JumpCrisscross
a year ago
Mitochondria are why I’m a Rare Earther.
In Earth’s history, mitochondrial endosymbiosis occurred once. Without that you don’t have the energy budget for complex life. Moreover, there may be a narrow window where it can happen: modern microbiology has defences and selection pressures that it make inhospitable to the hobbling chimeræ the first mitochondrial cells would have been.
Until mitochondria, the emergence of life from nothing is plausible. With mitochondria, its progression to complex, multicellular and intelligent life makes sense. Both processes in small steps can be replicated, more or less, in the lab. But that one moment is not and has not been. As a result, I think the universe has lots of living slop but very few plants and animals.
(Aside, look at ATP go: https://www.youtube.com/watch?v=lUrEewYLIQg&t=939s)
jjk166
a year ago
This process, known as primary endosymbiosis, happened at least twice, for mitochondria and chloroplasts. Further, while all chloroplasts (and more widely plastids) appear to share a common ancestor, there is evidence that mitochondria may descend from multiple lineages that underwent lateral gene transfer and/or convergent evolution. Nitroplasts are a likely another, separate instance of primary endosymbiosis.
There is also secondary endosymbiosis, where the endosymbiont organelles of one eukaryote are engulfed and incorporated into another eukaryotic cell to create a new type of endosymbiont. This has happened at least 8 times.
There are also theories that some other organelles are the product of other endosymbiosis events, many of which also have some of the hallmarks like their own genetic material. These theories are more speculative though.
It's also worth noting that while eukaryotes obviously gained some important capabilities from incorporating these endosymbionts, the endosymbionts they incorporated obviously managed to just evolve to perform those functions directly. Further, while one of eukaryotes' distinguishing features are mitochondria, there are several other major differences, and mitochondria are not believed to be what made eukaryotes better able to evolve complex multicellularity. Prokaryotes have indeed evolved multicellularity dozens of times, and we arbitrarily set our definition of complex multicellularity to distinguish from what prokaryotes have achieved.
Symmetry
a year ago
The first time it happened involved a huge number of changes in the host cell, like the creation of a nucleus. That makes it seem more likely that an already eukaryotic cell can more easily incorporate other endosymbiotes.
Observation of prokaryote/prokaryote endosymbiosis would be real evidence against the rise of eukaryotes being the or one of the main limitations in the number of intelligent species in our galaxy.
jjk166
a year ago
There's really only one change that mattered - phagocytosis. The ancestor of all was a prokaryote that practiced phagocytosis, the process of engulfing other cells. Endosymbiosis resulted from some of these engulfed cells not being digested.
There are no known modern prokaryotes capable of phagocytosis. Presumably the extinct prokaryotes who were capable, including those from the same lineage as the eukaryotes but which did not pick up mitochondria, were outcompeted by the eukaryotes who occupied the same niche.
Other changes like the origin of the cell nucleus and many other organelles can be readily explained by other malfunctionings of the phagocytosis process. Basically once you have the ability to pinch off parts of your cell wall into internal structures, you suddenly get a bunch of internal structures made of stuff that look surprisingly like cell wall.
hinkley
a year ago
I believe there was an article here suggesting rather enthusiastically that nitroplasts are endosymbiots. Sometime in the Spring I believe.
__MatrixMan__
a year ago
See also: nitroplasts
tasty_freeze
a year ago
In addition to what others have pointed out (chloroplasts), I think this makes another mistake. Although only the mitochondria and chloroplast lineages remain, it is possible it happened other times but those lineages were out-competed, for whatever reasons, and are now extinct.
JumpCrisscross
a year ago
> it is possible it happened other times but those lineages were out-competed, for whatever reasons, and are now extinct
Chlorophyll probably outcompeted retinal [1]. (The stuff in our eyes.)
The reduced form of my claim is that mitochondrial life so freakishly outcompetes its competitors as to be in a class of its own. Which still yields a rare Earth, albeit a first among many.
jjk166
a year ago
In an evolutionary process, one lineage running away is the most likely outcome. It's very unlikely that two competing lineages would evolve to be exactly equal at the same time and remain equal for an extended period of time.
JumpCrisscross
a year ago
> In an evolutionary process, one lineage running away is the most likely outcome
What are you basing this on?
quantadev
a year ago
It's based on the fact that one explanation of why there's not even millions more species of all life, is because the more successful ones simply cannibalized the less successful ones. This would've started even before complex life, almost at the chemical level.
I say cannibalized, because avoiding eating your own species is a higher brain function that would've came far later, so it came down to eat or be eaten. Still is frankly.
Jerrrrrrry
a year ago
>I say cannibalized, because avoiding eating your own species is a higher brain function that would've came far later,
Species (maybe only [di?]morphic ones) rarely kill other instances of their own species, only maim - usually to the point of socially/reproductive shame/selective behavior; as infra-species violence is usually done for sexual signaling.
