Convergent and divergent evolution

As a zoologist (yes even ichthyologists are zoologists) the way species from different continents with little or no genetic relationship can end up… looking like they might be cousins. Hedgehogs and echidnas. Or if you’re going to look at long, thin sticky tongues and a diet of underground insects, pangolins, anteaters and echidnas. That’s an example of convergent evolution. Different species facing the same problems/needs getting selected toward a similar end-design. But actually their nearest (genetic material) relations are something very different.

On the opposite extreme you have animals which are closely related but not that similar. Chimpanzees and humans… oh, wait. Besides sharing a lot of the same genes, the behavior of chimps and their diet, and social structure are not that divergent. And in looks, well some of you do look like you might be cousins of mine – even if I pretend I don’t know anything about you. But there are other, better examples. Rock hyraxes which bound around the cliffs of Africa and their nearest genetic relative the hippopotamus – which never bounds around cliffs, and can in fact be stopped by a sturdy (very sturdy) knee-high wall. There are assuredly a lot of extinct steps between them and their common ancestor, but one has to wonder if it did live in rivers and lakes and climb cliffs?

One sees the same in many things – from cultures to body shapes, even within a species like ours with huge geographical and environment spread. Look at Japanese rock-climber and say French one. They may look like their national stock in face, but the physiognomy is likely to be similar – because, duh, the requirements of power-to-weight ratio, and upper body strength for optimal brachiating are not dictated by nationality. The same is true of say long distance runners, or Sumo wrestlers. At a somewhat different level I have found scientists working on say fish population dynamics from China or Iceland (I have worked with both) are very like their national stereotype in broad external terms… yet within the working field were more similar to each other, than the Chinese guy was to a Chinese acrobat, or Icelandic guy was to an Icelandic pole dancer or a banker, for that matter.

It’s one of the reasons I find the current fashion of putting people in external characteristic pigeon-holes particularly nonsensical. The Zulu traditionalist has almost no common ground with a wealthy third generation-of-wealth pampered black American author. Both of these have more in common with me (and not all that much) than each other. I understand both imperfectly – but FAR better than they understand each other. But it’s just fine for the black author to write about the Zulu – because of the pigment of her skin, but wrong for me to write about either.

The same convergence is why so many of my American readers found so much to enjoy in Changeling’s Island (1) (Baen) (the text is a link. I get an extra percentage if you use it) –among several of my books with Australian or African settings rather than American – I was writing about people who are very like their those you might find in small communities across a dozen countries and Anglophone cultures. With some exotic differences — but these in a way are largely superficial. The environment that shaped those cultures and those behaviors is some ways very similar. Much the same root-stock of background and cultures went into the mix.

On the opposite extreme I’ve read a few (not all) Australian authors where I had so little in common I might as well have been reading the sf/fantasy of a NYC dweller. The Australian authors I’m thinking of inevitably are relatively successful in East and West Coast US urban centers, and unsurprisingly come from densely populated cosmopolitan urban centers themselves, and from the same social and educational strata as the typical Tor author. Especially given the pervasiveness of the internet at blending cultures, and the slavish imitation of the US coastal urban enclaves by coastal urban enclaves of Australia the biggest difference between the Urban arts grad in trad publishing from either is a confusion about whether it is hot or cold at Christmas.

Anyway, while all of this is interesting and possibly important from the writer’s point of view, why I was bringing this up was because I write sf (and also true, but less so in fantasy), which involve the concept of alien life. Now when designing these, you’re going to hit up against ‘they’re just humans with stick on antenna’ type complaints about the alien creations of many. And to fair I’ve said the same about a LOT of modern fantasy, where the horses (ubiquitous) are remarkably like the automobile, and huge usually medieval high societies exist without the slightest hint of the vast numbers of peasants and primitive agriculture required to support even a tiny landed gentry in the fashion described.

I’ve always found it valuable to posit the drivers of a convergent evolution for my alien species – otherwise, seriously… we might end up hippos meeting hyraxes, or shades of blue meeting colonial bacteria – unaware of the other’s existence, let alone sentience. But given the drivers for a sentience… there is reasonable chance in my opinion, that evolution will solve similar problems in similar Occam’s Razor ways, at least some of the time. Intelligent amoeba there may be, and tri-podal pseudo-lichens with seven sexes. But actually, bipedalism and bilateral symmetry, and binary reproductive strategies solve a lot of problems in the simplest possible way.

The trick, of course is to create the selective pressures. You’re an author. You get to do that.

