Importance of negentropy in the creation of life

[Hip]

TL;DR Summary

A supply of negentropy into a system is necessary to create states of higher order and complexity. Since the origin and evolution of life involves the creation of ever more complex molecular arrangements of atoms, life could not start without a sufficient supply of negentropy. So when considering celestial environments where life might be created from scratch and continue evolving towards greater complexity, presumably only environments with a good negentropy supply would be viable candidates.

Summary: A supply of negentropy into a system is necessary to create states of higher order and complexity. Since the origin and evolution of life involves the creation of ever more complex molecular arrangements of atoms, life could not start without a sufficient supply of negentropy. So when considering celestial environments where life might be created from scratch and continue evolving towards greater complexity, presumably only environments with a good negentropy supply would be viable candidates.

The Earth's surface and atmosphere have an abundant supply of negative entropy (negentropy). This is because most of the energy the Earth receives from the Sun is in the form of near infrared, visible and ultraviolet light (which are relatively low in entropy), whereas the energy the Earth radiates back into space is mostly in the deep infrared range (which is high in entropy). Thus although the amount of energy the Earth radiates out is equal to the energy it receives from the Sun, the Earth constantly enjoys a net gain in negentropy.

Without this constant supply of negentropy, evolution of life on Earth could not have taken place (since evolution is an increase in order and complexity). And if Earth was also the place where life first began, then that initial creation of life would presumably also be dependent on negentropy (because I believe creating more complex molecules equates to an increase in order).

Refs:
Evolution and the Second Law
Steps Towards an Evolutionary Physics
Thus when considering whether life may have independently emerged in other environments in our solar system (on other planets or moons), presumably these places would only be good candidates for creating life if they have a constant supply of negentropy.

So for example, both Jupiter's moon Europa and Saturn's moon Enceladus have large underground oceans of liquid water, an ingredient considered essential for the creation of life. However, the oceans in Europa and Enceladus are thought to be heated not by sunlight, but rather by tidal flexing from their planets' strong gravity. Now I am not sure if energy received by tidal flexing results in any net gains in negentropy. And if there is no supply of negentropy entering into Europa and Enceladus, then I do not see much chance of any life emerging or evolving on these two moons.

But I'd be interested in hearing other people's views on this.

 

[BillTre]

My view is that negentropy is necessary, but not sufficient, for life to arise.

I would include other sources, like tidal gravity effects on planets in a negentropy budget.
It would be important to also include all the negentropy that exists in the chemical make-up of a planets components.

The proper local chemistry will be one of those things that would be involved in making an environment sufficient for life. If the chemistry is not there, life will not easily arise.

 

[Hip]

My view is that negentropy is necessary, but not sufficient, for life to arise.

Certainly. It's generally believed that in order to create life you need a good universal solvent like water, in which atoms and molecular components can dissolve and float around, otherwise there's no mechanism to allow these atoms and molecules to move into contact with each other, in order to create more complex molecules by chemical combination.

I would include other sources, like tidal gravity effects on planets in a negentropy budget.

I wonder how much negentropy tidal effects provide in comparison to sunlight radiation?

It would be important to also include all the negentropy that exists in the chemical make-up of a planets components.

True, negentropy locked up in chemical form should be considered. But if those chemicals are rapidly depleted, I don't think they would be effective in creating life, because you need an ongoing negentropy source to not only create the very first stages of life, but to allow evolution of that life into more complex forms like single celled organisms.

 

[BillTre]

True, negentropy locked up in chemical form should be considered. But if those chemicals are rapidly depleted, I don't think they would be effective in creating life, because you need an ongoing negentropy source to not only create the very first stages of life, but to allow evolution of that life into more complex forms like single celled organisms.

