Why do so many kids get asthma in really polluted areas? Shouldn't their lungs adapt, according to the theory of evolution? And why are so many people getting cancer because of all the toxins in our environment? Shouldn't our bodies adapt to fight the toxins, or embrace them in some way? Also, how do...
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answers:
Cal King say: It appears that you think evolution will lead to the appearance of super organisms that are immune to anything found in the environment. That is simply not possible, because evolution cannot produce organisms that violate the laws of physics or chemistry. Protein for example, starts to denature at about 50 deg. C. This is a law of physics. No matter how many mutations one may have, we cannot produce proteins that can, for example, withstand temperatures that are 1,000 degrees. Evolution cannot produce organisms that violate the law of gravity either. Therefore just because living organisms cannot evolve to be impervious to some of the things found in the real world does not mean that there is no evolutionary change. All living organisms have DNA and DNA can be damaged by UV light. Therefore no matter how any organism may evolve, it may not be able to stop UV light from damaging DNA. Organisms can evolve ways to hide DNA from UV light, but that is the best any organism can do. Indeed we evolve pigments to shield our body from the harmful effects of UV light by absorbing it.
Further there are some instances in which organisms have successfully evolved ways to be unaffected by toxins. For example the earth did not use to have so much oxygen, and in fact oxygen is still poisonous to anaerobic bacteria. When photosynthetic bacteria evolved, they released a lot of oxygen into the atmosphere, which was toxic to most organisms. Yet, if you look around us, there are many living things that can not only tolerate oxygen, and they actually require oxygen to survive. Therefore what was once toxic to living organisms has now become vital and indispensable as well as non-toxic. Similarly, people may indeed evolve one day to be able to cope with the toxins that make us sick. After all, the mongoose has evolved immunity to cobra venom, and deer have evolved immunity for poison oak toxins.
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