Jump to content


Photo

Genetic Limitations To Evolution Between Kinds


  • This topic is locked This topic is locked
55 replies to this topic

#41 JayShel

JayShel

    Former Atheist

  • Moderator Team
  • PipPipPip
  • 777 posts
  • Gender:Male
  • Location:Florida
  • Age: 36
  • Christian
  • Creationist
  • Saved July 12, 2007

Posted 19 October 2011 - 11:11 PM

I am going to withdraw from this discussion because I no longer have the time. I am no expert by any means, and to be honest time and expertise are really what is required to participate in this forum. Also, I came here seeking the answer to a question.

As I would currently understand the results of my inquiry of this thread it would be this:

No, we do not currently know of genetic limitations that would prevent macro-evolution from happening.

I am currently reading into these threads and others to understand better both sides of points brought up in this thread:
http://www.evolution...opic=4648&st=40 is a discussion on "Dinosaur Feathers".
http://www.evolution...?showtopic=4466 "Macro Evolution Is Not The Accumulation Of Micro Evolution"

Thank you for your time.

#42 Ron

Ron

    Advanced Member

  • Member
  • PipPipPipPipPip
  • 6,530 posts
  • Gender:Male
  • Age: 50
  • Christian
  • Creationist
  • Johnstown, PA

Posted 06 November 2011 - 03:45 PM

No, we do not currently know of genetic limitations that would prevent macro-evolution from happening.


Nor do we have any evidence that macro-evolution could happen either (or has happened).

#43 JayShel

JayShel

    Former Atheist

  • Moderator Team
  • PipPipPip
  • 777 posts
  • Gender:Male
  • Location:Florida
  • Age: 36
  • Christian
  • Creationist
  • Saved July 12, 2007

Posted 04 February 2012 - 08:18 AM

Study researchers observed that both living organisms and computer programs that copy and transmit coded information have built-in error detection and error correction systems. These systems are required to maintain the information's integrity, which would otherwise be eroded by constantly accumulating random mutations.

The coded information, organized in small sets called "bytes" in binary computer code and "codons" in the DNA of living organisms, is able to tolerate some mutations. But the study's authors show that these mutations must occur within the boundaries of the error-correction systems or the whole program—or whole organism—will be irreparably harmed.
[...]
The dilemma this poses for naturalistic origins hypotheses is that big-picture evolution requires various genetic alterations, such as certain mutations and the wholesale addition of new information-rich sequences. But for the most part, mutation repair mechanisms guard against these very changes! So, in order for evolution to proceed, mutation protection has to be put on hold. And without mutation detection, errors quickly build up and wreck the system—hence the mutation protection paradox.
Coded information in living things gives the full appearance of being purposefully programmed to resist just the kinds of DNA alterations that would harm organisms. Unfortunately for evolution, these are also just the kinds of DNA changes that would be required to turn microbes into man. Evolutionists have yet to find any realistic resolution to this problem, but for creationists it is no paradox at all. Instead, it is another cellular signature from the Creator.
[Read More]


So a mutation is not automatically "kept" (selected for and spread to the population as a whole) when it is beneficial or neutral to the survivability and reproduction of the organism, but it must be critical to survival and reproduction, and also pass an error checker. Such bureaucracy!

#44 aelyn

aelyn

    Member

  • Veteran Member
  • PipPipPip
  • 383 posts
  • Age: 30
  • no affiliation
  • Atheist
  • Denver, Colorado

Posted 16 February 2012 - 06:29 AM

I don't really see what the problem is there. The error-correcting mechanisms aren't perfect, we know mutations do happen. As to why those error-correcting mechanisms are there in the first place, a replicator that replicates with fewer errors will usually end up with more copies than a replicator that replicates with more errors. Mostly because large errors are more likely to result in offspring that can't replicate than small errors are. So evolution will privilege replicators with low error rates, at least up to the point the error rates are so low it doesn't make that much of a different any more whether you have on mutation per billion base pairs or per hundred million.

