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espmp

Backwards evolution

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Hello

This is a question that I would like someone with insights in evolutionary theory to answer. I am neither a scientist nor have I studied the subject of evolution.

I am now halfway through Richard Dawkins essay-collection Science in the Soul, and I have a question regarding evolution, which Dawkins adresses a lot as a subject.

One of the basic principles of evolution is «survival of the fittest», but in my opinion that no longer seems to apply to the human race. I for example have severe allergies, and would probably not be alive 10 000 years ago. Either because I could not eat certain foods to sustain myself, or I would die from a fatal allergic reaction. My mother has diabetes and I’m guessing her chances would have been even worse than mine. So, we would both presumambly be dead, or we would never even have been alive in the first place because earlier humans with our genes would not have survived. The same idea, at least in my head, applies to humans with other genetically inherited diseases or syndromes. Some of those people are alive only with spesial care and aid, and would certainly not have survived in the past. It seems to me that we are defying the most basic principles of evolution, which in theory should apply to all life forms, in the fact that the «unfit» are allowed to survive (including myself) whereas we would not have had any chance in the past. 

So my question is this: are we humans in some way defying basic evolutionairy principles? And from a scientific perspective, is this «survival of the unfittest» a problem? It is quite evident that having the «best genes» from a survival standpoint does not grant the same benefit in modern society as it did 10 000 years ago. And at last, are humans as a race becoming weaker and more unsuited for survival because of this? 
 

The reason I am asking is because I have never seen this problem adressed. Not in high school, University (though I do not study science), nor in the books I have read. If anybody has an article or a book on this I would very much appreciate it, as I find this very interesting.

 

Thank you.

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We are not so much defying as deferring natural selection. The exceptional survivability of humans under current conditions is allowing more genetic variability to become part of our gene pool. Much of that will not add to survival and will, under harsher circumstances, be selected out, yet we do not know what will survive best in the future and there could be surprises. For humans that survival is often less about individual fitness than group fitness; having allergies but belonging to a group that manages itself better may still be better than having no allergies but belonging to a group that fights amongst itself.

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Yes that makes sense. So if one were to apply that to let’s say alligators, it means that in prosperous times with lots of prey more genetic variation would occur because specimens with «weaker» genetics would have the opportunity to thrive. And when there is less prey those genes would be selected out. Am I understanding this right?

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4 hours ago, espmp said:

One of the basic principles of evolution is «survival of the fittest», but in my opinion that no longer seems to apply to the human race.

It is important not to misinterpret this phrase (which was invented as a sort of advertising slogan for evolution by natural selection).

It does not mean the survival of the most "fit", in the sense of the most healthy. It means the survival of those who have the best fit for the environment (ie. those who are able to survive and reproduce in that environment).

All that human treatment for diseases has done is provide an environment where a wider range of people fit. This is not any different in principle from the invention of agriculture, or any other social or technological development.

Also important to note that evolution does not have a direction, so there is no "backwards."

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"Survival of the Fittest" actually refers to reproductive fitness: the individuals that can produce more offspring that themselves survive to reproduce are the ones that have the best chance for survival (actually, that's trivially deducible.) Darwin's Theory is really a specific case of the more general role of probability in Nature; things exist this way in Nature because they're the most likely to exist.

Random mutations are always occurring. Most are neutral; some are deleterious (worse) and occasionally some are immediately successful. More often than not, the neutral ones plod along in low numbers in the population until the environment changes, and then they can become beneficial ones. At that point, they will be selected and increase their numbers in the gene pool. The previously more efficient genes will then become the less efficient ones.

Type II Diabetes is an interesting case illustration. Once a pound of time ago, in the jungle where calories were hard to come by, an individual who could maintain body weight on only 800 cal per day would have a decided survival advantage over those who needed 1800 cal/d. Those genes were selected and were represented by a large gene frequency in the pool....Fast forward 40,000 yrs and  those descendants with the "easy keeper genes" find themselves in an environment where they can easily smother themselves in YoHos & DingDongs, and we see their BS rise to 250 and they have CAD before you know it. Those easy keepers were the ones who were insulin resistant-- good in the jungle, bad in civilization.

If society collapses or Bloomberg is elected president and outlaws BigGulps, they will once again have the advantage in survival.

The more varied & diverse the availability of alleles in the gene pool, the more likely a species will survive a change in the environment. It's the generalist species that survive or produce the next evolutionary stock and the specialists are usually doomed to extinction.

Edited by guidoLamoto

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