Saturday, November 14, 2015

Which animals have barely evolved according to National Geographic?

Liz Langley of National Geographic has posted an article on their website: Which Animals Have Barely Evolved?.

The answers are the platypus and the opossum. The overall impression she conveys to the general public is that these species have not evolved for millions and millions of years.

I don't agree. I think it's important to teach the general public that such statements flatly contradict modern evolutionary theory. If, in fact, we discovered modern species that showed no signs of having evolved for millions of years, this would refute modern evolutionary theory.

The accepted minimal definition of evolution is ... [What Is Evolution?]
Evolution is a process that results in heritable changes in a population spread over many generations.
... or something similar like "change in the frequency of alleles in a population."

The main accepted mechanisms of evolution are natural selection and random genetic drift.

The only way positive natural selection1 can stop is if an organism is so perfectly adapted to its current environment (external and internal) that every possible mutation is either deleterious or neutral. That includes all metabolic processes and every structure in the cell.

Nobody could rationally advocate such a claim.

The only way to stop random genetic drift is if there's no such thing as a new neutral or nearly neutral mutation and all such variation in the population has been eliminated.

No evolutionary biologist could possibly make such a claim with a straight face.

It's easy to test such ridiculous claims by looking at the genomes of the opossum and the platypus. The evidence shows that they have evolved at the same rate as all other species.

The article actually mentions this problem ...
“'Unchanged' is a tricky word,” Nizar Ibrahim, a paleontologist at the University of Chicago and 2014 National Geographic Explorer, says via email.

With only fossils to go by, scientists can examine an ancient animal's skeletal structure, but it's not the whole story. Physiology and DNA change somewhat over time, he says, both through the basic process of evolution as well as random genetic changes.

That said, two mammals that have undergone the fewest evolutionary shifts are the platypus and the opossum, says Samantha Hopkins, associate professor of geology at the University of Oregon.
Liz Langley did not pick up on this comment so she missed a wonderful teaching moment.

It's possible that Liz Langley isn't aware of modern evolutionary theory and that she actually believes that evolution comes to a halt as long as species live in a relatively constant environment. It's possible that she disagrees with the minimal definition of evolution and prefers a definition that only counts significant changes in external phenotype. Or, it's possible that she thinks that National Geographic readers can't handle modern evolutionary theory. If it's the latter, I disagree.


1. You can't stop negative natural selection unless there are no new deleterious mutations. That's also impossible.

60 comments :

  1. The accepted [but somewhat less than] minimal definition of evolution [because it doesn't cover macroevolutionary processes]...

    Even if we take only gross skeletal morphology as the only relevant data (as this article seems to have done), how is a platypus the most conservative? There are a few fossil platypodes, and they don't look that much like modern ones. Is it just that they're monotremes? But that focuses on a few anatomical details (most of them not even skeletal) in which monotremes are primitive and ignores all the platypus's bizarre derived characters. It's a smug, eutherian bias. And don't get started on their sex chromosomes.

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    1. And, to them, animals = mammals, I suppose? (They don't mention crocodiles, coelacanths, horseshoe crabs, nautiluses, dragonflies, sponges, etc.)

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    2. animals. One little offshoot of a eukaryotic lineage that ignores that vast majority of diversity, but does include us so I guess that makes it ok.

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  2. Professer Moran might be making a creationist point here.
    He stresses how unlikely milllions of years can go by without internal/external evolution process.
    AMEN. Yet most creatures look like they did ten million years ago. Horses/Rhinos and many others found in fossils in North america are almost identical to modern ones.A wee bit different but this wee makes the case for the lack of evolution.
    THIS is why everyone, nat geo, seens no evolution going on in creaturs that look almost the same after tens/hundreds of millions of years. Not my timeline eh!

    I never really hear evolutionist thinkers stress how evolution must always be happening especially over great periods in a constant constant way however small steps along that way?!

    its funny Samantha Hopkins says platypus has not changed and she knows because she is a GEOLOGY professer.
    Geology is not biology I insist.
    It is all based on deposition evidence and not real biology evidence.
    Thats why the impressions of change/non change happen.
    The platypus is no different then anyone else.
    it just survives because australia was cut off from more migrations of creatures at some point.
    I suspect they still want to say its a in between reptiles and mammals. its not.
    Just has traits as needed.
    MAYBE this nat geo thing is because of the attention modrn creationism gives stasis creatures relative to the fossil record.
    I note creationism is on their minds so much these days and they need to answer why non evolving creatures fits wITHIN evolutionary biology.
    I suspect this is the motivation and saying they really did evolve is not helping them.

