Freethought & Rationalism Archive

Vorkosigan · 03-07-2002, 01:07 AM

Consider an early earth populated by many different kinds of LIFE, a whole spectrum. Some doesn't replicate (MONKS). Some replicates, but with radically different changes in each generation (SIXTIES). Some is like the life we know today, conservative, but flexible (MIDWESTERNERS). Now natural selection ensues.....

What happens?

Over time -- several billion years, recall, the MONKS are all killed --disease, accident, dumb decisionmaking. They have no way to pass on beneficial traits. So one disease, sufficiently nasty, kills them all. Remember, no genetic variation, so no immunes in the outlying gene pools, so there are no survivors. Also, they are up against the MIDWESTERNERS, who, for all their conservativism, are a pretty ruthless bunch at keeping their beneficial traits.

Meanwhile, the SIXTIES breed like gangbusters. Same problems. No way to pass on beneficial traits. In fact, cross-generational mating is ruled out, because each generation is radically different from the next, a new species, in effect. Also, they are up against the MIDWESTERNERS, who, for all their conservativism, are a pretty ruthless bunch at keeping their beneficial traits. They are simply outbred and outcompeted, selection annihilates them too. Each generation faces the world exactly like the MONKS in the first example....and dies exactly like them.

Leaving only the MIDWESTERNERS.

Michael

OrderedChaos · 03-07-2002, 02:48 AM

Quote:

Originally posted by Scientiae:
[QB]I am in danger of making arguments for the opposing case... I guess the question is whether life could exist in the absence of nucleic acids. QB]

Does anyone watch the news anymore? I remember just a short while ago, everyone was in a panic over mad cow disease. What causes mad cow disease? A prion. What is a prion? Even simpler then a virus, it is just a protien and carries no genetic information. For more info on prions check out <a href="http://www.sciam.com/askexpert/medicine/medicine14.html" target="_blank">this</a>.

Principia · 03-07-2002, 08:19 AM

Ok,

So I should've argued that replicating life will naturally dominate. However, it still begs the question whether self-replicating machinery will always arise given 'proper' raw material and an energy source? For instance, in a nebulae that have been around for as long as Earth has, with gravitational energy as a driving source, why haven't we noticed self-replicating machinery that mimics life? (or perhaps we have?).

SC

Vorkosigan · 03-07-2002, 06:38 PM

Quote:

Originally posted by Scientiae:
Ok,

So I should've argued that replicating life will naturally dominate. However, it still begs the question whether self-replicating machinery will always arise given 'proper' raw material and an energy source? For instance, in a nebulae that have been around for as long as Earth has, with gravitational energy as a driving source, why haven't we noticed self-replicating machinery that mimics life? (or perhaps we have?).

SC

Why does it have to "always arise?" Isn't once enough?

Michael

tronvillain · 03-07-2002, 06:58 PM

Scientiae:

Quote:

For instance, in a nebulae that have been around for as long as Earth has, with gravitational energy as a driving source, why haven't we noticed self-replicating machinery that mimics life? (or perhaps we have?).

1)The proper raw materials or energy sources for replicators don't exist in a nebula.

2)The proper raw materials and energy sources for replicators do exist in a nebula, but they haven't formed.

3)Simple replicators exist in a nebula but haven't been observed.

4)Complex replicators exist in a nebula and are complex, but haven't been obsered.

[ March 07, 2002: Message edited by: tronvillain ]

Principia · 03-07-2002, 10:29 PM

Quote:

Why does it have to "always arise?" Isn't once enough?

Michael

Is it? Somebody above argued that evolution requires a reproducing system. Consequently, before the first self-replicating system, evolution was not in play. So, do we need another theory to explain how a self-replicating system is at all possible in the absence of a selective process?

SC

tronvillain · 03-07-2002, 11:02 PM

Scientiae:

Quote:

Is it? Somebody above argued that evolution requires a reproducing system. Consequently, before the first self-replicating system, evolution was not in play. So, do we need another theory to explain how a self-replicating system is at all possible in the absence of a selective process?

