Seedy Johnson I accept from a developmental basis: b) is more damning to me: a) Evolutionarily: The genetic precursors to the nervous system are found in a sponge, which lacks a nervous system. even though they CAN sense and respond to their environment. So their senses do work. HOWEVER: many of the genes are used for other purposes unrelated to nervous system function. So, unless I can identify sufficient nervous system function in organisms that lack nervous systems, I cannot claim a substitute nervous system from an evolutionary prior. I cannot. b) The neural tube extends on one side to the end of what becomes the spinal chord and the other side to the brain. The neural tube is closed in a cylinder. The ends, while differentiated, terminate. So yes, closed. I accept. “The part of the neural tube in the vicinity of the somites will form the future spinal cord. The rostral end of the neural tube will close and continue to grow to form the various structures of the brain.”

Seedy Johnson I accept from a developmental basis: b) is more damning to me:

a) Evolutionarily: The genetic precursors to the nervous system are found in a sponge, which lacks a nervous system. even though they CAN sense and respond to their environment. So their senses do work.

HOWEVER: many of the genes are used for other purposes unrelated to nervous system function.

So, unless I can identify sufficient nervous system function in organisms that lack nervous systems, I cannot claim a substitute nervous system from an evolutionary prior. I cannot.

b) The neural tube extends on one side to the end of what becomes the spinal chord and the other side to the brain.

The neural tube is closed in a cylinder.
The ends, while differentiated, terminate.

So yes, closed. I accept.

“The part of the neural tube in the vicinity of the somites will form the future spinal cord. The rostral end of the neural tube will close and continue to grow to form the various structures of the brain.”

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