    By the by. Humans have parts that have not evolved. our eyes and everything must of been with us already long ago since there is only slight difference from creatures.
    Has our eyes been evolving since separating from our fish/furry creature/early, late primate STAGE??
    Have we evolved internally(immune system) since the forks in the road at any stage?
    How does this work?

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    1. Robert,

      I've been very tolerant of your comments over the past few weeks but my patience is wearing thin.

      If you don't have anything constructive to say then please don't say anything at all. I don't object to your criticisms but they must be reasonable.

      I'm going to start deleting any of your comments that look like the one above and any that are off topic.

      Delete
    2. Byers, Don't you remember a few weeks ago when you said, over and over again, dozens of times, and very loudly on the Panda's Thumb that geology can't be used as evidence for evolution (I think your exact words were closer to "geo is not evo evidence," but that is all anyone could deduce that you meant)? But here, you use geology to make evolutionary--or counter-evolutionary--arguments. So which is it?

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    3. Feo is not bio evidence for evolution.
      What I say makes sense if one pays careful attention.
      These timelines for the fossils are not creationist ones.
      Yet one can cross examine the witness for the other side using theiur own words/concepts.

      SO in this case they are saying millions of years equals plenty of bio change as the process must be ongoing always and all that time must of made results.
      So i bring up their own fossil dates and say look at these fossils which are millions of years old BUT look like modern creatures almost completly.
      So questioning the concept that mill;ions of years demands great changes in biology due to evolution.
      THEN this lack of change disproves a particular point of evolution predictions.
      I'm only using their own claims of evidence AGAINST them. There is data info from fossils but no process info. In fact without the geology claims for when the fossils were deposited there is no biology evidence for evolution by fossils as they need the time.
      if the fossils don't show evolution EXCEPT by when they were deposited THEN they don't show in themselves biological evidence for evolution.
      In these points I think I have good points.
      People don't understand it I think.

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  3. Robert,

    I just want to say it seems you misunderstand in this case. A species may remain virtually unchanged for a very long time if we look only at the outward appearance, its physignomy. But when we study its genome, its DNA, the proteins and all such things, we discover that they have changed, they are not identical to their great-great-great... parents!

    That is because mutations do happen, all the time! Just keep that in mind: Mutations are a fact of life. There already are plenty of mutations in your own body since you were born! Your DNA today is not the same as when you were born.

    That are uncontroversial facts that you have to live with. It is bad luck when a person happen to suffer a mutation somewhere in his body when a body cell mutates into a cancer cell. You know what that means, don't you?

    All cells in the body are susceptible to mutations, cosmic radiation and a lot of other things may cause mutations.

    There is something called point mutations. They happen all the time, meaning that our genome is subject to "degradation" in the sense that it is subject to a constant, gradual change.

    When that happens to egg or sperm cells, we have got a heritable mutation. With luck (most of the time) it is harmless, but sometimes it is not: Downs Syndrome is but one of many examples.

    But point mutations accumulate over time such that over millions of years, the genome becomes significantly different from the original. The DNA codes are not the same, the proteins are different, but if the creature in question has been living in a stable environment it may still look the same, because there was no need to adapt as long as the habitat, its living conditions remained stable.

    There are many examples of that, Cockroaches, or the Coelecant. Today's coelecanths look like their forebears millions of years ago, and yet the genomes are different. Since much of the genome consist of non-coding genes, that means there is is much in the genome that may change without discernible effects.

    Easy to understand, isn't it?

    Sincerely, Robert, just thinking - like you claim you are doing alle the time, isn't enough! You need to learn the facts, you can't puul facts out yourself: You cannot create facts in your mind, what you are doing is akin to 'wishful thinking'. Do you think Einstein and other great scientist would get anywhere, thinking in the manner that you do?

    Clear thinking starts with taking hold of the facts. Conjecture from prejudice or ignorance leads to nonsense, a method of which you are a prime example.

