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Author Topic:   On the Origin of Life and Falsifiability
PaulK
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Joined: 01-10-2003
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Message 61 of 108 (780490)
03-15-2016 2:26 PM
Reply to: Message 57 by Genomicus
03-15-2016 1:30 PM


Re: Second Problem
quote:

Sure, and falsifying the RNA world model does not in itself falsify abiogenesis. If you have a falsification scenario for the RNA world model, by all means present it. I will then immediately concede that the RNA world model is falsiViable

By now you certainly ought to realise that I am not claiming that the RNA world is falsifiable. I am claiming that panspermia is not.

quote:

Really? Let's take the age of the Earth, for example. No matter how much evidence is presented that the Earth is approximately 4.5 Ga, the creationist can always resort to a divine mechanism (and they have) which accounts for observations of isotope-based dating. You will find that creationists can always account for a particular observation by inserting a divine mechanism, so the weight of the evidence seems to be of no weight at all! The blade that slices creationism away from the domain of science must therefore be the criterion of falsifiability. It is falsifiability, not the weight of evidence, that most starkly divides science from pseudoscience.

If Young Earth Creationism requires loads of ad hoc auxiliary hypotheses to protect it from falsification then it is already not science by my criteria. Why then, do I need to appeal to,any other ?

Edited by PaulK, : Cleaned up an auto "correction"


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Genomicus
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Message 62 of 108 (780518)
03-15-2016 11:10 PM
Reply to: Message 27 by caffeine
03-10-2016 2:43 PM


Re: caffeine -- Some Genomic Evidence for Panspermia
Yes, speculative models are of considerable value in driving exploratory science further. This is not -- in itself -- a criticism. However, there is much focus in current OOL research on establishing the biochemical plausibility of abiogenesis models, instead of hunting for clues that these models are grounded in historical reality. Contrast this with panspermia, where much of the evidence is of a historical nature rather than a focus on mere plausibility.

I don't see this to be the case from looking at the evidence you've presented for panspermia. Of the four studies you cited in support of panspermia; Rampelotto's you described as overcoming objections, which sounds very much like establishing plausibilty (I haven't read the article) and Mautner's and Melosh's are both explicitly establishing the plausibility of micro-organism's being transported through space.

Hey caffeine,

You are correct with regards to the above studies. I cited these in the OP so as to steer the discussion away from attempts to argue that panspermia could not have happened. However, while there is a considerably large volume of research indicating panspermia is feasible, there are also numerous studies that suggest it actually happened in biological history. For starters:


  • Molecular clocks of prokaryotes based on 32 well-conserved proteins present in both bacteria and Archaea suggest that bacteria diverged ~4.1 Gyr ago and Archaea diverged at ~4 Gyr (Battistuzzi et al. 2004). Yet the most ancient, definitively microbial fossils are found in Archaean rocks about 3.5 Gyr in age.

    This observation is in complete accord with the hypothesis of lithopanspermia. First, evidence suggests that there was a maximum number of habitable planets in the Milky Way when the Earth began its formation about 4.6 Gyr ago (van Bloh et al., 2003). So the emergence of biological life in our galaxy would have been most probable around this time. Under the lithopanspermia hypothesis, cellular life would have then evolved for several hundred million years before having the capacity to survive transport through space in planetary ejecta. Thus, life should be older than the first microbial fossils on Earth, and younger than about 4.6 Gyr -- precisely what this molecular clock analysis indicates.

    Opponents of lithopanspermia may respond with a technical criticism: the molecular clock observations can be waved away by positing rapid molecular evolution during the divergence of bacteria and Archaea. Yet this is not as convincing an argument as it may appear; first, use of different calibration points and minimum bounds than what was used in an earlier study (Sheridan et al., 2003) still closely match the molecular clock results of that earlier study, which would not be expected if the molecular clock results are due to a significantly elevated rate of molecular evolution early in prokaryotic evolution; and second, Battistuzzi and colleagues employed a Bayesian local clock, which would be more accurate than a global clock as it does not assume an identical molecular clock rate across all tree branches.

