Recap for new readers:
I wrote a long (~60k words) Motte post and am releasing it serially, one chapter per week. This is chapter two. Chapter one can be found here.
Last week's chapter was sorta obligatory foundation-work. This week we get to what I think of as the first really cool part. If you like this, let me promise that we are very much just getting started!
0102 - Horrific Engine
In the previous chapter we followed the first living organism and its descendants as they overcame various challenges and ultimately developed the killer tech known as the gender binary. Some ended up in forms which we'd call plants, worms, or fish.
In this chapter we’ll take a close look at a group which ended up in forms which we would recognize as bottom-feeding shellfish, rather like our Earth lobsters.
These shellfish live on an underwater mountain a few miles off the coast, the tip of which almost, but not quite, reaches the surface. (On the coast itself you might espy some ridiculous-looking fish who are starting to spend a truly alarming amount of time out of the water, but we’re not interested in them just yet.) The peak of the underwater mountain is the absolute best place to live: the deeper one goes there’s less light and less warmth and less food. Go down far enough and survival becomes impossible.
When these shellfish first colonized the sea-mount this wasn’t an issue. There weren't very many of them, there was plenty of space, and life was good for pretty much everyone for a generation or two. But no sooner did those first intrepid souls have offspring than they had a problem, because the peak is small and not everybody can fit.
The males know what to do: threaten and/or manhandle their weaker neighbors onto the next level down. And the females know what to do, too: hang out with the guys still on the peak, because obviously those are the ones you’d want fertilizing your eggs. After all, their offspring will be better able to secure access to primo territory and the resources that come with it. But this is still mostly okay. Life on the next rung down isn’t too bad, and there are plenty of females around still even if they’re not necessarily the most-attractive ones.
But then everybody has babies again and the problem is compounded. Not only do most of the babies spawned on the peak need to go, but the next level down is already occupied. So most of the offspring on the second rung are pushed to the third rung, and a lot of the offspring from the peak take over their dens, and a very happy, very few remain on the utmost peak.
That’s nice for them, but for everyone else it’s starting to become miserable. The males down on tier 3 are cold, hungry, overcrowded, and get only rare chances to mate, and with mainly-unattractive females. Those females aren’t happy either, since the males they want to be with aren’t interested in them. But life finds a way, and they more or less make it work.
Everybody has babies again. The ones on top mostly drop a level, the ones there mostly drop a level, and so on. This time life does not find a way; there’s simply not enough viable space. When all is said and done fully half of the new generation has ended up forced down into the darkness where they meet their end in cold starvation or in futile combat with each other for access to even the faintest glimmer of light. Even the ones on the second tier, where things aren’t so bad, are stressed because they know by deep monition that their offspring are likely to end up in that situation in a generation or two. This is because their offspring will likely be a little bit different, and different is generally worse. Since the parents weren’t able to make it to the top, this doesn’t bode well for the children. So everyone fights as hard as they can to hold on to their territory or even somehow, impossibly, to move up. The alternative does not bear consideration.
Equilibrium has at last been attained. It is painful and wretched and unbearable for most, but it also results in some really great shellfish! The mechanism is as follows:
Most of the males below the first two tiers stand practically no chance of moving up in the world. They are, after all, descended from those who couldn’t hack it at those levels. But mutations continue to accumulate, and sometimes they are beneficial, and at any rate the random recombinations of parental genetic material can still sometimes result in surprising boons. Different is only generally worse! So every now and then a lower-tier male is just born awesome, and he’s able to fight his way up to a higher level, get access to higher-quality females, and his special trait proliferates among the well-to-do. In the meantime, the descendants of all males but the best, and especially those suffering from high mutation load, rapidly sink to the bottom and die out within a few generations.
The females have their own games to play. The reproductive potential of a male is much greater than that of a female, but not entirely unlimited. The most successful males have their pick of mates and they have to choose somehow. The females directly vie for the attention of those males, while simultaneously attempting to bully each other away so as to reduce competition. If they’re not attractive (or confident) enough to get picked, they end up with the males on the next level down, which is progressively tantamount to genetic suicide the further they sink. Male shellfish don't invest in young and so aren’t as worried about mating with less-attractive females; they’ll get lots of chances to do better later. But females can only do it a few times, and they really loathe mating with low-value males.
Clearly ‘attractiveness’ is doing a lot of work here. What is it? What does it mean? It turns out that the males are looking for two primary traits: Low mutation load and the ability to produce healthy offspring (i.e. not too young, not too old, not significantly injured or debilitatingly-ill). Females are also looking for two primary traits: Low mutation load and the ability to seize and hold good territory.
