It is if the next generation is born with the tolerance instead of building it through exposure. The fish who have a propensity for tolerance are able to breed while those who don't are eaten. Over time, you get generations of whom the poison has no effect from birth. for example, where are the intermediate stages of a set of eyeballs?
Eye evolution is one of those items that is pretty well documented and can be seen in all its stages now in the mollusk to cephalopods, from simpler members of the family with just simple light censors to the advanced eyes of the squid and many stages in between.
They can’t be born with it unless it was in the parents’ genome already. *OR* if it happened along as a recombinant mutation in the genes. Over time those without the new gene or allele(s) become predominant in the gene pool, even if they are recessive, since those without the gene DIE more.
Box Jellyfish have TWO different eye designs. It’s like they were being bred to provide replacement sensors for some sort of electronic device.
So you are saying that it is “well documented”, that a light sensitive spot with all of the necessary combination of chemicals and material; the connective tissue with the correct balance of chemicals to allow the transference of this information to connect this light spot to the brain; the section of the brain that facilitates this tissue connection to be made to receive this stimulus; and the brain’s change so this new ability can be recognized -— (this ALL has to happen at the same time - one without the others is useless) -— THIS has been “well documented” -— all FOUR simultaneously occurring in one giant evolutionary leap ?????
would you like to explain that to me (and please use simple terms, I’m only an engineer - not a evolutionary scientist)
regards