um... we have always known about developing a tolerance for some thing...
That’s not quite ‘evolution’
for example, where are the intermediate stages of a set of eyeballs?
from no eyeballs to fully developed eyeballs, never any evidence of something in-between
nonsense - there are cave creatures with poor eyesight, but eyesight nonetheless.
Also moles fall into this category as well. Eyes, just not so good ones.
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.
Yeah, this is on the edge of either bad science or bad reporting.
What REALLY happened here is that those fish which ALREADY HAD a genetic resistance to the toxin survived to reproduce more than those members of the population which lacked those alleles/genes.
The non-resistanct fish did not live to keep their genes in the genome. Only those with the resistant gene survived and whelped their young.
This article hints at the usual bad language of ‘giraffes needed longer necks to reach the higher leaves so they adapted to have longer necks.’ um ... no.
Also see Lamarck — acquired traits are not inherited.
It has been shown that the rod and cone cells of our eyes are related to light sensitive brain cells that exist in a marine worm. This type of worm has not evolved itself much in the last 600 million years. link
So going from brain cells to light-sensitive brain cells would be an intermediate step.