Hey. I'm not a biologist, but I love to read about the evolutionary origins of different species. I also realized that the current knowledge on this matter is still incomplete. Now, when reading Wikipedia about cnidarians, ctenophora and other primitive types, I started to wonder. Cnidaria and ctenophora are very similar, so they are likely related, but it is still not known which type came first. I suddenly came up with a theory. We know that cnidaria have the poisonous cells filled with neurotoxins. They are rarely used as an offensive weapon, rather as a defense. Doesn't it mean that they evolved from an evolutionary pressure of some predators that had must have had neurons? Defensive weapon implies existence of some predator. The target of the poison (neurons) means that the predator must have had neurons. So, that means that cnidaria are more advanced than ctenophora and their predecessor more likely resembled ctenophora than the other way. We could also approximate the time when it all happened. The apperance of cnidaria must have occured shortly after the apperance of predators with neurons. Does this chain of thought have any probability of being true?