NASA Proposes "Water World" Theory For Origin of Life 115
William Robinson (875390) writes "A new study from researchers at Nasa's Jet Propulsion Laboratory has proposed the "water world" theory as the answer to our evolution, which describes how electrical energy naturally produced at the sea floor might have given rise to life. While the scientists had already proposed this hypothesis called 'submarine alkaline hydrothermal emergence of life' the new report assembles decades of field, laboratory and theoretical research into a grand, unified picture."
Not Evolution (Score:5, Informative)
This is the theory of abiogenesis, not evolution. Evolution is how life changes, not how it got started.
Re:Not Evolution (Score:4, Informative)
But how does Evolution prune the repication mechanism itself? If an early replicator was very sloppy and mutation prone, then any possible advantages occuring by random mutation would have little chance to be tested before other random mutations overwrote them or other mutations killed off the organisms carrying that mutation. Working backwards, let's start with modern DNA, in cases where there are many additional mechanisms to cut the mutation rate so the non-random part of Evolution has more time to work. Putting DNA inside a walled cell, and making that cell nucleated, both reduce the exposure of the DNA to chemicals that can mutate copies. Multicellularity further shields the DNA from some more mutagens, and lets Evolution prune cells with bad copies by apoptosis, which can't be used by single celled organisms. Right there, we have a trend in Evolution - Nature seems to be trying to reduce error rates to target, as you put it, the Goldilocks range. "Advanced" organisms, such as us, or mosquitos or oak trees, have many features that make the selection rate occur at an optimum, where Nature gets enough time for selection processes to occur. In fact, sexual selection is probably just another form of targeting that Goldilocks range, and I'm sure a professional biologist can think of may more examples than the four I've mentioned. Some more minor steps in this pattern might include the evolution of Alcohol Dehydrogenase enzymes and others, but that's getting beyond my depth.
But if we extrapolate a historical trend from that, the mutation rate must have been higher for 'primative' DNA based life, but the selection pressure must have been lower. Mutation must have been still higher if RNA was once the core molecule of heredity, which seems pretty solidly established. And if there's several more primative replicators, selection pressure must have moved glacially compared to the modern era. So how did selection have time even in 3 billion years to evolve DNA itself? If the earliest replicators were something like crystaline clays that were subject to a very modest amount of selection by erosion, as some biologists have speculated, how do we get the time for these to evolve through many stages to RNA and then DNA and eventually all the extra trimmings of today? Given that we've been in a DNA based biosphere for close to 1.5 billion years, that's about half the time since Earth cooled enough to support organic compounds,, and we're trying to cram probably at least 5 or 6 earlier replicators into less than half the time, knowing that each one was subject to less selection pressure than it's successor probably by orders of magnetude.
Entropy can Increase or Decrease Locally (Score:5, Informative)
"Random processes"? Any randomly assembled amino acid randomly disassembles as well; even Miller proved that.
The randomly assembled amino acid does randomly disassemble as well, but that is not what it must do. An amino acid may stay the same, disassemble, or it it may form a more complex molecule.
Here is a little demonstration of "randomly" assembling complexity in behavior. [vortexcortex.com] I have given each entity the ability to sense the left and rightness and ahead and behindness of 'energy' dots and their nearest peer. They also get a sense of their relative energy vs their peer. The inputs can affect two thrusters which operate like "tank treads". However, their minds are blank. They don't know what to do with the inputs or how they map to the outputs. The genetic program introduces random errors as copies runs of a genome from one parent then the other switching back and forth randomly. The selection pressure simply favors those with the most energy at the end of each generation by granting a higher chance to breed. Use the up/dn keys to change the sim speed, and click the entities to see a visualization of their simple neural network. The top left two neurons sense nearest food distance, the right two sense nearest entity, middle top is the relative energy difference of nearest peer. Note that randomness is constantly introduced, and yet their behaviors do not revert to randomness or inaction, they converge on a better solution for finding energy in their environment.
There is no pre-programed strategy for survival. Mutations occur randomly, and they are selected against, just as in nature. Given the same starting point In different runs / populations different behaviors for survival will emerge. Some may start spinning and steering incrementally towards the food, others may steer more efficiently after first just moving in a straighter path to cover the most ground (they have no visual or movement penalty for backwards, so backwards movement is 50% likely). As their n.net complexity grows their behaviors will change. Movement will tend towards more efficient methods. Some populations may become more careful instead of faster, some employ a hybrid approach by racing forwards then reversing and steering carefully after the energy/food is passed. Some entities will emerge avoidance of each other to conserve energy. Some populations will bump into each other to share energy among like minded (genetically similar) peers. Some will even switch between these strategies depending on their own energy level.
Where do all these complex behaviors come from? I didn't program them, I didn't even program in that more complex behaviors should be more favorable than less complex, and yet they emerged naturally as a product of the environment due to selection pressure upon it. Just because I can set the axon weights manually and program a behavior favorable for n.nets to solve the problem, doesn't mean randomness can't yield solutions as well. Today we can watch evolution happen right on a computer, or in the laboratory. All of this complexity came from a simple simulation of 32 neurons arranged in a simple single hidden layer neural net, with 5 simple scalar sensors and the minimal 2 movement outputs, with a simple single selection pressure. Each time you run the sim it produces different results, but all meeting the same ends, collect energy, reproduce. Just imagine what nature can do with its far more complex simulation and selection pressures... You don't have to imagine, you can look around and see for yourself.
In other more complex simulations I allow the structure of the n.nets and form of sensors to be randomly introduced and selection pressure applied. In larger simulations I allow the breeding and death of generations to occur continuously across wider areas and speciation will occur. Entities will develop specialized adaptations for a given problem space of the environment. I have created simulatio
Re:NASA Proposes "Water World" Theory For Origin o (Score:2, Informative)
because we think the universe had a beginning, the Big Bang.
That's not an accurate description - there's no requirement that the Big Bang be the beginning of everything. Something may have existed prior to that point; the Big Bang Theory makes no attempt to describe it.
Re:NASA Proposes "Water World" Theory For Origin o (Score:5, Informative)
"Well we don't understand this and probably never will, so we should ignore it."
Accepting that you don't understand something isn't the same as ignoring it. In fact making up myths about what might have happened is ignoring the reality that we don't know.
If it WAS created, then what? You are going to look pretty fucking stupid standing before the creator when you die, as smart as you think you are now.
This presupposes a long list of arbitrary ideas about the nature of a being that might have conciously created the universe:
There's absolutely no reason to believe any of these arbitrary assumptions to be the case, even if for some reason, apropos of no evidence whatsoever, you do decide to presume the universe is the consequence of a concious act.
Re:NASA Proposes "Water World" Theory For Origin o (Score:4, Informative)
He wasn't using it wrong.
The structure of this thread is:
Premise 1: The Universe exists.
Premise 2: Either something came from nothing, or something always existed.
Hypothesis: That something is God.
Counterargument: The Universe is also an internally consistent "something" to fit the premise. The Universe necessarily exists due to premise 1. God does not necessarily exist given the premises, and does not better fulfill either premise. Therefore the hypothesis is unsupported.
You need to introduce new premises or arguments in order to endow God with extra attributes so that the God hypothesis passes Occam's Razor.