One hypothetical origin of life on Earth involves the serpentinization of basalt through its reactions with water, which can produce H₂ and other chemicals. In addition, iron, sulfur, nickle can be released which can be used to catalyze reactions. These reactions are thought to be involved in life origins.
There is a lot of water and basalt on Earth which can drive these reactions. I have read are that an ocean volume of water (volume equal to the volume of the waters of all the oceans) has been absorbed by mantle rocks. So the depletion seems to have not been rapid. The reaction rate of water with rocks would depend upon the surface area of un-reacted rocks being exposed to the water. This only happens in particular areas like rift zones, and due to the slow rate of plate tectonics, these sources have not yet been depleted.

 

[kcren]

(since evolution is an increase in order and complexity)

I strongly question that assumption, even though I've said it before myself.

We have to be careful: a basic single-celled creature is certainly less complex than a greatly improved single-celled creature that descends from it. But they are not the same system (i.e. they are not the same atoms and energy in different states of organization). They are completely different systems of different atoms operating at different times in their environment. So, comparing the entropy of the two to determine entropy flow is nonsensical. The basic cell did not become the more complex cell, its information was simply a template for the formation of later cells. The overall environment (ecosystem) is the same before and after, therefore it is a single system, so the entropy of the entire ecosystem will increase (including all the unorganized raw materials before and the accumulated, broken-down dead cells between the two cell generations) unless you introduce negentropy, which happens via the sun.

This doesn't answer your original question but it may influence the discussion.
And it's a misconception that I'd love to see put to rest.

 

[Hip]

I strongly question that assumption, even though I've said it before myself.

I think it's certainly a good thing to consider and question. But I am not really following your argument, perhaps I am not understanding it.

If we consider some primeval puddle where we posit life began, prior to the appearance of life, the atoms and molecules dissolved in that puddle we can assume were evenly distributed throughout the water (just as when you dissolve some sugar in water, you get a uniform concentration of sugar throughout the liquid via random Brownian motion).

When a molecule is uniformly distributed in this manner, that is the highest level of entropy it can have. By contrast, if the molecules are confined to specific locations within the puddle, that would be a lower level of entropy. So when molecules are placed in particular locations, you lower the entropy, compared to when the molecules are uniformly distributed.

So as primeval living organisms first begin to manifest in the puddle, these start to place molecules in specific locations in their physical structure, because life functions not by having a random distribution of atoms and molecules, but by placing particular atoms and molecules in particular places within the organism.

As life continues to evolve and proliferate in the puddle, more and more atoms and molecules in the puddle acquire a precise location, rather than a random uniform distribution. In this way, over time, the order within the puddle increases (ie, the entropy decreases).

 

[kcren]

"Aha! The old spherical cows in the frictionless pasture trick!" -Maxwell Smart :)

Yes, if what you described happened in the absence of anything else, entropy would decrease in that puddle for the organization of a single cell out of nothing.

But the "puddle" is earth, not a small area on a sea shore (which even then would need to be 100% closed off from everything else to be considered a "closed system" to which the concept of entropy can apply). And Earth was anything but random by the time the seas and lands differentiated, there were ore deposits and relative concentrations of this and that. That's our actual starting point.

And once life is in the puddle, the process of living and reproduction and dying (thousands of generations) generates enormous amounts of waste, biodegrading cell bodies, etc. Living things leave entropy behind them. All of that entropy spread out across the entire planet has to be factored into the equation for the net entropy of the "puddle" we call earth.

Just comparing a cell from 1B years ago with a mouse now isn't a comparison of the same system. They are made from almost entirely different atoms, not a new arrangement of the old atoms, so one isn't a new state of the old system—it's a different system completely.

Only "Earth" might be considered a "system." And all the waste generated by all the critters that lived and died on Earth is a lot of entropy.

So, I don't believe that we can say that evolution is an increase in order and complexity. That would be like saying a crystal is more organized when it becomes a duck. They are made of entirely different atoms, entirely different things, not the same system, so the entropy comparison proves nothing about evolution. The statement (which I once said too) is an inherent logical fallacy, mathematical nonsense, and the second law is all about math.

