What if Chicxulub had missed?

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  • Martin54Martin54 Shipmate
    What if Chicxulub had missed?

    Serious answer:

    The Deccan Traps supervolcano would still have erupted (indeed, had already started erupting), so an extinction event would likely have happened anyway due to all the gas and ash it was throwing into the atmosphere. Whether it would have been as major an extinction event as the one that actually happened is moot, but it's not as simple as "no asteroid impact = no problems".

    Less serious answer:

    The world of today would have been populated by highly evolved dinosaurs, as shown in the seminal Theoretical Evolution reference work, 1993's "Super Mario Bros.".

    Meta observation:

    Is there no thread that can't be turned into a political treatise by the usual suspects? I swear, we could be talking about the return of Superted and someone would find a way to turn it into a dig against Boris/Trump/whoever. It's tiresome. Save it for the politics threads, please.

    "There is some evidence to link the Deccan Traps eruption to the contemporaneous asteroid impact that created the nearly antipodal Chicxulub crater in the Mexican state of Yucatán. Although the Deccan Traps began erupting well before the impact, argon–argon dating suggests that the impact may have caused an increase in permeability that allowed magma to reach the surface and produced the most voluminous flows, accounting for around 70% of the volume." Wiki
  • KarlLB wrote: »
    We don't know whether it's inevitable or not. It probably isn't. I mean, 3,500my of life on earth, it's only done more than float microscopically for the last 1,000my or so of that. So we don't really know whether multicellular life is even inevitable. It took a billion years to move on from being prokaryotic. It's not hard to believe it would never have happened, that and getting a central nervous system, concentrating the thinking bit of that CNS into a brain, and even then everything that separates Amphioxus from people who can read Ulysses.

    But for Christians, humans are inevitable? I mean, they are priced in
  • Sorry, priced in, surely?
  • I still can't read Ulysses.

    Oh well...
  • edited April 28
    KarlLB wrote: »
    We don't know whether it's inevitable or not. It probably isn't. I mean, 3,500my of life on earth, it's only done more than float microscopically for the last 1,000my or so of that. So we don't really know whether multicellular life is even inevitable. It took a billion years to move on from being prokaryotic. It's not hard to believe it would never have happened, that and getting a central nervous system, concentrating the thinking bit of that CNS into a brain, and even then everything that separates Amphioxus from people who can read Ulysses.

    Stephen Jay Gould, the evolutionary biologist, wrote in Full House (1996) a popular account of the statistical modelling of the diversity of like. What he noted is that at the start when there were only prokaryotic cells (simple cells without a nucleus), the variation possible was only toward complexity, and not toward being simpler, because there was nothing simpler. He used the example of a drunk person walking down a sidewalk/pavement with a brick wall on the one side and the gutter on the other. An extremely drunk person, if they fall, will end up in the gutter more often than against the wall, but most often in the middle of the walkway somewhere. The gutter being on the side of complexity where there is room - an evolutionary niche - for adaptation.

    I particularly recommend Gould's book Wonderful Life which describes the diversity of life 5-600 million years ago, and how both adaptation and chance gave us the body plans we see in all animals today (we have 4 legs, 5 fingers per hand/foot, not 6 legs, and not 8 fingers/toes). It does involve some work to read it, but it is worth it. It joins up science and the miracle of creation in a way that nothing else has before or since, and it doesn't skimp on the science, which is my complaint with nonsense from religious people who have limited science background (God of the gaps and other silliness), it also does not agree with people ignorant of religion, like Dawkins.

    Gould noted in Wonderful Life that the preserved fossils of the era show ancestors of insects, spiders, clams, worms, basically everything, and there is one worm creature with the precursor to a spinal cord. He also discussed the origin of eyes, which have evolved separately at least 6 times, none of which are related to any of the others. Trilobite eyes, for example, are made of calcium carbonate (baking soda), and insect compound eyes, and spiders (which typically have 5 eyes) have nil to do with each other. We also see in the fossil record that multiple creatures have looked like fish, currently whales and relatives, and modern fish, but dinosaur like fish have nothing to do with either whales and fish. Flying also: bats and birds are the current flyers, whose flying evolved separately and have nothing at all to do with each other's flight evolution.

    I was led in the 1990s to consider that, yes, in fact, life is probably inevitable, and certain types of evolution are also inevitable. As above, eyes are probably inevitable, certain swimming and walking body shapes, detection of sound, and increases in ability to find food and mates, which involves increased brain power. Humans in their current body form are probably not inevitable, but binocular vision (2 eyes) and some sort of upright posture with a large brain probably is. Most likely self awareness, and ability to contemplate oneself, others, place in the world, and "life the universe and everything". In this way of thinking, creation and God are much more impressive than our currently popular historical religious accounts, i.e., we have a start.
  • But there are two issues, surely. Whether humans are inevitable in biological terms, doubtful. In theological terms, yes.
  • Dave WDave W Shipmate
    I still can't read Ulysses.

