18 ms·

Charles Darwin’s hunch about early life was probably right

146 points by clouddrover 6y ago

rakkhi 6y ago
I'm more partial to the idea that a metabolic system to harness energy had to develop before replication and that life started in alkaline hydrothermal vents rather than ponds due to the delivery of energy and concentration of chemicals. Really enjoyed Nick Lane's writing on this topic, highly recommend his books. https://nick-lane.net/publications/origin-life-alkaline-hydrothermal-vents-2/ https://nick-lane.net/publications/origin-life-alkaline-hydr...
- jb1991 6y ago
  The article directly addresses that idea, and suggests it is not a likely answer: > ...according to a review published in May 2020, “the direct synthesis of amino acids or nucleobases” – both of which are crucial to life as we know it – has “not yet been demonstrated” under alkaline vent conditions.
  - Larrikin 6y ago
    It does not say that it isn't likely, just that it hasn't been observed. This is the first article on the topic I've seen that even suggest that it isn't strongest candidate.
    - matt-attack 6y ago
      But if it’s already been observed in other conditions (wet:dry cycles) why not just focus on those.
      - andrewflnr 6y ago
        Because it would be foolish to rule out ideas unnecessarily? Let's keep our options open.
rtx 6y ago
When I learnt about all the great scientist in school I was always amazed by their brilliance. However I always felt something was missing, what was so different about them that they were able to achieve so much. Even though I had heard Newton's quote about standing on shoulder of giants I was never able to understand it fully till much later. All these brilliant discovery had a thread going back to the beginning of our civilization.
- spockz 6y ago
  It is not just standing on shoulders of giants. It is also that we only hear about the success stories and hardly ever of the long road that lead to the insights and theories. We do this in our era as well which makes it easy to someone as brilliant and think of yourself as not brilliant because you experience your own failures and struggles but only see the successes of others.
  - JumpCrisscross 6y ago
    > It is also that we only hear about the success stories and hardly ever of the long road that lead to the insights and theories I have never truly understood a theory until I learned its broken precursors. One gets a taste of this in physics. Newton to special relativity. (I never got my head around GR.) Or earlier: the different models of atoms, from plum pudding to electron clouds. It’s a good tool poorly used outside a few examples.
  - easton_s 6y ago
    Watching the Cosmos series those giants in their times were like Atlases carrying their work and the social sigma of trying to break dogma. Many of them suffered greatly for us to enjoy the elevated view.
- samizdis 6y ago
  > Even though I had heard Newton's quote about standing on shoulder of giants I was never able to understand it fully till much later. There's an article about this [1] that I enjoyed reading a few years back, titled Standing on the Shoulders of Giants: The Story Behind Newton’s Famous Metaphor for How Knowledge Progresses [1] https://www.brainpickings.org/2016/02/16/newton-standing-on-the-shoulders-of-giants/ https://www.brainpickings.org/2016/02/16/newton-standing-on-...
cblconfederate 6y ago
for those impatient like me (aaargh!): > Darwin was proposing that life began, not in the open ocean, but in a smaller body of water on land, which was rich in chemicals
- herodoturtle 6y ago
  TL;DR champion. Thanks.
- kristianpaul 6y ago
  Thats also interesting > “But it’s something that could be trying to happen even now.” Could be happening on earth still or other planets he meant?
  - macintux 6y ago
    Earth, hence the “bacterium gobbles it up” idea.
  - dividedbyzero 6y ago
    Everywhere the conditions for these processes are met – though it's unlikely it would be going very far on Earth, as this planet is already teeming with bacteria and other life, some of which is certain to find proto-lifeforms delicious.
    - dTal 6y ago
      Not even proto-lifeforms - any pile of interesting organic chemicals is going to immediately be devoured (i.e. go moldy) well before it can spontaneously assemble into anything. This is why we have fridges..
      - LeonB 6y ago
        Or just oxidized by all this pesky oxygen the damn photosynthesis keeps leaking all over the place.
- 6y ago
singularity2001 6y ago
I'm more partial to the idea that RNA based life developed outside earth. (panspermia theory)
- jonathanlydall 6y ago
  I don’t dispute the possibility, but it does beg the question of why that’s more likely than life developing on Earth?
  - skohan 6y ago
    In a lot of ways it's just punting the problem isn't it?
    - hcarvalhoalves 6y ago
      I think Panspermia could explain why it's so hard to reproduce the first organisms in a lab by mimicking Earth's early conditions - we could be using the wrong conditions altogether. E.g. we could be ignoring the effect of solar radiation from another atmosphere, or very high/low atmospheric pressure, etc.
      - skohan 6y ago
        I mean it could also have taken a really long time, right? like the correct conditions could have existed for tens of thousands of years or more before the chance collisions occurred which resulted in self-replicating life.
