Sunday, April 25, 2010

Invalid hypothetical anatomy

Archy is speculating about Gould's idea that if you rewound the tape of life and replayed it, you might get some very different results…and he suggests that in a different world, molluscs could have replaced vertebrates as the dominant large metazoan. This is perfectly reasonable, but he chose to illustrate the concept, and my SIWOTI syndrome kicked in.
cuttle_w_raygun.jpeg
Noooo! He's got an arrow for a "large brain" pointing to an enlarged fleshy flap above the eyes. That's not where the cephalopod brain is located! They have a ventral nerve cord — the central brain would be deep, between the eyes and behind the beak, wrapped around the esophagus.
In this alternate universe, the intelligent cephalopods would be speculating about how those primitive, stupid vertebrates could have evolved into something as clever as they are, and they'd draw something frog-like and point to a puffy throat-sac and say, "look at its big brain!"

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