Like squirrels neutering each other, giraffes ruffling neck-fights, etc, it is not generally advantageous to actually hurt the opponent more than needed to signal dominance in a social hierarchy - this "gentleman" agreement is similar to all emergent collusion behavior exhibited by "free agents" in a limited pool; even without communication, the self-interested incentive to all follow a convergent rule will eventually emerge. Whether it be price fixing, social norms, or any other system where partially-regulated complex systems compete.
Additionally, for cannibalizing to be a positive-selective-trait, the species would had either adapted to eating the liver - the "resilience/filter" of a system, or had been "lucky" enough to identify/delineate/get repulsed by it.
Eating your own species liver would be nearly self-defeating-ly impossible from an evolutionary point of view and avoiding it but still eating your own species is too "taboo" (evolutionary artifact) of a benefit to ever randomly stumble into, especially against the benefits of 'good-sportsman-ship'.
smolder
a year ago
> it is not generally advantageous to actually hurt the opponent more than needed to signal dominance
It is advantageous to beat a rival and take their energy even within a species. That's part of the whole 'survival of the fittest' thing. Preserving them for cooperation or something like slavery happens, but it's a rare strategy specific to intelligent animals like the GP implies.
quantadev
a year ago
As Dawkins points out in `Selfish Gene`, it's the DNA sequence that's the evolutionary entity. For example, all mothers (and most fathers) protect their young even though it's a food source. Eating your own species (even children of other mothers) is counterproductive for the DNA itself, despite being productive for the particular copy of the animal doing the eating.
Jerrrrrrry
a year ago
>reserving them for cooperation or something like slavery happens, but it's a rare strategy specific to intelligent animals
I should had clarified, this is lower, more intuitive behavior. It is not, which is why it arises emergently in lower-complexity/class systems.
>beat a rival and take their energy even within a species
And if done with literal, figurative, social, and complex "CLASS", it is literally sexy too!
National Geographic is entertaining for many dimensions of reasons.
Actually dismembering your sexual-rival and literally consuming their poor caloric conversion is pitifully inefficient compared to making them a sub-ling, whether it be via hen-pecking or innate dominance. It made sense before sexual dimorphication (moreso), but less so now.
Ladies like a gentleman, and gentleman's agreements are literally non-colluding emergent behavior to abide by unspoken higher-order rules for one's own explicit conscious self-incentive (lower order, high entropy), but also the implicit collective unconsciousness incentive (higher social order, lower entropy)
Both are reslience traits, which only emerge when selected for.
quantadev
a year ago
I have no idea what you meant by liver. Maybe it's a biology term I'm unaware of. Certainly you didn't mean the organ. lolz.
Anyway, an interesting point about evolution is that things had to have been eating other smaller things long before the brain had enough processing power for "Species Recognition". It would've initially been a simple brain and rod/cone eye neuron and motor neuron in a fish that executed primary the rule of "See movement then execute tail wag, open mouth, close mouth" in that order. It takes like 5 neurons wired in a specific way to accomplish that. The first neurons had to have been that simple. Indeed the chain reaction of "input photon and convert energy into motor neuron charge potential" had to have been the actual chemical process that eventually developed the first neuron to begin with.
It was only after MUCH more evolution that avoidance of eating one's own species would've been possible by visual inspection of the prey. However, it's true it could have been a 'taste' signal where the scales of your own species had a bad enough taste that you spit it out rather than eating it, and that can be accomplished also with a brain of only a few neurons.
Jerrrrrrry
a year ago
Liver/kidneys are organs where toxins are filtered, from the prey the predator consumes.
I am not a biologist obviously.
Because of the "food chain" actually being a pyramid, those organs contain the same "toxins" that are to be avoided, exponentially accumulating in whatever "organ" had the function to add resiliency by storing these toxins.
quantadev
a year ago
Oh, I see. You expected people to infer "toxins" from the words "resilience/filter". Got it.
However, liver eating is a moot point regardless, because evolutionary theory would suggest eating toxins would have a bad taste/smell, so that organ would simply be avoided, while eating the rest. So it has no bearing on whether cannibalism happens or not.
Jerrrrrrry
a year ago
>However, liver eating is a moot point regardless, because evolutionary theory would suggest eating toxins would have a bad taste/smell, so that organ would simply be avoided, while eating the rest. So it has no bearing on whether cannibalism happens or not.
We have nothing but confirmation bias and little time to test anything macro.
However, we do have contra-positives and the like; in this case, we (ourselves) avoid Liver in some animals, and notice the M.A.D-avoidance agreement among more socially-complex systems.
You shouldn't eat your young, you should eat your rival tribes young.
Especially because the young hand't accumulated much toxins yet, relative to the adults. And it is easier to bash babies over rocks than grown adults.