Reader, it is of paramount importance that you appreciate the significance of mutation load, so please forgive what may seem a jarring diversion while I come at it again from another angle. Imagine a race of creatures, ‘walkers’, which stride perpetually across an endless grassland. Here and there, hidden in the grass, are plants which have heavy, cruelly-barbed, lead-dense ‘sticker’ seeds which embed themselves in the walkers’ flesh. They’re mostly minor annoyances, but some are bigger and heavier than others, and some just happen to work their way into sensitive and critical places on the body.
As they live out their lives, these walkers randomly run into anywhere between zero to a whole lot of these sticker-seeds. Most of the time the impact of any given sticker isn’t noticed, but sometimes a particularly nasty one is picked up which causes the walker to perish soon thereafter. Much worse, and more importantly, each of their offspring has a roughly 50% chance of inheriting each of the sticker-seeds from each of its parents. No, I don’t know how exactly. Dammit Jim, I’m a <redacted>, not a xenobiologist. But over generations, these accumulated sticker-seeds become a real problem. Babies with high accumulations often don’t make it to term, or else don’t survive childhood. Adolescents with high accumulation are weighed down, can’t move as quickly, require more calories to keep going, etc., and are less likely to reproduce. Perhaps they’re even born sterile in the first place, if the sticker-seeds were lodged in the relevant tender bits.
So each genetic line of this species can be thought of as having an ever-incrementing counter assigned to it, tracking the degree of impairment that has been accumulated. In a sense, each is living on borrowed time, since there is no way to shed the seeds (except for extremely rare fluke events which are, on this scale, so uncommon as to be irrelevant). Each walker lives under the doom passed onto it by its ancestors, and on average each parent passes half of that grudge on to its children in turn, such that between the two parents each offspring inherits a full load. What can they do? Only two things.
The first is obvious. Since offspring are likely to end up with roughly the average of their parents’ accumulated load, each of these creatures does its best to find a mate whose line has accumulated the least. Low-load individuals are prone to mating with each other and putting out low-load offspring, who naturally enough disdain higher-load individuals as mates. Thus in practice there’s what might be thought of as a core of low-load walkers preferentially reproducing with each other, and all the others are sort of slowly but surely degrading away from them, which process only accelerates with time, accumulated impairment/unattractiveness, and the corresponding reduction in number and quality of potential mates.
The other strategy is to simply have as many offspring as possible, trusting in probability to generate one or two who luck out and end up missing more than usual of their parents’ accumulated sticker-seeds. This doesn’t work if both parents have a sticker in the same spot, since the child will get that for sure, but a lot of the time the parents' sticker-seed distribution is diverse enough that less-burdened offspring are possible. And that minority of less-burdened offspring are then more capable of securing lower-mute-loaded mates for themselves than their parents could have done.
(This is another window into where 'different' can be a good thing. Inbreeding is a problem for reasons mentioned above, and a mate who is of roughly-similar quality but of a different line which has accumulated different mutations opens up the chance for offspring which will not be burdened with any given sticker-seed. Given enough offspring with a comparable but not-too-closely-related partner, some are likely to end up with lower load than either parent!)
All right, back to the shellfish on their underwater mountain. As we saw above, everyone wants the lowest-mutation-loaded mate they can get. Within that, baby-making is difficult and can easily go wrong, so males care a lot about a female’s age, focusing on her prime reproductive period. Females, in turn, care a lot about a male’s demonstrated ability to compete with other males, climb the slope, and secure territory. These things can outweigh perceived mutation load to a point, but only to a point, and both sexes always keep an eye to a potential mate’s perceived mutation load.
But how? Since they have no means of sequencing each other's DNA and are at any rate basically just sea-bugs, they must rely upon other proxies, such as visual cues. They’ve figured out a pretty elegant trick for this, which works as follows.
As we know, mutation load causes both perceptible and imperceptible changes. All else being equal, then, it’s probably the case that, the more visibly-divergent an individual’s features are from the population average, the more mutations that individual has accumulated. Unusual, aberrant features indicate deviation from the population average. There are other tells, such as asymmetry, bumpy/discoloured exteriors, and so on, but the big one is just conformity of an individual’s features to the population average. Even visually, different is generally worse.
What this means in practice is that there is a tiny, competent (good-adaptation-rich), attractive (low mute load) population on the peak. Some of the offspring born there belong and are able to take their place among those elite. Most are ever-so-slightly different from (that is, generally slightly inferior to) their parents, and so end up below them. The apple doesn’t fall far from the tree, as they say, but it does tend to fall a little bit downhill. Sometimes, random recombination of traits on the next level down results in an individual who can climb a level or two, perhaps even all the way to the top. But for the most part, mobility is almost universally downward and one-way.
All of which leads to the point of this chapter, which is that I want you to be able to see these dynamics in your mind’s eye, because they are breathtaking and beautiful in their cruelty and perfection, and illuminate every part of the world around us. So please have patience and join me on a trip to the theatre of the mind.