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    1. I know this information. They always say it.
      I'm not sure how sure they are about the genes of creatures found in fossils said to be millions of years old.
      Anyways. The whole thread was about how evolution must be going on always and so millions of years must of made a difference.
      OKAY. I do see outward looks as the point of evolution. We can't see inside of fossils but likely its the same as they are now for creatures in a linegae.
      I know they are perfect matches in looks. Horses/Rhinos etc found in famous ash fosilized grounds out west.
      If its being said here evolution has gone on greatly but only affects the genes without bringing changes, or very much, to creatures over millions of yeas then i might of missed a point.
      Hmmm. Then the point would also be all creatures, including ourselves, have been in stasis for millions of years. Only less then the famous cockroaches/fish etc.
      That means the nat geo article was right if they were just addressing practical evolutionary changes. The fact of inner genetic evolution is almost irrelevant to their case. They meant about looks.
      I think your side should stress not evolution has been going on greatly over millions of years for some lineage but that it doesn;t bring evolutiuon of body parts easily at all but only in more genetic ways.
      Fossils from ten millions of years ago, their geology, are dead on look alikes for most creatures today. There has been no body evolution relative to the time.
      In fact thats the origin of PE concepts. Or it forced those concepts.
      Are you saying the Nat geo article was wrong as the thread said? Where if so?

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    2. "I know they are perfect matches in looks. Horses/Rhinos etc found in famous ash fosilized grounds out west."

      Have you seen those fossils, Robert? Because I have. I don't know of any horses that have three toes on each foot, do you? The fossil rhinos also lack horns entirely, quite unlike today's rhinos.

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    3. CMJ
      I saw them in nat geo magazine and often on the internet. They have artists that represent them.
      Toes and horns are trivial details and fall within what I said about minor changes.
      yet the horse/rhino etc are otherwise identical to modern.
      Its been a long time, they say millions of years, and so the rate of evolution must be fantastic little. Of coarse they would say PE is going on.
      My point is that millions of years have passed with little to less bio change as indicated in well preserved fossils. So demanding evolution is hardly going on for some..
      are you saying these horse/rhinos have been greatly affected by evolution on thier visable anantomy in the last ten million years?
      many people don't understand how creatures have not changed in these claimed lenghts of time. They focus on roaches and fish but everything today is unchanged for a long time.

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    4. Toes and horns are trivial details

      Indeed, just last week I woke up with two extra toes on each foot and a large horn in the center of my forehead and thought nothing of it. Why, the folks at the office asked if I'd gotten a new haircut, because they thought something might be different but nothing obvious had changed.

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  4. There is good evidence of morphological change among coelocanths. Take a look at these illustrations.

    https://ecologicablog.wordpress.com/2013/08/24/coelacanths-are-not-living-fossils/

    I link to a blog summarizing the article because the research article itself seems to be behind a paywall.

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    1. I suppose to an ID creationist a fish is a fish is a fish. If a lay person compares a primitive sarcopterygian like Miguashaia with Latimeria, they look "almost the same", and differences that would strike a specialist at once (say, no three-lobed tail, dorsal and anal fins with no fleshy stalks in Miguashaia) are easy to ignore if you don't know what to look at. The picture shows no size differences. Adult Miguashaias were up to 45 cm long. The modern coelacanths are almost five times longer (and a hundred times heavier).

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    2. Oops, The fish are shown "not to scale", but Casane and Laurenti give their length in metres. I can hardly believe I didn't see those numbers when I looked at the diagram the first time -- I concentrated on the anatomical details of the fishes. It only shows how selectively we look at things.

      Anyway, the sarcopterygians shown in the diagram range from 10 cm to more than 2 m in length (in addition to less obvious differences). No change at all, no, no, sir.

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  5. National Geo is the mag that published a fake fossil without vetting it. They are not exactly the go to source for science.

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    1. And Rupert Murdoch just cleaned house.... :(

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    2. Yes, they did. And when the fossil was found be made up of two other fossils made to seem like they fit together, National Geographic published that, too. They're not perfect, but they seem to try to do the right thing.

      Or they did, pre-Murdoch.

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  6. Laurence A. Moran: "Evolution is a process that results in heritable changes in a population spread over many generations."

    "descent with modification"; CD

    'Common descent' runs into a brick wall with the falsification of all theories on 'last universal ancestor.'

    How can the theory of evolution be considered anything but pseudoscience, without a single workable hypothesis to support 'last universal ancestor?'

    NASA astrobiologist Chris McKay, 2012; "The scientific study of the origin of life is still early enough that there's not even a consensus on how to approach the problem..."