(per Carl Sagan)
Jerrrrrrry
a year ago
yes, Q.E.D; the ambiguity of our lingua franca can be an "accumulate toxin" of sorts when trying to articulate higher-order ideas, as words (especially used as analogies) can carry implicit deprecated weight, and without the resilience of good-faith inference, can lead to misunderstandings, mis-alignment, or walking/talking write/right past each other.
quantadev
a year ago
--or-- yes, when someone writes a very unclear sentence and then blames the reader for not understanding it...even going so far as to accuse the reader of bad-faith motivations.
Jerrrrrrry
a year ago
>>> ...for cannibalizing to be a positive-selective-trait, the species would had either adapted to eating the liver - the "resilience/filter" of a system, ...
>I have no idea what you meant by liver. Maybe it's a biology term I'm unaware of. Certainly you didn't mean the organ. lolz.
>writes a very unclear sentence and then blames the reader...to accuse the reader of bad-faith motivations....
Did we both edit our posts....to improve accuracy, increase resiliency, and to compete ideas?
literally mesa-Q.E.D.
quantadev
a year ago
You edited your post after first insulting me, then deleting the insult. Yes I saw it, but I removed my acknowledgment of the insult, only after you removed the insult. But you weren't done yet...just taking care not to have "flaggable" wording. Now it's more stilted language and Latin FTW. Did I miss anything?
Jerrrrrrry
a year ago
nope, just demonstrated my point further-er-er:
neither of us had the incentive to either acknowledge our edits nor call the other out,
nor face the (perceived, social, higher-order) dissonance of being slightly unclear or "wrong" due to our own ego/self-interest (conscious, lower ordered self);
the emergent behavior then (gentleman's agreement) was to preserve our own ego's and not call out each other edits - which most people would never do, because:
our slightly varied ideas compete more fiercely for the same finite pool than other, completely niche-unrelated abstractions.
we are 4 layers deep now, but ill reduce for conciseness (for lurkers fwiw)
dont shit where you eat <- evolved trait to avoid waste-by products
dont hit a man when he's down <- highly effective altruism is still beneficial
morality is cowardice <- ties this all together from highest order (ego) to the id (fear of being replace)
we are now full circle.
quantadev
a year ago
And now back to reality: I only edit posts to add an important point or fix a typo, but you edited your post to remove the insult it initially contained.
Jerrrrrrry
a year ago
The insult was my inference that we should assume good faith, and that you had not done so (provably, by your 'lulz' snark); which you clearly did not show when assuming something other than the "liver" would be a organ of filtering toxins.
A decently display of faith should at least warrant a re-parsing of my (actually perfectly unambiguous) grammatical clarity, of which you implied was less than so.
Warrants the question, why not admit my posit:
That slightly-varied entities competing for the same/similar finite/limited supply pool of resources/demands will tend towards -- as an emergent behavior of both short-term disorderly self-incentivization and the stochastic long-term higher-order unconscious collective collusion -- the tendency to compete until dominance over **reproductive** rights are secured, but no more. The more fiercer the competition, the more selective the sieve, the more the dominant traits propagate: up to a plateaued point. Further complexity/order can than be more efficiently achieved by lessening the furiousity of the competition to a point of cooperation, which then innately lends itself to more hierarchy, efficient use of energy.
Take it from Roko the Replacer:
According to Sigmund Freud's psychoanalytic theory, the "fear of being replaced" is most closely linked to the concept of "castration anxiety," particularly within the context of the Oedipus complex, where a young boy fears his father will punish him for desiring his mother by castrating him, essentially rendering him "replaced" in her affections.
Free to continue discussion; but the under the Ego lies the Id, and I'm not well versed in that science yet, still approximating.
quantadev
a year ago
The crux of the misunderstanding was that you assumed any reader would know a reference to liver is a reference to "toxicity" apparently based purely on the nearby words "resilience" and "filter". That was a flawed assumption, and ambiguous unclear writing.
Jerrrrrrry
a year ago
Artifacts of evolution such as tribalism/xenophobia are the most obvious examples/analogs.
But really, and "slightly" varied instance of yourself is the "most" likely to compete for the same, infinite pool of resources.
smolder
a year ago
The success of birds, bees, trees, plankton, mammals and so on. Many life forms have been rendered obsolete when the right adaptation comes along and forms a new branch.
jjk166
a year ago
The second sentence of the comment.
aydyn
a year ago
Does it yield a rare Earth? If we didn't have mitochondria and had something say 20% less efficient, why couldn't multicellular life still exist?
JumpCrisscross
a year ago
> why couldn't multicellular life still exist?
We don't know the fundamental energy requirements of complex life. The threshold may be 2%. It may be 19.995%. If non-mitochondrial metabolism is common, the Earth would still be rare in that we'd be the "fast" biosphere. The high-octane species. Given how power-intensive intelligence is, that might be material. (Or it might not.)
