Cambrian Predator Had Modern Eyes
An exquisite fossil alleged to be 515 million years old shows a compound eye so complex, it looks as good as any modern insect’s eye. The eye belonged to Anomalocaris, the fearsome predator of Cambrian seas, one of the key players in the Cambrian explosion – the sudden appearance of all the animal phyla in the earliest rock layers.
The discovery was announced in Nature.1 Previous fossils of Anomalocaris did not show clearly the structure of the eye. Paterson et al. found samples in South Australia with exquisitely preserved impressions in rock, so clearly defined that individual lens facets (ommatidia) could be studied for their optical properties. They counted 16,000 ommatidia in these eyes, compared to 3,000 for modern houseflies and 28,000 for dragonflies (the modern insects with the sharpest vision). The complete eyes were 2-3 cm across on this swimming shrimp-like arthropod that grew as large as 2 meters. Their arrangement on stalks protruding from the body provided excellent vision probably over a 360° field of view.
As with pixels in a camera, the more ommatidia, the better the image quality. In New Scientist, Paterson was quoted as saying that “Anomalocaris had remarkable vision, rivalling or exceeding that of most living insects and crustaceans … Very few modern animals, particularly arthropods, have eyes as sophisticated as this.” It would be impossible to modernize these modern eyes. PhysOrg included a photo of the rock impression showing the detailed lenses, while Live Science shows what the creature looked like. The Illustra Film Darwin’s Dilemma opens with animations of this amazing hunter and swimmer in action.
The authors promised to discuss “the origin of compound eyes.” Did they deliver? The reader can judge whether this statement in abstract answers the question:
These fossils also provide compelling evidence for the arthropod affinities of anomalocaridids, push the origin of compound eyes deeper down the arthropod stem lineage, and indicate that the compound eye evolved before such features as a hardened exoskeleton. The inferred acuity of the anomalocaridid eye is consistent with other evidence that these animals were highly mobile visual predators in the water column. The existence of large, macrophagous nektonic predators possessing sharp vision—such as Anomalocaris—within the early Cambrian ecosystem probably helped to accelerate the escalatory ‘arms race’ that began over half a billion years ago.
So far, no delivery. They’ve only stated that the eyes, being present, may have driven subsequent evolution of other animals. A search for the word “origin” only shows a repeat of that idea down in the paper, instead of answering how Anomalocaris got its sophisticated visual equipment, rivaling that of modern insects. A search for “develop” yields a similar frustrating assertion: “The structure and development of ommatidia in arthropod compound eyes support a single origin some time before the latest common ancestor of crown-group arthropods,” the abstract says – but that only makes sense if one already assumes they evolved. It doesn’t say how they evolved. Searching on the word evolution or evolve is no help, either; the most relevant part of the paper is remarkably empty of empirical evidence:
The finding that Anomalocaris, resolved more basally than Schinderhannes in the arthropod stem group, possesses the same kind of ommatidial packing as in Schinderhannes and crown-group arthropods pushes the origin of compound eyes further down the arthropod stem group. As such, compound eyes evolved earlier than the origin of a hardened tergal exoskeleton and biramous trunk limbs (the latter characters being present in Schinderhannes but not anomalocaridids). We infer that the stalked eyes of all Radiodonta (that is, anomalocaridids) are arthropod-type compound eyes. Previous inferences of this character distribution based on gross morphology (size and stalks) now have direct support. The mode of growth of the anomalocaridid eye is presumed to be the same as in other arthropods, in which new elements are added at the margins of the visual field. The next most stem-ward (basal) taxon in the arthropod stem group, Opabinia,2 also has stalked eyes, but direct observation of ommatidia is needed to ascertain whether they are compound.
Unpacking that paragraph means that elaborate compound eyes are now established to appear earlier than previously thought. In other words, they failed to deliver on the origin of compound eyes, except to say that they evolved because they evolved earlier. Their evolutionary tree shows this group earlier than trilobites (which were known to have elaborate eyes), and no eyed organisms before them other than Opabinia (which might have had compound eyes), and Kerygmachela, which is thought to have been blind. This is what they labeled “The early evolution of compound eyes” in the caption.
Maybe the popular press can help. PhysOrg tried: “The discovery of powerful compound eyes in Anomalocaris confirms it is a close relative of arthropods, and has other far-reaching evolutionary implications,” the article teased. “It demonstrates that this particular type of visual organ appeared and was elaborated upon very early during arthropod evolution, originating before other characteristic anatomical structures of this group, such as a hardened exoskeleton and walking legs.” Bottom evolutionary line: the eye “appeared.”
Enter New Scientist: “Paterson says the threat of Anomalocaris would have forced other species, both prey and other predators, to evolve rapidly. Hard shells were an obvious way to go, and evolved soon after,” Michael Marshall wrote – again dodging the question of where the top predator got its vision. Live Science was not even a contender: “Such precise vision would have given these predators an advantage over their prey, which would need to evolve their own visual capabilities to avoid being eaten.” Anyone else want to try? A scientific explanation for “How the arthropod got its eyes” is waiting to be written. Till then, it’s just so story-like.
1. Paterson et al., “Acute vision in the giant Cambrian predator Anomalocaris and the origin of compound eyes,” Nature 480 (08 December 2011), pp. 237–240, doi:10.1038/nature10689.
2. In addition to Anomalocaris, the film Darwin’s Dilemma also includes animation of Opabinia and other species found in the Burgess Shale.
Here we go again. When confronted with the sudden appearance of a complex organ, the Darwinists resort to miracle words like appeared, arose, developed, or evolved, with (1) no explanation for how an unguided process produced a sophisticated visual system, and (2) no transitional forms leading up to it. The evolutionary explanation, therefore, could not be considered any less miraculous than creation, and more so, since there is no designing intelligence to fabricate, assemble, and program the parts. Remember that eyes by themselves are just part of the problem. They need to be connected to a retina, optic nerves, a brain, muscles, instincts, and maintenance systems, and then combined into a functioning animal able to use all of that equipment.
The authors must be forced to admit the obvious. They have no other explanation than to say eyes just popped into existence at the beginning, fully formed, fully functional, fully designed. This is the same old Popeye theory of evolution we’ve seen over and over again (5/31/2005, 12/13/2007, 10/31/2010 commentaries).
I’m Popeye the Darwin man;
I fabricate all I can.
I fight to the finish
To ID diminish;
I’m Popeye the Darwin man.