Brian Thomas Misses the Point

I could use that headline for every article, but “Fossil Skin Pigment Evolved Three Times?” is a particularly strong example. A new paper in Nature – which you can read all about in this blog post by palaeontologist Shaena Montanari – investigated fossil pigment of three different extinct marine reptiles and concluded that the trait known as melanism had independently evolved in each of them. This is to say that a darker colouring, perhaps for the purposes of heat absorption and retention, was selected for and became dominant in each group of animals separately. But Brian Thomas has apparently misread this to mean that the pigment melanin, which is what produces the colour, independently evolved three times and has written a 13-paragraph article based on this misconception.

For example, he says:

According to the Nature study authors’ reconstruction, the same melanin-manufacturing capabilities evolved three separate times. This outlandish difficulty provides the third clue that these pigment evolutions never really occurred.

To emphasise quite how profound this mistake is I’ll draw your attention to a type of melanism that you may be more familiar with: the “industrial melanism” of the peppered moth (above). While some creationists like to quibble over the photographs taken during the original Kettlewell experiment, it is indisputable that the originally dominant trait was for the moths was to be lighter coloured, but that during the 1800s they were much more likely to be darker before returning to the lighter trait in more recent times. This change did not involve the evolution and devolution of melanin, however, but simply the rise and fall of a trait that created more of it than usual. Melanin is widespread in the animal kingdom; melanism is less so.

That really wraps up the main thrust of the article, but there are a few specifics you might be interested in:

It’s as easy to say “melanin evolved by natural selection” as it is to say “computers evolve by weather changes,” but the details reveal reasons to reject statements like these.

That would be what they call a ‘joke.’ A footnote adds:

Or, in the technical language of Nature (reference 1), “It is therefore feasible that selective pressures for fast growth, large size and/or homeothermy also selected for melanisation in extant (and fossil) leatherbacks,” although no analysis of practical feasibility was presented.

Again, see how he confuses melanin with melanism (“melanisation”).

The next paragraph says:

Four Polish researchers published a review paper in 2013 describing some of the cells, signaling pathways, proteins, and hormones involved in making melanin, including features that precisely distribute melanosomes across the skin during embryonic development. They include tyrosinase, tyrosinase-related protein 1, tyrosinase-related protein 2, microphthalemia transcription factor (MITF), E-cadherins, P-cadherins, protease-activated receptor-2 (PAR-2), stem cell factor (SCF), neuregulin 1, cysteine DOPAquinone, DOPAchrome tautomerase (TYRP2/DCT), antiapoptotic protein Bcl-2, protein fibrils, hepatocyte growth factor (HGF), endothelins, adrenocorticotropic hormone, collagen, fibronectin, integrins, endothelins, c-kit, Wnt proteins, Delta membrane protein, and others.

Look at those strange words! Clearly melanin could never have evolved at all! Continuing on this vein, Thomas says:

Since no experiment has ever demonstrated a natural process inventing even a single biochemical like these, and since experiments have demonstrated that selection of mutations cannot invent them, why expect evolution to invent melanin manufacturing and distribution once, let alone three separate times, in these marine reptiles?

This is cited to a certain infamous Ann Gauger/Douglas Axe collaboration – you know, the one about which YEC Todd Wood said:

Instead of ancestral reconstruction, Gauger and Axe focused directly on converting an existing enzyme into another existing enzyme. That left me scratching my head, since no evolutionary biologist would propose that an extant enzyme evolved directly into another extant enzyme. So they’re testing a model that no one would take seriously? Hmmm…

Yes, that one.

Anyway, the one other thing I wanted to point out is that Thomas still hasn’t gotten his head around the notion that hardy molecules like melanin can actually survive millions of years. He says:

A second challenging clue is the presence of original biochemistry in specimens assigned an age of, for the ichthyosaur, 190 million years. The researchers offered no reason why melanin should ever be expected to last even a tiny fraction of that supposed span. If the fossils were actually that old, then their melanin should have chemically broken down long before now, leaving nothing behind.

Since the last time this specific issue came up I’ve found an article by an actual chemist on the OEC website Reasons to Believe explaining how eumelanin (a type of melanin) could have survived in the squid ink sac that Thomas has previously talked about. In addition, a news article associated with this story says:

“Our results really are amazing. The pigment melanin is almost unbelievably stable. Our discovery enables us to make a journey through time and to revisit these ancient reptiles using their own biomolecules,” said Dr Per Uvdal of the Lund University’s MAX IV Laboratory, a co-author of the study published in the journal Nature.

This whole argument should be retired. A good place to start would be the speedy retraction of this ICR article, I think. Such a simple error as this is not a good look.

(Here’s a screenshot in case that actually does happen.)