  - jcims 6y ago
    I'm of the same notion, just because the basic combinatorics of various features of even the simplest self-replicating life forms are so exceedingly unlikely that to me the idea that they were developed stochastically in relatively rapid succession in the first billion years on earth just doesn't add up. It will become clear that I'm no expert, but this has fascinated me a bit and I've seen a few articles about simplest self-replicators. In a lab they've constructed enzymes [1] that are able to do some replication with as few as 160-190 bases of RNA, but they aren't self-replicating, they spew out some subset of themselves. RNA is just half of DNA with each base in a particular sequence being one of four possible nucleotides (A, C, G and U). In the smallest case above, you have 160 nucleotides giving the entire string of RNA a molar mass of ~ ~50kDa [2] (approximately 50kg per mole of that RNA string). There are ~4^160 combinations of just this extremely short and as far as we know insufficient string of RNA to build even the simplest self-replicator. 4^160 is approximately 2e96 combinations. If you wanted to try every one of those combinations, you would be assembling (2e96 / 6e23) approximately 3e72 moles of RNA. To do it in one shot you would need more mass than in the observable universe (closer to a billion universes). To do it with just the mass of the earth (forget surface/hydrocarbons/biomass) in four billion years you'd have to recycle at relativistic speeds. Obviously it happened, and the above 'needle in a haystack' assessment has many problems as well. But the numbers are so big that no matter how you slice it I can see a scenario where it plausibly only happened once in the history of the universe. Either that or the stochastic parts of the explanation of abiogenesis are incomplete. 1 - https://doi.org/10.1126/science.1200752 https://doi.org/10.1126/science.1200752 2 - https://bionumbers.hms.harvard.edu/files/Nucleic%20Acids_Sizes_and_Molecular_Weights_2pgs.pdf https://bionumbers.hms.harvard.edu/files/Nucleic%20Acids_Siz...
sktrdie 6y ago
To me beginning of life is a combinatorial issue. You have to have the right combination of lots of different things (chemicals, weather conditions, time etc) to have it happened. What’s scary (or interesting) to me is that we have access to labs and are capable of quickly iterating with lots of different combinations; yet no life arised. If it’s hard in a lab it’s probably a lot harder in nature where to get a different set of combinations you need a new planet! Hence why I think life is rare in the universe.
- marcosdumay 6y ago
  Not to detract on your conclusion (I do think like is hard due to some estimates on chemical combinations), but there are way more planets than experiments on Earth about abiogenesis.
- tylerjwilk00 6y ago
  Indeed. One thing labs lack that the early earth had in the plenty is space (for multiple "experiments") and time.
- simonh 6y ago
  Take the volume of all the lab experiments ever done, multiplied by the length of time those experiments were run for. Next take the entire volume of Earth's primordial oceans and multiply by a few hundred million years, roughly the period during which life arose on Earth. What's the ratio between those two results? The fact that something arose once in the latter tells you very little about what's happening in the former.
  - brk 6y ago
    I understand your point, but in the lab scenarios we are theoretically using ideal(ish) conditions (or, at least what we think are ideal conditions). In the random nature scenario, probably 99% of all the instances would be immediately discarded for potential because of 1 or more clearly suboptimal conditions.
    - 6y ago
sizt 6y ago
Although the majority of people consider evolution to be a fact, Darwin himself labeled it a "Theory" of Evolution, not empirical.
- confidantlake 6y ago
  Gravity is also a theory.
  - paulmooreparks 6y ago
    And music.
    - sizt 6y ago
      Music is not a theory although there is a theory of music, but not a very good one.
- fifnir 6y ago
  > The meaning of the term scientific theory (often contracted to theory for brevity) as used in the disciplines of science is significantly different from the common vernacular usage of theory.[4][note 1] In everyday speech, theory can imply an explanation that represents an unsubstantiated and speculative guess,[4] whereas in science it describes an explanation that has been tested and widely accepted as valid. These different usages are comparable to the opposing usages of prediction in science versus common speech, where it denotes a mere hope. Please take a minute to consider this and realize that you should never repeat what you just said.
  - sizt 6y ago
    Although the majority of people consider evolution to be a fact, Darwin himself labeled it a "Theory" of Evolution, not empirical.
    - paulmooreparks 6y ago
jokoon 6y ago
it has a name, you know: https://en.wikipedia.org/wiki/Abiogenesis https://en.wikipedia.org/wiki/Abiogenesis
beefman 6y ago
The letter: https://www.darwinproject.ac.uk/letter/DCP-LETT-7471.xml https://www.darwinproject.ac.uk/letter/DCP-LETT-7471.xml
dctaflin 6y ago
I can't quibble with anything in the article except the title. There are too many viable alternative scenarios to call Darwin's idea "probably right."