In fact once reproduction is that faithful there can be advantages to either (slightly) higher or (slightly) lower error rates; the former are more risky but allow one to change faster, and maybe "jump" out of local maxima, while the latter are more efficient and allow one to "home in" on the optimum more precisely. That's speaking as a programmer tweaking an evolutionary algorithm; biological evolution doesn't have such foresight. But IIRC there are bacteria who change their mutation rate depending on the environment : they have higher rates of mutation when stressed. And even among eukaryotes you have some species that alternate between S@xual and asexual reproduction, also depending on how stressful their environment is.

I'm not sure what the author of the article is saying; they either seem to assume that the error-checking mechanism doesn't allow any errors at all (it does), or that evolution requires huge mutations in a single generation (it doesn't).

So a mutation is not automatically "kept" (selected for and spread to the population as a whole) when it is beneficial or neutral to the survivability and reproduction of the organism, but it must be critical to survival and reproduction, and also pass an error checker. Such bureaucracy!

Would you mind explaining a bit ? I'm afraid I don't understand that sentence.

#45 JayShel

JayShel

    Former Atheist

  • Moderator Team
  • PipPipPip
  • 777 posts
  • Gender:Male
  • Location:Florida
  • Age: 36
  • Christian
  • Creationist
  • Saved July 12, 2007

Posted 17 February 2012 - 05:39 PM

I don't really see what the problem is there. The error-correcting mechanisms aren't perfect, we know mutations do happen. As to why those error-correcting mechanisms are there in the first place, a replicator that replicates with fewer errors will usually end up with more copies than a replicator that replicates with more errors. Mostly because large errors are more likely to result in offspring that can't replicate than small errors are. So evolution will privilege replicators with low error rates, at least up to the point the error rates are so low it doesn't make that much of a different any more whether you have on mutation per billion base pairs or per hundred million.

In fact once reproduction is that faithful there can be advantages to either (slightly) higher or (slightly) lower error rates; the former are more risky but allow one to change faster, and maybe "jump" out of local maxima, while the latter are more efficient and allow one to "home in" on the optimum more precisely. That's speaking as a programmer tweaking an evolutionary algorithm; biological evolution doesn't have such foresight. But IIRC there are bacteria who change their mutation rate depending on the environment : they have higher rates of mutation when stressed. And even among eukaryotes you have some species that alternate between S@xual and asexual reproduction, also depending on how stressful their environment is.

I'm not sure what the author of the article is saying; they either seem to assume that the error-checking mechanism doesn't allow any errors at all (it does), or that evolution requires huge mutations in a single generation (it doesn't).


Would you mind explaining a bit ? I'm afraid I don't understand that sentence.


I think this article was more of an argument for the idea that since the genetic code is complex, requires translation, and has a built in error checker, so it implies an intelligent designer. Other codes this complex have always came from intelligent beings (humans). I misunderstood the context of this article. My mistake.

Macro evolution does not require huge mutations, it requires large amounts of mutations that add traits, and add structures (in addition to altering current traits and possibly deleting some which is micro-evolution and devolution) etc without harming the organisms ability to achieve reproduction. Fixation would require that the overall traits of the organism are critical to the organisms surviving to achieve reproduction. I don't see a specific genetic barrier yet, I have not seen an observed example of such a mutation. I am still looking into this subject.

#46 aelyn

aelyn

    Member

  • Veteran Member
  • PipPipPip
  • 383 posts
  • Age: 30
  • no affiliation
  • Atheist
  • Denver, Colorado

Posted 17 February 2012 - 06:03 PM

I think this article was more of an argument for the idea that since the genetic code is complex, requires translation, and has a built in error checker, so it implies an intelligent designer. Other codes this complex have always came from intelligent beings (humans). I misunderstood the context of this article. My mistake.

