Abiogenewhat?

Okay, as much as I enjoy telling the development saga, it’s past time for a rant against ignorance. It’s like running for charity, only replace the foot blisters with throat ulcers and the happy children with offended denialists.

Upon what topic of irredeemable stupidity should we feed this rant monster, so it can grow into a big and healthy eldritch abomination whose only desire is to see this world die in internet flame wars? Irreducible complexity? Second law of thermodynamics? Micro vs macro evolution?

No… I’m going to go earlier than that, to a pet hate of mine. The claim: “A cell can’t form by chance.”

From experience, this claim is often accompanied by a bit of good ol’ statistical abuse. The claimant will find a protein, calculate the probability of that protein being that protein, and show off the result as if adding enough to the exponent somehow makes a number important. Here’s a good example from Talk Origins:

”The proteins necessary for life are very complex. The odds of even one simple protein molecule forming by chance are 1 in 10113, and thousands of different proteins are needed to form life.”
Watchtower Bible and Tract Society. 1985. Life–How Did It Get Here? Brooklyn, NY, pg. 44.

Of course, anyone with a basic understanding of statistics and a good pair of heavy boots can kick your ass over this. It’s possible to use the same logic to “prove” that Hydrogen can’t possibly be more common than all the other elements, because each naturally occurring atom only has a 1 in 91 chance of being hydrogen. Besides, the sheer extent of lies upon misinformation upon things-deliberately-overlooked involved in getting these sort of numbers normally indicates the person using them is either a professional charlatan or copy-pasting from the website of a professional charlatan. If you’re interested, check out Lies, Damned Lies, Statistics, and Probability of Abiogenesis Calculations on Talk Origins. I know it’s a little dated, but it’s a fine start. I’ll stay here and deal with the simpler aspect of the claim, using slightly smaller words, not least because I don’t understand all the big ones.

So improbable... not.
(img src: http://www.astrobio.net/pressrelease/83/one-handed-life)

A common answer to the cell-forming-by-chance claim (aside from the fact that the original reproducer is believed to have been far simpler than a modern cell, and was probably little more than a fairly complicated molecule in the right solution to allow it to “reproduce”) is that the forming of the “first cell” has nothing to do with evolution. And that’s perfectly true: this is the domain of abiogenesis, and an acceptance of the still-relatively-young science behind abiogenesis has bugger all to do with accepting the oversized mountains of evidence for evolution. Even if abiogenesis turns out to be a load of rubbish when it comes to explaining the existence of life on earth, evolution remains a highly convincing explanation for the diversity of life on earth.

But that answer is also a cop-out. Abiogenesis is still the most likely method by which life arose on our planet, and as a hypothesis it’s a heck of a lot more complete than the juvenile concept anti-evolutionists so often seem to have of it: namely, that the pieces of a cell “rolled together” purely by chance.

As already stated, the original reproducer was most likely little more than a complicated organic molecule that made copies of itself. Even so, this still sounds like a complex thing to have come about at first, (well, not really: “Self-replicators can be incredibly simple, as simple as a strand of six DNA nucleotides (Sievers and von Kiedrowski 1994)”) until you realise that it didn’t just “come about”: it was the end product of a long chain of natural biochemical reactions, which are far from uncommon. They’re everywhere, reacting with each other and with the results of their own reactions.

Sadly accurate

Given the size of our planet, and the incomprehensible time-frames we’re talking about, is it really so hard to believe that the right sequence of biochemical reactions could result in some sort of imperfect chemical replicator?

Now if you’re a denialist, there’s a good chance you are even now rolling your eyes and saying “it’s all just speculation, he has no evidence”. To which I say: Yes. You’re right, it is speculative. That’s the nature of abiogenesis. We’re talking about microscopic chemical reactions that happened billions of years ago: what “evidence” could we possibly produce aside from a plausible, reproducable path from chemestry to life? We don’t have a TARDIS. But we do have the ability to reason, and sometimes the similarities are striking.

The ‘evidence’ for abiogenesis is that there is life on earth now, and that it wasn’t always there. From these two facts, we can offer plausible explanations, and try to prove them wrong one by one until we’re left with only one option. This is where denialists fail at science. They offer implausible explanations, then try to prove the plausible ones wrong.

I’m not saying there wasn’t a deity who intervened directly and breathed life onto our dead earth 4 billion years ago, or a race of organic engineers who designed the earliest life, or a temporal traveller who accidentally dropped his sandwich in a rock pool. All of these things are possible, in the same way that me being a brain in a jar, or having been created memories-and-all last Thursday, is possible.

