8 ms·

The ctenophore’s brain and the evolution of intelligence

81 points by urahara 9y ago

briga 9y ago
In his book What Technology Wants, Kevin Kelly makes a pretty convincing case that evolution, and by extension technology, is convergent upon certain forms. The eye evolved independently several times in natural history not by coincidence, but because the eye is a universally useful structure that an evolutionary process will eventually stumble upon. The same is true of ideas and the same is probably also true of brains. I wouldn't be surprised if life on other planets had forms similar to life on earth, simply because so many of biological structures on earth are so well optimized towards survival.
- meri_dian 9y ago
  When you think about it, it's not that surprising. Function driven body parts like the eye will evolve to optimize function. Almost by definition there will be one optimal design. The superficial diversity we see in, say, Birds of Paradise plumage has more freedom to evolve in different ways because there are many more ways for a bird to 'look good' to other members of its species than to design an eye that functions well.
  - vbuwivbiu 9y ago
    Sorry to be that person, but nothing evolves "for" any one function. And one can't prestate the potential set of functions of any subsystem of an organism. It's the other way around: systems evolve, we ascribe functions to them after the fact. It's better to say that similar environments, pressures and circumstances result in similarly evolved features.
    - posterboy 9y ago
      Are you a nihilist or just parroting? I for one don't even do anything "for" anything. It's funny how your argument can be applied against determinism and free will at almost the same time.
      - vbuwivbiu 9y ago
        Actually I believe in free will, and I don't think the universe is deterministic, and I am partially parroting. But evolution has no purpose and nor does the universe. Purpose is something we humans (and possibly other animals) invent for ourselves, i.e. purposes are created by evolution.
        posterboy 9y ago
        But evolution does work via purpose, whereas mutations that aren't fulfilling a purpose will not create an evolutionary advantage. So the antropomorphism is just a sylogysm. Maybe eg. the dying of species, broadly taken as an evolutionary mechanism, doesn't seem to serve an advantages purpose, although maybe it's just a mutation of (local) state all the same, so maybe or not that's advantageous for the universe.
      - kahnpro 9y ago
        A purpose implies intent or some kind of forethought, which evolution works completely without. It's not a positive action (there is light so we need to develop eyes), but a passive result (there is light so the ones who happened to have eyes survived more often and reproduced more successfully).
        posterboy 9y ago
        As a matter of fact, antropomorphisms are a very popular figure of speech and I've never seen much come from a remark against the preoccupation of evolution. The funny thing is, when you talk about human procreation suddenly there is intent and the goal post could be shifted to exclude those cases where pregnancy was not expected and I could probably question the cases where it's intended too because "a child" is a very broad cincept and as after thought not all cases turn out as expected and I would keep shifting in the same way you were about evolution, just to provoke discussion about free will and where to draw the line. Maybe frequent reminders against creationisms are necessary to provoke fundamentalists, which I don't personally have contact with, so this meme is just boring.
  - tzs 9y ago
    But aren't there quite a few ways to design a well functioning eye? Compare insect eyes to human eyes to mantis shrimp eyes, and there are some pretty big differences.
    - sqeaky 9y ago
      A given environment will give a certain kind of pressure and demand a certain kind of solution. Bring the ancestors of mantis shrimps to the treetops and neothlithic apes to the ocean floors and they would both die... If you fix that and let them somehow compete on vision they would likely converge on eyes like the those currently living in the environment have.
