A New Theory About Why Life Exists

[Argylas]

Hi, I'm sorry if this has already been posted on the forum, but I recently found a very interesting new theory by Jeremy England - an assistant professor at the MIT, about why life exists. You can read an article about his theory here - https://www.quantamagazine.org/20140122-a-new-physics-theory-of-life/

Basically his theory, as far as i can understand (and I'm not a scientist by any means) is that the creation of life in a given system is inevitable, because life turns out to be the most efficient mechanism of increasing entropy in an "open" system.

I would generally feel very skeptical about such "groundbreaking" theories, but this one resonates well with my strong (but not based on any true scientific facts) belief that there is no or at least very little distinction between living and non-living matter in the grand picture of things and that our anthropocentric view of the universe is what makes us classify these two things as inherently different.

I would be glad to hear the opinion of people here with a better scientific background than me (which would probably be more than 90% of you) on this theory and whether it really presents a new promising train of thought for biochemists to consider.

[Greenfire32]

Don't have enough time to read the full text right now, but I got to the part where it goes:

“You start with a random clump of atoms, and if you shine light on it for long enough, it should not be so surprising that you get a plant,†England said.

Aaaand that's one HELL of a claim...Not quite sure I can get behind this one as based on the above alone, there should be life on just about every planet in our solar system/galaxy/universe...and there isn't.

So first things first: cool theory, now get to work on some of that pesky evidence. Second, maybe this theory needs a partner theory. If life is inevitable, why hasn't it cropped up more?

Right about now is the part where I tell you that I, myself, am no scientist. But this sure does feel an awful lot like pseudoscience rather than actual science.

Not saying this new theory is ridiculous, but without...really anything to back it up other than "you know what I think?" I can't really accept or appreciate it yet.

[Camacha]

If life is inevitable, why hasn't it cropped up more?

My guess is you missed the 'wait long enough' part

[Nuke]

life does contribute to entropy. but i dont think the scale is anything compared to other entropy machines in the universe, such as stars, black holes and the like.

[-Velocity-]

If life is inevitable, why hasn't it cropped up more?

I'm not sure I buy this theory either, but it IS somewhat interesting. However, there's a decent counter to your above statement. Life should not be capable of coming into being in all conditions. In addition, some conditions should be more favorable to the formation of life than others, and should give rise to life first. Earth may be an example of this. Additionally, life on Earth has now evolved space travel, and, with luck, will soon be spreading to other planets, asteroids, and maybe even deep space. If humans can pull it off, the development of space travel and the colonization of offworld habitats will be the among the greatest achievements by Earth life in the history of life, right up there will the colonization of dry land, multicellular structures, and photosynthesis.

A lot of people set humans above other life forms and see us as somehow different, but the fact remains we are just Earth life, cousins to all other living things, and so most certainly yes, Earth life appears to be on the doorstep of evolving the ability to send "spores" across the gulf of space to colonize previously unreachable and uninhabitable environments. We're living at a very, very special time, and I just wish more people saw it the way I do. We have the ability to accomplish one of the greatest achievements in the 3.6 billion year+ history of life on this planet, if we can just pull ourselves out of the mud.

So, anyway, to make a long story short, life may be much more ubiquitous in the not-too-distant future, at least in this solar system.

Edited December 12, 2014 by |Velocity|

[MBobrik]

One of the things that sound profound, but may be very trivial when looked at closely. Increasing entropy more means you are just extracting more energy from the environment, which , anything else being equal, grants you a survival advantage. Life thus evolves to collect energy pretty efficiently, and thus to efficiently increase total entropy. On the other hand, life, bacteria, fungi and saprophytes could live off a dead tree branch for months, but one forest fire will consume it in minutes, and thus increase entropy much faster than life ever could.

.

And it says nothing about the creation of life. Surely, at molecular level, the thermodynamically more favorable reaction usually outcompetes the less favorable. But there are kinetic considerations as well. It is more likely, that the first self-replicating reaction won over other chemical reactions not by releasing the most entropy, but by being able to proceed kinetically much faster, because, well, the catalyst reproduced itself.

Edited December 12, 2014 by MBobrik

[trekkie_]

Life exists because things like DNA synthesis is a natural property of the physics of the universe, under the right conditions at the right time that is.

The idea that the universe somehow leans toward creating life to increase entropy, is flawed in every way. That almost gives the impression that the universe would literally be making decisions and acting accordingly. Just think about the impact of life on earth even to just our own solar system.....it's basically zero effect, over hundreds of millions of years. Meanwhile, during that same period of time, 'natural' entropy having nothing to do with life, dwarfs any entropy caused as a result of life.