Imagine, if you will, the population of shellfish on this underwater mountain. Think of each one as a single point of light, its brightness corresponding to its overall genetic quality. Now remove the mountain itself from the picture, leaving just the points.
What you should be seeing is something like the electric bulbs on an invisible Christmas tree; a cone shape covered in lights, dim at the bottom and getting brighter toward the top, until at the utmost peak (corresponding to the star or angel) there’s a brilliantly-glowing mass of luminescence.
Watch as a new generation is born: The cone-shape becomes densely populated all over as new individuals pop into existence, but almost all of them immediately begin filtering downward and dislodging others along the way, finding their level as it were. The ones near the bottom, already so much less bright than the ones at the top, rapidly fade down and out of sight.
More generations cycle, faster and faster. Pulses of light emanate from the top and spill down the slopes in cascading waves, innumerable motes springing into existence and precipitating downward, ever-dimming, eventually sliding into the eternal darkness and winking out entirely.
And sometimes — rarely, but sometimes — look! A mote of light, brighter than the surroundings of its origins, rising to take its place closer to the warmth and light and security of the peak. And if it had something special, that catches on, and the peak is forever after a little brighter than it had been before.
This is how the population adopts what is beneficial while holding to what is good. This is want and privation for almost all. This is children striving their hardest even against their own siblings, warring in futility to hold on to what meager territory their parents had, knowing that most must fail and be diminished. This is despair and frustration for the great many, realizing that they’ll never have the mate that is their heart’s greatest desire, while sensing with every fibre of their being that to accept less is to embrace the void.
The clock can be hard to see but it's always ticking, and every time it does it’s down, down, down for almost everyone. Even the lucky few at the top are soon supplanted by younger, hungrier competitors and rapidly lose their place in the sun.
This is the horrific engine. It has given the shellfish everything they have that is good and worth having. Each generation is, on average, just a little bit better than the one that came before, as beneficial mutations accumulate and detrimental ones are cast into the outer darkness. But the cost in misery is staggering, both in each current generation and across the unspeakable chasms of time.
Or at least it would be, if we weren’t talking about a bunch of dumb crustaceans. Thankfully it doesn’t work that way for people, right?
Hold on to your hats.
Before we turn away from the shellfish and their underwater mountain I'd like to explore two further mechanisms of their development.
First, you might be wondering what constitutes an 'optimal' shellfish. It's an interesting question, actually, because perfection for these shellfish is defined both by the natural environment and by competition with their own kind. But the interesting part is that there are many such seamounts in the oceans of Tidus, and on each of them — quite independently! — organisms keep evolving into almost the exact same forms. That is, the form of the perfect shellfish continuously emerges organically from the process of life in environments which suit it. Two fairly different ancestors can migrate to two totally-unconnected seamounts and, many generations later, their descendants may look identical to all but the most-trained eye. This is called 'convergent evolution'.
Put another way, the process of life on any given seamount, the 'horrific engine', is precisely the process which generates the occurrence of the perfect shellfish. It is as though there were an ideal solution out there in the ether, and as though life naturally tends toward it, even if groping blindly. Do note, however, that near-identical results are only possible under near-identical selection pressures.
Second, recall the highly-variable and unpredictable tides for which Tidus is named. Every so often, the moons align such that a much higher tide than usual rolls in and is sustained for years or perhaps even generations at a time. When this happens, the vast majority of the shellfish population is wiped out, leaving only those few who manage to maintain their position atop the peak. Thankfully, these are also the ones which represent the treasure store of the population; that is, its combined accumulated good mutations and the well-preserved overall low mutation load, which were purchased with the suffering and death of, well, everyone else.
The tide could, in theory, get high enough to snuff out even those on the absolute peak. Such things have happened many times before, to other species. Most species that have ever existed, in fact. But it hasn’t happened to the shellfish (yet), or else we wouldn’t be talking about them.
Even so this cataclysm turns out to have a silver lining. Under normal conditions, the sea mount has reached its carrying capacity and is more or less maximally saturated with shellfish. Competition is fierce enough that practically zero deviation from optimal genetics or behavior is tolerated. But when that very high tide recedes, for a few generations, it’s back to the way things were when the mountain was first settled. Plenty of room for everyone for the foreseeable future, and even less-than-optimal offspring have a solid chance to do well for themselves.
This represents a rare and wonderful opportunity. Unusual strategies, both genetic and behavioral, may be developed and deployed. They may even get the chance to be iterated and improved upon over a few generations before the vice tightens once again. And, thanks to the marvel of sexual reproduction, they can even be combined in new and surprising ways — for a little while. In this manner, new developments may have time to catch on and establish themselves where usually they wouldn’t have a chance. This is known as a ‘boom-bust cycle’, and is an integral factor in the continued evolution toward the more-perfect shellfish. Long may it scuttle beneath shallow waters!
Next week: Chapter 03: Colour Blue
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