4 ms·

> Meanwhile, evolving resistance also comes at a cost. We don’t know that directly, but we can infer it pretty well. If resistance to tetrodotoxin were cheap a

• pokpokpok 1y ago
  Not wrong, but one could frame that as a "cost" that you pay in the space of genealogical problem solving. Having one less constraint makes it easier to adapt to other evolutionary pressures
  • y-curious 1y ago
    Agreed, it's just shorthand/abstraction. Just like my for-loop in python doesn't actually mean my computer speaks Python
  • arp242 1y ago
    I omitted some bits from the quote for brevity and HN's faux-quoting sucks, but that's not really the type of "cost" the article is talking about: "maybe they’re suffering from much more subtle neurological effects, like being prone to insomnia or hallucinations or sexual dysfunction. Or maybe they’re just a bit dim."
• aaron695 1y ago
  [dead]
• odyssey7 1y ago
  That claim jumped out to me as well. Evolution is supply and demand, cost and benefit, capacity and constraints, none of it balanced by anything apart from luck.
  • mattigames 1y ago
    This is categorically false, we know evolving bigger brains required us to reduce our muscle mass compared to other primates, for the energy budget required to create such brains.
    • pegasus 1y ago
      And those adorable koalas made the opposite bet, shrinking brain size in order to conserve energy so as to be able to carve a niche no other mammal cared for: https://youtu.be/dXUp_JMQjvg https://youtu.be/dXUp_JMQjvg
    • odyssey7 1y ago
      That cost and benefit trade-off emerged as an opportunity only through luck and it survived only through luck, even if the odds were in its favor.
      • mattigames 1y ago
        That's a very broad definition of the word luck, like saying I landed a job by having luck that some company was offering that role, therefore everything is luck, and communication wise would make the word almost useless.
        • odyssey7 1y ago
          You’re comparing the intelligent design of your job search to evolution.
          • mattigames 1y ago
            Luck is defined as something happening that was unlikely to happen, so having that in mind that evolution kept happening that is no luck, happens on every living organism (last specimens before extension being the exceptions), that the smarter apes got to reproduce is not luck, it is predictable, that they had to use less muscles if they are smarter is also predictable, that muscles are something primates can give up easier than e.g. liver function it is fairly predictable, that you would prefer to take better care of your smarter offspring is also fairly predictable (not saying it's morally justifiable), and so there are so many aligned factors and feedback loops at play that calling it luck would be a disservice, yes evolution has a slight "brute-force" approach to it that arguably involves "luck" but that it's just a small part of it
• aqme28 1y ago
  But a nonzero number of animals and people die of tetrodoxin poisoning, so there is some pressure. Therefore if it were cheap and easy enough, it’s likely we all would have evolved it. That cheapness threshold might just be incredibly high.
  • amanaplanacanal 1y ago
    If it is rare enough it probably doesn't exert much selection pressure. Has anybody modeled what percent of a population has to die from something for the protective gene to become widespread?
    • gptacek 1y ago
      If you're willing to abstract a bit from populations of animals to populations of bacteria, there is the minimum selective concentration (MSC), which is the smallest amount of antibiotic you can add to the growth medium and detect antibiotic resistant bacteria competing out non-antibiotic-resistant bacteria: https://revive.gardp.org/resource/minimal-selective-concentration-msc/?cf=encyclopaedia https://revive.gardp.org/resource/minimal-selective-concentr...
    • thaumasiotes 1y ago
      > Has anybody modeled what percent of a population has to die from something for the protective gene to become widespread? The question is incoherent. The gene spreads if the organisms carrying it average more children. It unspreads if they average less. All of them could be dying of the same thing, and it wouldn't matter. The rate of spread is given by the https://en.wikipedia.org/wiki/Selection_coefficient https://en.wikipedia.org/wiki/Selection_coefficient , but cause of death isn't relevant.
• mekoka 1y ago
  I think it might be more useful to look at the author's claim from the other side of the lense. We do carry around barely useful traits, like resistance to toxins that we seldom come in contact with. We can assume that carrying such traits is cheap. If resistance to tetrodotoxin was one such cheap trait, it might have been more prevalent, but it's not so, it could be inferred that it's expensive. Or at least, not cheap.
  • pegasus 1y ago
    That resistance to toxins we don't encounter often enough to constitute selective pressure, we carry around only if it's the accidental byproduct of another selected-for trait. Otherwise entropy would take care of it, sooner or later. Parent is right, evolution doesn't pay an annual subscription fee for some service which was useful in the past and might come in handy in the future.