[-Velocity-]

Life exists because things like DNA synthesis is a natural property of the physics of the universe, under the right conditions at the right time that is.

The idea that the universe somehow leans toward creating life to increase entropy, is flawed in every way. That almost gives the impression that the universe would literally be making decisions and acting accordingly. Just think about the impact of life on earth even to just our own solar system.....it's basically zero effect, over hundreds of millions of years. Meanwhile, during that same period of time, 'natural' entropy having nothing to do with life, dwarfs any entropy caused as a result of life.

No, it has nothing to do with global entropy, it has to do with local entropy. What they're saying is that it is a general property any system to arrange itself so that it can create as much entropy as possible. In nebulae, this means that stars form to convert rest mass into radiation and neutrinos. On a world with the right chemicals and the right energy sources, this may mean that life will frequently emerge to catalyze entropy-producing chemical reactions.

I'm not convinced myself. Entropy works through probability- there are more "disordered" states than "ordered" states. But the steps that you take to get from ordered to disordered are not all equally probable. If life is highly improbable, then couldn't the probability of increasing entropy through the actions of life be smaller than through non-biological means?

[MBobrik]

What they're saying is that it is a general property any system to arrange itself so that it can create as much entropy as possible.

Then any dry wood would catch fire, instead of being slowly decomposed, or submerged into a peat bog and converted to coal, because that way it would create entropy much faster.

edit:

And in general, the total entropy production of earth is determined only by the spectrum of outgoing electromagnetic radiation, which is in turn determined mostly by albedo across the spectrum, and absorption spectrum of earth's atmosphere. And while life surely influences both, I don't think that it does in a way that maximizes total entropy production.

Edited December 12, 2014 by MBobrik

[xenomorph555]

I uh, guess life finds a, uh way... :S

[Francesco]

Life exists because things like DNA synthesis is a natural property of the physics of the universe

About this point: do we know that DNA/RNA synthesis is a requirement for "life" to exist?

Do we know other non-DNA based forms of life?

[trekkie_]

About this point: do we know that DNA/RNA synthesis is a requirement for "life" to exist?

Do we know other non-DNA based forms of life?

Even if non DNA life exists, it would still be a natural property of the physics of the universe, given the right conditions.

[NERVAfan]

I don't know about the actual theory, but...

Second, maybe this theory needs a partner theory. If life is inevitable, why hasn't it cropped up more?

Maybe it has. We really haven't looked!

The Viking experiments were horribly insufficient given modern knowledge of microbiology (which has advanced enormously since then) and haven't been followed up - and the most likely places to find life on Mars would be underground/inside rocks anyway.

No one has looked in Europa or Enceladus water.

It's possible that life could exist in Titan's hydrocarbon seas, or maybe even in gas/ice giant atmospheres/supercritical "atmo-oceans" (is there a word for that?) but we wouldn't know how to detect it since it would be so different.

I think life on Mercury, the Moon, or other airless/waterless bodies can pretty much be ruled out due to the lack of a fluid medium... but everywhere else is still possible, IMO.

[Aningaaq]

This isn't a new theory.

[Dodgey]

Hypothesis, not theory. Please don't misuse that word. The general public is confused as it is.

[YNM]

If life rises up from such effort, why haven't the whole surface of Earth do photosynthesis ? Else, why there exist plants ?

I know that statement is fairly short-minded. I know it must be due to the different behavior of different elements, and the different conditions these atoms are placed at. I mean, while Sun itself being heated from the inside, it does nothing but to set loose and creating solar wind. While Mercury and Venus are nearer to Sun (so receive more stimulation, and so you hope it to happen faster), the effect is that they might receive more radiation that instead break things loose. While Jupiter are radiating by itself, there's no life inside because of the enormous pressure.

There's another thing that one may point out through : live only appears because of the right stimuli. Else, there won't be life. Just be glad that the Earth were placed this way...

I'm agree that it's more of a hypothesis. You need more observations and simulation / models to see whether it could happen or not, whether it's also affected by other external things or not.

[Dodgey]

Duplicate post

[sndrtj]

On the other hand, life, bacteria, fungi and saprophytes could live off a dead tree branch for months, but one forest fire will consume it in minutes, and thus increase entropy much faster than life ever could.

Faster != more efficient per se. The total energy per gram of dead tree as used by detritivores is probably much higher than a simple forest fire. So life is, in the end, better at it. Not necessarily faster, but better.

[John FX]

So some people are saying `If things exist that are better at increasing entropy than life, why does life exist`

That`s very similar to the argument `If we evolved from monkeys, why are there still monkeys` and the answer is the same.

