Life essentially arose from amino acids. Period. In fact, life still does arise from amino acids this very moment. It's the question of how the 20 (I think it's 20) amino acids  arose from essentially non-living materials, that defies a clear answer. (But then, many things about natural history defy a quick and easy answer- I suppose that's what makes such subject matter a worthwhile pursuit)

There are hundreds of amino acids in nature, but only 22 proteinogenic ones (out of which 20 are common).

However, it isn't much of a mystery how they form. The standard particle model of physics pretty much gives it up. Amino acids are being formed in clouds of cosmic dust all over the universe - and it seems inevitable that these will later arrange themselves into an ever increasing pattern of even more complicated structures at every time and in every place the conditions for this evolutionary step is feasible.

My personal beef with the concept of "life" is that we assign it to organic molecular structures that are arranged into complex and self replicating systems only. Thus we form the peculiar idea that "life" is something local and exclusive that either A) "just happens" or B) is created by a supernatural being, whereas if we did away with the artificial division line between living and non-living, we would arrive at a more wholesome perspective of the situation, as it were.

Way of thinking about the issue - it makes good sense to me and eliminates the whole ignition point of organic life that theists love so well. There's no way that in a natural system things would be on/off - alive/dead.

Rotifers, viruses and bacteria all have the ability to "die" as a defense mechanism. Makes me wonder what sort of definition of life we should be taking into account. Is a self replicating organism life or does the term include potential and thus encompass shut down viruses, seed pods and fertilised eggs? I think as the Marquis is suggesting, the true definition of what lives should be measured on a broad scale and is much bigger than we generally consider. 

Interesting thoughts. We know that the chemicals that we think of as relevant to life can be found in space, in Miller Urey experiments and now the article in the OP provides yet another way that they could arise.

That coupled with the fact that the universe is pretty much the same everywhere that we look suggests that life as we know it probably is inevitable in any environment that can support the right mix of chemicals. I would even go a step past that and say that something fairly similar probably happens in places that would kill anything on our planet.

Perhaps on some other planet that has a much higher atmospheric pressure that would break down the amino acids that we tend to favor might support enough of the other amino acids that are known to exist. Then we might find that life based on a slightly different chemistry is indeed possible.

I would even be willing to say that there may be chemical environments which are entirely different from our own that could generate what we probably ought to call life. We just have not found such an environment yet.

We look to carbon as critical because it can generate so many complex chemicals in our own environment but it can probably do that in radically different conditions as well. Perhaps on a planet that has an ocean of liquid methane.

For that matter, carbon is not the only element that can form complex molecules. Astronomers recently found an exoplanet that has the right range of temperatures for iron to pool as a liquid, vaporize and possibly rain back in liquid form. Sure, even if we allow for interstellar travel, we will never set foot on such a planet but that does not mean that complex chemistry is forbidden to such an environment.

All of the wool gathering aside, I would also agree that it is pretty much a bad idea to say that life could be an is/is not dichotomy. Abiogenesis would be a process where complex chemicals form from simpler ones. At some point, it is probable that one could look at some sample and say that it meets a reasonable definition of life. However, what about another sample that is, say, half as complicated? Complicated chemistry is going on in such a sample but is it alive?

The 'Xenogenesis' theory? (I forget what it's actually called)

Also, what exactly (in this case) is the "standard particle model", as it is used in your post?

My knowledge of molecular biology is, frustratingly, quite low.

             Mevolution           August 25, 2000



reading new scientist i sickly saw we must have
come from mud these torrential ecosystems spawned by
evolving viruses and bacteria their need for
living places blindly moulding us holding hands
with us injecting direction into our dna driving us
feeding our lust, our need, love too, and ambition
our adventure urge they grew to spread us out, to
cover all earth with billions of homes for bugs

First off, a clear and concise definition is helpful:

vi·rus
 
 /'va?r?s/ Show Spelled Pronunciation [vahy-ruhs] Show IPA
–noun, plural -rus·es.
1.     an ultramicroscopic (20 to 300 nm in diameter), metabolically inert, infectious agent that replicates only within the cells of living hosts, mainly bacteria, plants, and animals: composed of an RNA or DNA core, a protein coat, and, in more complex types, a surrounding envelope.

If you say so....

Maybe I should have specified: ...control a number of viruses, including retroviruses. We are able to use 'dead' viral bodies as vaccines, we are able to manipulate the genetic code of viruses, we are even capable of modifying our own genetic code using retroviral genetic engineering. Limited experiments have been conducted to correct diabetes (type I, I believe) in laboratory animals... though any useful by-products of this genetic engineering is years away from becoming safe-to-use medicines (or cures, rather).

Spanish Flu was exponentially more destructive for it's own time.... and it eventually disappeared. Smallpox was even more destructive (and eventually eradicated). Hells, even HIV was more deadly from it's first two years of spread in the US than H1N1 has been thus far.... and there is no signs of HIV or any number of older virus species dwindling or disappearing.

The evidence, as I understand it, is that (an overwhelming majority of) viruses arise out of poorly maintained genetic reproduction in cellular life. I will, however, cede that early life (or proto-life) undoubtedly started as a few strands of RNA, later morphing into DNA after a few eons (or epochs), and ultimately developing a complex array of chemical reactions known as a cell. These primordial nucleic acid formations are not at all unlike the speculated forms that viruses and viral pathogens are believed to take at their earliest possible stage of existence. This by itself, however, does not make viruses a "dominant life form on earth", by any stretch of the imagination. They are interesting initiators of genetic mutation and (occasionally) transmission -given what I know and what little you decided to share in this thread- and nothing more.

Now, my access to current research is limited, as I will gladly admit, but is H1N1/Swine flu (whose casualty numbers barely reach into the dozens in the US) the best possible example you have to offer??

...I'm glad it's just a joke, too.

That reads a lot like "and that a large part of our beliefs are composed of theisms. In fact, we couldn't live without them: All belief systems of all persons on this earth is about interacting with theists."

I am curious, based on your current knowledge... which type of organism creates and shares more genetic material, on-a-daily-%-of-genetic-codons-produced basis: cellular life (by itself), or viral pathogens (by itself, exclusively with the reproductive help of cellular life)?

  To say that viruses are the dominant form of life on Earth... is based on faulty, largely rigid and inflexible logic, IMO. Viruses (currently) exist as a consequence of cellular life; (many) cellular organisms might have originated from 'viral' nucleic acids. But the irrefutable proof of this is not there, to my knowledge. I would, however, so love to be introduced to evidence to the contrary...

I will agree with that sentence if the underlined words get changed thusly:

"A large part of our cognitive matrices are composed of memes. [....] All mental processes of all persons on this earth is about interacting with ideas."

FYI, more generally, there would be no cellular life without viruses (only a small fraction of them are pathogens).

Yeah, and if you cut each human into small enough pieces and strung those pieces end-to-end they could reach as far as you like.

Total relative volume or biomass is the only comparison that makes sense, and yes at least one scientist has made the point that:

"The total biomass and biodiversity of viruses is truly staggering," says microbiologist Nick Coleman, from the University of Sydney in Australia.

From an article you should appreciate: http://www.cosmosmagazine.com/node/1024

So, yes, your point about the number and variety of viruses is relevant even when we use more rational measures.

The other point, which renders the claim about "dominant" somewhat dubious, is that by their nature that are totally dependent on cellular lifeforms for their replication. Which is the reason they are traditionally regarded as borderline classifiable as actual "life-forms" in their own right.