More fundamentally: we have no plausible alternate chemistries that don't bootstrap on mitochondrial life. (We do for photosynthesis.)
addaon
a year ago
> Given how power-intensive intelligence is
I’m not convinced there’s a reason to think intelligence is inherently power-intensive. Based on our limited samples, it’s certainly energy intensive, but there’s no reason it couldn’t be slowed down. In a world with less power available to life, one would expect speeds of e.g. predators and prey to be slower, allowing a slower intelligence to still provide an advantage.
JumpCrisscross
a year ago
> not convinced there’s a reason to think intelligence is inherently power-intensive
Sure. But we know it empirically is. Our brains are expensive.
addaon
a year ago
> Sure. But we know it empirically is. Our brains are expensive.
But our brains have mitochondria. As do our prey, and our predators. Is there any reason to suppose that the absence of mitochondria implies less potential for intelligence, instead of the potential for equal but slower intelligence? Mitochondria are about power production, not energy production -- they are a very dense source of ATP, but the reactions they use would provide equal energy even if less concentrated.
aydyn
a year ago
I think that's a little farfetched since a lot of prokaryotes show the beginning stages of complex multi-cellularity.
jibal
a year ago
I don't understand why anyone would commit to so adhering to a speculative hypothesis H as to call themselves an "H-er", especially one so pointless and vague as "Rare Earth". There is some probability that a random star has intelligent life on orbiting planets, but we have no idea what that probability is. The original "Rare Earth" proposal suggested that the Earth may be the only such planet in the galaxy, but at that rate there could be hundreds of billions of Earths.
rgbswan
a year ago
> There is some probability that a random star has intelligent life on orbiting planets, but we have no idea what that probability is.
100%. The evolutionary pattern of our solar systems formation and earth ending up, temporarily, in just the right spot isn't rare but (was) a matter of time/timing.
Now one could argue that the stellar objects carrying specific components necessary for life did not hit every or many solar systems but every single simulation (in my head) of the big bang's aftermath reveals that it's at least multiple hundreds of thousands, given how much the observable universe has revealed so far in the places that we looked.
outworlder
a year ago
Mitochondria seems to have been an 'accident', yes.
That does not mean that other lifeforms in different planets require mitochondria or equivalent organelles. As long as they can perform the necessary chemical reactions (which could be different in a different environments) and extract enough energy, they should be good.
How did mitochondria evolve in the first place? Could they have remained as independent organisms and use their massive energy budget to evolve independently?
JumpCrisscross
a year ago
> long as they can perform the necessary chemical reactions
That mitochondria are conserved as an independent organelle across almost [1] all eukaryotes, across billions of years of history, suggests this is something the nuclear can’t easily in house.
outworlder
a year ago
Maybe!
That could also suggest that any other strategies were just out competed by this one and lost the opportunity to develop further.
JumpCrisscross
a year ago
> other strategies were just out competed by this one and lost the opportunity to develop further
Absolutely. It also means--however--that any niche where alternative did exist, when exposed to mitochondrial life, they lost.
Now that I think about it, it would be pretty funny if we're this universe's cheela [1], a freakishly overclocked biosphere that runs faster not because it had to but because it happened to.
ajuc
a year ago
Evolution is path-dependent. Notice that mammals were comprehensively outcompeted by dinosaurs till asteroid removed them and gave mammals time and niches to develop in. If you recreated dinosaurs right now they would lose to mammals (for example to homo sapiens).
It's perfectly possible that mitochondria are the dinosaurs of "cell powerplants" that just haven't encountered the asteroid to let other (ultimately better) solutions develop.
xeeeeeeeeeeenu
a year ago
https://en.wikipedia.org/wiki/Monocercomonoides
>It is the first eukaryotic genus to be found to completely lack mitochondria, and all hallmark proteins responsible for mitochondrial function. The genus also lacks any other mitochondria related organelles (MROs) such as hydrogenosomes or mitosomes. Data suggests that the absence of mitochondria is not an ancestral feature, but rather due to secondary loss.
jamiek88
a year ago
There are organisms without mitochondria too though. So it’s viable.
JumpCrisscross
a year ago
> are organisms without mitochondria too though. So it’s viable.
True, it's an anaerobic ersatz cnidarian [1] that may be an escaped cancer [2].
Rumudiez
a year ago
> [discovered in] gut bacteria from a researcher’s pet chinchilla
wow. we could be surrounded by so many extraordinary organisms and not even know it because there's so much variety just in our own backyards
satvikpendem
a year ago
There was a study where participants were asked to swab their belly buttons and lots of new organisms were found.
https://www.theatlantic.com/health/archive/2012/12/1-458-bac...
im3w1l
a year ago
Absolutely fascinating. Especially the exotic multicellularity part. Maybe if it evolves even more multicellularity it will struggle with cancers of its own and have to reevolve tumor suppression, wouldn't that be something?!
mjan22640
a year ago
The benefit of mitochondria is in the isolation of the high power reactions, that involve chemically aggressive elements, from the rest of the cell. That allows for high energy throughput without self damage. Cells that do not have mitochondria run the same or analogous power producing reactions, but at a much lower volume, to keep the damage sustainable. An alternative option to mitochondria would be to evolve some means for isolation of the power production.