    This discrepancy between molecular clock analyses of life's most basal lineages and the paleontological record has puzzled some researchers; however, the lithopanspermia model elegantly explains this observation in a single stroke.

  • The gene set of the LUCA was sufficiently large enough to allow for transport through space of microbes. In other words, the bulk of phylogenetic and genomic evidence invariably point to the conclusion that the LUCA was not a progenote (which would have been unable to survive the ionizing radiation of galactic cosmic rays), but instead had a sophisticated repertoire of protein parts, including several of the core proteins of bacterial flagella (here I am bringing up bacterial flagella only as a way of highlighting the not-so-primitive state of the LUCA).


The fourth, Wallis (2003), I'm a bit surprised that no one else has picked up on yet, as this is a wildly speculative article about the dinosaurs being wiped out by poisonous fungi from space. It's short, and I would highly encourage everyone to read it; including yourself, as I get you impression you may not have based on your relatively complimentary description.

I did, in fact, read Wallis' 2003 paper prior to writing up the OP. It is indeed speculative, but it's not "wildly" speculative IMHO -- unless you would also grant that label to the RNA world model. The distribution of Aib-polypeptides in the paleontological record are tentatively suggestive of a biogenic origin; further work would have to be done in order to shed more light on this.

References

Battistuzzi, et al., 2004. A genomic timescale of prokaryote evolution: insights into the origin of methanogenesis, phototrophy, and the colonization of land.

van Bloh, et al., 2003. Maximum number of habitable planets at the time of Earth's origin: new hints for panspermia?

Sheridan, et al., 2003. Estimated Minimal Divergence Times of the Major Bacterial and Archaeal Phyla.


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ICANT
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Posts: 5577
From: SSC
Joined: 03-12-2007


Message 63 of 108 (780521)
03-15-2016 11:21 PM
Reply to: Message 50 by PaulK
03-15-2016 9:55 AM


Re: Second Problem
Hi PaulK,

PaulK writes:

No, I mean that - among other reasons - creationism is not science because it HAS been brought down by the weight of difficulties, at least so far as scientific investigation is concerned.

Would you care to have a serious discussion about Biblical creation which does not have the baggage or weight of difficulties that YEC creationism does? If so message me and I will start a thread.

God Bless,
Aaron


"John 5:39 (KJS) Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me."

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Genomicus
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Message 64 of 108 (780530)
03-16-2016 7:16 AM
Reply to: Message 60 by PaulK
03-15-2016 2:18 PM


How again is the RNA world model more general than lithopanspermia?

Strictly speaking lithopanspermia doesn't include abiogenesis so much of what you said is irrelevant.

What specifically did I say that was irrelevant?

And I would say that the whole "travel to earth on a meteorite" - which is the only part you offer as falsifiable - is quite specific.

And I would say that "Base-pairing coupled with thermal and catalytic activity allowed for polynucleotide replication" is quite specific. You're going to have to make a better case that the RNA world is more general than lithopanspermia.

So then if not by exhaustive trial, how?

By showing some restriction that cannot be overcome.

And how are you going to show that there is some restriction that cannot be overcome without exhaustive trial?

And the reason panspermia has lower theoretical content in relation to historical claims is what?

Because it doesn't include abiogenesis. If it did *that* part would be even less historical than earthly abiogenesis research.

That doesn't actually answer my query, though, and looks rather circular. Let me try again: why is it that lithopanspermia has lower theoretical content than, say, the RNA world model? What is the intrinsic property of lithopanspermia that gives it more historical content (see, e.g., my discussion of molecular clocks in my response to caffeine's post) than the RNA world model? Is it that there are quite a few knowledge gaps when it comes to the RNA world, in contrast to lithopanspermia?


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PaulK
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Posts: 12688
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Message 65 of 108 (780533)
03-16-2016 8:23 AM
Reply to: Message 64 by Genomicus
03-16-2016 7:16 AM


I'm afraid your post makes it obvious that you aren't interested in productive discussion. I've made my points, and there is really nothing more I need to say.
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Blue Jay
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Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 66 of 108 (780544)
03-16-2016 11:17 AM
Reply to: Message 55 by Genomicus
03-15-2016 12:57 PM


Hi, Genomicus.

