Another week, another silly article at the C4ID website! Antony Latham, a GP in the Outer Hebrides, has penned a peculiarly illogical article (The compound eye of arthropods is a model for designing specialised digital cameras) leading from a paper which outlines how the arthropod compound eye has been used as a model for designing digital cameras. Ultimately, of course, he takes the usual creationist tack of claiming (i) that the evolution of visual systems has not been explained, and that (ii) this means that supernatural creation is the only alternative answer. Since Latham believes (I think) in only one more divine entity than I do, I guess that means the biblical god.
But what’s the basis for this claim that we don’t know how eyes (in this case compound eyes of arthropods) evolved? His claim is that we have no direct physical evidence (i.e. fossils) – and dismisses the paucity of soft-bodied fossils as an explanation because we have the Ediacaran fauna. The Ediacaran fauna are somewhat enigmatic (see the image to the right) – we don’t really know what kind of organisms these were, or whether they had light-sensitive structures (let alone structures capable of forming or perceiving images). Fossils of soft-bodies Pre-Cambrian organisms are still rare, and it seems likely that primitive eye-spots might be hard to recognise in such fossils.
Fossils are of course not the only evidence that may be used to study the evolutionary origins of eyes – biologists look at biochemical, molecular, genetic and of course morphological evidence within extant taxa. We also have functional studies, such as those concerning the transcription factor Pax6, which appears to be involved in the early stages of forming eye structures in diverse taxa.
But what is striking about the creationist approach – and let’s face it, Intelligent Design creationism is no exception – is that creationists cannot even be bothered to look at the depth of scientific investigation into questions around the origins and evolution of eyes. Instead they revel in their ignorance and proudly proclaim (generally erroneously) that evolutionary biology can’t explain <something>, therefore a god/creator/designer must have done <something>. Latham cites Gould’s Wonderful Life – a 24 year old popular science account of the rediscovery of the Burgess Shale fauna. I scratched my head a bit at this: while it is well over 20 years since I read it, I didn’t recall any attempt to describe the evolution of compound eyes. Sure enough, the three mentions of eyes found in the index merely point to descriptions of Burgess Shale arthropods which have compound eyes. [Latham also cites his own work, The Naked Emperor: Darwinism Exposed, portions of which can be read via Google Books. On the basis of those samples, I am unlikely to cough up for the book.]
Creationists, whose view of the world is seemingly blinkered by the closed and literalist view of a ‘holy book’, appear to believe that scientific investigation has similarly reached its limits and what is not yet understood will never be understood. Just a quick Google search reveals numerous publications in which biologists have applied, and are evidently continuing to apply, a wide variety of approaches to address the question of the origin and evolution of eyes (I’ve listed a couple below). As usual, the Intelligent Design creationist approach is found seriously wanting.
Oakley (2003) On Homology of Arthropod Compound Eyes Integr. Comp. Biol. 43 (4): 522-530. doi: 10.1093/icb/43.4.522 – addresses the issue of whether the compound eyes of arthropods are monophyletic or not: that is, whether they arose more than once in the arthropods.
Gehring (2011) Chance and Necessity in Eye Evolution Genome Biol Evol 3 1053-1066.doi: 10.1093/gbe/evr061 – Gehring’s lab discovered that the transcription factor Pax6 seems to play a universal role in the initiation of eye development during development. Gehring proposes (on the basis of conserved function between vertebrate and insect Pax6) that eyes are derived from a single evolutionary origin. This review is worth reading for the overview it provides of the conserved genetic pathways in eye development.
Just as I was about to publish this, an article by Rosa Rubicondior popped into my feed: Dunning-Kruger Creationists. It seems rather relevant.