Tuesday, 23 October 2012
“Grandmother, Why Do You Have Such a Big Brain?”
Cambrian animals were by no means simple. A fossil of Marrella splendens (Marrellomorpha). Image courtesy of Wikipedia Commons.
Early animals should not be as complex as modern ones, at least not according to Darwinian evolution. But sometimes they are.
Gregory Edgecombe, a palaeontologist at the Natural History Museum in London, and colleagues recently published a paper in Nature. Among other animals, they examined the fossil of a well-preserved small invertebrate called Fuxianhuia assumed to be 520 million years old.
Edgecombe acknowledges that the brain of Fuxianhuia is "fairly sophisticated” and strikingly similar to today’s insects and some crustaceans.
If a brain does not change in “520 million years”, then evolution is in big trouble. After all, the Cambrian Explosion was a huge dilemma for Darwin. It still seems to be – at least for his modern successors.
Switek, Brian. 2012. Picking an ancient brain: Traces of an early arthropod’s neural tissue might be evidence of a long-running evolutionary arms race. Nature News (10 October).