Genomicus writes:

Wait. So in your effort to demonstrate that lithopanspermia is not falsifiable, you're divining the possible existence of analogs of proteases, ABC transporters, and nucleases, which would have then been lost under mysterious selective pressure that somehow allowed such a loss to not affect the reproductive fitness of the population in a negative way, and wherein no homologs were preserved; and then cells evolved proteases, ABC transporters, and nucleases.

I have three objections to your comment here:

  1. I don't really understand why this evokes such incredulity from you. The validity of this data as a falsification hinges on the premise that there is no other means of tolerating cosmic radiation aside from certain patterns in the abundance/diversity of proteases, ABC transporters and nucelases. Accepting that premise requires a fair helping of hubris, doesn't it?

  2. I don't really understand why you think LUCA and FUCA should be similar. After all, in the panspermia model, FUCA is supposed to have come from an alien planet, so it seems quite reasonable to anticipate a whole suite of very novel selection pressures immediately after arrival on Earth. So, there seems plenty of reason to anticipate massive genomic changes occurring between FUCA and LUCA; and it seems a bit hasty to dismiss any possibilities the way you have.

  3. And besides, isn't this the exact form of the argument you used to demonstrate the unfalsifiability of the RNA World hypothesis? That is, what if someone published a phylogenetic tree claiming to provide evidence about the existence of self-catalytic RNA's coded in the genome of LUCA? Wouldn't that beg a couple of big questions about whether or not those RNA's were the actual prebiotic RNA catalysts, and about why/how those prebiotic catalysts became encoded into LUCA's DNA? How is that substantively different from the questions Dr A is asking now about Panspermia?

Edited by Blue Jay, : No reason given.


-Blue Jay, Ph.D.*

*Yeah, it's real

Darwin loves you.


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Dr Adequate
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Posts: 15929
Joined: 07-20-2006
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Message 67 of 108 (780553)
03-16-2016 2:04 PM
Reply to: Message 66 by Blue Jay
03-16-2016 11:17 AM


I don't really understand why you think LUCA and FUCA should be similar. After all, in the panspermia model, FUCA is supposed to have come from an alien planet ...

And not only that, but one sufficiently different from Earth that abiogenesis was plausible there but not here.


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PaulK
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Posts: 12688
Joined: 01-10-2003
Member Rating: 2.8


Message 68 of 108 (780555)
03-16-2016 2:12 PM
Reply to: Message 66 by Blue Jay
03-16-2016 11:17 AM


quote:

I don't really understand why this evokes such incredulity from you. The validity of this data as a falsification hinges on the premise that there is no other means of tolerating cosmic radiation aside from certain patterns in the abundance/diversity of proteases, ABC transporters and nucelases. Accepting that premise requires a fair helping of hubris, doesn't it?

I'm sure that exhaustive testing of all the alternatives has been done. After all Genomicus can't think of any other way to falsify the idea that there are alternatives.


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caffeine
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From: Prague, Czech Republic
Joined: 10-22-2008
Member Rating: 5.5


Message 69 of 108 (780557)
03-16-2016 2:56 PM
Reply to: Message 62 by Genomicus
03-15-2016 11:10 PM


Re: caffeine -- Some Genomic Evidence for Panspermia
Molecular clocks of prokaryotes based on 32 well-conserved proteins present in both bacteria and Archaea suggest that bacteria diverged ~4.1 Gyr ago and Archaea diverged at ~4 Gyr (Battistuzzi et al. 2004). Yet the most ancient, definitively microbial fossils are found in Archaean rocks about 3.5 Gyr in age.

