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Evolution/why no evolution for survival?


Hi Dana,

Thanks for your reply regarding my question "why no evolution for survival". I need some clarification. Suppose a particular trait is advantageous for an organism, now how do the genes in the body know that it is advantageous as they are just chemicals. For example, let us consider an organism which is terrestrial and it finds flying to be advantageous for survival.  How that information is passed on to the genes and brains of the organism so that the subsequent generation will have that "flying" genes. Please note that I read all the links you sent.


Dear Ameen,

The genes don't really "know" what is adaptive.  Natural selection works *because* certain genes are adaptive.  If a gene promotes survival and reproduction, then it is more likely to be passed on to the next generation than genes that don't promote survival and reproduction as effectively.

Of course, it's a little more complicated than that, since genes are inherited in a package called an organism.  There are various models to explain how some less adaptive genes are still passed on (Balancing Selection).  But the bottom line is that a gene (and its phenotypic manifestation) can be:

adaptive - increases the likelihood of an organism surviving and reproducing
maladaptive - decreases the likelihood of an organism surviving and reproducing
neutral - does not affect the likelihood of an organism surviving and reproducing

Over time, adaptive traits governed by genes should result in those genes being passed to the next generation in greater proportion than less adaptive genes.  Their greater representation in future generations is a *result* of their being adaptive, not a result of the genes "trying" to do anything.

Hope that helps.



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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.

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Exotic DVM Magazine (veterinary journal)

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

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