Re: Abiogenesis .

Kevin O'Brien (Cuchulaine@worldnet.att.net)
Mon, 30 Nov 1998 20:27:21 -0700

>Sorry about the delay...
>
>At 01:41 PM 11/17/98 -0700, Kevin wrote:
>>Greetings Brian:
>>
>>"Apparently you are unaware that the same word is often defined
differently
>in different fields."
>>
>>Which is irrelevant, since abiogenesis is a biological/biochemical
>phenomenon, so therefore the biochemical definition is the only one that
>matters.
>>
>
>My main interest is in clarity. I will concede your point to a
>certain extent in that greater clarity would be achieved by
>using the biochemical definition for abiogenesis and then
>simply referring to the origin of life as the origin of life.
>I will try to do this in the future.<<BTW, do you have some
>technical references that establish this definition. If you
>presented them in the past I'm afraid I missed them>>
>
>But, if one is interested in clear communication then one should
>take into account what meaning someone else might be attaching
>to a word. This is not a biochem e-mail list after all.
>

No, but that would be like trying to have a scientific discussion using a
definition of work as "the sweat of one's brow".

>
>BH:===
>>"Ellington also wrote an excellent piece for t.o several years ago
>entiltled: <Origins of life: A redefinition>....In particular his
>statement: 'Evolution is a fact. Abiogenesis is not.' Now, if the
>Miller-Urey experiment is an example of abiogenesis as used in the origin
of
>life community then abiogenesis is
>>obviously a fact, wouldn't you agree?"
>>
>
>KO:====
>>Yes, I would. But you have to understand, Ellington was writing a
>simplified piece for a lay readership, not a rigorous scientific review for
>his colleagues. As such, he used abiogenesis in a less rigorous fashion
>(which I believe he was wrong to do). For that paper he meant it as you
do:
>the origin of life. In that respect I would agree that it is not a proven
>fact that life arose naturally. However, ask him if abiogenesis in the
>proper rigorous sense is a fact and I'm sure he would agree.
>>
>
>This seems to me an entirely reasonable explanation. Let's suppose that it
>is true. If so then it indicates that Deaddog is more interested
>in communicating ideas clearly than he is in using technical words.
>Very commendable, IMHO.
>

But you can do both; both Sagan and Gould do it all the time quite
successfully.

>
>BH:===
>>"Note the word necessarily. More on this below."
>>
>
>KO:===
>>You didn't answer my question, though. If "life is not metabolism based
on
>biomolecules, then please define
>>>"life".
>>
>
>I didn't answer because I failed to see the relevance of your question.
>

If we are discussing the origin of life, we need to know what "life" means
to have a reasonable discussion. I simply wanted to hear yours since you
seemed to insistant upon separating the origin of "life" from the origin of
biomolecules.

>
>If you insist, let me say that I prefer the definition of life I
>found on a web page several years ago:
>
>"Life is that which dies when you stomp on it"
>
>OK, just kidding. Everyone realizes I think how difficult it is
>to define life. Most other definitions I've seen attempt to
>add more ingredients than metabolism. For example, I seem to
>recall Eigen throwing in ability to reproduce and mutability
>into the equation.
>

Both of which require metabolism.

>
>These could easily become problematic of
>course. I'm guessing one reason you asked this is to feel out
>whether I have vitalistic tendencies. If this is the case let
>me say that I believe that the physical phenomena we call life,
>regardless how it ends up being defined, is fully explainable
>in terms of physical laws. For the time being I'm quite happy
>to take your definition.
>
>[...]
>
>>BH:====
>>"Well, this is very interesting, but also beside the point I was trying to
>make. If you look through the references below you will find examples of
>experiments which qualify as abiogenesis according to your definition. Let
>me turn the argument around from my previous statement. If the origin of
>life occurred a la Miller, then most perhaps all of these examples would
not
>have anything to do with the origin of life. This is why I said that
>abiogenesis (as you've defined it) does not *necessarily* have anything to
>do with the origin of life on earth."
>>
>
>KO:=====
>>Since abiogenesis has nothing to do with "the origin of life" as you
>describe it (whatever that phrase means), your point is relevant. However,
>if I may play Devil's advocate for a moment and argue from your point of
>view, since life itself is complex, we should not be looking for a single,
>simple origin. A number of abiogenetic mechanisms might have been working
>simultaneously -- atmospheric gas reactions, hydrothermal vent reactions,
>cometary/meteoric impacts, thermal copolymerization, solid-state catalysis,
>etc. -- in a number of different ways to create first biomolecules, then
>metabolic systems, then replicating systems and finally life. To claim
that
>only one mechanism could do it all is like claiming that only natural
>selection or only genetic drift or only saltationist events are needed to
>explain the whole of evolution.
>>
>
>Yes, very good. I like this idea a lot and would not be surprised
>at all if this is the way it turns out. But my point has to do
>with necessity. It isn't necessarily so. For example, there may
>be many laboritory abiogenesis experiments involving conditions
>never present on early earth. All of these examples of abiogenesis
>would therefore have nothing to do with the origin of life.
>

And those that have already been done have been proved wrong fairly quickly,
at least so my literature searches tell me.

>
>By the way, you asked what I meant by "the origin of life",
>i.e. your parenthetical comment "whatever that phrase means".
>What I meant was exactly as you describe in your sentence above:
>"...in a number of different ways to create first biomolecules,
>then metabolic systems, then replicating systems and finally life",
>i.e. the last three words.
>
>>By the way, thanks for the references.
>>
>
>your welcome.
>

Kevin L. O'Brien