    One can't remove falsifiability of 'last universal ancestor'; reducing it to pseudoscience.

    As it stands now, the theory of evolution is falsified.

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    1. Go do some research on what is meant by "last universal common ancestor", and how this differs from "origin of life." Come back and let us know what you've learned. Off you go, now!

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    2. While we are at it, ItBeMw could also do some research on what a "paragraph" is and how it is different from a "sentence".

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    3. "...all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed." CD

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    4. ItBeMw, that was more than 150 years ago. Can we return to the 21st century? Do read up on LUCA and why it has little to do with the origin of life.

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    5. "...all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed."

      And even if that was the current hypothesis, that would not represent the LUCA.

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    6. quibble: "to evade the point of an argument by caviling about words"

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    7. ((Origins of life)): Common ancestry put to the test

      Editor's summary

      ((Universal common ancestry)) (UCA), the idea that all terrestrial life is genetically related, from some “warm little pond” as Darwin put it, has become ((central to modern evolutionary theory)).

      http://www.nature.com/nature/journal/v465/n7295/full/465168a.html

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    8. Why did you post that, ItBeMw? To refute your own argument? Your honesty is most admirable. It takes a big man to admit when he is wrong.

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    9. Nobody's quibbling here. LUCA is the most recent common ancestor of all extant life. Since common descent is testable and has been positively tested against the model of multiple ancestry (see Theobald 2011), the existence of a unique LUCA is a reasonable conclusion in the light of current knowledge. But LUCA was not the first living thing on Earth. It was itself the product of earlier evolution, which may have taken tens or hundreds millions of years.

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    10. Worth noting that ItBeMw's link takes you to an earlier article by Theobald that showed much the same thing. ItBeMw linked it so he he could provide the source for the quote mine from the editor's summary in the top right corner.

      That's known as an "own goal."

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    11. Oh, yeah. I didn't even bother to follow it. ItBeMw's one-sentence lines and weird punctuation put me off.

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    12. All living things evolved from a common ancestor
      Origin of life on Earth: Lecture outline No. 18

       The origin of life on earth

       The last common ancestor.

      https://www.utdallas.edu/~cirillo/nats/day18.htm


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    13. The lecture outline ItBeMw links to doesn't clearly differentiate between the origin of life and the last common ancestor of all extant living things. (It's just one lecture in a whole class.) ItBeMw would do well to read Piotr Gąsiorowski's comment above at November 18, 2015 12:01:00 PM. Of course, for it to do any good he'd have to read with comprehension.

      LUCA is well supported. We don't know much about the origin of life (a different concept) but chemists are answering some of the relevant questions. There's no reason (yet?) to think that a natural processes are insufficient to explain what happened.

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    14. "...all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed." CD

      I'm guessing ItBeMw doesn't understand anything about questions concerning the origin of life which primarily involve aspects of chemistry, but rather well imagines there existed some sort of fully formed lifeforms "into which life was first breathed".

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  7. ItBeMw: I don't understand your point at all. You seem to be saying that the LUCA is the same thing as abiogensis, but you keep posting links to sources that point out it isn't. But you want it to be, because you think that if science doesn't exactly understand abiogenesis, then its not true, and if abiogeneis and the LUCA are the same, then the whole of evolution is disproved.

    OK so far. But what I want to ask you is this. Do you really not understand everything in the links you've been posting and that has been explained to you here, and therefor think that abiogenesis and LUCA are the same (and that this presents some sort of problem for science), or if realize that they are not the same (and that they present no problem) and you are just trying to confuse the ignorant?

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  8. "Lecture outline No. 18 ... The origin of life on earth. ... The last common ancestor." University of Texas

    Anebo: "has been explained"

    From the explanations I've gotten so far, I think I'm on a high school blog.

    Is there anybody here that actually knows anything about the theory of evolution, and isn't afraid to discuss it without hiding behind false word quibbling?

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    1. There are two basic problems with your approach so far, problems that make it difficult to take seriously the idea of discussing evolution with you.

      First, you've confused the terms "origin of life" and "last universal common ancestor", which are importantly different, and you dismiss pointing out the problem as "quibbling." That suggests that you don't understand these terms and won't fully understand what you're saying or what we might say to you. If the cause of the problem is ignorance rather than stupidity, you can fix that.