I didn't actually read the article that much, I was mostly working from your account and quote of it; it's just as possible the misunderstanding is on my side ;)

Macro evolution does not require huge mutations, it requires large amounts of mutations that add traits, and add structures (in addition to altering current traits and possibly deleting some which is micro-evolution and devolution) etc without harming the organisms ability to achieve reproduction. Fixation would require that the overall traits of the organism are critical to the organisms surviving to achieve reproduction. I don't see a specific genetic barrier yet, I have not seen an observed example of such a mutation.

There are mutations that add structures wholesale (often mutations to quite high-level genes that result in additional fingers, legs instead of eyes, things like that), but those very big mutations don't have a very important role in evolution because in general big changes are way more likely to be detrimental than anything else and get culled out immediately. You yourself seem to agree with this when you say macro evolution requires large amounts of mutations instead of huge mutations, so I'm not sure what you mean when you talk about observed examples of "such a mutation".
Fixation however doesn't require a trait to be critical to organisms; indeed given enough time even neutral traits will achieve fixation. Even detrimental traits can achieve fixation, it's just less likely (although it's more easy to achieve fixation in small populations, which is why the founder effect can also work with detrimental traits... see some islanders who have terribly high rates of Huntington's disease. IIRC, which I might not...). It's a simple consequence of random walks. Given a number of alleles, the frequencies of all those alleles will fluctuate randomly over time... except that as soon as one of them gets to 100% the game is over. And one WILL cross the 100% mark eventually, because random walks eventually reach every value.
In practice new alleles are constantly being introduced because mutations occur all the time. But fixation does NOT require a trait to be critical... or even beneficial ! Being beneficial merely increases the odds.

#47 JayShel

JayShel

    Former Atheist

  • Moderator Team
  • PipPipPip
  • 777 posts
  • Gender:Male
  • Location:Florida
  • Age: 36
  • Christian
  • Creationist
  • Saved July 12, 2007

Posted 17 February 2012 - 06:44 PM

I didn't actually read the article that much, I was mostly working from your account and quote of it; it's just as possible the misunderstanding is on my side ;)


There are mutations that add structures wholesale (often mutations to quite high-level genes that result in additional fingers, legs instead of eyes, things like that), but those very big mutations don't have a very important role in evolution because in general big changes are way more likely to be detrimental than anything else and get culled out immediately. You yourself seem to agree with this when you say macro evolution requires large amounts of mutations instead of huge mutations, so I'm not sure what you mean when you talk about observed examples of "such a mutation".
Fixation however doesn't require a trait to be critical to organisms; indeed given enough time even neutral traits will achieve fixation. Even detrimental traits can achieve fixation, it's just less likely (although it's more easy to achieve fixation in small populations, which is why the founder effect can also work with detrimental traits... see some islanders who have terribly high rates of Huntington's disease. IIRC, which I might not...). It's a simple consequence of random walks. Given a number of alleles, the frequencies of all those alleles will fluctuate randomly over time... except that as soon as one of them gets to 100% the game is over. And one WILL cross the 100% mark eventually, because random walks eventually reach every value.
In practice new alleles are constantly being introduced because mutations occur all the time. But fixation does NOT require a trait to be critical... or even beneficial ! Being beneficial merely increases the odds.


I take fixation to be the spreading of a trait to the entire population. This does require the overall traits of an organism to be critical to reproduction and other traits to fail critically, otherwise the organisms without the trait would not disappear.

The key in my understanding is mutations that add traits and structures that were not previously present within the organism. I understand that if there is a common ancestor to all life as evolution requires, it would take many of these information and structure changing, altering, increasing, and decreasing. We have seen decreasing (devolution) and changing and altering of traits (micro-evolution) but I don't see information and structure increasing mutations. You say that when we observe mutations that add structures wholesale, they are often weeded out, so there still needs to be mutations that add information (new structures and traits). These are the mutations that I have yet to see.