Uh, yes? If it's not physically possible for a self replicating system to spontaneously form under any conditions, then there's a big gap to explain. That isn't what turtonm was talking about - such a formation could be extremely unlikely and as a result only have happened once. I don't think that it is, though the formation of complex life may be.

Personally, I like Origins of Life by Freeman Dyson.

Automaton · 03-07-2002, 11:05 PM

Something that does not replicate cannot be called life. It would just be a metabolism, and thus adding an acid to a base could be called life.

Quetzal · 03-08-2002, 12:51 AM

Quote:

Originally posted by Scientiae:
Is it? Somebody above argued that evolution requires a reproducing system. Consequently, before the first self-replicating system, evolution was not in play. So, do we need another theory to explain how a self-replicating system is at all possible in the absence of a selective process?SC

Before you achieve self-replication, all you're dealing with in all the current abiogenesis theories is deterministic chemistry. There may be some preferential bonding, but I'm not sure that you could call it "evolution".

Principia · 03-08-2002, 07:37 AM

OK, so how should I sum this up for my Christian friends? Should I argue:

1) Abiogenesis is not the purview of evolution theory;
2) An event like the creation of self-replicating machinery is unlikely (but obviously not improbable);
3) The event does not imply a Creator.

Point 3) seems a bit flaky for me. It is what my friends are implying.

SC

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03-07-2002, 01:07 AM	#11
Vorkosigan Contributor Join Date: Jan 2001 Location: Barrayar Posts: 11,866	Consider an early earth populated by many different kinds of LIFE, a whole spectrum. Some doesn't replicate (MONKS). Some replicates, but with radically different changes in each generation (SIXTIES). Some is like the life we know today, conservative, but flexible (MIDWESTERNERS). Now natural selection ensues..... What happens? Over time -- several billion years, recall, the MONKS are all killed --disease, accident, dumb decisionmaking. They have no way to pass on beneficial traits. So one disease, sufficiently nasty, kills them all. Remember, no genetic variation, so no immunes in the outlying gene pools, so there are no survivors. Also, they are up against the MIDWESTERNERS, who, for all their conservativism, are a pretty ruthless bunch at keeping their beneficial traits. Meanwhile, the SIXTIES breed like gangbusters. Same problems. No way to pass on beneficial traits. In fact, cross-generational mating is ruled out, because each generation is radically different from the next, a new species, in effect. Also, they are up against the MIDWESTERNERS, who, for all their conservativism, are a pretty ruthless bunch at keeping their beneficial traits. They are simply outbred and outcompeted, selection annihilates them too. Each generation faces the world exactly like the MONKS in the first example....and dies exactly like them. Leaving only the MIDWESTERNERS. Michael

03-07-2002, 08:19 AM	#13
Principia Veteran Member Join Date: Mar 2002 Location: anywhere Posts: 1,976	Ok, So I should've argued that replicating life will naturally dominate. However, it still begs the question whether self-replicating machinery will always arise given 'proper' raw material and an energy source? For instance, in a nebulae that have been around for as long as Earth has, with gravitational energy as a driving source, why haven't we noticed self-replicating machinery that mimics life? (or perhaps we have?). SC

03-07-2002, 11:05 PM	#18
Automaton Senior Member Join Date: Jan 2002 Posts: 717	Something that does not replicate cannot be called life. It would just be a metabolism, and thus adding an acid to a base could be called life.

03-08-2002, 07:37 AM	#20
Principia Veteran Member Join Date: Mar 2002 Location: anywhere Posts: 1,976	OK, so how should I sum this up for my Christian friends? Should I argue: 1) Abiogenesis is not the purview of evolution theory; 2) An event like the creation of self-replicating machinery is unlikely (but obviously not improbable); 3) The event does not imply a Creator. Point 3) seems a bit flaky for me. It is what my friends are implying. SC

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