    Oh well...

    I'm too slow to the punch. I guess some of us have more in common with Amphioxus than we thought! Still, lots more neurons than C. elegans.
  • But self aware creatures? I'm convinced that, yes. With eyes, yes. With complex communication, yes. With intellect, yes. There are more yeses. We might be more bird-like, like dinosaurs, perhaps radial like octopuses.

    Re if we were bird-like, what would chairs look like? What looks like their knees (actually ankles) bend the other way.
  • Dave W wrote: »
    I still can't read Ulysses.

    Oh well...

    I'm too slow to the punch. I guess some of us have more in common with Amphioxus than we thought! Still, lots more neurons than C. elegans.

    You're too kind!

  • Re if we were bird-like, what would chairs look like? What looks like their knees (actually ankles) bend the other way.

    I would assume just the same, but the face would be pointing over the back of the chair (now the chest support of the chair). Rather like certain guys use chairs, in my experience.
  • I've recently read Gould's Wonderful Life (and it is excellent). He very much stresses the role of Contingency (essentially, chance, in a single, unrepeatable and irreversible direction) in evolution.

    Conway Morris (who has worked very closely with Gould) stresses the role of Convergence in evolution - that environmental factors determine the morphology of lifeforms, however they are derived.

    For Conway Morris, that penguins (birds), dolphins (mammals) and sharks (fish) share the same bodyshape as ichthyosaurs (reptile) is a result of the viscosity of water and a carnivorous diet channelling bodyshape into a single mode. For Gould, there can be no such 'channelling': that contingency simply winnows out branches of the tree-of-life, leaving niches free for survivors to exploit. (This is as far as I understand it - I have actually corresponded with Conway Morris in the distant past).

    Intelligence is a difficult quality to pin down. Some birds (corvids especially) appear intelligent. Octopodes probably are intelligent, but in ways we don't yet understand. Dolphins are usually the go-to for non-human intelligence, but again, it's difficult to tell how much is anthropomorphising and how much is actual smarts. If Chicxulub had missed (and it's common to refer to a meteorite by the name of the area it which it fell, so calling the meteorite Chicxulub is just fine) then, barring any concurrent or subsequent extinction event, it's still incredibly hard to say what may or may not have happened.

    Gould would have probably argued that contingency would make such guesswork futile and pointless. We have what we have because of contingency, and we can't rewind and replay the tape of life. Birds were already evolving in the Cretaceous, and we could have had a scenario where avians overtook the general saurians in dominance - but it's a crapshoot and no one knows.

    Conway Morris would probably argue (I'm not up do date with his current thinking) that the same environmental factors that pushed our particular common ancestor to develop a larger brain (the evolutionary advantage being to transmit change - outside of generational genetic mutations - in an almost instantaneous fashion) would have arisen at some point, to some species, making the rise of intelligence inevitable.
  • Dave WDave W Shipmate
    edited April 28
    Dave W wrote: »
    I still can't read Ulysses.

    Oh well...

    I'm too slow to the punch. I guess some of us have more in common with Amphioxus than we thought! Still, lots more neurons than C. elegans.

    You're too kind!
    Sorry, my disappointment that you beat me to the opportunity for an excellent self-deprecating joke has made me clumsy. I really did mean to imply “some of us” in the ordinary sense rather than “some of us (not me, but you know who I’m talking about.)”
    ... both adaptation and chance gave us the body plans we see in all animals today (we have 4 legs, 5 fingers per hand/foot, not 6 legs, and not 8 fingers/toes).
    This can’t be right, can it? Surely there are far more animals (even species of animals) with 6 limbs than with 4 limbs.
  • It depends of where you draw the boundary between animal and non-animal. If animal is vertebrate, then that excludes the insects and arachnids with more limbs. Vertebrates have four limbs by an accident of evolution, for some reason that plan gave an advantage over the early vertebrates with different numbers of limbs which didn't lead to species that survived. Why that should be seems to be a mystery.
  • Barnabas62Barnabas62 Purgatory Host, 8th Day Host, Epiphanies Host
    Martin54

    The OP. It is a bit odd! But I think there is a really good more general issue for serious discussion. That is the impact of catastrophes on evolutionary processes.

    As No_Prophet observed, the Permian-Triassic extinction event was a more widespread catastrophe. And there have been several catastrophes in the history of the earth.