146 points by clouddrover 6y ago

I'm more partial to the idea that a metabolic system to harness energy had to develop before replication and that life started in alkaline hydrothermal vents rather than ponds due to the delivery of energy and concentration of chemicals. Really enjoyed Nick Lane's writing on this topic, highly recommend his books. https://nick-lane.net/publications/origin-life-alkaline-hydrothermal-vents-2/ https://nick-lane.net/publications/origin-life-alkaline-hydr...

jb1991 6y ago
The article directly addresses that idea, and suggests it is not a likely answer: > ...according to a review published in May 2020, “the direct synthesis of amino acids or nucleobases” – both of which are crucial to life as we know it – has “not yet been demonstrated” under alkaline vent conditions.
- Larrikin 6y ago
  It does not say that it isn't likely, just that it hasn't been observed. This is the first article on the topic I've seen that even suggest that it isn't strongest candidate.
  - matt-attack 6y ago
    But if it’s already been observed in other conditions (wet:dry cycles) why not just focus on those.
    - andrewflnr 6y ago
      Because it would be foolish to rule out ideas unnecessarily? Let's keep our options open.

rtx 6y ago

When I learnt about all the great scientist in school I was always amazed by their brilliance. However I always felt something was missing, what was so different about them that they were able to achieve so much. Even though I had heard Newton's quote about standing on shoulder of giants I was never able to understand it fully till much later. All these brilliant discovery had a thread going back to the beginning of our civilization.

spockz 6y ago
It is not just standing on shoulders of giants. It is also that we only hear about the success stories and hardly ever of the long road that lead to the insights and theories. We do this in our era as well which makes it easy to someone as brilliant and think of yourself as not brilliant because you experience your own failures and struggles but only see the successes of others.
- JumpCrisscross 6y ago
  > It is also that we only hear about the success stories and hardly ever of the long road that lead to the insights and theories I have never truly understood a theory until I learned its broken precursors. One gets a taste of this in physics. Newton to special relativity. (I never got my head around GR.) Or earlier: the different models of atoms, from plum pudding to electron clouds. It’s a good tool poorly used outside a few examples.
- easton_s 6y ago
  Watching the Cosmos series those giants in their times were like Atlases carrying their work and the social sigma of trying to break dogma. Many of them suffered greatly for us to enjoy the elevated view.
samizdis 6y ago
> Even though I had heard Newton's quote about standing on shoulder of giants I was never able to understand it fully till much later. There's an article about this [1] that I enjoyed reading a few years back, titled Standing on the Shoulders of Giants: The Story Behind Newton’s Famous Metaphor for How Knowledge Progresses [1] https://www.brainpickings.org/2016/02/16/newton-standing-on-the-shoulders-of-giants/ https://www.brainpickings.org/2016/02/16/newton-standing-on-...

cblconfederate 6y ago

for those impatient like me (aaargh!): > Darwin was proposing that life began, not in the open ocean, but in a smaller body of water on land, which was rich in chemicals

herodoturtle 6y ago
TL;DR champion. Thanks.
kristianpaul 6y ago
Thats also interesting > “But it’s something that could be trying to happen even now.” Could be happening on earth still or other planets he meant?
- macintux 6y ago
  Earth, hence the “bacterium gobbles it up” idea.
- dividedbyzero 6y ago
  Everywhere the conditions for these processes are met – though it's unlikely it would be going very far on Earth, as this planet is already teeming with bacteria and other life, some of which is certain to find proto-lifeforms delicious.
  - dTal 6y ago
    Not even proto-lifeforms - any pile of interesting organic chemicals is going to immediately be devoured (i.e. go moldy) well before it can spontaneously assemble into anything. This is why we have fridges..
    - LeonB 6y ago
      Or just oxidized by all this pesky oxygen the damn photosynthesis keeps leaking all over the place.
6y ago

singularity2001 6y ago

I'm more partial to the idea that RNA based life developed outside earth. (panspermia theory)