pieter_mj
a year ago
Mitochondria are bacteria that were endosymbioticized into what became the eukaryotic cell. Mitochondria can still survive (live) independently and functionally in the blood when they're separated from platelets and microvesicles. Mitochondria are the software that epigenetically switch nuclear DNA genes on and off. That sofware can be tweaked by light, for instance UV light or IR light. mtDNA mutates x1000000 more rapidly than nuclear DNA.
dekhn
a year ago
uhh where did you get " Mitochondria are the software that epigenetically switch nuclear DNA genes on and off."
gus_massa
a year ago
> Could they have remained as independent organisms and use their massive energy budget to evolve independently?
There are independent mitochondrial relative. They are mostly parasites that live inside cells.
From https://en.wikipedia.org/wiki/Mitochondrion
> The proto-mitochondrion was probably closely related to Rickettsia.
From https://en.wikipedia.org/wiki/Rickettsia
> Being obligate intracellular bacteria, rickettsias depend on entry, growth, and replication within the cytoplasm of living eukaryotic host cells (typically endothelial cells).
> Most notably, Rickettsia species are the pathogens responsible for typhus, rickettsialpox, boutonneuse fever, African tick-bite fever, Rocky Mountain spotted fever, Flinders Island spotted fever, and Queensland tick typhus (Australian tick typhus).
liyamchitayat
a year ago
One interesting thing is that many reactions actually have to occur in their own compartment- and since we have not lost the mtDNA, it may suggest that having an additional control center is beneficial.there are some interesting theories about the relations of that to lifespan https://www.cuimc.columbia.edu/news/mitochondria-are-flingin....
im3w1l
a year ago
Couldn't it be that we haven't fully lost mtDNA because it's simply a very slow process that has not yet run its course?
aydyn
a year ago
Given how old mitochondria are it seems more likely that its more efficient to have its own DNA.
DNA isn't just abstract information, it's also where the first step of protein / enzyme construction occurs. DNA location matters.
WalterSear
a year ago
> Could they have remained as independent organisms and use their massive energy budget to evolve independently?
This presumes that their energy budget was massive to begin with, rather than being selected for over time.
Symmetry
a year ago
It's more that cells can have large numbers of mitochondria than that teach produces a large amount of power. Prokaryotic cells can grow large, but because they respirate over their surface they are energy limited.
patcon
a year ago
Mitochondria allowed who different energetic regimes and structures. Like the scaffold that allows multicellular organisms to even hold together simpler are not possible (energetically) without mitochondria. It took the whole marriage of the two systems to allow the energy state (the "chemical reactions" as you say) to be possible
SFI Complexity podcast has a few great episodes on this
smolder
a year ago
Right, the requirement for life is an entropy gradient sustained long enough as well as the right materials present to capture that.
eboynyc32
a year ago
It’s so pathetic to keep hearing that dna is an accident , life is an accident, mitochondria is an accident. What is an accident that natures says “oooops”. When will we take our heads out of the sand and realize the universe is alive and creating everything. There are no goddamn accidents !!!!
AlphaEsponjosus
a year ago
What? When saying that "X" is an accident, nobody means "nature says 'oooops'. Nature is neither conscious nor alive, if universe were alive and creates and shapes life, why is there so many errors happening in the universe?
Everything exist by " accident", and that means that is the result of random events that happen unexpectedly in unimaginable places, leading to an environent were the outcome of this events causes more random events.
Why universe insist in making life so uncommon if it has the secret to create and replicate?
jibal
a year ago
People whose heads are out of the sand reject that misunderstanding of the universe and nature, neither of which are agents.
exe34
a year ago
all happy little accidents!
qudat
a year ago
Like other gradients (heat, pressure, chemical) it might seem rare, the gradient guides its occurrence. A power efficiency gradient was going to happen eventually, accident or otherwise.
hughesjj
a year ago
Yup. That it happened isn't by chance, but the particular instance being the one to happen & dominate is by chance.
casenmgreen
a year ago
I may be wrong, but I recall reading recently it had been found the same event had occurred again, fairly recently (hundreds of thousands of years, could be millions) in some species of bacteria or something like that.
Here's a thought, also; maybe once this has happened, it tends to crowd out needing to happen again.
JumpCrisscross
a year ago
> it had been found the same event had occurred again, fairly recently
Would love to know the source if you have it.
joshuahedlund
a year ago
Might be referring to this: https://newatlas.com/biology/life-merger-evolution-symbiosis...
casenmgreen
a year ago
Huh. This is the correct news, but a different article to the one I recall. However, very interesting;
> The first occurred about 2.2 billion years ago, when an archaea swallowed a bacterium that became the mitochondria.
> The second time happened about 1.6 billion years ago, when some of these more advanced cells absorbed cyanobacteria that could harvest energy from sunlight.
