King of the Castle
- Apr 30, 2000
- Reaction score
A SECOND publication this week by Australian National University scientists on the evolution of the eye has rebuffed intelligent design proponents who argue that such a complex organ could not have been arrived at gradually.
Paleobiologist Gavin Young discovered in a 400-million-year-old exposed former tropical reef that a fossil of a placoderm, a bone-covered predator fish, had eye casings that showed a transitional arrangement of muscles and nerves.
Earlier, ANU Centre of Excellence in Vision Science head Trevor Lamb published a paper that called the deep-sea hagfish, with primitive photoreceptors for eyes, the missing link in the evolution of the organ of sight.
Dr Young's placoderm and its visible muscle and nerve canals were evidence of an intermediate stage between jawless and jawed vertebrates, he said.
"It is transitional ... in that it is the only example among all living jawed species and all extinct jawed vertebrates where we have the combination of jaws plus a primitive eye muscle arrangement."
The eyeball was connected to the braincase by cartilage, as in modern sharks, and there was a primitive eye muscle arrangement as in living jawless fish.
Dr Young said that arrangement was different from all modern vertebrates, in which there is a consistent pattern of tiny muscles for rotating each eyeball.
Creationists and proponents of intelligent design argue that knowledge of evolution is gleaned from living creatures and that there is no historical evidence of evolution.
Dr Young said: "They would say 'all evolution is hypothetical and that all evidence is from living animals and yet you (scientists) maintain you know what happened 450 million years ago?. Where's the evidence?'.
"What's important with our fossils is that they demonstrate that something as complex as the vertebrate eye can be recovered from the fossil record from 400 million years ago.
"It shows there is a history."
The placoderm fossils were found about 10 years ago in the former reef near Lake Burrinjuck, west of Canberra.
Dr Young's findings are published in the latest edition of Biology Letters, a journal of the Royal Society, London.
I'm sure God just put it there to fool us, right?