[HN Gopher] Adaptation to a Viscous Snowball Earth Ocean as Path...
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Adaptation to a Viscous Snowball Earth Ocean as Path to Complex
Multicellularity (2021)
Author : rbanffy
Score : 33 points
Date : 2025-01-03 17:08 UTC (5 hours ago)
(HTM) web link (www.journals.uchicago.edu)
(TXT) w3m dump (www.journals.uchicago.edu)
| quotemstr wrote:
| Such a mechanism would make complex life even _more_ rare in the
| universe. Better this solution to the Fermi paradox than that
| sentient species tend to destroy themselves with technology.
| pfdietz wrote:
| We want the Great Filter to be behind us.
| rbanffy wrote:
| I very much love the idea the Great Filter being behind us,
| but, just in case, we shouldn't ignore the possibility of
| multiple Great Filters.
| pfdietz wrote:
| Every time a SETI search comes up empty, I am happy.
| rbanffy wrote:
| Every time it comes up empty I think of how many filters
| we still have to clear.
| pfdietz wrote:
| If we find abundant ET life, it's evidence we're fucked,
| since at least one filter is in front of us. Only by
| having little or no ET within cosmological distances
| would the possibility remain open there's no GF ahead of
| us.
| wholinator2 wrote:
| Please explain because i would intuit the opposite. The
| less life's we see, the less likely that life survives
| to/through technological ages that would allow them to
| talk to us. If we see abundant life the it must be very
| easy to survive, thus less filters
| pfdietz wrote:
| If life is abundant, there must have been something to
| prevent it from spreading, now or in the distant past.
| The fact that we evolved in an apparently empty universe,
| rather than in one that's been totally colonized, implies
| something stops this from happening. This thing is called
| the Great Filter, and it's apparently extremely
| effective.
|
| If the GF is in front of us, in a universe with lots of
| ETI, our chances of evading it are extremely small. After
| all, no one else has; why would we be so special?
|
| Nick Bostrum has called detection of ETI, or even complex
| ET life, the worst news mankind would ever receive. It
| would be a death sentence for our future.
|
| https://nickbostrom.com/papers/where-are-they/
| svnt wrote:
| You can have abundant life that is functionally isolated
| by physics, or said differently, by the degree of
| technological and societal advancement required to
| traverse the space between.
|
| Great distances and inherent speed limits seem like a
| decent way to accomplish that.
| pfdietz wrote:
| I think it's clear that interstellar travel, while not
| trivial, should be possible for a civilization just a bit
| more advanced than our own. The energy or material
| resources required for interstellar colonization are very
| small compared to the resources available. It doesn't
| even require relativistic speeds, although reaching (say)
| 0.01 c doesn't require outrageous engineering, just a
| large spacecraft and lots of hydrogen bombs.
|
| Now, perhaps it's universally true that civilizations
| don't advance much beyond where we currently are, or
| don't persist for sufficiently long for interstellar
| colonization to be successful. These would also be very
| depressing outcomes if they are imposed on us by the GF.
| api wrote:
| Space is called space for a reason. I feel like even
| scientifically knowledgeable people have a hard time
| wrapping their heads around just how much _space_ is out
| there.
|
| Here's a good place to start:
|
| https://joshworth.com/dev/pixelspace/pixelspace_solarsyst
| em....
|
| Signals diminish with the square of distance. SETI would
| never hear anything from other stars unless it was
| broadcast with insanely high transmit power or was
| directed right at us (and still very powerful). Nobody
| would do that unless they knew someone was here actively
| listening.
|
| https://briankoberlein.com/blog/et-phone-home/
|
| So for example, to reach the Centauri system (the nearest
| star) with a signal as powerful as the signal Voyager
| sends to Earth would require a transmit power of over 100
| megawatts at a minimum. That's just the nearest star. It
| gets exponentially harder as you go further out. For more
| distant stars you're talking gigawatts or terawatts or
| beyond.
|
| Even barring concerns about attracting attention, why
| dedicate that kind of resources to operate an
| interstellar border blaster if you don't even have a
| reason to think anyone's listening, and if you won't get
| a reply for hundreds or thousands of years?
| api wrote:
| I've always seen a problem with the idea of the great filter:
| why do we think the filter is one thing or one discrete
| barrier?