The problem with this sort of reasoning is that there do not really exist many meaningful calibration points when we're discussing this sort of age. It's very complex to establish whether ancient bacterial fossils are in fact fossils rather than abiotic artefacts - assigning them to a clade is essentially impossible. We can only assume the emergence of bacterial clades by geochemical arguments - we can tie the rise in atmospheric oxgyen c. 2.4 Gya to cyanobacteria, for example. The problem with this is that geochemistry in complicated and there is still much we don't understand, so there is little agreement on when oxygenic photosynthesis actually arose. While we can agree it's there by 2.4 Gya, some researchers push it up to a billion years earlier; as their geochemical models include sinks for oxygen that explain it's late rise. The origins of methanotrophy are argued to be anywhere between 4 billion and 700 million years ago, as the same chemical data can often be explained by different biotic and abiotic processes.

From a phylogenetic point of view, of course, we have the further issue of assuming that a particular chemical pathway was done by the same organisms 3 billion years ago as it was now, so these aren't necessarily that useful as calibration points. You were talking earlier about Cavalier-Smith's arguments about polarity in evolution - worth noting is that his argument on this subject has Archaea diverging only about 850 million years ago.

On the subject of the oldest definitively prokaryotic fossils, I think more caution is needed. You can read here Brasier et al. (2006) on the difficulties of ruling out abiotic processes to form Archaean 'fossils' (but look relatively quick if you want to, as this goes behind a paywall at the end of the year). The science on early life is too difficult for us to proclaim any dates with confidence yet.

However, even if we did choose to accept that life is this old, there seems to be a huge unjustified leap in the next step in your reasoning. Without any clear model of the actual process by which life arose, how can we possibly be justified in saying something is a long or short time? We're not talking about life arising in an hour. Is 16 million years a short time? Why? That's an incredibly long time from our perspective - maybe that's an ample sufficiency of time for life to arise.

It is premature to seek an explanation of how x could happen so quickly without a model of how long x should be expected to take.

--------------------

I will try to come back to Wallis' article later. Been a while since I actually tried to put some work into a post - takes time! Don't know how you can bang all these out.


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caffeine
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Posts: 1263
From: Prague, Czech Republic
Joined: 10-22-2008
Member Rating: 5.5


Message 70 of 108 (780772)
03-20-2016 3:33 PM
Reply to: Message 62 by Genomicus
03-15-2016 11:10 PM


Fungi from spaaaaaaace!
I did, in fact, read Wallis' 2003 paper prior to writing up the OP. It is indeed speculative, but it's not "wildly" speculative IMHO -- unless you would also grant that label to the RNA world model. The distribution of Aib-polypeptides in the paleontological record are tentatively suggestive of a biogenic origin; further work would have to be done in order to shed more light on this.

'Wildly speculative' was the polite way of puttiing it. 'Steaming pile of horseshit' would be the franker and more accurate way of describing it. I had intended to get around to writing a more detailed critique, but learning about the evolution of polypeptides via Google is more complicated than expected.

Such knowledge is unnessecary to dismiss this article, however. Before you discussed the use of phylogenetic arguments to dismiss panspermia scenarios. Phylogenetically, we know that fungi are deeply embedded in the terrestrial tree of life. They are opisthokont eukaryotes closely related to animals. And yet Wallis is seriously proposing as a plausible hypothesis that peptaibol-producing fungi like Trichoderma arrived from space just over 65 million years ago. This is not a suggestion we should be taking seriously.


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Genomicus
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Posts: 815
Joined: 02-15-2012
Member Rating: 4.7


Message 71 of 108 (780785)
03-21-2016 5:16 AM
Reply to: Message 69 by caffeine
03-16-2016 2:56 PM


Re: caffeine -- Some Genomic Evidence for Panspermia
Hey caffeine,

Molecular clocks of prokaryotes based on 32 well-conserved proteins present in both bacteria and Archaea suggest that bacteria diverged ~4.1 Gyr ago and Archaea diverged at ~4 Gyr (Battistuzzi et al. 2004). Yet the most ancient, definitively microbial fossils are found in Archaean rocks about 3.5 Gyr in age.

The problem with this sort of reasoning is that there do not really exist many meaningful calibration points when we're discussing this sort of age.

