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Information Theory Places New Limits On Origin of Life
KentuckyFC writes:
Most research into the origin of life focuses on the messy business of chemistry, on the nature of self-replicating molecules and on the behavior of autocatalytic reactions. Now one theorist says the properties of information also place important limits on how life must have evolved, without getting bogged down in the biochemical details. The new approach uses information theory to highlight a key property that distinguishes living from non-living systems: their ability to store information and replicate it almost indefinitely. A measure of this how much these systems differ from a state of maximum entropy or thermodynamic equilibrium. The new approach is to create a mathematical model of these informational differences and use it to make predictions about how likely it is to find self-replicating molecules in an artificial life system called Avida. And interestingly, the predictions closely match what researchers have found in practice. The bottom line is that according to information theory, environments favorable to life are unlikely to be unusual.
Raising "Information Theory" above " the messy business of chemistry, on the nature of self-replicating molecules and on the behavior of autocatalytic reactions" is putting the cart before the horse. Empirical data should always trump theory where the two differ.
First God created the Heavens and the Earth. Then he created life. Ten thousand years ago. That is the only information theory you need.
It's a fallacy that entropy always increases ON EARTH, and therefore life is impossible to have evolved naturally, because it violates the 2nd law of thermodynamics. That's only true in a closed system, which most definitely the Earth is not. There's this "Sun" bombarding the planet with energy, constantly.
Stop bringing thermodynamics into biochemical or origin of life questions. It's irrelevant.
Except in a universe with billions and billions of galaxies, each containing billions and billions of stars ... some of us assume that, statistically, the 'unusual' happens all the time.
In the last 30 years our understanding of how many stars have planets has changed entirely. We used to think there would be a small amount with planets and that we were really unique. Now, not so much.
These conditions may well be unusual. But there's a lot of unusual to go around, to the point that it almost seems like it would be happening over and over again.
Lost at C:>. Found at C.
We understand entropy, but have we considered that a symmetrical and opposite phenomena could exist and be primarily responsible for creation of life? That is, some property of information to self-organize that leads to creation of life, and later to creation of intelligence?
I thought you were joking for a minute. It seems like anytime I am working on something and I'm really into it someone tries to burst my bubble by quoting a law of thermodynamics.
There are a few points along the way where development of life on earth had to go one way, or the other, and was not able to sustain both directions. For example, the chirality of amino acids where the overwhelming majority of them are L forms even though there is no physical restriction on the creation of the D form. Similarly the DNA double helix is right-handed in almost all cases.
One interesting thing about this is that if we were to find a planet filled with plants made up of D amino acids and left-handed DNA we may find ourselves unable to consume those plants for nutritional value.
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
If we define life as the ability to organize and propopagate information then the highest form of life is a salt crystal or any self propagating organization of atoms with long range order. A diamond has far lower entropy than any living system. Like wise if we define it as system that processes energy to propogate itself then we have Fire as the ultimate for of life.
clearly gasses (disorded are dead) and crystals are dead. SO is life a liquid (in the middle of the two)? Again obviously not.
The best definition of a living system in terms of information tehory concepts I have come across is the one by David Wolpert who coined in the term self-dissimilarity in reaction to the vogue study of self-similarity in self-organizing systems. For example, a pile of sand is self-organizing system that is ever changing but also ever-self simmilar. it's not alive either
so solids, liquids, gasses and self-simmilar self organizing systems are all bankrupt as a informational definition of life. What's self-dissimilarity then?
It's the concept that the organizational principles of a system can suddenly change as one crosses scales.
imagine one zooms out from a microsope from the atomic scale. at first you see the atom and it has some interesting symmetires in the way the electron oribits have some simmilarities. at a higher scale we see the molecule. then the collection of molecules. soon we see the patterning of molecules.
we observe that this is infact cell. then many cells. then it's an organ. then its many organs. then an animal. then a school of fish. then zooming our we see schools of fish separated across the ocean.
the key insight is this. at each scale everything you infer about the information content and predictibitly of adjaceny in the pattern works to predict the patterns propoagation at a slightly larger zoom. Up until it suddenly fails. you reach the edge of the liver or the edge of the cell or the edge of the animal. then the lower scale is useless in predicting how the next scale up is organized.
these abrupt steps in dissimilarity is a halmark of living systems. the degree of information gain at the step is phenomenal. this is different than saying for example that a composite rock is alive. the difference is that the system is processing information and energy across these organizational boundaries. that's pretty much the best definition of life interms of a single defintion that can be plotted on a graph. the x-axis is the zoom, and the y-axis is the predictability of the next larger scale from the lower one. you see steps. that plus the processing of information across steps is a living system. If you accept this you might feel like their are non-traditional defintiions of life as well. for example, if a bacteria is living thing, is it possible that a community of bacteria is also a lvifing thing. Perhaps the earth is too.
What's intriguing here is that systems with this property may imprint themselves on other systems. you might for example be able to spot radio emissions or atmospheric molecular composition that displays the imprint of dissimilar steps in it's self organization.
SO unless this theory considers this, I'm skeptical about it. Salt is self organizing but it's not alive. It is however highly probable. Indeed eutectic separation is highly propable but it's just physics not life.
Some drink at the fountain of knowledge. Others just gargle.
environments favorable to life are unlikely to be unusual.
