Whoops, eye[I] was wrong: “Eye evolution questioned” was the headline on a report in The Scientist. “Invertebrates with vertebrate-like vision challenge the idea that the two groups of organisms have distinctly different visual receptors.” Will Darwin concede, then? After all, he’s pressed against the wall: “The standing dogma of eye evolution is challenged with the discovery of an invertebrate that sees light like vertebrates do, rather than like their more closely related cousins, according to a study published today (March 1) in EvoDevo.” Dogma is a strange bedfellow in a science article, but this one, a “standing dogma,” must have been sleepwalking in the lab.
One possible Darwinian escape is obfuscation: “Now the story is more complicated than it was before, when we thought there was a clear-cut division between vertebrates and invertebrates.” One outsider noted that evolutionary expectations had influenced prior work: “No one has looked for opsins in many animals, and this is exactly what we should be doing.” Should implies moral responsibility.
Rather than concede the argument to intelligent design, The Scientist offered more ways out for Darwin, such as bluffing: “Now it’s unclear which photoreceptor originally gave animals sight, and which kind evolved to sense light later. Or, perhaps an ancestor used both receptors to see, and over the millennia, one variety or the other lost its visual function.” The reporter did not seem to notice this answer only multiplies problems for evolutionary theory. Instead, Amy Maxmen cheerfully noted that ciliary opsin genes have even been found in sightless brachiopod embryos. Parrying that surprise into a win for evolution (02/25/2010), she ended, “brachiopods may provide key insights into how vision first evolved.”