The only things we could logically ask is:

Original entire Earth entropy <? Evolved entire Earth entropy

because the Earth as a whole can be considered a mostly-closed system. And if that equation is true, that would be due to negentropy from the sun and other sources.

Or we could say:

Evolution gives rise to more ordered, complex systems using information from less complex systems.

Yes, true. But that says nothing about the entropy change in any of the systems.

 

[Hip]

And Earth was anything but random by the time the seas and lands differentiated, there were ore deposits and relative concentrations of this and that.

I would think the oceans themselves would be fairly uniform in their chemical content. Billions of years ago, the moon was 10 times closer to the Earth than it is now, resulting in large tides which would have helped dissolve and distribute minerals from the rocks into the seas.

If we assume life started in the oceans, then those oceans were just like our closed system puddle, only larger. The only aspect that was not closed was the constant sunlight hitting the oceans and providing the negentropy.

So as life appeared in the oceans, the entropy dropped.But a thought experiment would work better in this situation: supposing we knew the exact molecular ingredients of the primordial soup that would lead to life, given the right help (that help might come in the form of energetic UV light, lightning strokes, and so forth).

If we imagine that primordial soup locked up into a large sealed glass sphere to make it a close system, then as life appears in the sphere, entropy decreases. It has to. So we can say that the appearance of life requires a supply of negentropy.

 

[jbriggs444]

as life appears in the sphere, entropy decreases. It has to

Not sure I follow this. If I have a piece of bread plus a mold spore or two in a sealed and insulated container, life appears and entropy increases.

 

[Hip]

Not sure I follow this. If I have a piece of bread plus a mold spore or two in a sealed and insulated container, life appears and entropy increases.

If you take the situation where mold is eating nutrients from some substrate containing a uniform distribution of nutrients, then order increases and entropy decreases in that situation.

 

[jbriggs444]

If you take the situation where mold is eating nutrients from some substrate containing a uniform distribution of nutrients, then order increases and entropy decreases in that situation.

No. It does not.

 

[anorlunda]

This thread started in the Astronomy section, but it has become a discussion of evolution. Therefore, I moved it to Biology.

 

[BillTre]

All of these are open systems (the organism, the environment) so you can't really consder them as thermodynamically isolated systems.
I think of these open systems as defined by what's going in and out. Low entropic materials go into living things and high entropic things come out.
Living things live off of low entropic sources they can find in their environments. Their waste products are of higher entropy.

Within its environment (also containing a living organism), the living organism will contribute less low entropy materials than it will generate high entropic materials (such as its cellular structure). Otherwise it would be like a perpetual motion machine.
On the other hand, it will generate complexity as it organizes more materials into the molecular complexity of living animated matter and generates more living organisms by reproduction. But this will always be at the cost of high entropy waste.

If you take the situation where mold is eating nutrients from some substrate containing a uniform distribution of nutrients, then order increases and entropy decreases in that situation.

An entropy decrease would occur in the growing mold cells, but overall considering the the combination of the organism and the environment it is interacting with, it should lead to an overall increase in entropy.

The relationship between complexity and order is not simple. Something very simple can be very ordered (like a crystal), but something complex can be ordered in a different manner (such as the highly ordered structure of a fly eye, which nonetheless will have some degree of disordered atoms within its cells, within the details of neural arborizations and interconnections that generate that part of the nervous system's adaptive output.

The basic cell did not become the more complex cell, its information was simply a template for the formation of later cells.

In a sense, the first primitive cells did become the more complex cells. There is a cytoplasmic continuity throughout evolution where the cell structure is passed on directly from a parent to daughter cells. This underlies the biological continuity of life on earth.
On the other hand, information from the parental cell(s) is clearly used to pattern the structure and function of the daughters.
And as selection feeds out the less adaptives versions of this information, it may well lead to increases in complexity of that information, as it is adapted to its environment (although not always).

But they are not the same system (i.e. they are not the same atoms and energy in different states of organization). They are completely different systems of different atoms operating at different times in their environment. So, comparing the entropy of the two to determine entropy flow is nonsensical.