And from that things flow logically, and you’re much less likely to create implausible beings.
It’s kind of like motive, but at the species level.

16 thoughts on “Convergent/divergent

  1. I can’t help buy notice that implausible beings dominate the nightly news.
    (And Douglas Adams’ writings would be much less without them.)
    I agree about convergent evolution, but the universe is hostile to life in all sorts of different ways, and there are times I strongly suspect that life itself is fundamentally absurd.
    Which, of course, isn’t appropriate for many stories, or even most of them.
    That said, if the inhabitants of Kipling’s India are more exotic than your aliens or fantasy races… (Well, I guess you’d fit right in with most of the stuff published nowadays. )

  2. “But it’s just fine for the black author to write about the Zulu – because of the pigment of her skin, but wrong for me to write about either.”

    Yes, Nora is running her mile this week. New story out, big spread in the papers. Guaranteed Hugo nom, the story is chock full of everything those scooter-riders love. Scolding, racism, perverse sex, its all there.

    The inside of that woman’s mind is a manure pile, given how she talks.

  3. Nit: what info I can find places the hyrax in the same evolutionary tree as elephants (albeit very distantly). Whereas the last I saw about hippos had decided they were a whale that came back out of the ocean. Anyway, point being you can’t really tell by looking; DNA evaluation showed falcons were related not to hawks, but rather to parrots.

    Likewise, SF/F and intersectional literature both use words, and look similar on the printed page, but are in fact completely unrelated.

  4. One of the fun things is to start with an alien (or fantasy) species that’s different from humans, say, size-wise, and then start thinking about how that would affect things like architecture. If you have a dominant species that is preferentially quadrupedal, so most of the time the largest members of the species stand a meter tall, what does that mean for ceiling height? Do they have staircases, or ramps, or only single-storey buildings? That alone makes for some brain-stretching fun.

  5. I found the “Slow Train” aliens to be an interesting mix between different biology and similar “ways of thinking”.

    Dave, were they your creation or Eric’s creation? 😀

  6. And from that things flow logically, and you’re much less likely to create implausible beings.
    It’s kind of like motive, but at the species level.

    This is my #1 complaint against the “my aliens are realistic, they’re absolutely nothing like humans!” type stories.

    Well, maybe it’s tied with the “my aliens are different in a way that makes it so I can call the other guy a poopy head,” but they often overlap….

    Anyways, a lot of the time the differences are just there because it’s the opposite of what humans do, not because it actually makes any sense.

    1. Or the Aliens do anything the author wants no matter how crazy because “They Are Aliens”.

      IE There’s no internal logic to their behavior.

  7. I’ve thought similar for quite a while (ha! same solution for same problem, different people) and decided not to care if my aliens were incomprehensibly alien or not. A fish and a porpoise have the same shape. Tool users need a way of manipulating tools. Offspring need to be raised and socialized. The abstract needs to be part of the world of the mind. Would competition or survival of the fittest ever not be true? Could any alien society grow to create their own spaceships without strong cooperative and tribal tendencies?

    “The aliens don’t understand telling lies.”

    Well, how is that possible? How can they imagine tomorrow if they can’t imagine what isn’t (yet) true?

    1. “The aliens don’t understand telling lies.”

      A good example of poor world-building.

      I might accept an alien species that find it difficult to lie without being caught in the lie among themselves. (Whether via telepathy or acute senses.)

      But even then, I suspect the game of lying by telling partial truths might be strong among them.

      Still it be interesting (both ways) for them to deal with humans who can lie without being easily caught.

      For example, a human dealing with them might imagine that they couldn’t lie only to be taken in by a “partial truth that’s actually a lie”. 😈

      1. Or because the future hasn’t happened yet, anything said about the future is a suggestion at best. Trade agreements. Shipping lanes. What time an appointment is.

        Not necessarily efficient things not to be precise about. “Well, sure, I said that I’d be at the dock with your goods at 9am today, but I said that yesterday when today hadn’t happened yet, and as should be obvious to anyone, nothing is real until it happens.”

  8. I’ve never accepted the “You gotta be XYZ to write about XYZs” position.Did Ann Rice need to be a vampire? She oncw wrote a story that was soft-core S&M, and got indignant when reviewers started saying she must have a kinky secret sex life. I suppose Twain was unable to “authentically” write Jim, and RAH couldn’t write most of “I Will Fear No Evil.”
    The chasm between say, Henry V and me is much greater than the gully between me and MLK. AmI to be admonished for writing about the one and not the other? Both?

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