> And now, scientists have discovered that it’s happening again. A species of algae called Braarudosphaera bigelowii was found to have engulfed a cyanobacterium that lets them do something that algae, and plants in general, can’t normally do – "fixing" nitrogen straight from the air, and combining it with other elements to create more useful compounds.
So, tremendously rare, at least to our knowledge at this time, but not a one-off.
casenmgreen
a year ago
Yes. That's the one. Thank you.
user
a year ago
aardvark179
a year ago
Chloroplasts also evolved from separate organisms and are now effectively organelles. So this is t a one off event.
ASalazarMX
a year ago
And even if those hadn't become organelles, who knows if they (or mitocondrias) could have evolved towards multicellular life on their own? They were already organisms to begin with.
liyamchitayat
a year ago
Yes! and there are additional cases, like the nitroplasts that we recently discovered. https://en.wikipedia.org/wiki/Nitroplast
quantadev
a year ago
All planets with a diverse chemical makeup will stumble across accidental formation of a replicator molecule. It's 100% certain. That's all that's required for "life".
People have theorized even a 50 base pair segment of RNA might be capable of building exact copies of itself, either by snapping in half and auto-forming the same other half, or by other means. Since there's two sexes, it was perhaps a "halving" at that level, that early on, which led ultimately to TWO sexes, but that's a side point.
We can even predict the probability of any 50 base pair ordering. It's 1/(4^50). That's 30 zeroes in the denominator. Now consider that a single glass of water has 10^23 molecules. That's 7 orders of magnitude difference. So the amount of water you need to cross that magnitude threshold is 7. Turns out that's exactly the size of an Olympic swimming pool. 10 million cups of water.
So statistically, a planet with an ocean volume only as large as a swimming pool has the "Statistical Power" (power of large numbers) to find ANY 50 base pair combination (give or take an order of magnitude or two) Once it finds a replicator, life has started, and so has evolution. And that's guaranteed within the first minute or so, at reasonable temperatures. Now multiply that time by the average age of a planet, and you begin to realize, statistically life is guaranteed, in any chemically diverse scenario with reasonable temperatures.
dekhn
a year ago
Interesting argument, but nobody believes that a diverse chemical makeup is sufficient to guarantee life.
You can wave big numbers around but none of that makes a convincing argument; it's not hard to construct any number of scenarios where self replicators are started but don't lead to true life.
Also you're comparing a gram of water to a bunch of bases; H2O is not DNA.
quantadev
a year ago
Sure we don't have proof that all life will form from essentially "binary" data, (although technically ours is made of 4 bases, not 2), but it's almost axiomatic that life will find the simplest possible way to store information before it finds the more complex ways. Ergo DNA is almost binary, but quarternary instead. It's nearly digital.
Insofar as your H20 vs DNA comparison, I merely used water as a way to show relative "scale". That is, HOW MUCH fluid volume (relative to the order of magnitude of size of atoms) would it take to contain the requisite number of RNA. Because when it comes to probabilities of finding astronomically unlikely combinations, astronomically large numbers is key. I think in a mole of random Rubicks cubes, hundreds will be "accidentally solved" (I forgot those numbers, so check my math, on that one)
The reason I threw in the "give or take 2 orders of magnitude" caveat was precisely because I knew someone like you would accuse me of relating H20 to RNA in a way in which I didn't. Other planets will have different atoms, not necessary water-based life, but planets even the size of a swimming pool have the "numbers game" power to create life.
dekhn
a year ago
Are you aware that at high concentrations, DNA, RNA, and proteins all have serious problems? For example, DNA and RNA are highly charged, with strong repulsion effects, while also having large greasy areas. At the concentrations you're describing, the DNA and RNA would not be functional as we know it.
quantadev
a year ago
Right. The "thought experiment" math is a tight packing of theoretical RNA molecules, and not intended to be taken literally, without a dilution factor; but only to show [some] people their intuition is WAY off about the power of large numbers to "create" unlikely patterns.
For example, if you ask most people how many randomly occurring Rubiks Cubes will just be accidentally solved even with Avogrdro's number of them, their answer is usually zero; and unsurprisingly they're the same ones claiming there had to be a God to create even the initial replicator.
QuiteSocialized
a year ago
For this to hold, each of those water molecules in that swimming pool needs to somehow turn into a random 50 base pair chain of RNA.
Those RNA molecules are also going to be ~two orders of magnitude larger than a water molecule, so you're going to need a bigger pool...
To actually replicate, some loose ingredient molecules must also be present, and in reasonable quantities to be at hand in any given place in the pool.
The argument you are actually making is that a vessel that is filled with randomly assembled chunks of RNA not shorter than 50 base pairs each, the quantity of which equal the number of molecules of water in an Olympic pool, would contain life with probability ~1.