But they are not the most likely, plausible, or scientifically supported explanation. That would be Abiogenesis.

/rant
Qu

* * * * * *

“The year is 2033. The last survivors of the Flame War have fled into underground bunkers beneath the shattered remnants of the once great social networking sites. The surface world is given over to unrestricted porn and 4chan mutants. Humanity teeters on the dark brink of extinction.

But we are those who will never give in to despair. We will return to our shattered internet, though it costs us our lives, our very identities. We do not forgive. We do not forget. But we will rebuild.”

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  1. #1 by Gravel on December 1, 2011 - 9:26 am

    I was impressed with the tendency of certain lipids to form discrete membranes in their own right – if you get the right shape, the ideal conformation is roughly a spherical membrane-like compartment. Sure, real membranes these days are complicated, but the concept is pretty straightforward. And RNA does double-duty as information and catalyst . . .

    All you need is a tiny bit of replicating RNA in a membrane and presto-chango, you’re on your way.

    Also, to know the likelihood of something, you need comparisons for other likely stuff – just making up numbers and multiplying them together is unlikely to get you the right answer.

    (Still totally enjoying this series – just intensely busy these days.)

  2. #2 by IceM on March 23, 2012 - 10:46 am

    Personally i find it hard to believe in Abiogenesis. But i find also hard to believe the religious theory. My bet is that when the Universe was created, it already had some primitive forms of proteins or something, and as the planets and atmospheres formed, they would spawn randomly by chance in random planets , and if the planets could support life, they evolve, if they cant, they wont.
    Sorry biology is not my strong, i am more of a Philosophy\Physics area. And no, i am not religious.

  3. #3 by ququasar on March 23, 2012 - 1:35 pm

    Hmmm… that’s an interesting hypothesis, but I don’t think it holds up under scrutiny. See, the big bang theory gives us gives us some pretty good estimates as to the average temperature of the universe early in it’s lifetime, and it was hot. Like really really hot. I’m not talking “so hot it melts metal”, I’m talking “so hot it vaporises neutrons into a plasma of their consituent sub-atomic particles” (okay, technically it vibrates them apart, but “vaporises” sounds so much cooler). There’s no way a complicated molecule like a protein or amino acid could survive.

    It was only as the universe cooled that protons and neutrons, and then atoms, and later molecules, and after that complicated molecules like protiens, became viable. So they had to have come into existance some time after the birth of the universe.

    /Thankfully, this isn’t as far fetched as it sounds. Simple elements, like hydrogen and helium, form naturally as the universe cools. Heavier elements, things like iron and carbon, are born in stars and supernovae as the hydrogen is fused. Molecules form from those, and organic molecules like amino acids can form through pure chemestry in a whole variety of ways. We’ve found traces of amino acids on other planets, and even in the vaccum of space, which gives some merit to the idea that life formed elsewhere and was transported here (though it still seems more likely that life formed in an environment less hostile to it).

    All of this is just natural chemistry: no biology or evolution involved. Much of it is actually fairly well understood, and verified by experimental testing. It leads to planets sort of like what you suggest: atmospheres and oceans with loads of organic molecules floating in them, waiting for life.

    But all of this still leaves thats leap from ‘organic molecules’ to ‘life’, which is what the theory of abiogenesis tries to step in and explain.

  4. #4 by tom on January 13, 2014 - 11:46 pm

    The faith based myth of the atheist. Abiogenesis is a hypothesis that is unscientific and unsupported by any evidence!! The hypothesis teaches that life arose from inorganic dead chemicals which came to life over the course of one billion years!

    Atheists attempt to use in their desperation is “lab created RNA and protocells” as proof for abiogenesis.These experiments are highly orchestrated by very intelligent chemists, NOT unguided natrual chemical processes!

  5. #5 by ququasar on January 14, 2014 - 8:38 am

    Uh… that’s not actually true.

    Assuming the most likely variants of the hypothesis, the chemicals from which life arose would have been organic, and quite volatile (I’m not sure what you mean by “dead”). And most research into the subject indicates that those sort of chemicals would have been common on early earth, especially in shallow water like rock pools. Chemical processes generate them frequently, and they get washed down to the water level as sediment.

    So abiogenesis posits that self-replicators could have emerged from organic, chemically-active compunds, mixed thoroughly in water and exposed to sunlight.

    Which is a similar environment to those in which labs generate artificial self-replicators.

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