Our son is researching for an in-class debate on the topic of whether the eyeball demonstrates evidence for design or evolution. Any good articles or websites to help us strengthen his position on the evolutionary side?
Hi Jessica,
Probably the evolution?-no-way! argument will center on all the marvelous intricacies of the eye (and vision in general). These are so amazing, how could it be the result of an undesigned process?
In your sonâs position, I would affirm right from the start that I view evolution itself is an amazing mechanism that reflects the ingenuity and creativity of the our God, the creator of the universe. Transcription of DNA between generations is almost perfect, allowing our capabilities to be passed on from generation to generation. But there is just enough change between generations so that new capabilities can sometimes be acquired. The reason that many students in your sonâs class can eat and drink dairy products is that 6 different lactase persistence mutations have been fixed in various branches of the human tree over the past 30,000 years. And in fact, every student in your sonâs class has about 70 different mutations that make their DNA different from either of their parentsâ.
As for the eye itself, one good resource is to learn about the evolution of opsin proteins that enable vision. It turns out that the opsin genetic sequences of various species form a nested hierarchy that reflects the evolutionary history and relationships of those species. Scientific American published a good article on the subject in 2013; it gives some helpful background information on how opsins work along with some links to the technical literature for the intrepid explorer.
Peace,
Chris
If we were the only creatures with complex eyes and there werenât different fossil types from 600 million years ago, having evolved from a hundred million years before, including arthropod compound eyes, then we might be justified in suspecting alien intervention in the past couple of hundred thousand years. In fact it would indicate bizarre divine intervention to constantly suppress the evolution of vision. But there are. And how this demonstrates Godâs ingenuity and creativity I have no idea.
https://link.springer.com/article/10.1007/s12052-008-0084-1 might be a good reference. Focusing on mollusks is both unlikely to be well-addressed by the opposition and perhaps not quite so distressing as human evolution.
For an example of possible anti-evolutionary arguments, Telescope-Like Eyes in a âSimpleâ Mollusk | Evolution News might be an easy target to practice critiquing. âSimpleâ is, of course arbitrary - scallops have had just as long as any other animal to evolve eyes, even though they lost their brains evolutionarily.
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If not too much of a rabbit trail, he may find it interesting to reference the ocelli - or simple âeyesâ - present in a lot of insects. For example, the common yellow jacket wasp (vespula sp.) has a triad of ocelli in addition to a pair of compound eyes. These simple ocelli eyes lack the elaborate retina found in vertebrate eyes and nor the complex lensing of compound eyes. Ocelli may reflect something of what an intermediate stage in eye evolution could have looked like. Ie. what began as a light sensitive cell, developed in time to something like an ocellus, and then then into something more complex.
The point being that the âWow, eyes are so complex! Evolution no way!â argument only holds water if one allows the proponent of that argument a tightly bound sample of what constitutes an eye, namely, vertebrate eyes. Broaden the sample of âeyesâ to include simpler sight organs and the âwowâ argument begins to look more like selective sampling, which I believe it is.
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@paleomalacologist, thanks for that post on the diversity of mollusc eyes. I had no idea how varied they were.
Molluscan eyes are extremely varied, ranging from a simple eye cup or pit eye that is open to the environment to closed lens eyes much like those seen in fish (Fig. 1), compound eyes that superficially resemble the eyes of flies, pinhole eyes, and eyes with mirrors. In fact, molluscs have some of the greatest morphological diversity of eye types among all animals, with seven to 11 different lineages possessing eyes (von Salvini-Plawen and Mayr 1977). The size of molluscan eyes ranges from less than 0.02 mm (0.00078 in.) across in the diminutive small spot snail, Punctum minutissimum (Timothy Pearce, Carnegie Museum of Natural History, personal communication), to more than 27 cm (11 in.) across in the colossal squid ( Mesonychoteuthis hamiltoni ), about 11 times the size of a human eye (Black 2008; Lilley 2008