Now, the ocean is large, and a billion years is a long time, but I'm a long way from convinced that the chance of life is 100% on any given suitable planet.
quantadev
a year ago
That's a decent analysis of the things this "thought experiment" doesn't address. I'm not a chemist but I think in a sea of AT and GC pairs even mixed with water, the ability to find every random sequence possible is near certainty:
Especially when you multiply by the number of swimming pools of all ocean water (10^14) by the number of minutes of the history of Earth (10^15), and consider that the probability of the accidental 50 base pair replicator forming needs to have those 29 extra zeroes, in the numerator (not the denominator). So the likelihood, now that I add more info, has just gone up 29 orders of magnitude. lol. (BTW. the 1 minute assumption will be temperature dependent, and is a guess at how long it takes reactions to take place).
The whole thing is a rough approximation like the Drake Equation is, and each number is an estimate. If you want to attack the Thought Experiment, at it's weakest point, just question the initial assumption, which is the biggest guess of all, that some unique 50 base pair RNA can replicate itself.
UniverseHacker
a year ago
There are a huge number of different organelles that evolved independently through events like this- other people mention chloroplasts but there are many others, and probably many yet undiscovered.
I would argue that the type of event that produced mitochondria is likely not rare at all, but certain pairings will so outcompete others that we should expect only one to survive and dominate.
WWWWH
a year ago
I have a chloroplast for you on line two; can you hold?
JumpCrisscross
a year ago
They're sensitive about the Oxygen Holocaust [1][2]?
ordu
a year ago
> Moreover, there may be a narrow window where it can happen: modern microbiology has defences and selection pressures that it make inhospitable to the hobbling chimeræ the first mitochondrial cells would have been.
I don't think it is a very persuasive argument, because it is possible that modern microbiology has defenses because it has mitochondria. I know almost nothing about cells from a few billions years ago, but it seems plausible to me that they were ambivalent towards intrusions of other cells, it can be beneficial or disadvantageous depending on an intruder. Moreover beneficial intruders could give a lot of evolutionary advantage, not like today, when all important things (like mitohondria) are already here. In theory, bacteria could benefit a lot, but there are no ecological niches for a bacteria with mitochondria, all are claimed by some eucaryotes, which are highly adapted.
It is a very common thing in evolution. For example, there are bats, but they cannot evolve and replace birds, because there are birds. Bats have their niche, but they cannot outcompete birds at being more birds than birds. If they were given a chance, then maybe they could try to catch up with birds, but they didn't have a chance and they will have it only if some cataclysm will wipe out birds and leave bats.
hshshshshsh
a year ago
If reality can emerge out of nowhere I don't see it unlikely for life to emerge in some other planet.
JumpCrisscross
a year ago
> If reality can emerge out of nowhere I don't see it unlikely for life to emerge in some other planet
If everything however unlikely is likely because creation is unfathomable, sure.
hshshshshsh
a year ago
Not everything. Life in particular. Because without life (a conscious observer) reality cannot exist. So it should be a property of reality for life to emerge.
9dev
a year ago
Isn't that kind of mixing up the chain of causation? Without a winner, a lottery cannot exist (or at least, at p=0, it's nonsensical). That doesn't automatically imply there are a lot of winners, however.
hshshshshsh
a year ago
I think what I am trying to say is consciousness (life) is reality. And so all kind of planetary experiences can exist inside consciousness as it's contents since consciousness is capable of generating all kind of content.
There is nothing specific about our consciousness that makes it unique to earth.
dekhn
a year ago
Your philosophy is consistent with panpsychism (https://en.wikipedia.org/wiki/Panpsychism). Not really clear how this affects the major discussion here, which is about objective reality as determined by science, and so far as we can tell, neither life nor consciousness is not a prerequisite for reality. It's a fun idea to play with but firmly outside the realm of something we could experiment with scientifically.
timschmidt
a year ago
You are mistaking the map for the territory: https://en.wikipedia.org/wiki/Map%E2%80%93territory_relation
hshshshshsh
a year ago
Can you explain in simple terms? I see physical reality as almost redundant and consciousness seems to be able to do everything.
timschmidt
a year ago
From the first paragraph of the linked article:
"Mistaking the map for the territory is a logical fallacy that occurs when someone confuses the semantics of a term with what it represents. Polish-American scientist and philosopher Alfred Korzybski remarked that "the map is not the territory" and that "the word is not the thing", encapsulating his view that an abstraction derived from something, or a reaction to it, is not the thing itself. Korzybski held that many people do confuse maps with territories, that is, confuse conceptual models of reality with reality itself."
hshshshshsh
a year ago
Okay. I can see that in day to day life. People confusing sentences with actual knowing. Like labeling something a tree and thinking you know what a tree is because you know it's a "tree".