How can you not argue against not having that be untrue?
I blew my wife's mind the other day when I pointed out that we are literally just a small component of a single, globe-spanning, four billion year long chemical reaction. A single, very long running checmial reaction. It's pretty neat when you think about it.
...but it's being eaten...by some...Linux or something...
Except we there is so much we do know........ for sure
There is water on the moon, and mars.
Gravity is real, ok !
....if we were to find a planet filled with plants made up of D amino acids and left-handed DNA we may find ourselves unable to consume those plants for nutritional value.
More importantly, they would not be able to consume us for nutritional value.
So, we'd be junk food?
Great, that makes me feel much better. :-P
Lost at C:>. Found at C.
or they will taste like peppermint. :)
Too esoteric?
The Kruger Dunning explains most post on
Meh. Information is basically tied to entropy. You can reduce entropy (which is to say, you can order information); it just takes energy to do so (and in the process releasing waste heat).
So, basically, this says nothing more useful than "Life requires a source of free energy, and a way to reject waste heat."
Sure, but we knew that already.
http://www.geoffreylandis.com
not able to sustain both directions
But either direction may have turned out to be viable. So at this decision node, the probability of life would be 1. On the other hand, given an initial equal distribution of forms, had one been non viable, the other would have out-competed it.
What we need to look for is what the probability of local maxima or dead ends is. Where some process is preferred at that point and is selected. But for which more advanced branches do not exist.
Have gnu, will travel.
"unlikely to be unusual" - you mean "likely to be common"
This is bad news for humanity.
...right?
Never let a lack of data get in the way of a good rant.
a key property that distinguishes living from non-living systems: their ability to store information and replicate it almost indefinitely.
As Douglas Hofstadter pointed out, it's actually more complicated than merely indefinite replication. It has to allow variance while still retaining the ability to replicate. Sure, there are clones everywhere, especially outside the animal kingdom, and they still considered "living". So the quote is still technically true. But it doesn't capture how immensely more difficult it was for life we observe here on Earth to come about. It also raises an interesting question. Did non-varying life have to come about first, in order to saturate the environment with organic compounds? Did the varying life then come about later, piggy-backing on this enriched environment? Or can you go straight from an abiotic world to varying life?
"Love heals scars love left." -- Henry Rollins
> a key property that distinguishes living from non-living systems: their ability to store information and replicate it almost indefinitely
My cp command is alive!!
... the window (from our single data point) seems rather tight.
Except that our sun isn't the most common type of star in the universe. IANAA (Astronomer), but I recall hearing (possibly from the New Cosmos series) that dwarf stars are far more common than G type stars. Since they put out a constant volume of energy for a very, very long time, this would give life plenty of time to evolve into intelligent lifeforms. The more massive a star, the shorter a window of time for life to evolve near it, so it would make sense for us to focus our efforts looking at smaller stars.
HA! I just wasted some of your bandwidth with a frivolous sig!
"The new approach is to create a mathematical model ... And interestingly, the predictions closely match what researchers have found in practice"
Unless the mathematical model was built *before* any of those practical empirical test results, it is not at all interesting or surprising that the model happens to match the pre-existing data.
or they will taste like chicken. :)
Too esoteric?
There. FTFY.
No, no, you're not thinking; you're just being logical. --Niels Bohr
Steaks and Ice Cream and Chocolate and what not made with D Amino acids and no weight gain. Fantastic
Take all the static measurements possible of a live mouse. Then suffocate it. Immediately repeat all the measurements. They will be identical. Yet the difference in entropy (in the sense of disorder) between the live mouse and the mouse carcass is dramatic. “Life” is one of the great scientific unknowns. Creating the conditions for life is not the same as creating life from scratch. When Louis Pasteur started his work, the assumption of the scientific community was that microbes regularly spontaneously came into being. To date, science has never observed such a phenomena.
Not to burst anyones bubbles but haven't Intelligent Design proponents been saying this for years?
Actually, this is very important factor of the "cycle of life" in many cases.
Being able to eat plants is good, but having them be able to recycle humans/animals waste products (including bodies) is equally important. Otherwise, what are you going to feed the plants?
Related work:
http://arxiv.org/abs/1209.1179
surprisingly no references between Adami and England.
"Self-replication is a capacity common to every species of living thing, and simple physical intuition dictates that such a process must invariably be fueled by the production of entropy. Here, we undertake to make this intuition rigorous and quantitative by deriving a lower bound for the amount of heat that is produced during a process of self-replication in a system coupled to a thermal bath. We find that the minimum value for the physically allowed rate of heat production is determined by the growth rate, internal entropy, and durability of the replicator, and we discuss the implications of this finding for bacterial cell division, as well as for the pre-biotic emergence of self-replicating nucleic acids."
Plants might not be intelligent enough to realize that until too late (for us).
Please, can KentuckyFC repost the last sentence without the double negative.
Yeah, finally biology (the 'butterfly collecting' adventure labeled as a science) has something like a 'first principle' to hang on to.
Nothing shows biology to be more a 'butterfly collecting' venture than the repeated surprise biologists express when they find life in environments where they never expected to. You would think they had learned by now. Regardless, a theory with bona fide first principles clearly lays out that finding life supporting environments is the norm.
"Consensus" in science is _always_ a political construct.