      - SomeStupidPoint 9y ago
        Don't insects and monkeys live in overlapping environments with radically different eye structures?
        joeyo 9y ago
        Path dependency. Insect eyes and vertebrate eyes presumably each occupy their own unique minima in the energy landscape. Even if we could describe a cost function that picked one of them as more globally optimal, moving from one to another would be hideously expensive. It's also possible that compound eyes have an advantage at smaller eye sizes---or maybe a better way to put it: their disadvantage relative to vertebrate eyes is less pronounced for equally small eyes. Pure speculation on my part though.
- fenwick67 9y ago
  Whiskers/feelers are another one that comes to mind as evolving several times.
- dekhn 9y ago
  The ratchet is a the simplest universal physical mechanism that seems to fall out of physics into chemistry and biology all the time. eyes are a bit more subtle. It would be really interesting to know the specific trajectories of evolution that led to the formation of sensitive pigments (probably the earliest vision systems), through the development of lenses, etc.
  - sitharus 9y ago
    You can see a fair bit in the Cephalopod order, from the Nautilus (https://en.m.wikipedia.org/wiki/Chambered_nautilus https://en.m.wikipedia.org/wiki/Chambered_nautilus) which has no lens, the Cuttlefish with monochromatic vision through to the Octopus. It's interesting to observe the differences, cephalopods don't have blind spots and can perceive polarised light.
    - dekhn 9y ago
      I'd rather see the actual historical events that happened (like a movie made by a time machine) rather than reconstructions from extant organisms and fossils. BTW, humans can kinda see polarized light (https://en.wikipedia.org/wiki/Haidinger%27s_brush https://en.wikipedia.org/wiki/Haidinger%27s_brush). Interestingly, cuttlefish have monochromatic vision but their camouflage matches the color of their surroundings. Presumably, they get the color signal through color-capable receptors in their skin.
      - sitharus 9y ago
        Cuttlefish are weirder than that, the current theory is their W-shaped pupil causes chromatic aberration on the retina and they can use that to detect colour. http://news.berkeley.edu/2016/07/05/weird-pupils-let-octopuses-see-their-colorful-gardens/ http://news.berkeley.edu/2016/07/05/weird-pupils-let-octopus...
        devrandomguy 9y ago
        Wow! I wonder if we could we potentially infer color from black & white photos of celestial objects, by this technique? Maybe it could be combined with the adaptive optics that attempt to cancel stuff like this?
- posterboy 9y ago
  Or maybe, we tend to categorize eye-like organs as similar and as universally useful structures because that's what we are looking for, doesn't always mean it's really there though.
zero_one_one 9y ago
I had watched a clip from Hellraiser earlier today, and after a long day at work read the title of this post as "The Cenobite's brain..." :) Reading the article was equally as interesting had the above been true - there has always been repetition of patterns in nature (which has certainly driven evolution) - repeated behaviour testing the state of the surrounding influences to see if and where the behaviour can influence or manipulate the state itself in order to learn and grow, and to move to testing new behavioural patterns within similarly fluid environmental states - behaviours that have grown from those proven to further the species (species propagation-related or not). The behaviour itself may not change, but the state in which it is enacted is almost certainly never the same twice Survival of the fittest is not necessarily down to strength and force - moreso down to species continually banging their head against a wall until they break, or indeed the wall moving in step with their behaviour(s).

