Probably because it doesn't exist in almost deadly situations in nature. Only in very low concentrations or completely deadly (volcanoes). Besides, if something will be beneficial it doesn't automatically mean that it will evolve.
Low is something relative. According to this: Concentrations as low as 667 ppm can cause up to 50% of the body's haemoglobin to be converted to carboxy-haemoglobin (HbCO).
Evolution doesn't always do everything that is conceivably beneficial, even if the survivability benefit outweighs the cost. In this case, though, I can think of a few plausible reasons why an aversion to carbon monoxide would be of limited benefit. In nature, the place we are most likely to encounter it in deadly levels is as a result of a fire, and most animals already have an aversion to fire or extreme heat that would probably serve to protect them. Once the fire is gone, carbon monoxide would dissipate on its own rapidly under most realistic conditions. Substantial combustion in enclosed spaces was probably rare, apart from our occasionally carrying our own fires into caves. Also, our ability to smell hydrogen sulfide (H[sub]2[/sub]S) and ammonia (NH[sub]3[/sub]) may have been more important to detect putrefaction (and thus to separate good and bad sources of food and potable and unpotable water), rather than as a means to avoid the gases themselves.
http://www.sciforums.com/showpost.php?p=1921110&postcount=19 You don't even know what you believe...Please Register or Log in to view the hidden image! http://www.cnn.com/TECH/9801/15/contaminated.rock/index.html http://nssdc.gsfc.nasa.gov/planetary/marslife.html http://space.newscientist.com/article/mg15220610.200 http://www.gasresources.net/DisposalBioClaims.htm
guys and girls...we cannot smell CO because it is not a functional group and has no functional group to bind to the receptor protein in our nose. TGP protein...was it
Yea, biological origin does not mean they are alive. It means they are produced by living organisms or are the result of biological processes. What don't you understand about that ?
look Enmos...we are a machine...ok...we can't fly...now you ask me, "well draqon, why can't we fly?"....because we don't have the wings to fly...but you ask me again..."why not?"...well we just dont have the wings to fly... what dont you understand? :bugeye:
In addition to things like logistics...think about it...what if we could smell carbon monoxide...what if we could smell nitrogen...and all other light molecules? well then, wouldnt that require our nose to have bigger and more receptor proteins? wouldnt that also mean we would constantly be smelling something...even though we could care less what nitrogen in air smells like? For example...it could be burning outside and we could be in danger but because we (hypothetically speaking) have a receptor protein to smell nitrogen in air, we cannot get a smell of the burning ash from the fire...kaboom we are dead... meanwhile the guys and girls who cant smell nitrogen in air but can smell ash...got to be alive...made babies...and passed on the genes.
The chemical elements in the periodic table are not "produced" by living organisms. Chemical elements are not the result of any biological processes. Rather, biological organisms are "produced" by the chemical elements. Do you know what element means? This is the chemistry forum. Do you know what chemistry is? Kindly take your vitalist biologic nonsense to the pseudoscience forum or religion forum where it belongs.
Wtf ? Where did I say ELEMENTS are produced by biological organisms ? Where did I say ELEMENTS are biogenic ?