#48 aelyn

aelyn

    Member

  • Veteran Member
  • PipPipPip
  • 383 posts
  • Age: 30
  • no affiliation
  • Atheist
  • Denver, Colorado

Posted 18 February 2012 - 10:58 AM

I take fixation to be the spreading of a trait to the entire population. This does require the overall traits of an organism to be critical to reproduction and other traits to fail critically, otherwise the organisms without the trait would not disappear.

That is indeed what fixation means, and it doesn't require a trait to be critical, or even beneficial, or even neutral... Unless by "critical" you mean that the trait doesn't make reproduction impossible; of course traits that are that deleterious can't reach fixation because they can't spread at all.
If I may, have you studied some statistics ? I could try and explain the maths behind that conclusion but I'd need to know where to start... For example, the explanation would be very different depending on whether or not you've heard of random walks.

The key in my understanding is mutations that add traits and structures that were not previously present within the organism. I understand that if there is a common ancestor to all life as evolution requires, it would take many of these information and structure changing, altering, increasing, and decreasing. We have seen decreasing (devolution) and changing and altering of traits (micro-evolution) but I don't see information and structure increasing mutations.

The problem is having a consistent definition of those terms though. Never mind "information", what do you mean by "altering" vs "decreasing" or "increasing" ? I would expect "altering" to cover all of those things. In particular, I'm curious as to which examples of traits decreasing you're thinking of, and why you're separating them from the examples of traits altering ?

#49 JayShel

JayShel

    Former Atheist

  • Moderator Team
  • PipPipPip
  • 777 posts
  • Gender:Male
  • Location:Florida
  • Age: 36
  • Christian
  • Creationist
  • Saved July 12, 2007

Posted 18 February 2012 - 01:21 PM

That is indeed what fixation means, and it doesn't require a trait to be critical, or even beneficial, or even neutral... Unless by "critical" you mean that the trait doesn't make reproduction impossible; of course traits that are that deleterious can't reach fixation because they can't spread at all.
If I may, have you studied some statistics ? I could try and explain the maths behind that conclusion but I'd need to know where to start... For example, the explanation would be very different depending on whether or not you've heard of random walks.


I am not just talking about one trait, because ALL of the organisms traits must be critical (one gene can affect multiple traits) and sometimes there are multiple mutations, especially between generations of non-criticality. If there is no criticality for an organisms whole set of traits in order for them to reproduce ie, without them the organisms would not be able to survive in the environment, then there is no reason for only that organism with the traits to be selected and replace the rest of the population.

I think I have a basic/decent understanding of statistics as far as mathematical formulas. It's hard to say, its been awhile since I took a statistics course.


The problem is having a consistent definition of those terms though. Never mind "information", what do you mean by "altering" vs "decreasing" or "increasing" ? I would expect "altering" to cover all of those things. In particular, I'm curious as to which examples of traits decreasing you're thinking of, and why you're separating them from the examples of traits altering ?


Altering a trait, for example, a mutation that causes purple eyes would modify an existing trait. Decreasing would be fixation, variety of traits disappears in favor of one trait, so if there were only brown eyes possible throughout an entire population. Increasing would be adding a structure or chemical process to the eye as the starting point of changing the way it works as a whole. As for why I separate them, its because they are separate concepts.

#50 aelyn

aelyn

    Member

  • Veteran Member
  • PipPipPip
  • 383 posts
  • Age: 30
  • no affiliation
  • Atheist
  • Denver, Colorado

Posted 20 February 2012 - 05:53 PM

I am not just talking about one trait, because ALL of the organisms traits must be critical (one gene can affect multiple traits) and sometimes there are multiple mutations, especially between generations of non-criticality. If there is no criticality for an organisms whole set of traits in order for them to reproduce ie, without them the organisms would not be able to survive in the environment, then there is no reason for only that organism with the traits to be selected and replace the rest of the population.