81 points by urahara 9y ago

In his book What Technology Wants, Kevin Kelly makes a pretty convincing case that evolution, and by extension technology, is convergent upon certain forms. The eye evolved independently several times in natural history not by coincidence, but because the eye is a universally useful structure that an evolutionary process will eventually stumble upon. The same is true of ideas and the same is probably also true of brains. I wouldn't be surprised if life on other planets had forms similar to life on earth, simply because so many of biological structures on earth are so well optimized towards survival.

meri_dian 9y ago
When you think about it, it's not that surprising. Function driven body parts like the eye will evolve to optimize function. Almost by definition there will be one optimal design. The superficial diversity we see in, say, Birds of Paradise plumage has more freedom to evolve in different ways because there are many more ways for a bird to 'look good' to other members of its species than to design an eye that functions well.
- vbuwivbiu 9y ago
  Sorry to be that person, but nothing evolves "for" any one function. And one can't prestate the potential set of functions of any subsystem of an organism. It's the other way around: systems evolve, we ascribe functions to them after the fact. It's better to say that similar environments, pressures and circumstances result in similarly evolved features.
  - posterboy 9y ago
    Are you a nihilist or just parroting? I for one don't even do anything "for" anything. It's funny how your argument can be applied against determinism and free will at almost the same time.
    - vbuwivbiu 9y ago
      Actually I believe in free will, and I don't think the universe is deterministic, and I am partially parroting. But evolution has no purpose and nor does the universe. Purpose is something we humans (and possibly other animals) invent for ourselves, i.e. purposes are created by evolution.
      - posterboy 9y ago
        But evolution does work via purpose, whereas mutations that aren't fulfilling a purpose will not create an evolutionary advantage. So the antropomorphism is just a sylogysm. Maybe eg. the dying of species, broadly taken as an evolutionary mechanism, doesn't seem to serve an advantages purpose, although maybe it's just a mutation of (local) state all the same, so maybe or not that's advantageous for the universe.
    - kahnpro 9y ago
      A purpose implies intent or some kind of forethought, which evolution works completely without. It's not a positive action (there is light so we need to develop eyes), but a passive result (there is light so the ones who happened to have eyes survived more often and reproduced more successfully).
      - posterboy 9y ago
        As a matter of fact, antropomorphisms are a very popular figure of speech and I've never seen much come from a remark against the preoccupation of evolution. The funny thing is, when you talk about human procreation suddenly there is intent and the goal post could be shifted to exclude those cases where pregnancy was not expected and I could probably question the cases where it's intended too because "a child" is a very broad cincept and as after thought not all cases turn out as expected and I would keep shifting in the same way you were about evolution, just to provoke discussion about free will and where to draw the line. Maybe frequent reminders against creationisms are necessary to provoke fundamentalists, which I don't personally have contact with, so this meme is just boring.
- tzs 9y ago
  But aren't there quite a few ways to design a well functioning eye? Compare insect eyes to human eyes to mantis shrimp eyes, and there are some pretty big differences.
  - sqeaky 9y ago
    A given environment will give a certain kind of pressure and demand a certain kind of solution. Bring the ancestors of mantis shrimps to the treetops and neothlithic apes to the ocean floors and they would both die... If you fix that and let them somehow compete on vision they would likely converge on eyes like the those currently living in the environment have.
    - SomeStupidPoint 9y ago
      Don't insects and monkeys live in overlapping environments with radically different eye structures?
      - joeyo 9y ago
        Path dependency. Insect eyes and vertebrate eyes presumably each occupy their own unique minima in the energy landscape. Even if we could describe a cost function that picked one of them as more globally optimal, moving from one to another would be hideously expensive. It's also possible that compound eyes have an advantage at smaller eye sizes---or maybe a better way to put it: their disadvantage relative to vertebrate eyes is less pronounced for equally small eyes. Pure speculation on my part though.
fenwick67 9y ago
Whiskers/feelers are another one that comes to mind as evolving several times.
dekhn 9y ago
The ratchet is a the simplest universal physical mechanism that seems to fall out of physics into chemistry and biology all the time. eyes are a bit more subtle. It would be really interesting to know the specific trajectories of evolution that led to the formation of sensitive pigments (probably the earliest vision systems), through the development of lenses, etc.
- sitharus 9y ago
  You can see a fair bit in the Cephalopod order, from the Nautilus (https://en.m.wikipedia.org/wiki/Chambered_nautilus https://en.m.wikipedia.org/wiki/Chambered_nautilus) which has no lens, the Cuttlefish with monochromatic vision through to the Octopus. It's interesting to observe the differences, cephalopods don't have blind spots and can perceive polarised light.
  - dekhn 9y ago
    I'd rather see the actual historical events that happened (like a movie made by a time machine) rather than reconstructions from extant organisms and fossils. BTW, humans can kinda see polarized light (https://en.wikipedia.org/wiki/Haidinger%27s_brush https://en.wikipedia.org/wiki/Haidinger%27s_brush). Interestingly, cuttlefish have monochromatic vision but their camouflage matches the color of their surroundings. Presumably, they get the color signal through color-capable receptors in their skin.
    - sitharus 9y ago
      Cuttlefish are weirder than that, the current theory is their W-shaped pupil causes chromatic aberration on the retina and they can use that to detect colour. http://news.berkeley.edu/2016/07/05/weird-pupils-let-octopuses-see-their-colorful-gardens/ http://news.berkeley.edu/2016/07/05/weird-pupils-let-octopus...
      - devrandomguy 9y ago
        Wow! I wonder if we could we potentially infer color from black & white photos of celestial objects, by this technique? Maybe it could be combined with the adaptive optics that attempt to cancel stuff like this?
posterboy 9y ago
Or maybe, we tend to categorize eye-like organs as similar and as universally useful structures because that's what we are looking for, doesn't always mean it's really there though.

zero_one_one 9y ago

I had watched a clip from Hellraiser earlier today, and after a long day at work read the title of this post as "The Cenobite's brain..." :) Reading the article was equally as interesting had the above been true - there has always been repetition of patterns in nature (which has certainly driven evolution) - repeated behaviour testing the state of the surrounding influences to see if and where the behaviour can influence or manipulate the state itself in order to learn and grow, and to move to testing new behavioural patterns within similarly fluid environmental states - behaviours that have grown from those proven to further the species (species propagation-related or not). The behaviour itself may not change, but the state in which it is enacted is almost certainly never the same twice Survival of the fittest is not necessarily down to strength and force - moreso down to species continually banging their head against a wall until they break, or indeed the wall moving in step with their behaviour(s).