Moore's Law and the Origin of Life 272
DoctorBit writes "MIT Technology Review is running a story about an arXiv paper in which geneticists Alexei A. Sharov and Richard Gordon propose that life as we know it originated 9.7 billion years ago. The researchers estimated the genetic complexity of phyla in the paleontological record by counting the number of non-redundant functional nucleotides in typical genomes of modern day descendants of each phylum. When plotting genetic complexity against time, the researchers found that genetic complexity increases exponentially, just as with Moore's law, but with a doubling rate of about once every 376 million years. Extrapolating backwards, the researchers estimate that life began about 4 billion years after the universe formed and evolved the first bacteria just before the Earth was formed. One might image that the supernova debris that formed the early solar system could have included bacteria-bearing chunks of rock from doomed planets circling supernova progenitor stars. If true, this retro-prediction has some interesting consequences in partly resolving the Fermi Paradox. Another interesting consequence for those attempting to recreate life's origins in a lab: bacteria may have evolved under conditions very different from those on earth."
No. (Score:4, Interesting)
A single base pair is not alive, not even in a primitive way. The extrapolation is invalid. A more interesting statement would be the minimum complexity of the first living things 3.5-4.0 billion years ago.
Or... maybe your assumption is wrong (Score:5, Interesting)
All of this assumes that the complexity of life, as he defines it, increases at a relatively constant rate. There is no reason that this has to be true. Environmental effects on organisms increases selective pressure and causes evolution to progress at a faster rate. Cataclysmic events happen every now and then and causes extinctions and hardship on surviving organisms. Seems pretty uneven to me...
Re:Looks like creationism... (Score:4, Interesting)
The problem with the kind of creationism some people are advertising is that they insist that it happened around 6000 years ago. A lot of scientists would be ok with the idea of creationism -- if you allow it to happen billions of years ago as the spark that created life, but then let life evolve independently. But of course then humanity is not special -- unless the creator helped things happen this way for the purpose to create intelligent life.
So creationism/intelligent design is OK, and a higher being managing/guiding the universe is OK; it just doesn't make sense for it to have happened 6000 years ago.
Moore's Law has nothing to do with this (Score:5, Interesting)
Cataclysmic events may be required (Score:5, Interesting)
... Cataclysmic events happen every now and then and causes extinctions and hardship on surviving organisms
Indeed, it appears that periodic cataclysmic events are required in order to keep evolution going.
We've seen several eras in Earth's history where life appears to "stagnate" at some level, proceeding with little-or-no change for long periods. The last of which was the "age of dinosaurs", which lasted 170 million years or so, depending on how you define the starting point. It ended with the Chicxulub impact.
We also see numerous examples of species which are largely unevolved; for example, ants have been around for 120 million years and one species [americanscientist.org] of prehistoric ant is apparently still living in the Amazon. Coelacanths [wikipedia.org] have been around in their present form for about 400 million years.
The overall impression is that life tends to "stagnate": once life evolves into an efficient survival mechanism, there's no pressure to evolve further. Evolution aims at being a better "fit" for the unchanging environment, but more complexity is simply not needed.
This is why I believe the Drake equation [wikipedia.org] is overly optimistic. I think it omits the factor "fraction of star systems that experience occasional planetary meteor strikes". If we ever travel to another star, we're likely to find it teeming with life, but stagnated at some level.
This may be one factor (of possibly several) that explains the Fermi paradox.
The "doubling rate" identified in the article may be an artifact of Earth, and that's only if Genome complexity [fourmilab.ch] is even a reasonable measure to make. Lilies have 30x the genome size of humans - another explanation might be that genome complexity is related to genome size, which does not have much selection pressure. It's not a peer-reviewed paper.
Re:Or... maybe your assumption is wrong (Score:3, Interesting)
All of this assumes that the complexity of life, as he defines it, increases at a relatively constant rate.
The paper merely states that given: ...at least one of the above has serious flaws.
1) Our current understanding of evolutionary rates,
2) Our current understanding of the age of the earth,
3) Our current understanding of the origin of life
Re:Looks like creationism... (Score:3, Interesting)
But this idea also seems to have some improbable time scales. The summary says "just before" the earth formed, but in fact they are claiming that life is more than twice as old as the earth. And that would be an earth that was pretty inhospitable to life until another billion years or so.