I don't think making it about all traits instead of one changes the situation. Either way, fixation doesn't even need a trait to be beneficial for it to happen. It's a probabilistic process, being beneficial merely helps. Am I right by the way that when you say traits need to be critical, you mean that no trait is superfluous, nor could be replaced by a slightly different version of itself without impairing functionality ? In other words, that traits or sets of traits that are merely slight improvements or neutral variations on what the other organisms have, couldn't become fixed ?

Basically, say you have a population with several alleles of one gene. There are no mutations, the population is perfectly mixed, and the probability of an individual passing their allele on to their offspring depends on the allele and nothing else. Say all the alleles are neutral, to simplify. Each individual with an allele will have one offspring with that allele, or none, or ten... with a certain probability. Since it's all neutral we can say it's a bell curve. So say the population contains N individuals with the allele, the next generation will contain a number which is likely a bit above or a bit below or at N, or further with a lower probability. Basically how common the allele is in the next generation depends only on how common it is in this generation.
When you do this generation after generation you get what Wikipedia tells me is a Gaussian random walk, which is a Markov chain, a series of random numbers with each one depending on the previous one only. (The random walk is called that way because it's based on the concept of a drunk person trying to make their way along a wall). Those things have specific mathematical properties, which includes the fact that given infinite time they cross every point an infinite number of times. i.e. given enough time the odds of them reaching any point is goes to 1.
But the thing is, once an allele reaches 0% it's done; obviously it can't get passed on if no individual has it. Same thing once it reaches 100% : that means all the other alleles are at 0% so the allele stays at 100% forever; it's been fixed. And given the conditions I gave, one allele will always eventually reach fixation.
These are all neutral alleles, remember.
One can also calculate the probability that an allele will reach fixation (basically it's its frequency in the population) and how long it will take on average for an allele to reach fixation or extinction (and here I refer you to Wikipedia: ) (it's proportional to the population size)
http://en.wikipedia....ixation_or_loss

Now in real life there are tons of conditions that make fixation not always happen - for example in a sufficiently large population it can take such a long time it can be ignored (although beneficial mutations are more likely to fix sooner, so there's that), there's always mutation introducing diversity, if the population isn't well-mixed different alleles can subsist in different sub-populations, you can have different selection pressures that make the odds of an allele passing on to the next generation change depending on the place, the time, the other alleles in the population, or even that allele's own frequency (in particular if it's an allele that becomes deleterious if it's very common and beneficial if it's really rare, like immunity-related alleles, it's unlikely to ever go extinct or be fixed).

None of those things however require an allele, or collection of alleles, to be "critical", as in the organisms would die without that version. The more strongly beneficial something is the more likely it is to be fixed and the faster it will be fixed, to be sure, but it's all probabilistic. The probability doesn't need to be "1" for something to happen.

Altering a trait, for example, a mutation that causes purple eyes would modify an existing trait. Decreasing would be fixation, variety of traits disappears in favor of one trait, so if there were only brown eyes possible throughout an entire population. Increasing would be adding a structure or chemical process to the eye as the starting point of changing the way it works as a whole. As for why I separate them, its because they are separate concepts.

It's a good thing I asked because I never would have guessed that was what you meant by those words, thanks for the explanation. IIRC (and I may very well not, it was months ago) we pretty much went over all that already in the previous pages so I'll leave it there.

#51 gilbo12345

gilbo12345

    Veteran Member

  • Veteran Member
  • PipPipPipPipPip
  • 7,000 posts
  • Gender:Male
  • Interests:Completed BBiotech (Honours)

    Currently studying Masters of Teaching.

