be changed.

Due to heavy pollution and lots of greenhouse gases, fresh oxygenated air is reducing from atmosphere and lots of Carbon dioxide is getting generated. There is however nitrogen present in much amount. Humans are trying to save themselves by learning to breathe Carbon Dioxide exactly like trees or separating Carbon and Oxygen.....

Can evolution change the most basic thing: "Breating Oxygenated air" to breathing a convenient air, whatever is available?

You're talking about evolution to respond to this. Evolution is a grindingly slow process and won't work as a fix like this. You'd need to consider genetic alteration by artificial means.

However humans actually deal with these problem by using technology. We're more likely to create a controlled living and working space and employ breathing apparatus that to try altering ourselves genetically. The technical challenges of the former are trivial compared to the challenges posed by the later.

Is it even possible that even can adapt these changes in them?

No.

Your entire body chemistry is dependent on Oxygen. A creature not using oxygen would be entirely different from a human (or anything else we know of).

The side effects of trying to change to another breathable gas would be basically to require every single human biochemical process to be altered. We simply lack the capability of doing this and it's way beyond anything we would expect to be able to do for the imaginable future.

If yes, can anyone with the help of some science (I don't know), please provide the probability or the positive possibility of the same?

Nil.

As I've said, humans would try and find a (simpler) solution for the short term : adapting living quarters and using filters and artificial climate control (i.e. inside structures).

Trees and $CO_2$

As you mention trees and $CO_2$ note that the more likely scenario is using some form of cellular organism to generate Oxygen for us in vast facilities. Why alter humans when we might more easily create cellular life that can do exactly what we need - generate Oxygen for us ?

The Human Condition

Humans don't generally respond to problems they create by changing humans or human behavior. They "solve" the problem by finding the simplest (and most cost effective) fix using gadgets and technology that lets us carry on doing what we were. Altering human biochemistry is the very last thing that would be done.

Psychologically most humans would be violently opposed to such a physical change.

Sociologically I think even if some people did allow such a drastic change, they'd become a social grouping or minority, possibly hated by most other people ( "Carbos" leaps to mind as a term ). Humans do so like to hate people who are different. People who are different with an advantage would be really top of the list for dislike.