This sort of comment might get a layperson thinking that the dozens and dozens of scientific papers published on molecular clock analyses of prokaryotic phylogeny is little more than evolutionary biologists dreaming stuff up. I find this argument suspect as it seems to imply that the aforementioned problem has not been tackled by those in the field, when in fact the paper I cited -- and many others -- understood the nature of the problem and properly addressed it with the appropriate methodology.

Consider the following approaches to resolving the problem meaningful calibration points for prokaryotic phylogeny:

(1) The use of calibration points based on lineage-specific biomarkers, such as okenane (associated with gammaproteobacteria) and chlorobactane (found in the green sulfur bacteria at about 1.6 Ga).

(2) The use of node age constraints as calibration points, thereby providing information as to the minimum absolute ages of the nodes in the tree (which can be pretty easily done with Bayesian software like MrBayes).

(3) The use of eukaryote divergence times as inferred by paleontology and extrapolating to prokaryotic lineages while controlling for rate differences among prokaryotes and eukaryotes.

(4) The use of statistical tests (e.g., likelihood ratio test and relative rate test) of primary structure data to determine the extent to which a global molecular clock holds for a particular set of sequences. And if a global molecular clock does indeed hold, then only a few calibration points are needed.

(5) The use of local molecular clocks based on Bayesian and maximum-likelihood approaches to increase the reliability of molecular clock estimates even when there are few calibration points and when a global molecular clock is rejected.

It's very complex to establish whether ancient bacterial fossils are in fact fossils rather than abiotic artefacts - assigning them to a clade is essentially impossible.

That depends on the bacterial fossils under consideration, though.

We can only assume the emergence of bacterial clades by geochemical arguments - we can tie the rise in atmospheric oxgyen c. 2.4 Gya to cyanobacteria, for example. The problem with this is that geochemistry in complicated and there is still much we don't understand, so there is little agreement on when oxygenic photosynthesis actually arose. While we can agree it's there by 2.4 Gya, some researchers push it up to a billion years earlier; as their geochemical models include sinks for oxygen that explain it's late rise. The origins of methanotrophy are argued to be anywhere between 4 billion and 700 million years ago, as the same chemical data can often be explained by different biotic and abiotic processes.

Understood, but:

(1) There are quite a few other biomarkers other than oxygenic photosynthesis tied to prokaryotic clades that can yield fairly realistic calibration points, as mentioned above.

(2) We can test for useful calibration points based on whether removing these calibration points significantly alter the node ages. If they do not, then they are pretty accurate calibration points.

(3) You keep mentioning that certain parts of this are "complex" or "complicating." That may be an idiosyncrasy of your diction, in which case I wholly understand, but I am sure you do acknowledge that the complexity of a field of knowledge does not mean it cannot be understood. There is a very robust literature on a wide range of biomarkers, for example, as much energy has been put into elucidating the details of such markers.

From a phylogenetic point of view, of course, we have the further issue of assuming that a particular chemical pathway was done by the same organisms 3 billion years ago as it was now, so these aren't necessarily that useful as calibration points.

That argument looks pretty ad hoc when you combine the observation of certain biomarkers with molecular and paleontological arguments. E.g., these biomarkers are often found in geological sites alongside other biomarkers; taken together, these all point to having been produced by organisms not at all unlike the modern bacterial clades they are thought to be ancestors of.

You were talking earlier about Cavalier-Smith's arguments about polarity in evolution - worth noting is that his argument on this subject has Archaea diverging only about 850 million years ago.

Since Cavalier-Smith's (arguably weak) transition analyses can't be used to establish absolute dates of origin, his figure in the paper (from which I believe you got the 850 million years) cannot be taken to be any sort of evidence for absolute ages.

More later.


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Genomicus
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Member Rating: 4.7


Message 72 of 108 (780787)
03-21-2016 8:52 AM
Reply to: Message 69 by caffeine
03-16-2016 2:56 PM


Re: caffeine -- Some Genomic Evidence for Panspermia
On the subject of the oldest definitively prokaryotic fossils, I think more caution is needed. You can read here Brasier et al. (2006) on the difficulties of ruling out abiotic processes to form Archaean 'fossils' (but look relatively quick if you want to, as this goes behind a paywall at the end of the year).

