Seashell Evolution and World War 2

Behold kintsugi, the Japanese art of repairing objects with gold, so as to draw attention to the uniqueness of the repaired object. Hopefully, the significance of this will become apparent when I'm done typing up this story.

I'd like to relay a story from one of my evolutionary biology professors (liberal arts degree, anyone?). Although this occured around 18 years ago (and my retelling is undoubtedly affected by the vagaries of human memory multiplied by the ravages of time) this one stuck with me, and I think I've got the gist of it down here.  Although it's hard to be certain, I THINK that the biologist I'm speaking about is Geerat Vermeij (now at UC Davis). 

The story discusses how lessons from seashell evolution helped America win World War 2. ​

Nice example of repair in an otherwise butt-ugly shell.

Seashell Evolution, Writ Small

Obviously, there are many different types of seashells out there. There are countless variations on width, length, color spiral number, overall size, protrusion number and design, etc. The biologists natural question is how this came to be - surely there are an abundance of designs for different organisms that are best adapted to specific depths, predators, etc - this is classical evolution - but how do individual members of a species come together and genetically hard-wire into them a single best design for the species? 

The (natural) occupant of any shell is totally defensive. When a predator comes calling, the shells occupant sucks itself into the deepest recesses of its carapace and hopes that its shell is strong enough to withstand the assault. If it is, life goes on. If the design is not strong enough, game over eh? 

In the 1940s, a new graduate student (Vermeij...?) arrived. This guy was blind, but apparently amazingly talented - he could identify a massive range of shells simply by holding them. It's not the kind of thing that gets you laid, but still an interesting party trick. Due to his reliance on tactile stimulation in his studies, Vermeij made an interesting observation during his study of fossilized shells - a large proportion of the shells in the fossil record had been damaged at some point during the animal's life. Surprisingly, this little bit of information was enough for him to make an interesting deductive leap and solve one of the most perplexing questions concerning the current state of seashell diversity. This, consequently, would make him a huge celebrity to the dozens of malacologists out there (still not a great way to get laid). 

I'll ask you to use your imagination for a moment and imagine a predator attacking a mollusk. For all but the largest shell-dwellers (teenage mutant ninja turtle-sized), the shell is not going to be so tough that it cannot be damaged. Thus, smaller creatures have to rely on a bend-but-don't-break strategy. A shell with an unusual configuration that prevents a predator from exerting force or leverage (think of how goddamn hard it is to open clams or oysters) or a design that is designed to eventually frustrate a predator into abandoning the morsel inside as not worth it  would be optimal.  

In the case where the shell is good enough, the end result of this process is a shell that is, to some extent, damaged. This is bad, obviously, for the occupant, but there are protocols for this sort of thing. The occupant of the damaged shell will go to work repairing the damage almost immediately. What else is there to do when you have no means of going anywhere? Anyway, any repair leaves a line where the reconstruction begins. More attacks, more demarcations of repair. And these signs of repair are forever evident, even after the occupants death. This means that the record of repair can persist into the fossil record. 

Slap those two facts together - a repaired shell indicates a "successful" shell from an evolutionary standpoint and unrepaired shells mean that their occupant was too busy turning into something else's shit - and you have just enough info to get somewhere. Using his observations, Vermeij was able to reconstruct and predict distinct records of successful shell designs based largely upon the frequency at which they exhibited signs of repair. He was able to use this data to explain how certain shell types that were very, very different were successful in persisting through long periods of history, influencing the wide variety of shell designs that persist to this data. 

Now this may seem like a clever little realization with a nicely-packaged 'aha' moment, but that doesn't change the fact that it doesn't really affect us ONE DAMN IOTA. This is a shared feature of highly academic stubjects like evolutionary biology and quantum mechanics (and, as a side note, more students and young professors should use the 'who gives a shit' test before deciding on a course of research).

But this is where it gets really interesting - this story is the exception that proves the rule. In my big finish, I'm going to tell you how insights from seashell repair were indirectly parlayed into the war effort in the 1940s. 

The Flying Seashells of World War Two

As most people know, wars are won by resources; a side that can throw more resources into a battle will eventually wear down a force comprised of more capable fighters (the American Civil War is an excellent example of this). In this idea that logistics win battles, perhaps the most critical component to any side is preserving whatever one's greatest single limiting factor is. This could be metal for tanks, gasoline, food, anything. In the later days of WW2, the limiting factor for the Allies was people. This was particularly true in the air - American factories could produce a new plane every couple of hours, but the highly-trained air crews were much harder to replace and incredibly valuable. Returning a crew from a mission was the top priority of the Air Force.

Every day, the Allies would launch bombing missions from their bases behind the front lines. These were almost always directed at industrial targets (so to reduce the ability of the Germans to produce the goods for war, following the whole industry-of-war paradigm). Particularly in the early days, when strikes were launched from England, each mission followed a predictable script. Bombers would take off and be accompanied by fighter planes over the channel. As the smaller fighters ran low on fuel, they turned back for England, leaving the larger, slower bombers alone. Once they reached their target, bomb crews would fly through a hail of anti-aircraft fire (the Germans knew what was up, and put their guns around factories, railroads, etc.) and drop their bombs before immediately turning around and running for home. 

This was the most dangerous point of most missions. Once they were spotted, the German Luftwaffe would scramble fighters to intercept the bombers before they could escape. Smaller, faster fighters would engage the bombers at close range in a gun battle in which they had a distinct advantage. If a bomber lost an engine and fell behind the pack of retreating Allied planes, it would be torn apart like a buffalo separated from from the herd. The danger ended as the when the bombers reached a point close enough to England where friendly fighter planes could again protect them.  

How did the US approach protecting their most important human assets? By preventing crashes. This is going to sound ridiculously simplistic, but it needs to be said to advance the narrative: The leading cause of death for air crews was, you know, being shot down. In the era before missiles, this could be accomplished in one of two ways - by creating a plane that could either outrun enemy fighters and ground guns... or by creating a design that could weather them and keep flying. With the nascent aerospace industry at the time, the government opted to go the tough route. Enter the B-17, the Flying Fortress, a plane that was nonpareil in its ability to fly through all kinds of abuse. 

After its introduction in the late 1930s, the B17 underwent several modifications before reaching the true badass status achieved during the daylight bombing raids in Europe in the 1940s, and in these redesigns is where the our story of evolutionary biology comes back into play: engineers tasked with improving the B17 used the same basic strategy that Vermeij employed in identifying successful seashells.

Here's how they did it: designers watched planes take off from fields in England for missions over Europe. Then, when the planes returned, they noted which parts of the planes were damaged. The goal was to study the effects of damage and create a hardier plane that would more reliably return the precious air crews contained within. While this straightforward approach worked, the design team noticed something unusual, almost mysterious - invariably, certain portions of the planes that returned were hardly ever damaged. From this observation, the designers reached an second, more important conclusion. Have a guess at what it is?

The undamaged parts of the planes weren't the safest, places to be, as one might assume. The opposite is true - the undamaged pieces were the most critical to the plane's operation (remember that there's a selection bias in play - the design team was only studying the planes that actually came back from the antiaircraft fire and enemy fighters). Using this knowledge to identify weak points in the aircraft design, engineers were able to reverse engineer susceptible regions, further improving the durability of the plane to the point where the aircraft has an almost legendary status among WW2 vets. 

I thought this was a pretty cool story. Although my tastes in research skew towards the pragmatic, it's a nice reminder that something like seashell evolution, with no apparent point, isn't always as useless as it sounds.

Usually, but not necessarily. 

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