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Evolution/why no evolution for survival? - followup


Hi Dana,

Thanks for your reply. The progression of the organs is apparently seen in the living organisms during the evolutionary history. Consider the evolution of brains and neurons, humans have them better than any other organisms. As it was mentioned, the adaptive mutation  have worked in this case. So the genes have apparently got better in this case during each level of species.

I was wondering how could better genes have evolved as if they are intelligently designed as they are just chemicals. Do you think we humans can make an organism similar to human with proper design in 4.5 billion years. If we cant make it, how could nature make humans in 4.5 billion years without any intervention.


Dear Ameen,

Many people make the mistake of thinking that evolution is random, and that changes happen randomly.  They also have the mistaken idea that this means that there has not been enough time for complex structures to have evolved from simpler beginnings.  Neither of these is true.

Natural selection is not random,  Once an adaptive mutation occurs, if it increases its bearer's reproductive success, it should be passed on and magnified in the next generation.  Natural selection can cause structures to change quite rapidly in many cases, sometimes so fast and to such extremes that biologists have dubbed certain examples of this as "runaway natural selection," as in the case of runaway sexual selection:

Some evolutionary biologists consider the human brain to be a product of runaway sexual selection.  Humans have long preferred mates who are intelligent, and will usually choose as intelligent a mate as will select him/her in return.  If humans with high intelligence (and we are assuming here that intelligence has a hereditary component, which it very likely does) tend to choose mates with high intelligence, then their offspring will also likely share not only that trait, but also the preference for a mate with that trait.  You can see how such a trait can be magnified over generations, and it would not take billions of years (or even millions; perhaps just tens of thousands or even less) for a brain with human intelligence to evolve.  It's not by random chance.  It's by selection.

No divine intervention required:  humans are capable of selecting mates for "desirable" (read:  adaptive) traits all on their own.



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Dana Krempels


I can answer questions about evolutionary mechanisms and theory, including genetic drift, mutation, natural selection, etc. I also can clear up misconceptions about evolution as it's sometimes talked about by those not well-versed in the subject (e.g., some politicians and many religious fundamentalists).


I have a Ph.D. in Biology, and presently teach Evolution and Biodiversity, Genetics, Botany, and Zoology at the University of Miami.

House Rabbit Society Beta Beta Beta Biological Honor Society

Exotic DVM Magazine (veterinary journal)

B.S. in Biology B.A. in English Ph.D. in Biology

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