Just comparing a cell from 1B years ago with a mouse now isn't a comparison of the same system. They are made from almost entirely different atoms, not a new arrangement of the old atoms, so one isn't a new state of the old system—it's a different system completely.

I really disagree that the identity of the atoms has anything to do with it.
I though atoms of a particular type were supposed to be anonymous in thermodynamics. Their individual identities not relevant.

I think the real issue is not that you can't in theory compare these two entities WRT entropy, but that people can not figure out how to count up the entropy in order to make comparisons in complex systems like these. This to me, comes down to comparisons of different ways of considering complexity, how to measure it, and how it trades off with considerations of entropy.

Following the atoms are different logic, you could also say that you can't compare two sister bacterial cells entropy for the same reasons (different systems made of different atoms). This does not seem like a good argument to me.

Furthermore, the functional complexity of particular little features of an organism (say the structure of a fly's eye) only reveal their functional complexity within the integrated functioning of the whole fly (the alert signal the fly eye may generate to visual indications of approaching danger are not adaptive unless connected to a nervous system that gets the fly to move out of the way of danger). The fly in turn only appears adaptive WRT its interactions with the environment in which it evolved, not with some other environment.

These are not simple problems.

 

[Hip]

Thanks for your post, @BillTre. I take your point about the relationship between complexity and entropy not being simple.

Perhaps an easier approach to determining the likelihood of life arising in a given planetary environment is examining the energy flux into that environment. Life requires an ongoing source of energy to operate. On Earth there is plenty of energy, as each square meter on the Earth receives in the order of 1 kW of power from the Sun. Both on land and in the oceans, photosynthesis hardnesses this incoming solar power, and this is how the Sun's energy is turned into chemical form, and then enters into and fuels the entire chain of life on Earth.

The Earth as a whole receives 173,000 terawatts of power from the Sun on a continuous basis. Ref: 1 So there's lot of available energy to power life.

But what about the subsurface ocean of Europa, what energy flux does this ocean receive from tidal heating? Well it's actually a trivial calculation to work this out, and the answer is that the oceans of Europa receive only about 5 terawatts of powder from tidal heating (for my calculation, click on "Europa power calculation").

A 5 terawatt power supply for Europa's subsurface ocean is minuscule, about 35,000 times less that the power supply to Earth.

So if there is life in Europa's subsurface ocean, those lifeforms are going to be desperately short of energy. Thus I expect if life exists there, it will not be the sort of energetic life we see on Earth's oceans: I would doubt there will be any swimming lifeforms like jellyfish, octopuses or fish on Europa, because there is just not enough power for all that energetic swimming. At best you might have some non-moving creatures with extremely slow metabolisms in Europa's ocean.

Spoiler: Europa power calculation

Calculation of the amount of power in Watts received by Europa's oceans from tidal heating:

In equilibrium, the power the oceans receive from tidal heating will be equal to the power dissipated by thermal conductivity through the Europa ice sheet and out into space. So to calculate the power dissipated by thermal conductivity, we need the following data:

Europa surface area: A = 610,00,000 km2 = 6.1 x 10^13 m.
Ice cover thickness estimate: S = 10 km = 10,000 m.
Europa average surface temp: -190ºC
Europa subsurface ocean temp: assume around +50ºC
Difference in temperature between ocean and surface: d = 240ºC.
Ice thermal conductivity (at -100ºC): k = 3.48 W/mK. Ref: 1

Total power dissipated through entire Europa ice sheet given by equation: Power = kAd / S Ref: 1

So power dissipated = 3.48 x 6.1 x 10^13 x 240 / 10,000 = 5.1 x 10^12 = about 5 terawatts

So the power received by Europa from tidal heating is about 5 terawatts.

 

[Hip]

There is an error in my above calculation: the surface area of Europa is half the value I stated above (the surface area is in fact 3 x 10^7 km2), which means the power received by Europa from tidal heating works out at about 2.5 terawatts.