Posted: May 01, 2012 11:52 pm
And these usually add to the number of assumptions being made. They cannot set up their models without making assumptions.
Rumraket wrote:CharlieM wrote:Its too remote to do anything else
The conditions extant on the early earth has left evidence in ancient rocks, or specifically the crystals contained in them, like Zircons. That makes it at least partially observational. These observations can then be used as starting points when doing experiments.
In a ScienceDaily news item, Setting the Stage for Life: Scientists Make Key Discovery About the Atmosphere of Early Earth, they have this to say:
For decades, scientists believed that the atmosphere of early Earth was highly reduced, meaning that oxygen was greatly limited. Such oxygen-poor conditions would have resulted in an atmosphere filled with noxious methane, carbon monoxide, hydrogen sulfide, and ammonia. To date, there remain widely held theories and studies of how life on Earth may have been built out of this deadly atmosphere cocktail.
Now, scientists at Rensselaer are turning these atmospheric assumptions on their heads with findings that prove the conditions on early Earth were simply not conducive to the formation of this type of atmosphere, but rather to an atmosphere dominated by the more oxygen-rich compounds found within our current atmosphere -- including water, carbon dioxide, and sulfur dioxide.
So scientists had made assumptions about the atmosphere on the early earth for decades. And they used these assumptions to set up their experiments. Now these assumptions have been turned on their heads. Until the next time when the new assumptions will no doubt be superceded.
Rumraket wrote:CharlieM wrote:The proposed RNA molecules would be delicate things, how long would they be able to remain in a dormant state?
I see you're arguing from a position of an RNA-first hypothesis. Even if we just run with that, they're still not assumed to be free living, bare molecules. They're envisioned to be enclosed in fatty acid vesicles which live inside precipitated mineral structures near hydrothermal vents. They don't get to survive leaving these conditions until the molecular machinery that allows this has evolved.
I am going with the RNA-first hypothesis because I thought that was the most popular hypothesis at the moment. I'm sure conditions inside these mineral structures would be vastly different from conditions outside in the wide ocean. So the proto-organisms must have fortuitously developed the ability to survive in these external conditions before they actually ventured out into them. They would have had to be pretty sophisticated to be able to survive in both of these diverse environments. After leaving the comfort of their mineral homes they would need energy to build the molecules they needed for survival. Assuming this energy come from chemical reactions there are a few questions I have. How did they convert it into energy they could use? How did these early replicators distinguish between needed chemicals and harmful chemicals and to ingest just the beneficial ones? Were there enough of these required chemicals around away from the original specialized environment? These questions may or may not have been reasonably answered. Either way I'd like to know what the answers are.
Rumraket wrote:
Again you're infusing nature with teleology.
Nature is already infused with teleology. It is evident in such things as birds building nests, sperm and egg coming together, mason wasps building their little prisons.
Rumraket wrote:
It would be more correct to say that life managed to evolve the ability to spread out and thrive.
Yes the same way that a zygote manages to spread out and develop. It can do this because the environment that it moves into is fit for it to thrive.
Rumraket wrote:CharlieM wrote:Okay so they could synthesize ribose, but you have to assume that in the wider environment there were ample amino acids and phosphates too.
Why do I have to assume that? Why can't they have evolved the ability to synthesize these compounds themselves from the bottom-up, like chemoautotrophs do today near hydrothermal vents and in the earth's crust?
So, while still in their original environment, did they also evolve the necessary mechanisms to use chemicals other than they were used to dealing with?
Yes it seems to be ubiquitous.
In other words your assumption trumps that of Jennifer G. Blank, Ph.D and her team as reported here
And it could because conditions had been well prepared.
Rumraket wrote:
Your caricture doesn't mean it didn't happen, and the event itself isn't evidence that it was planned. It's a bit like the extremely improbable series of events required throughout the history of the planet that lead to the 2004 Indian Ocean earthquake and tsunami.
The only reason you happen to ascribe any meaning to the origin of life is because you supposedly resulted from it. It's a bit telling why you aren't all up in your arms about the very special conditions that, for example, produced the great red spot on jupiter. Was that intended too?
Speaking of Jupiter, here is someone who thinks its presence is necessary for life to develop on earth:
Solar systems that lack a Jupiter-sized object that can perturb mineral-rich asteroids inward toward terrestrial planets also have dim prospects for developing life, Lauretta added.
You continue:
Rumraket wrote:
I think you'd be even more surprised if we found we were the product of events that couldn't lead to us. The realization that conditions that favored the origin of life, were extant at the origin of life really shouldn't surprise anyone. Ever heard of Douglas Adams puddle?
Its no surprise that Douglas Adams puddle fits so well into its environment. What it should ask itself is, "Why have I been given the ability to ponder my own existance? After all I would fit in just as well whether I was aware of the fact or not. My existence does not depend on my awareness, so why do I have this ability?