Evolution does not work like that.

[MBobrik]

Faster != more efficient per se. The total energy per gram of dead tree as used by detritivores is probably much higher than a simple forest fire. So life is, in the end, better at it. Not necessarily faster, but better.

That's the ambiguity. Do they mean maximum entropy production per second ? Then fire wins. Do they mean maximum total entropy ? Then fire loses to life because even when chemical end-products might be the same, fire released a lot of low entropy types of energy like light and infrared. But in this case, life would lose to slow uncatalyzed oxidation, which might take millennia, but produces the most total entropy.

[Kryten]

About this point: do we know that DNA/RNA synthesis is a requirement for "life" to exist?

Do we know other non-DNA based forms of life?

We're reasonably sure that life started with RNA, and DNA are proteins are later developments. We don't have a good model for life without at least RNA, and we certainly haven't found any.

[KerikBalm]

Its obvious that life increases entropy.

It would violate thermodynamics if it didn't.

I think its a big leap to say that life exists to increase entropy.

Life has to increase entropy to exist, but I think its useless to say that increasing entropy is *why* it exists.

Pluto could be fusing hydrogen at its core to increase entropy, and simply radiating heat, which is rather high entropy (indeed, heat death due ot entropy is the fate of the universe it seems).

But it doesn't because of constraints of physics.

Life exists or doesn't exist within those same constraints.

As to the OP - yea, from a physics point of view, there is no real difference between living and non living systems. Indeed, an in depth study of life will lead to studying a bunch of non-living "subsystems" of life, and a very muddled view on what is and is not life.

FWIW, viruses with entirely RNA genomes exist.

So there are discrete biological agents that undergo evolution by replication with mutation and natural selection, that do not contain DNA.

But most people choose to put them on the non-life side of the arbitrary line between life and non-life.

[Bill Phil]

Maybe we're in a low-entropy part of the universe, and the universe decided to increase entropy here. I don't know, just a thought.

[Three1415]

In my opinion, this claim makes little sense. Life should be prevalent simply because, if one includes the entire universe and every object in it as "species" undergoing Darwinian selection, the structures that will become most common are the ones that can replicate themselves most efficiently--i.e, life under my general definition of it (any self-replicating, evolving structure). Thus, life should be the most prevalent object in the universe, simply because it intrinsically exhibits the characteristics most beneficial to increasing its numbers.

[sndrtj]

Its obvious that life increases entropy.

It would violate thermodynamics if it didn't.

Life increases entropy at the global level, but locally it seems to actually reduce it. Actually, it's one of the major hallmarks in determining what is "alive": homeostasis. That's not a contradiction; AFAIK, thermodynamics is fine if entropy is decreasing in a local area, so long the entropy of the entire system keeps increasing.

Take the following analogy: We have a sea, and a sun. Water is evaporated by the sunlight heating the sea - the sun's energy is now sort of in "stasis" as evaporated water. To increase entropy, that energy must be released. How to release that energy: condensing the water (which in itself releases energy), forming rain, which releases most of its kinetic energy again as heat when it smashes into the surface. However, when having pure water, that condensation is rather inefficient. One needs some contaminant, a disturbance, to nucleate the condensation. Once that nucleation has happened tho, condensation is inevitable, your cloud of water vapor rapidly condenses into rain drops, and entropy will increase much faster than without contaminants in the sky.

Life is basically that disturbance. Life converts sunlight super-efficiently into (waste) heat. Once one has life, it's probably quite inevitable that it spreads and catalyzes that entropy increase all over your environment. Just like our drop of rain - which is highly ordered on a local level as compared to the unstructured mess of a cloud of gas - life _itself_ tho is highly structured. It's probably difficult to get life in the first place, but once it is there, it will likely rapidly colonize your entire planet. ("Rapidly" is of course a relative term). I wouldn't say it's however inevitable life will arise by definition, as there will be some requirements for its formation. Just like rain requires the correct mix of vapor pressure, saturation (humidity) and temperature no matter whether there is a nucleation, life requires some (so far mostly unknown) general requirements to exist. Unlike our rain analogy, however, life can adapt, and it is inevitable it WILL adapt and actually become ever better at its job once it exists. That's evolution for you. Everything that can self-replicate and self-mutate can and will evolve; that's pure and simple logic.

As for viruses, I entirely agree with you it's rather arbitrary to not include them into "life". They do carry genetic information, evolve, replicate and mutate. However, it would be ignorant to ignore the fact that they are indeed different from canonical life. They rely on other living things to replicate and mutate. They don't self-replicate and and self-mutate.