ctenophores

For an eye-opening introduction to ctenophores, look up some youtube sequences of Beroe eating other ctenophores.

If you haven't watched youtube videos of ctenophores eating one another yet, you are in for a treat.

Evidently ctenophores don't use serotonin anymore, and have found some other molecule they like better for what they are doing.

Seeing how alien ctenophores seem, despite having evolved here, the thesis seems shaky.

Too much fluff for a very basic point: ctenophores are different kinds of organisms than we’ve come to expect.

In this view, ctenophores are the last representatives of one of those alternatives.

I found this quote interesting: > Recent discoveries have shown that ctenophores have no synapses, the tiny connections between neurons.

We still have the problem of the ctenophores.

My question is whether ctenophores sleep.

For ctenophores and for several other groups of simple animals the main method of locomotion is by using cilia, not muscles, and this appears to be a primitive characteristic of animals.

- Ctenophores (comb jellies) might have evolved nerves independently.

[1],[2] So it would seem as if the ctenophores lost the ability to produce these chemicals, and went on to develop a nervous system that didn't require them.

I can't make sense of this: "Moroz reached this conclusion by testing the nerve cells of ctenophores for the neurotransmitters serotonin, dopamine and nitric oxide, chemical messengers considered the universal neural language of all animals.

“Different” appears 24 times in the article, almost every single instance of which is just, “ctenophores are different.” There’s not much more information in this article than that.

The fact that ctenophores use a different set of neurotransmitters is taken by Moroz as strong evidence that neural systems evolved more than once - and furthermore, according to the article, "Moroz now counts nine to 12 independent evolutionary origins of the nervous system" on the basis of other differences.