|
| Why couldn't there be a very large number of low-probability
| filters and/or a continuous probability of failure spread
| across billions of years? Add them all up and the cumulative
| effect would be the same as a single great filter, but there
| would not be one single primary hurdle that needs to be
| cleared.
|
| This and the Fermi paradox itself are really just
| speculations. We have only one data point, which makes it
| impossible to say anything definitive.
| pohl wrote:
| Wouldn't it potentially make it less rare, if it turns out to
| be an additional mechanism? (Isn't it possible that there'd be
| multiple paths?)
| billiam wrote:
| I think the rare Earth hypotheses get it backward, it all looks
| unlikely when you only have one data point. I think that
| complex life finds a way and it all looks like a six cushion
| bank shot in retrospect.
| billiam wrote:
| This is more of a hypothesis than a well-rounded and evaluated
| theory. I could argue that rather than the viscosity of seawater
| the isolation of hydrothermal vents during the Snowball Earth
| period was the primary driver of eukaryote evolution and
| diversity. Isolation makes evolution speed up, and homogeneity
| slows it down in general. Fascinating to think about it though.
| pdl410 wrote:
| Isolation = Energy concentration
| pdl410 wrote:
| The endosymbiosis that resulted in the harnessing of
| mitochondrial energy production appears to have only happened
| once (see work by Nick Lane) and resulted in a ~20 fold
| increase in available energy to the cell was followed very
| closely by the Cambrian explosion. We could still all still
| be bacteria today without it.
|
| https://nick-lane.net/wp-content/uploads/2017/05/Lane-J-
| Theo...
| baq wrote:
| Once in a billion years is some very long odds bet. Drake's
| equation should include this as a separate factor.
| sandworm101 wrote:
| If it happened by chance, then we are alone in the
| universe. If literally trillions of bacteria all living
| and dying (ie evolving) with generations measured in
| hours ... and it still took a billion years to happen,
| then there is no hope for multicellular life elsewhere.
| There would have been more bacteria in earth's ancient
| ocean than there are planets in the visible universe.
| Hope of ever contacting multicellular aliens is over.
|
| OR ... the switch to multicellular life was triggered by
| some sort of event, an evolved response to an
| environmental change. In that case then it is reasonable
| to think that it would happen on other planets too. So I
| really do hope that it wasn't a matter of pure chance. I
| want us to meet or at lease hear someone else some day.
| PittleyDunkin wrote:
| > an evolved response to an environmental change.
|
| This is still a "by pure chance" event, yea? Otherwise
| we're just back to intelligent design. Surely the issue
| is that we have fundamentally few ways of analyzing how
| probable that single event is/was.
| sandworm101 wrote:
| Mutations occur by chance. With trillions of bacteria,
| mutations are a constant. Each possibly mutation is
| happening somewhere. Natural selection then dictates
| which mutations thrive when the environment favors them
| to do so. Evolution is a system, not a lottery.
|
| There is also a meta layer to evolution, that organisms
| can "evolve to evolve", that the rate of "random"
| mutations can itself be an evolved trait. Sexual
| reproduction arguably is such a system: an evolved system
| that regulates future evolution. So even base mutations
| may not be totally random.
| pdl410 wrote:
| https://www.quantamagazine.org/scientists-re-create-the-
| micr...
| HarHarVeryFunny wrote:
| It seems to me that multicellularity and the corresponding rise
| of complexity would be very useful adaptations in ANY
| evolutionary environment. They would give the species more
| capabilities and help to "game the game" by creating more axis of
| future variation. How can a unicellular critter compete with all
| the varied descendant species of a multicellular one?
|
| No doubt water temperature/viscocity - environmental factors -
| did provide an evolutionary pressure for some extant species, but
| it seems highly speculative to try to write an exact evolutionary
| history of what factors drove what changes.
| Avshalom wrote:
| >>How can a unicellular critter compete with all the varied
| descendant species of a multicellular one?
|
| The prevalence of unicellular life on Earth should tell you
| that this is a malformed question.
| HarHarVeryFunny wrote:
| Yes, I suppose, although of course at one time it had been
| 100%. Maybe only the strongest lineages survived ?
|
| What I really meant, rather than multicellularity being
| invincible, was that it's an obviously beneficial direction,
| and doesn't seem like it would need any extreme environmental
| stress to prove beneficial.
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