I can get through most paywalls, actually, so if there's ever a paper you'd like me to dig up in full, just pass the word on to me.

Brasier et al., 2006, is indeed an interesting article and an insightful read. However, I suspect you are misunderstanding my argument (no doubt due to my late night attempts at communication!). My argument here is not in any way the idea that life on Earth would have had too little time to emerge (this is a line of reasoning that some researchers have used to justify panspermia, but is not my approach here). Rather, my argument can be summarized thusly:

(1) The oldest, definitively prokaryotic fossils go back roughly 3.5 Ga. Even this may be generous, however, and life on Earth may have emerged at an even later date.

(2) Molecular clock analyses based on (a) multiple protein sequences from multiple prokaryotic taxa, and (b) different molecular clock approaches with a variety of calibration points in each study all converge on a more-or-less unanimous conclusion: that prokaryotes are more than 4 billion years old, and less than 4.5 billion years old.

(3) This is complete accordance with lithopanspermia, wherein biological life arose some 4.5 Ga ago on other planetary surfaces -- when there was a maximum number of habitable planets in the Milky Way -- and subsequently evolved sophisticated molecular machinery over the course of hundreds of millions of years before being transported to Earth. In other words, if lithopanspermia is correct, then life should be older than the dates for the first paleontological indications of fully-formed microbial life. And this is what multiple molecular clock analyses seem to suggest.


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Genomicus
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Message 73 of 108 (780788)
03-21-2016 9:11 AM
Reply to: Message 70 by caffeine
03-20-2016 3:33 PM


Re: Fungi from spaaaaaaace!
'Wildly speculative' was the polite way of puttiing it. 'Steaming pile of horseshit' would be the franker and more accurate way of describing it. I had intended to get around to writing a more detailed critique, but learning about the evolution of polypeptides via Google is more complicated than expected.

I'd be interested in seeing if there's actually much of an argument behind your florid prose describing this paper.

Such knowledge is unnessecary to dismiss this article, however. Before you discussed the use of phylogenetic arguments to dismiss panspermia scenarios. Phylogenetically, we know that fungi are deeply embedded in the terrestrial tree of life. They are opisthokont eukaryotes closely related to animals. And yet Wallis is seriously proposing as a plausible hypothesis that peptaibol-producing fungi like Trichoderma arrived from space just over 65 million years ago. This is not a suggestion we should be taking seriously.

And not one Wallis is making per se. He proposes the following two scenarios as possible explanations for the geologic distribution of Aib peptides: (1) that fungi from space landed on Earth, and that the genomes of these fungi encoded genes for Aib polypeptides, or (2) an unknown kind of microbial organism landed on Earth, equipped with genes for Aib polypeptides; these genes were subsequently transferred to fungal genomes.

Your attempt to refute (1) by pointing to the long branches of fungi in eukaryote phylogenies fails to consider that it's hypothetically possible for fungi-like organisms to land on Earth with that lineage going extinct -- but not before some of their genes were laterally transferred to other fungi clades and certain prokaryotes.

So what really needs to happen is this: first, analyze genes encoding Aib polypeptides and see if there are indicators of having been acquired through horizontal gene transfer (e.g., through GC-content analysis); second, conduct relevant molecular clock analyses to determine when these genes first arose.

Anyways, what's your explanation for the particular distribution of Aib in the K/T transition?

Edited by Genomicus, : No reason given.


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Genomicus
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Message 74 of 108 (780795)
03-21-2016 8:35 PM
Reply to: Message 59 by Dr Adequate
03-15-2016 1:49 PM


@Dr Adequate
Really? Let's take the age of the Earth, for example. No matter how much evidence is presented that the Earth is approximately 4.5 Ga, the creationist can always resort to a divine mechanism (and they have) which accounts for observations of isotope-based dating. You will find that creationists can always account for a particular observation by inserting a divine mechanism, so the weight of the evidence seems to be of no weight at all! The blade that slices creationism away from the domain of science must therefore be the criterion of falsifiability. It is falsifiability, not the weight of evidence, that most starkly divides science from pseudoscience.