But how did anyone verify there is an underlying reality outside consciousness? It's just an assumption right?
dekhn
a year ago
Yes, it's taken on faith by scientists that we live in an objective universe with cold hard reality outside our consciousness. It seems like a reasonable assumption, consistent with all our observations. It seems not unreasonable to assume that in the early universe there was nothing living, then at some point, through random chance, the first living things became alive (possibly from some non-alive replicators), and then later, the first living things with consciousness came to be. Again, all of this is consistent with our observations, but effectively taken on faith/treated as an assumption.
timschmidt
a year ago
> But how did anyone verify there is an underlying reality outside consciousness?
It's the stuff which continues existing when we stop believing in it.
WalterSear
a year ago
A 'quantum observer' is merely a physical system that interacts with the quantum system being measured. It doesn't have to be conscious or animate.
dekhn
a year ago
There is no known scientific principle or theory with experimental support that without a conscious observer reality cannot exist. It's not something that can be tested, and lies in the realm of philosophy, not science.
hshshshshsh
a year ago
I don't think reality has this property that what cannot be tested through scientific method is not true.
dekhn
a year ago
It might not, you wouldn't be able to convince anybody that something is true, but cannot be tested- that's philosophy and religion.
hshshshshsh
a year ago
I think David Deutsche has this idea that the best explanations should be treated as true even if you can't test it.
user
a year ago
thrw42A8N
a year ago
That sounds like a catch-22
Anotheroneagain
a year ago
Only if you assume it went the seemingly straightforward way, but it could have been more complex. Maybe at first there was no particular limit to unicellular life, and there were unicellular lifeforms both small or large. But the big ones had a terrible problem avoiding getting parasitized by microscopic ones. As, there is one wall to breach, and once it gets in, it's in for good. So maybe eventually one of the bigger ones developed multicellularity as a kind of internal defence wall system, rather than multicellular life evolving from tiny cells clumping together. This gave it an enormous advantage at larger sizes, as all pathogens had to invade the cells one by one, and most of the macroscopic unicellular organisms perished, and some unicellular eukaryotes evolved since then.
ricksunny
a year ago
Robin Hanson #HardSteps
https://m.youtube.com/watch?v=0lKliaFllPA&t=910s (timeatamped)
jibal
a year ago
Earth is so rare that there might merely be hundred of billions of others (say, one per galaxy).
zero_bias
a year ago
There are a lot of sub Neptune planets, the reason why there are only a few earth alike planets is just lack of powerful telescopes and observation time. As technology improves, we’ll find much more planets like ours. Earth is not unique in any way
VMG
a year ago
How do we know it only happened once? Maybe it happened multiple times but only one version survived while the others were outcompeted?
JumpCrisscross
a year ago
> How do we know it only happened once?
We don't. But we know we can't replicate it, have never observed it, don't seem to find half-assed attempts at it in the wild and that there weren't multiple competing chemistries that found themselves co-existing, there was one.
stoperaticless
a year ago
I would like to present you with Chlamydia.
I find it remarkable that chlamydia cells, fully enter host cells and live there stealing of resources.
I would call it evolutions “half-assed attempt” at endosymbiosis. (Disclaimer: evolution has no goal)
hurpdurpdurp
a year ago
I know nothing about biology, pardon my ignorance. From the article it sounds like mitochondria were a separate organism that has perhaps simplified through specialization and is currently on the boundary of being an independent life form. It also sounds like there are other structures (golgi apparatus are mentioned?) which are not on the bubble. Are we sure that there is not an arrow of time here, where once those other structures were also semi-independent and have become less so?
More broadly, it leads me to wonder whether cellular life might eventually/might have at some point specialize towards hosting novel endosymbioses.
Either scenario, assuming what I'm saying isn't just total nonsense, would seem to make the state of mitochondria less of a one-off event and more of the instance of that event we are around at the right time to observe.
liyamchitayat
a year ago
Hi! thanks for taking time to read :)
Those other membrane bubbles inside out cells don't have any of the machines we expect to be associated with cellular life- but you never actually know!
Also, this is def not a 1-off, and happened many times, including chloroplasts in this new nitroplast we found https://en.wikipedia.org/wiki/Nitroplast
maxerickson
a year ago
So only a few billion planets with complex life?
JumpCrisscross
a year ago
> only a few billion planets with complex life?
Or trillions or tens or ones. Depends on what number you put in the exponent. Currently, we don't have useful constraints on that figure.
(A lot of popular astrobiology pulls the "if we could only get 1% of the market we'd be billionaires" schtick.)
dylan604
a year ago
The astrobiology schtick is just a what if thought experiment though, and nothing proven nor claimed to be fact. It's just a way to show that the scale of the universe is "hugely, mind-bogglingly big" while trying to pull a number that our squishy lobes could comprehend. If 1% of mind-bogglingly huge number, then 1% of that, then 1% of that yields a still mind-bogglingly big number. The laws of large numbers would suggest something as well. Otherwise, "its an awful waste of space"
JumpCrisscross
a year ago
Sure. The point is 1% is a huge fraction for a lot of things. Market share. And many reaction cross sections.