    Enjoys games of tactics and strategy.
  • Age: 25
  • (private)
  • Creationist
  • Australia

Posted 22 February 2012 - 07:42 AM

... wikipedia isn't that scientific... Just sayin'

#52 aelyn

aelyn

    Member

  • Veteran Member
  • PipPipPip
  • 383 posts
  • Age: 30
  • no affiliation
  • Atheist
  • Denver, Colorado

Posted 22 February 2012 - 08:41 AM

... wikipedia isn't that scientific... Just sayin'

Wikipedia is what it is. It has many flaws, but for knowing the basics of something it's absolutely adequate, and if one wants to find out more it has usually has links to the relevant primary literature. I specify when I look something up in Wikipedia so that others know where I got the information so they can check it for themselves. If you have doubts on anything look it up, check that the information is well-sourced and consistent with other authorities on the topic. Taking something as gospel for no other reason than it being on Wikipedia is foolish, but dismissing it for the same reason is just as ridiculous.

#53 gilbo12345

gilbo12345

    Veteran Member

  • Veteran Member
  • PipPipPipPipPip
  • 7,000 posts
  • Gender:Male
  • Interests:Completed BBiotech (Honours)

    Currently studying Masters of Teaching.

    Enjoys games of tactics and strategy.
  • Age: 25
  • (private)
  • Creationist
  • Australia

Posted 22 February 2012 - 09:36 AM

Wikipedia is what it is. It has many flaws, but for knowing the basics of something it's absolutely adequate, and if one wants to find out more it has usually has links to the relevant primary literature. I specify when I look something up in Wikipedia so that others know where I got the information so they can check it for themselves. If you have doubts on anything look it up, check that the information is well-sourced and consistent with other authorities on the topic. Taking something as gospel for no other reason than it being on Wikipedia is foolish, but dismissing it for the same reason is just as ridiculous.


Of course and I use it as a base for my science studies for the basics.. However I have noticed in terms of evolution and such that it generally is very biased towards evolution, (but so is many sites on the internet, each site has their own agenda either for or against evolution or other stuff)

I've seen the age of the fossil bird Confuciusornus change from approx 150 million years to approx 120 million years... Perhaps because Archeopteryx also existed at 150 million years... this is my assumption so isn't that credible.

#54 aelyn

aelyn

    Member

  • Veteran Member
  • PipPipPip
  • 383 posts
  • Age: 30
  • no affiliation
  • Atheist
  • Denver, Colorado

Posted 22 February 2012 - 11:39 AM

Of course and I use it as a base for my science studies for the basics.. However I have noticed in terms of evolution and such that it generally is very biased towards evolution, (but so is many sites on the internet, each site has their own agenda either for or against evolution or other stuff)

I've seen the age of the fossil bird Confuciusornus change from approx 150 million years to approx 120 million years... Perhaps because Archeopteryx also existed at 150 million years... this is my assumption so isn't that credible.

On scientific topics Wikipedia has a bias towards the scientific consensus. That does make it a good source for information on what the scientific consensus is, which is what I usually use it as.
It is a bit less good on cutting-edge science; it isn't that it doesn't get updated fast, it does, but if there are many pages relating to a topic they won't all get updated at the same time or in the same way when a new discovery is made. Active fields of paleontology are a good example of this. With the all the maniraptoran fossils being found in China all the time these days the different Wikipedia pages on the subject sometimes contradict each other on details, with some having the latest news and others not having been updated yet, or conversely some including unconfirmed new discoveries while on other pages the editors wait to see how things pan out first.
Even in those cases it's still a very good resource, it's just better to cross-check between different pages and look at the sources to see what's what.

As for the age of Confuciusornis in particular it could have been initial disagreements about its age although I've never heard of any, or it could simply be a mistake that got corrected. But I have no clue what that has to do with Archaeopteryx. You can disagree with paleontologists' dating techniques but those techniques aren't arbitrary, and they don't give paleontologists leeway push the date up or down by 20% on a whim.

#55 gilbo12345

gilbo12345

    Veteran Member

  • Veteran Member
  • PipPipPipPipPip
  • 7,000 posts
  • Gender:Male
  • Interests:Completed BBiotech (Honours)

    Currently studying Masters of Teaching.