Well, that's the Duhem-Quine thesis made flesh, isn't it? We can save the appearances for any hypothesis by postulating the existence of an omnipotent being who used his miraculous powers in such a way as to lead us to false conclusions.

For example, whatever we discovered about LUCA's ability to resist radiation, we could say: "But maybe lithospermia is still true, but maybe there is a God who in his infinite wisdom used his mighty powers to screen FUCA from radiation in its passage through the cosmic void". And now lithospermia is unfalsifiable too. Likewise, the proposition that there was an elephant in my house, which you agreed was falsifiable, becomes unfalsifiable --- because what if God teleported the elephant in and then out again without it having to pass through any of the doors?

In order to use the idea of falsifiability at all, we have to rule out, methodologically, such things as a (willfully or inadvertently) deceitful God, the Cartesian demon, and the brain-in-a-jar hypothesis as the sort of auxiliary hypotheses that people are allowed to propose.

More precisely, what we methodologically rule out when it comes to falsifying a hypothesis are auxiliary hypotheses that do not increase the degree of falsifiability of that hypothesis, as stated previously:

"If we wish to defend scientific hypotheses from a putative falsification, then we must structure our objections as independently testable hypotheses, or modifications to hypotheses should increase their degree of falsifiability. In other words, if an objection merely papers over the problem, serving no purpose other than to quarantine or excuse the apparent failure and thereby reduce explanatory content, then it has no scientific merit."

So we methodologically rule out gods because that auxiliary hypothesis merely papers over the problem and does not increase the degree of falsifiability of the hypothesis under consideration.

Once again, then, it is not a matter of the "weight of evidence." This is not a very good line of demarcation between science and pseudoscience, as no matter how heavy the weight of evidence might be against a particular hypothesis, auxiliary hypotheses can always be conjured. Thus, what matters here is falsifiability: do auxiliary hypotheses increase the degree of falsifiability or do they simply function as a kind of quarantine?

Edited by Genomicus, : No reason given.


This message is a reply to:
 Message 59 by Dr Adequate, posted 03-15-2016 1:49 PM Dr Adequate has responded

Replies to this message:
 Message 75 by Dr Adequate, posted 03-21-2016 8:48 PM Genomicus has responded

  
Dr Adequate
Member
Posts: 15929
Joined: 07-20-2006
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Message 75 of 108 (780796)
03-21-2016 8:48 PM
Reply to: Message 74 by Genomicus
03-21-2016 8:35 PM


Re: @Dr Adequate
Well, unless I'm missing something, and I do have a nasty headache right now, this is somewhat beside the point. The point is that creationism is falsifiable, unless you allow the creationists the sort of auxiliary hypotheses that we don't allow anyone.

Once again, then, it is not a matter of the "weight of evidence." This is not a very good line of demarcation between science and pseudoscience, as no matter how heavy the weight of evidence might be against a particular hypothesis, auxiliary hypotheses can always be conjured. Thus, what matters here is falsifiability: do auxiliary hypotheses increase the degree of falsifiability or do they simply function as a kind of quarantine?

Well, no. Falsifiability is a very low bar, it just identifies the sort of thing that could be science. It doesn't mark off science from pseudoscience: there are any number of things which are eminently falsifiable and would be science if they were true, but are pseudoscience because they are false --- or, strictly speaking, because the weight of the evidence is against them. Homeopathy, for example, is practically the paradigmatic pseudoscience, and is readily falsifiable: we can test whether homeopathic medicine works better than placebo. It's a pseudoscience because it doesn't.


This message is a reply to:
 Message 74 by Genomicus, posted 03-21-2016 8:35 PM Genomicus has responded

Replies to this message:
 Message 77 by Genomicus, posted 03-21-2016 9:08 PM Dr Adequate has responded

  
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