Evolution naturally produces better features: stronger muscles,teeth and minds. Killing the weakest, evolution wipes defectivegenes out of populations.
The mutations are necessary for advance. However, they arerandom and, thus, mostly negative. Right? How does the natureeliminate them from the population?
I see that one mechanism is polygamy: male have higher mutationrates. They tend to reproduce as much as possible. Female havelower mutation rates, they couple with only with best men andcontribute much more to their offsprings. So, men generate as muchrandom solutions as possible, whereas the role of female is toconserve the best of them. This means that the most of the male(bad mutations) die unreproduced. This eliminates the bad mutationsand favours the progress of good qualities. The higher animalsstarted to form harems and tournaments over their ownership. Thisfurther fosters the elimination of weak men and profileration ofstrong genes. However, human monogamy has disabled this selectionmechanism. Best men are dedicated to only one woman. Other womencannot mix their genes with other good genes from previousgenerations. They are forced to look at the low quality men, whocarry degenerate mutations. Might be it is monogamy that makes ushuman but it implies that all genes reproduce.
Yet 100 years ago it was not a big deal since we still hadanother filter: our grandfathers were born in families that hadnormally 10 children (I am speaking about Russia) and only 2-3survived until reproduction (the population increased reallyslowly). I bet that those who survived had really good health:thanks to the bad health and immense selection pressure, thenegative mutants are eliminated immediately and populationmaintains a perfect genome (aka biologic health). Killing moreweakest in the current generation improves the health of nextgenerations.
However everything has changed during the 20th century. Theadvances in economy and medicine have almost eliminated theselection. The selection pressure has relaxed to essentially zeroso that everybody survives and leaves the same amount of offspring(and some scientists are even concerned that degradatoryindividuals leave more offsprings than the prosperous ones). Wehave even eliminated the infant mortality. We use baby incubatorsso that the people with the weakest health could survive andreproduce as normal and we are proud of it. It may sound strangebut the mutation rate has not changed at all. Does it mean that thehuman genome is in danger?
I see the situation like you have inherited a perfect mechanismand decided not recovering it from the inevitably adverse action ofentropy, that degrades it constantly. There is a constant chance,d, that every good gene is affected by a mutation. It is afraction of healthy genes that will fail passing to the nextgeneration. This will leave only (1-d) genes healthy inthe next generation. The fraction of healthy genes will melt like1, (1-d), (1-d)
