TFF asked:
"Is that evolution or adaptation?"
I guess if the new version is more effective at surviving in the new environment then it becomes an adaptation. It will lead to evolution if this adaptation leaves more descendants . Of course a mutation becomes an adaptation only if it leads to survival. Are these fish able to reproduce? Do the babies born with partial brains survive? I believe I know many people with partial brains.
DA wrote:
"evolutionary changes tend to be gradual."
Perhaps. But we don't really know. What about punctuated equilibrium? We may be observing an actual evolutionary change. If so the evolution-deniers will have some explaining to do.
I totally agree that the poisons we as a species are dumping must have an effect, even if mainly to speed up our own extinction. I actually think "nature" is quite capable of rapid adaptation even though mass extinctions may be involved in the process.