    I have unearthed a pdf for any who have the time for more detailed reading. On the subject of Evolutionary Catastrophe. Here is a link.

    https://the-eye.eu/public/WorldTracker.org/Science/Biology/Evolutionary Catastrophes - The Science of Mass Extinction - V. Courtillot (Cambridge, 2003) WW.pdf

    It puts Chicxulub in perspective.

    I'm not by any means an expert in this field but I found the book serious and readable.

    I think the real answer to your question, Martin54 is "things would have been a lot different!" As they would have been if any of the catastrophic events hadn't happened.

    The world and its living organisms are the end product of the things that have happened.


  • Doc Tor wrote: »
    I've recently read Gould's Wonderful Life (and it is excellent). He very much stresses the role of Contingency (essentially, chance, in a single, unrepeatable and irreversible direction) in evolution.

    Conway Morris (who has worked very closely with Gould) stresses the role of Convergence in evolution - that environmental factors determine the morphology of lifeforms, however they are derived.

    For Conway Morris, that penguins (birds), dolphins (mammals) and sharks (fish) share the same bodyshape as ichthyosaurs (reptile) is a result of the viscosity of water and a carnivorous diet channelling bodyshape into a single mode. For Gould, there can be no such 'channelling': that contingency simply winnows out branches of the tree-of-life, leaving niches free for survivors to exploit. (This is as far as I understand it - I have actually corresponded with Conway Morris in the distant past).

    Intelligence is a difficult quality to pin down. Some birds (corvids especially) appear intelligent. Octopodes probably are intelligent, but in ways we don't yet understand. Dolphins are usually the go-to for non-human intelligence, but again, it's difficult to tell how much is anthropomorphising and how much is actual smarts. If Chicxulub had missed (and it's common to refer to a meteorite by the name of the area it which it fell, so calling the meteorite Chicxulub is just fine) then, barring any concurrent or subsequent extinction event, it's still incredibly hard to say what may or may not have happened.

    Gould would have probably argued that contingency would make such guesswork futile and pointless. We have what we have because of contingency, and we can't rewind and replay the tape of life. Birds were already evolving in the Cretaceous, and we could have had a scenario where avians overtook the general saurians in dominance - but it's a crapshoot and no one knows.

    Conway Morris would probably argue (I'm not up do date with his current thinking) that the same environmental factors that pushed our particular common ancestor to develop a larger brain (the evolutionary advantage being to transmit change - outside of generational genetic mutations - in an almost instantaneous fashion) would have arisen at some point, to some species, making the rise of intelligence inevitable.

    You and I could have a long chat. I have Simon Conway Morris' book "The Crucible of Creation" which is probably what you've read?
  • Dave WDave W Shipmate
    It depends of where you draw the boundary between animal and non-animal. If animal is vertebrate, then that excludes the insects and arachnids with more limbs. Vertebrates have four limbs by an accident of evolution, for some reason that plan gave an advantage over the early vertebrates with different numbers of limbs which didn't lead to species that survived. Why that should be seems to be a mystery.
    Defining animals as vertebrates is pretty idiosyncratic - and anyway there are still vertebrates with no legs. Maybe we should just go ahead and define animals as things with four legs, and then talk about how mysterious it is that all animals happen to have four legs?
  • Dave W wrote: »
    Dave W wrote: »
    I still can't read Ulysses.

    Oh well...

    I'm too slow to the punch. I guess some of us have more in common with Amphioxus than we thought! Still, lots more neurons than C. elegans.

    You're too kind!
    Sorry, my disappointment that you beat me to the opportunity for an excellent self-deprecating joke has made me clumsy. I really did mean to imply “some of us” in the ordinary sense rather than “some of us (not me, but you know who I’m talking about.)”

    Oh, I'm just being wicked. :mrgreen:

  • Dave W wrote: »
    It depends of where you draw the boundary between animal and non-animal. If animal is vertebrate, then that excludes the insects and arachnids with more limbs. Vertebrates have four limbs by an accident of evolution, for some reason that plan gave an advantage over the early vertebrates with different numbers of limbs which didn't lead to species that survived. Why that should be seems to be a mystery.
    Defining animals as vertebrates is pretty idiosyncratic - and anyway there are still vertebrates with no legs. Maybe we should just go ahead and define animals as things with four legs, and then talk about how mysterious it is that all animals happen to have four legs?