I find the idea quite incredible:
And yet they claim this finding with scant evidence that there is life anywhere else. Maybe there was some ancient life on Mars, but nothing more complex than bacteria, and even in this theory there could be nothing more complex than bacteria (that can survive in space rocks), and some version of that is floating around all over the place and somehow we're isolated from anything that could have evolved to our level of complexity after having more than twice the time to do so.
Not buying it at all.
Holy Data Cherrypicking! (Score:4, Interesting)
The critical "plot" in the article from which the age estimate is derived has 6 data points: "prokaryotes," "eukaryotes," "worms," "fish," and "mammals." Nowhere in the article is the selection criteria for these 6 particular categories explained. In other words, out of the hundreds of major categories of life which the authors might have chosen to plot, they arbitrarily pick 6 that vaguely fall on a log-linear line (with a bit of fudging for "functional, non-redundant genome"). Give me a big scattery cloud of hundreds of potential data points, and I can reach whatever conclusion you want with the proper selection of a half dozen.
I'm a little skeptical (Score:3, Interesting)
The article really is not convincing, for several reasons:
Their graph, the one that supports the whole enchilada, has five data points. Color me unimpressed that they were able to fit a function to five data points. Furthermore, the specificity of classification even within the graph varies a lot- prokaryotes are a much broader classification than worms, fish, or mammals. Is there variance in the amount of functional base pairs within the prokaryotes? I don't know- I'm not a biologist. Their paper doesn't clarify this point at all. How do I know that they are not cherry-picking their organisms to fit an exponential curve?
They're extrapolating backwards without good justification. Even if the growth is exponential, what affects the time constant? Some organisms reproduce slower than others, which surely affects the exponential rate of growth. If bacteria existed on space-bound pieces of rock, would they be able to reproduce at the same rate as a bacterium in a pond? Surely the microbiology of the "first organism" would be very different than that of organisms many billions of years following? Would mutations occur more rapidly in space, increasing the rate at which function base pairs would grow?
They assume the origin of life had one base pair. I'm not a microbiologist- does it make sense for the DNA of the first organism to have one base pair? If the organism instead had 10 base pairs, their estimate for the origin of life is knocked forward by a billion years or so. Even without that, the error bars on their analysis are +/- 2.5 billion years, just due to statistical uncertainty.
They reference a "Another complexity measure yielded an estimate for the origin of life date about 5 to 6 billion years ago." Why are the results so different? What were the error bars on their data? They claim that those results are incompatible with an origin on Earth, but if the error bars are similar to those on their claims, then that statement doesn't hold water.
Re:Looks like creationism... (Score:4, Interesting)
But if you think like Wolfram, it's all an algorithm, and this reductionist algorithm is the basis in the post.
I think these kinds of discussion suffer from lack of philosophical literacy. Creationists are clearly wrong in whatever they think about the mechanisms of speciation. They don't pop out of nowhere "just because", and replacing "just because" with "because god so wished" doesn't improve the notion a bit. On the other hand evolutionists rarely notice that a process of natural selection doesn't create something "new", it only causes a (mathematically preexisting) potential arrangement of atoms, one of an infinite set, to actually appear. The set of all possible carbon-based DNAs hasn't changed since the Big Bang, or even before it. Natural selection only makes some of them appear as actual combinations of carbon atoms, it neither adds nor subtracts from the full set.
Re:Looks like creationism... (Score:5, Interesting)
On the other hand evolutionists rarely notice that a process of natural selection doesn't create something "new", it only causes a (mathematically preexisting) potential arrangement of atoms, one of an infinite set, to actually appear
The problem with "philosophical literacy" is that it makes you say things like "mathematically pre-existing" as if it meant something other than "non-existent".
You seem to want to reify the mathematical language we use to describe reality, as if the tool we use to describe the world and which we have invented and adapted to describe the world ever more deeply, somehow "predates" the world that language was invented to describe.
I see no reason to privilege math over English in this regard. Both are just languages we use to describe, understand and communicate our understanding. Neither has any ontology apart from us, the beings who invented them, and to impute otherwise is both unwarranted and uninteresting. There is no explanatory need to do so, nor any operational test we can apply to test the validity of the hypothesis (although it would be damned interesting if you could come up with one.)
