A surprising find for evolutionary neuroscientists is that a tiny life form that lived more than half a billion years ago had a brain. Creatures like Cardiodictyon were not supposed to have had brains.
MindMatters sort of ‘buried the lede’ on the actual article. Early arthropods were already known to have brains, but this new study changes the concept of how the brains are organized.
The authors propose that all brains, from arthropods to vertebrates, have the same basic plan and the same basic functional connections to inputs and outputs.
In Cardiodictyon, three brain domains are each associated with a characteristic pair of head appendages and with one of the three parts of the anterior digestive system.
“We realized that each brain domain and its corresponding features are specified by the same combination genes, irrespective of the species we looked at,” added Hirth. “This suggested a common genetic ground plan for making a brain.”
This has important implications when comparing the nervous system of arthropods with those of vertebrates, which show a similar distinct architecture in which the forebrain and midbrain are genetically and developmentally distinct from the spinal cord, they said.
This uniformity is actually better news for the design side than a timeline change. It adds one more brick to Behe’s “evolution by subtraction” mode.
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I’m especially receptive to this info right now because I’m animating the embryonic development of larynx, outer ear, ossicles, etc. Each structure starts as several social clubs of default cells, located on specific segments of the embryo. Each little social club knows which part of the ultimate structure it is meant to become, and knows how to shape itself into its destination part and how to move into the joined-up structure. It’s way beyond astonishing. Purpose on top of purpose on top of purpose.