jonathanlydall 6y ago
I don’t dispute the possibility, but it does beg the question of why that’s more likely than life developing on Earth?
- skohan 6y ago
  In a lot of ways it's just punting the problem isn't it?
  - hcarvalhoalves 6y ago
    I think Panspermia could explain why it's so hard to reproduce the first organisms in a lab by mimicking Earth's early conditions - we could be using the wrong conditions altogether. E.g. we could be ignoring the effect of solar radiation from another atmosphere, or very high/low atmospheric pressure, etc.
    - skohan 6y ago
      I mean it could also have taken a really long time, right? like the correct conditions could have existed for tens of thousands of years or more before the chance collisions occurred which resulted in self-replicating life.
- jcims 6y ago
  I'm of the same notion, just because the basic combinatorics of various features of even the simplest self-replicating life forms are so exceedingly unlikely that to me the idea that they were developed stochastically in relatively rapid succession in the first billion years on earth just doesn't add up. It will become clear that I'm no expert, but this has fascinated me a bit and I've seen a few articles about simplest self-replicators. In a lab they've constructed enzymes [1] that are able to do some replication with as few as 160-190 bases of RNA, but they aren't self-replicating, they spew out some subset of themselves. RNA is just half of DNA with each base in a particular sequence being one of four possible nucleotides (A, C, G and U). In the smallest case above, you have 160 nucleotides giving the entire string of RNA a molar mass of ~ ~50kDa [2] (approximately 50kg per mole of that RNA string). There are ~4^160 combinations of just this extremely short and as far as we know insufficient string of RNA to build even the simplest self-replicator. 4^160 is approximately 2e96 combinations. If you wanted to try every one of those combinations, you would be assembling (2e96 / 6e23) approximately 3e72 moles of RNA. To do it in one shot you would need more mass than in the observable universe (closer to a billion universes). To do it with just the mass of the earth (forget surface/hydrocarbons/biomass) in four billion years you'd have to recycle at relativistic speeds. Obviously it happened, and the above 'needle in a haystack' assessment has many problems as well. But the numbers are so big that no matter how you slice it I can see a scenario where it plausibly only happened once in the history of the universe. Either that or the stochastic parts of the explanation of abiogenesis are incomplete. 1 - https://doi.org/10.1126/science.1200752 https://doi.org/10.1126/science.1200752 2 - https://bionumbers.hms.harvard.edu/files/Nucleic%20Acids_Sizes_and_Molecular_Weights_2pgs.pdf https://bionumbers.hms.harvard.edu/files/Nucleic%20Acids_Siz...

sktrdie 6y ago

To me beginning of life is a combinatorial issue. You have to have the right combination of lots of different things (chemicals, weather conditions, time etc) to have it happened. What’s scary (or interesting) to me is that we have access to labs and are capable of quickly iterating with lots of different combinations; yet no life arised. If it’s hard in a lab it’s probably a lot harder in nature where to get a different set of combinations you need a new planet! Hence why I think life is rare in the universe.

marcosdumay 6y ago
Not to detract on your conclusion (I do think like is hard due to some estimates on chemical combinations), but there are way more planets than experiments on Earth about abiogenesis.
tylerjwilk00 6y ago
Indeed. One thing labs lack that the early earth had in the plenty is space (for multiple "experiments") and time.
simonh 6y ago
Take the volume of all the lab experiments ever done, multiplied by the length of time those experiments were run for. Next take the entire volume of Earth's primordial oceans and multiply by a few hundred million years, roughly the period during which life arose on Earth. What's the ratio between those two results? The fact that something arose once in the latter tells you very little about what's happening in the former.
- brk 6y ago
  I understand your point, but in the lab scenarios we are theoretically using ideal(ish) conditions (or, at least what we think are ideal conditions). In the random nature scenario, probably 99% of all the instances would be immediately discarded for potential because of 1 or more clearly suboptimal conditions.
  - 6y ago

sizt 6y ago

Although the majority of people consider evolution to be a fact, Darwin himself labeled it a "Theory" of Evolution, not empirical.

confidantlake 6y ago
Gravity is also a theory.
- paulmooreparks 6y ago
  And music.
  - sizt 6y ago
    Music is not a theory although there is a theory of music, but not a very good one.
fifnir 6y ago
> The meaning of the term scientific theory (often contracted to theory for brevity) as used in the disciplines of science is significantly different from the common vernacular usage of theory.[4][note 1] In everyday speech, theory can imply an explanation that represents an unsubstantiated and speculative guess,[4] whereas in science it describes an explanation that has been tested and widely accepted as valid. These different usages are comparable to the opposing usages of prediction in science versus common speech, where it denotes a mere hope. Please take a minute to consider this and realize that you should never repeat what you just said.
- sizt 6y ago
  Although the majority of people consider evolution to be a fact, Darwin himself labeled it a "Theory" of Evolution, not empirical.
  - paulmooreparks 6y ago

jokoon 6y ago

it has a name, you know: https://en.wikipedia.org/wiki/Abiogenesis https://en.wikipedia.org/wiki/Abiogenesis

beefman 6y ago

The letter: https://www.darwinproject.ac.uk/letter/DCP-LETT-7471.xml https://www.darwinproject.ac.uk/letter/DCP-LETT-7471.xml

dctaflin 6y ago

I can't quibble with anything in the article except the title. There are too many viable alternative scenarios to call Darwin's idea "probably right."