There are certainly many cases where our mathematical description has to be "fixed up" by hand to actually describe the world, the most obvious one being the excess of solutions to almost all the basic differential equations we use in physics, particularly the things like the backward-in-time solutions to any given wave equation. (That the time-reversed solutions of the Dirac equation can be given meaning does not change this, it merely emphasizes what a poor tool mathematics is for describing the universe in all the other cases where the advanced wave has no apparent physical meaning.)
Given what a lousy tool math is to describe the world, it would be very, very weird if the world were somehow "following" math. The hypothesis that we invented math to describe the world in much the same way we invented to stone ax for changing the world looks a lot more plausible.
Re:Looks like creationism... (Score:4, Interesting)
Personally, I don't think it matters what a person believes in that regard. The universe looks to be 14 billion years old, so you might as well say that it is so, even if it chronologically has only been around for 6 thousand or so.
To posit that God made a universe with a perfect apparent history of 14 billion years only 6000 years ago according to God's wristwatch would create deep quandaries to any theist is thinks non-superficially. If God creates apparent facts, why are those facts not true? Why does God need to create a universe of lies?
Re:Looks like creationism... (Score:4, Interesting)
"unless the creator helped things happen this way for the purpose to create intelligent life."
Assuming that humanity is evidence of intelligent life is a very big assumption.
Well, let's do science to it: Back problems due to poor adaptation to walking vertically. Nerves that run under your feet. Your retinas are upside down and thus have a hole / blindspot where the blood vessels go through. Hooves exist, so do better spines like giraffe's necks, and cephalopod's eyes are right side out with no blind spot required (blood in the back, receptors in the front) so it's not like "god" didn't do it right elsewhere. I just can't believe a benevolent deity created man. If so, we were made to suffer and be laughed at.
Then you look at yourself and think, Oh, look, I don't have fur like other mammals do! Then you look about at other mammals that don't have fur... They are aquatic or have aquatic ancestors: Whales, Elephants, Manatee, Walrus, Hippopotamus. A small portion like the naked mole rat simply live underground -- They're all in contact with stuff more dense than air. What about those aquatic creatures though? Don't they all get layers of blubber -- fat concentrated towards the outside rather than distributed in the core. A dog, horse or even cow will die from fat clogging its heart long before it can reach the level of percentage of body fat that a human can reach -- That's because our fat isn't concentrated in our core, it's blubber. We have superior breath control than Apes & Chimps do -- They'll never learn to talk like we can. We can hold our breath, hell, you can pressurize your mouth and your soft palette will close off your sinus, making an air/water tight seal. The chimps and apes don't stand upright -- but they do when they're crossing or wading in water... They don't have our dexterous opposable thumbs and dexterous digits because they don't catch prey. Our hands would be pretty good for catching fish.
So, when we look at things rationally, and compare the evidence, it seems unless there's a prevailing scientific theory that we came from aquatic apes, then both religion and science are fucking morons. YOU ARE NAKED. YOUR ANCESTORS WERE MERFOLK OR MOLE PEOPLE!
Re: Non-peer reviewed... (Score:3, Interesting)
I read the paper, and many many more. Here's an appropriate complexity measure:
http://www.biomedcentral.com/1471-2148/11/140
According to studies of protein complexity, life fits in the earth's timeline, as cited above. New protein folds emerge about every 100 million years, and that is the rate limiting step for the building blocks of complexity. Proteins.
The authors of this arXiv study apparently do not consider redundant protein domains or replicates of functional RNA (like multiple copies of ribosomal genes).
It's like assuming every time one forks a new Linux distro, there is suddenly twice the code complexity.
Imagine taking distro watch - counting the total number of bits along a timeline for all the distros, and applying the same analysis. Now wouldn't it be funny to see if the analysis shows the origin of Linux predates Torvalds' birth? You might think that there was something wrong with the assumptions - or would you rush to print that you just proved Torvalds could not have written Linux?
Copying information is easy, even if it is "functional", but it does not mean significant new complexity is added. That requires a deeper understanding of redundancy.
Yes they say they deal with the c-value enigma, but not completely in comparison with the above noted paper. Which they do not cite or consider.
Too busy writing hyperbole, which they provide no evidence for, nor counter arguments commonly found in the peer-reviewed literature.