    • mekoka 1y ago
      You may just be trying to disagree with the author for sport. > we carry around only... Not true. We can carry resistance to some ancestral pressure which isn't part of the current environment. > sooner or later... Yes, sooner when it's costly, later when it's less so, through normal evolutionary pressure (entropy and all). The point is, most species at time T do carry traits that aren't that useful to them anymore. The costlier ones yield enough negative fitness points in evolutionary game theory to rid the gene pool of them quicker. It brings us right back to the author's original argument.
      • catlifeonmars 1y ago
        It would be interesting to see how toxic these newts would remain if the garter snakes were eradicated. If this was indeed a costly trait, we should see a drop in toxicity over a long period of time (possibly evolutionary time). To rule out coincidence, you could follow multiple lineages as they speciated. In fact, looking at related newts whose ancestors were toxic (assuming the trait is not novel in these ones) would give us some idea as well.
• skipants 1y ago
  Yes! Thank you! I’m barely knowledgable when it comes to biology and I still get annoyed when evolution is framed as cause-and-effect.
  • pegasus 1y ago
    No need to be annoyed. I think if you look deeper, you might find that, in fact, all occurrences of what we call cause and effect are of a similar nature.
  • bsder 1y ago
    Well, there is some "cause-and-effect" in evolution. Whenever a species winds up isolated in a cave, it loses eyesight really quickly in evolutionary terms because making and maintaining an eye is so metabolically expensive. So, while the mutations are random, any of them that can save the energy of developing vision get selected for very quickly. So, even though the mutations are random, it really looks like "cause-and-effect" from the outside: get isolated in cave->lose vision; get exposed to outside light again->regain vision. By the same token, changes that aren't very expensive metabolically will have very weak "cause-and-effect" because there is no particular pressure to carry the mutations forward or clean them up.
• mattigames 1y ago
  Survivorship bias, you perceive it doesn't come with a cost, but perhaps some species that were exposed to it died from it because they failed to adapt because it does come with a cost they couldn't pay, so they went extinct, like it's wildly common.
• bsder 1y ago
  > An ancestor lost the trait for vitamin C synthesis by chance, and because these primates were living in trees eating lots of fruit with vitamin C, evolution simply didn't notice. There is no disadvantage to being able to synthesise vitamin C, and no advantage in dropping the trait. The fact that guinea pigs, fruit bats, and passerines (almost half of all bird species!) also have a mutated GULO gene suggests that there is in fact some pressure to get rid of it as soon as it is bioavailable from diet.
  • wbl 1y ago
    Eh, enzyme mutations leading to inactivity aren't uncommon. It could just be drift when enough vitamin C is available.
• lurquer 1y ago
  > There is no disadvantage to being able to synthesise vitamin C, and no advantage in dropping the trait. So why did the trait of that mutant primate spread throughout the entire population? There should instead be a mixture of those who can and those who can’t synthesize vitamin C. (Indeed, one should perhaps not so blithely assume that there was sufficient fruit for everyone and so C didn’t matter… for it is precisely the ability to survive in times of drought and scarcity that drive evolution, and there id no reason to suspect a population that could synthesize their own vitamin C was less fit than a population that couldn’t. The issue of vitamin C is far from simple…)
  • shellfishgene 1y ago
    It's more likely that a mutation in the gene/pathway arose multiple times independently, instead of one spreading through the population.
  • arp242 1y ago
    There is no reason for it to spread, but also no reason for it not to. Presumably there was another (completely unrelated) trait, and it happened to spread because of that. > There should instead be a mixture of those who can and those who can’t synthesize vitamin C. Probably was for a long time. All of this happened about 60 millions years ago. It's been a while.
• ashoeafoot 1y ago
  Reptilian Predation squeezed mamalian reproduction into the fast and the furious . Meanwhile birds and turtles reproduce hapoy at methusalem ages. No creator, no design, just merciless pressure that stupidly rewards successful maiming to adapt.
• pfdietz 1y ago
  > There is no disadvantage to being able to synthesise vitamin C, Synthesizing vitamin C takes energy, energy that could be used for other biological processes. It's also possible excess vitamin C has some minor deleterious effect. For example, it's an antioxidant, and these render immune cells somewhat less effective against certain threats (which they use oxidizing chemicals to destroy). It's been found larger doses of the ACE vitamins causes increased growth of lung cancer, probably due to reduced immune attack. Some have argued against this idea, though, although I'm not convinced by the argument (see if you can spot the problem.) https://pmc.ncbi.nlm.nih.gov/articles/PMC3145266/ https://pmc.ncbi.nlm.nih.gov/articles/PMC3145266/