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Author | Topic: Abiogenesis | |||||||||||||||||||||||
RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
go back and look and you will see if looking for the answers is what you want to be
you continue to misinterpret. not my problem. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
one last chance to think:
where do viruses come from?
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DNAunion Inactive Member |
Go back and look and you will see that I have not made errors, and if you claim I have, they you are wrong.
You continue to reject logic and science...not my problem. [This message has been edited by DNAunion, 03-24-2004]
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DNAunion Inactive Member |
quote: Uhm, how is that any kind of last chance when it is the FIRST time you asked me that question? Here, let me give it a try. One last chance to think AbbyLeever: what's the difference between the lysogenic and lytic cycles? [This message has been edited by DNAunion, 03-24-2004]
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
you are full of yourself aren't you.
bye. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
I didn't claim that you made errors
just that your views were incomplete. enjoy yourself.
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DNAunion Inactive Member |
Okay, let me sum up these exchanges. Although your original point was correct, your two supports for that point were both flawed. I agreed with your point, but exposed the flaws in your support.
Let's go back to the original.
quote:
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Brad McFall Member (Idle past 5063 days) Posts: 3428 From: Ithaca,NY, USA Joined: |
It would be a curious thought indeed if we considered prions as a live and virses as dead. I do hope DNAunion is correct and we are out of Alice's rabbit hole.
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Loudmouth Inactive Member |
quote: Without going into levels of complexity, prions and viruses do have major differences between them. A prion is just a catalytic protein, nothing more. A virus is much more complicated and actually contains a genome. Perhaps a prion is alive in the same way fire is alive. Fire does reproduce and consume resources, two of the characteristics of life. As to the origin of viruses, I think they came about after cellular life. They could have been the first gametes, but mutated in such a way that they fell under the control of evolutionary mechanisms and now live as separate entities. Perhaps they are "diploid" gametes that developed selfishness in the Dawkins sense (I use diploid loosely, meaning complete in an allele sense compared to haploid with half of the alleles). Lytic and lysogenic stages of bacterial phages could explain this, especially with the lytic stage being initiated by DNA damage. If the bacteria in the past experience damage, dispersal of DNA material in packets could have helped survival of subsequent generations by a type of sexual reproduction. Are viruses alive? No. Are they important in understanding evolutionary mechanisms? Yes. They are important for understanding life and diversity, but are themselves not alive.
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Very curious indeed. But don't get sidetracked by DNAUnion's dogmatic misapprehensions of my position:
http://EvC Forum: Abiogenesis
Finally, DNA can exist outside a living cell although it degrades with time -- no longer has the mechanic doing tune-ups ... but it is not the minimum requirement for abiogenesis to have occurred. Viruses use an abbreviated RNA that hi-jacks the cell mechanism to replicate its nefarious (to us) messages. Then we get to prions like the ones that cause mad cow disease, which are even less 'complete' than viral RNA ... http://EvC Forum: Abiogenesis
What I would expect to see, is that once a self replicating element has been achieved, that a number of similar experiments would follow using different conditions --- if for no other reason than to see how easily life could evolve on other planets: what are the limiting factors? http://EvC Forum: Abiogenesis
The {bottom up} question of abiogenesis is not life but the first replicator. The {top down} question of abiogenesis is what is the absolute simplest possible form of life. Dissecting DNA down to an absolute minimum for bacteria to still qualify as life brings us very close to virus type stuff at this point though controversy ensues. http://EvC Forum: Abiogenesis
The evidence to date is that viruses do not replicate on their own within the environments that we know about. The absence of evidence is not evidence of absence however, and does not rule out that a certain environment may exist wherein viruses could replicate. That environment could be something closer to a primordial environment or one of the extremophiles type or depend on a random input of energy in a pre-bio soup. It is also possible that the viruses have lost mechanisms where they have found easier mechanisms to use from cells than from their {original development}, even though that {original mechanism} may have differed significantly from modern cell biology. This would mean that they are not devolved bacteria but a separate form of life, perhaps one entirely based on RNA. ... we don't know. As mentioned regards prions, the development of a replicator is a relatively necessary first step whether it can be classed as {life by some definition or other} or not, even if that replicator uses a clay or crystal structure to form a molecular production {not so much Xerox as Widget building} machine. Perhaps "replicator" is the wrong word and we should be looking for "implicators" ("imps" for short?) first. http://EvC Forum: Abiogenesis
The question was (and is) whether something else can provide the missing elements that are currently provided by living cells to allow {viruses or close cousins} to reproduce. Could that have been how the first replicators worked. You will note that nowhere do I state that I consider either viruses or prions to be alive or that they fit a definition of life, but raise them solely as examples of mechanisms by which replication occurs (such replication being classified as a condition for "quasi-life" in one of DNAUnion's citations). Replication which now depends on cell mechanisms for support, but may not have in the distant past if other similar mechanisms were available. I stand by what I said, consistently, here, and refuse to get into a one-upmanship contest. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Additional thoughts.
(1) is it possible to have a proto-cell structure that is not self replicating but which is held together in a stable (relatively) form for considerable periods of time? ie - does the cell structure come before the replication process or the vice versa? a primordial chicken and egg question. Or do replicators and protocells develop independently ... there has been some research on the development of membranes as a first level of cell development. (2) is abiogenesis better aligned with xenobiology (earth as a special case) or with biology. Considering that the original environment on earth was quite alien to the environment that we know, I would place it with xenobiology. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
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Brad McFall Member (Idle past 5063 days) Posts: 3428 From: Ithaca,NY, USA Joined: |
I think there is presently a FALSE, did iIi say "false" dicotomy of replication and metabolism in mole bio today engendered if not in whole, in part by Freeman Dyson. I know how WRONG in particular but not this particular that Dyson can be AFTER musing over a comment Kaufmann's BOOTS gave my spirit when walking to the chemistry dept at Cornell about Dyson in the field. I think making this explict is furthering only the current depressive relation of chemisty and psycholy only and may help an artist apply nanotech but no more.
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Darwin Storm Inactive Member |
???? Does not compute...
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
metabolism being the process of repair and maintenance of the cell and replication being the process of making a copy of specific cell structures I would have to agree.
It is more a matter of degree than a different process. Like micro and macro evolution. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
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DNAunion Inactive Member |
Don’t be fooled by AbbyLeever’s attempt to save face. He’s wronghe knows itwe all know it.
quote: In the third part of AbbyLeever’s first sentence, it refers to DNA (or a living cell, which would be even worse for him/her, so we’ll go with DNA). So we have:
quote: Agreed. But then AbbyLeever goes on to support his/her paragraph’s opening sentence by giving two examples, both of which are flawed supports.
quote: Too bad for AbbyLeever that viruses ABSOLUTELY REQUIRE DNA, transitively, in order to do that. Support rejected.
quote: And since prions are not living, they are irrelevant to abiogenesis: furthermore, prions also REQUIRE DNA, transitively, in order to "replicate". Support rejected. As I originally pointed out, and consistently pointed out, AbbyLeever's only two supports are both flawed. And none of his attempts to distract us from this fact, by switching subjects, works. [This message has been edited by DNAunion, 03-27-2004]
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