    Enjoys games of tactics and strategy.
  • Age: 25
  • (private)
  • Creationist
  • Australia

Posted 22 February 2012 - 05:45 PM

On scientific topics Wikipedia has a bias towards the scientific consensus. That does make it a good source for information on what the scientific consensus is, which is what I usually use it as.
It is a bit less good on cutting-edge science; it isn't that it doesn't get updated fast, it does, but if there are many pages relating to a topic they won't all get updated at the same time or in the same way when a new discovery is made. Active fields of paleontology are a good example of this. With the all the maniraptoran fossils being found in China all the time these days the different Wikipedia pages on the subject sometimes contradict each other on details, with some having the latest news and others not having been updated yet, or conversely some including unconfirmed new discoveries while on other pages the editors wait to see how things pan out first.
Even in those cases it's still a very good resource, it's just better to cross-check between different pages and look at the sources to see what's what.

As for the age of Confuciusornis in particular it could have been initial disagreements about its age although I've never heard of any, or it could simply be a mistake that got corrected. But I have no clue what that has to do with Archaeopteryx. You can disagree with paleontologists' dating techniques but those techniques aren't arbitrary, and they don't give paleontologists leeway push the date up or down by 20% on a whim.


At the time I saw it changed, a few days prior we had evos on here attempting to claim that archeopteryx evolved into confuciusornus (or are part of a progression of bird like states, you get what I mean). I'm not saying that the discussion here directly caused the change but it does seem abit fishy when people claim they are part of a link and then the dates change so hypothetically they could fit into the link... (rather than living in the same time period).

#56 aelyn

aelyn

    Member

  • Veteran Member
  • PipPipPip
  • 383 posts
  • Age: 30
  • no affiliation
  • Atheist
  • Denver, Colorado

Posted 23 February 2012 - 07:32 AM

At the time I saw it changed, a few days prior we had evos on here attempting to claim that archeopteryx evolved into confuciusornus (or are part of a progression of bird like states, you get what I mean). I'm not saying that the discussion here directly caused the change but it does seem abit fishy when people claim they are part of a link and then the dates change so hypothetically they could fit into the link... (rather than living in the same time period).

You're "not saying" anything but it "seems a bit fishy", okay...
Actually I don't really get what you mean, because one species evolving into another and two species being part of a progression of X-like states are two very different things. The first is one paleontologists almost never say, especially for such ancient fossils; the closest they'll come to might be "this species probably evolved from ancestors very much like that other species". But the main thing is according to the theory of evolution two species can absolutely be "parts of a progression of X-like states" while living at the same time. Different lineages can go in different directions, and there is no set date on when a lineage must go extinct. So if Confuciusornis was 150 million years old, all that would mean is that birds evolved a lot earlier than was thought and Archaeopteryx is a primitive form that survived longer than the others, instead of one of the earliest bird-like dinosaurs known. There would be no reason to change the dates over this, and even less reason to change the dates because random people on the internet claim a direct ancestor-descendant relationship that paleontologists wouldn't endorse in the first place.

As it happens digging a little deeper I've found out that the Yixian formation where Confuciusornis and many of the other Chinese bird and dinosaur fossils were found was originally dated at around 145 million years and was later found out to be much younger, putting it at the current age of 125 million or so years. That sounds like what you're talking about, but the paper I've seen talking about this is from 1999, over ten years ago... Wikipedia didn't even exist then. (... according to Wikipedia at least :P )
Also, to believe the paper in question (http://www.nature.co...l/400058a0.html, "Cretaceous age for the feathered dinosaurs of Liaoning, China", I can send it to anyone who's interested), the previous age estimations for the formation were based on comparisons with other loosely-dated sites and evaluating the flora and fauna, i.e. they weren't that reliable in the first place and there was some controversy on what the actual date was... which I'll guess this paper helped resolve.

Any "fishiness" that happened occurred some time before that date-change on Wikipedia, which was likely either a typo or a mistake from someone who had outdated information.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users