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Religious Ceremony Leads To Evolution of Cave Fish
An anonymous reader writes "A centuries-old religious ceremony of an indigenous people in southern Mexico has led to evolutionary changes in a local species of fish, say researchers at Texas A&M University. Apparently since before Columbus arrived, the Zoque people would venture each spring into the sulfuric cave Cueva del Azufre to beg the gods for bountiful rain. As part of the ritual, they released into the cave's waters a leaf-bound paste made of lime and the ground-up root of the barbasco plant, a natural fish toxin. The rest is worth reading, but the upshot is that the fish living in the cave waters eventually got wise, genetically speaking."
The difference is the method of selection: In one case, humans are altering the environment of a species, resulting in evolutionary changes.
Selective breeding involves just that, selecting the traits you want in the animal and then breeding only animals with those traits. Selecting what you breed.
The environmental alteration version doesn't involve any conscious desire for selection; any meddling that alters survival and breeding rates is good enough. These people aren't purposefully poisoning the water to select the fish in the river that are hardest to poison.
I'd say that the new fish were indeed unable to breed with the fish without the adaptation, as those fish were dead