    As I understand it, even limbless vertebrates like snakes retain some genotypic and (in some cases) vestigial phenotypic expression of the four-limbed body plan. I think there is a reasonable observation that we don't have examples of vertebrates with 6 or 8 limbs, nor do we have land dwelling or flying creatures much bigger than, say, a rabbit (if that) from any invertebrate species. You can find such in the sea (giant squid, octopodes) but not on land or in the air. I think that is significant, and possibly indicative of particular advantages of an internal skeleton in providing reasonable efficiencies in larger bodies.
  • Marvin the MartianMarvin the Martian Admin Emeritus
    The way some monkeys and lemurs can use their tails it may as well be an extra limb. Maybe in a few million years that’s where evolution will take them?
  • Segmented worms. It's all down to worms.
    The way some monkeys and lemurs can use their tails it may as well be an extra limb. Maybe in a few million years that’s where evolution will take them?

    Old world monkeys and kin don't have tails. Only western hemisphere. Tails was the original version of the body plan. They won't grow back.
  • DafydDafyd Shipmate
    edited April 29
    Old world monkeys and kin don't have tails.
    Yes, they do, though in some macaques it's vestigial.

    (Apes are monkeys from the old world but aren't "Old world monkeys": non-ape monkeys from Africa and Eurasia are all more closely related to each other than to apes.)

  • Marvin the MartianMarvin the Martian Admin Emeritus
    Segmented worms. It's all down to worms.
    The way some monkeys and lemurs can use their tails it may as well be an extra limb. Maybe in a few million years that’s where evolution will take them?

    Old world monkeys and kin don't have tails. Only western hemisphere. Tails was the original version of the body plan. They won't grow back.

    Not on the species that have already lost them, no. But that doesn’t mean they aren’t immensely useful for the ones that still have them.
  • KarlLB wrote: »
    The session was on Drama. We were charged with the dramatic task of pacing with a pre-occupied demeanour. To that we were then asked to add acting that we had something stuck to our hands that we couldn't get off. After a few minutes, the tutor asked which Shakespeare character we had now acted.

    About a third of the class (including me) replied "Lady Macbeth". It was all the non-English specialists.

    Interesting. I haven't "done" the Scottish play either (the other English set "did" it for GCSE; we did Henry V) but I'm familiar enough with the plot and some of the famous lines (is this a dagger?) through general cultural osmosis. I think I might actually be the only person in my family who hasn't seen it performed on stage.

    But I had a completely different impression, and wouldn't have thought of Lady Macbeth at all. 'cause I don't see Lady M's imagined bloodstained hands as "having something stuck to them" - rather I see them as "being dirty", which is an entirely different concept. So I was imagining pacing up and down with a sheet of paper or piece of wood glued to my hands - the result of a superglue accident, perhaps, and the sort of thing that features in slapstick comedy.

    So then you ask me which Shakespeare character is a bit of an ineffectual clown that is likely to have some object stuck to them, and I start to imagine it as a way of puncturing the dignity of Malvolio in Twelfth Night, or something. My brain wasn't anywhere remotely close to Lady M.
  • KarlLBKarlLB Shipmate
    edited April 30
    To me, "hands being dirty' is a subset of "something stuck to them" - mud, oil, something unmentionable due to Cat, blood. I can't see them as totally different at all. It's quite possible the tutor said "something on your hands that won't come off" - it all seems the same kind of thing to me.

    Funny how people's minds work.
  • Merry VoleMerry Vole Shipmate
    Enjoying this thread, and just musing that a YEC (Young Earth Creationist) (like Edwin Poots, the Northern Ireland agriculture minister expected to be the new leader of the Democratic Unionist Party) can't join in any of this debate, 6000 years being not long enough for any significant evolution to occur. I think you can't debate with YECs in the same way you can't with conspiracy theorists.
  • It's been pointed out that there are a lot of similarities between YEC and political conspiracy theories. It could be argued that conspiracy theories evolved from YEC. Though, obviously, such an argument with a YEC would be pointless ...
  • TurquoiseTasticTurquoiseTastic Shipmate
    edited May 2
    To be fair to Poots all but one leaders of the DUP so far have probably been YECcies. Paisley certainly was and would no doubt have held forth about it at length. Robinson probably was although it probably wasn't as big a deal for him. Foster definitely wasn't (just one more symptom of her incipient liberalism and sell-out tendencies I guess...)

    I don't think YEC arguments are pointless, as long as you recognise that it's not really an argument about science but rather about theology. If a YEC feels that accepting evolution is tantamount to apostasy, obviously it will be emotionally difficult for them to do so.
  • Martin54Martin54 Shipmate
    It's been pointed out that there are a lot of similarities between YEC and political conspiracy theories. It could be argued that conspiracy theories evolved from YEC. Though, obviously, such an argument with a YEC would be pointless ...

    Eeee-volved?!
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