      Second, you don't seem to grasp an important part of the relationship between origin of life issues and the theory of evolution. The fact that evolution occurs is abundantly demonstrated by patterns of variation in extant organisms and fossils, by sequences of fossils, by patterns of genetic variation, by observations of changing modern organisms, and by understanding of how population genetics works, all supported by the findings of geology and even astronomy. Right now, there's no reason to think that life's origin can't be explained well by natural processes. But even if we found out that life was planted on earth by aliens or that some supernatural being started it, evolution would still be true. It certainly wouldn't be "falsified."

      It's likely that you are concerned with very basic questions about whether the origin of life is fully natural, materialistic, or whether a supernatural being is involved. You may have questions about how humans are related to the rest of life. Clarify what's bothering you and figure out what the relevant terms mean, and this exchange of comments with you might become a useful and interesting discussion.

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    2. bwilson295: "origin of life" and "last universal common ancestor"

      You need to document your points, if it's not just pointless quibbling.

      Wikipedia: 'Evolutionary history of life"' -> '(((Origins of life)))' -> "Biologists reason that all living organisms on Earth must share a single (((last universal ancestor)))..."

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    3. Maybe this will help you out, ItBeMw:

      Who are the last (as in most recent) common ancestors between you and your cousin? Your grandparents, right?

      Does that mean your grandparents were the first human beings to ever live?

      The correct answer is "No."

      You could go thru the same process with any other person now living on earth. Go thru each of your family trees, and eventually you'll come to a person that is common to both. That would be the LCA between you and that person.

      You could do the same with any two, or three, or more people. And, in fact, you could do the same with every single person now alive on earth. But the most recent common ancestor of every person on earth would not be the first person who ever existed, In fact, he or she probably existed only a few years ago.

      The same applies to the LUCA of all organisms alive today. That organism would have lived a long time after life first arose on earth

      Hope that helps.

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    4. ItBeMw,

      "You need to document your points, if it's not just pointless quibbling."

      There's no need for documenting something so obvious. If you wanted to understand this would have ended long ago. There's a reason the last universal common ancestor is called "last," rather than "first." It's quite simple. From that it should be easy to understand why the LUCA should not be mistaken for the first life.

      Sure, a lot of journalists and others who write for lay people often put origin of life and last universal common ancestor in a single sentence. That is no excuse for you to refuse to think when something this simple is explained to you. You ask time and again is this is a high school web site. From your comments, and your refusal to pay attention, it would seem like you would be better off at an elementary school one.

      You're too much of an imbecile.

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    5. lutesuite,

      Nicely explained. Let's see how this ItBeMw idiot manages to miss the point again.

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    6. Oh, I realize I was wasting my time with him. But some people seem to be honestly confused on this point (present company excepted, of course) and could benefit from its being clarified.

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    7. Did catch an error, though:

      "...he or she probably existed only a few years ago."

      Should say "...a few thousand years ago."

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  9. The LUCA is an organism from which all life today is descended from. This creature had a relatively modern genetic structure and metabolism. There would have been plenty of other life on earth at the time it existed, some of it perhaps radically different. It was the result of millions or tens of millions of years of evolution from the origin of life which had happened long before. What don't you understand?

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    1. Anebo: "...would have been plenty of other life on earth..."

      Meanwhile, back on the real world...

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    2. Meanwhile, back on the real world...

      Which you quite plainly don't understand, as Anebo is perfectly correct.

      To make it so obvious that you'll have to try even harder to misunderstand, let's draw the parallel to language.

      At some point far back in human society, there were people communicating using language that became the foundation for all human languages spoken today. People had communicated before that point, and there were people communicating at the same time, but their communications did not survive to become the foundation for all that came afterward. And there were branches that came after these people - for example, the people who first communicated using the ancestor of all Indo-European languages, and after that the people who communicated using the ancestor of all Romance languages.

      Or you can use genetics on a more recent and specific scale, tracing homo sapiens back to mitochondrial Eve and Y-chromosomal Adam. Again there were predecessors and contemporaries of each of these, but in the constant nested branching patterns that heredity/evolution makes, those people were at the roots of the branches that led to us.

      It's no different than finding the first of your family's ancestors in America (if, for example, you live in the USA). This couple obviously had parents, so there were certainly family members who had gone before them, and perhaps they had siblings or cousins, so there may have been one or more family members who were their contemporaries. But they were the ones who led to you. Finding the Last Universal Common Ancestor is the same thing, you just have to go back a few billion years. :-)

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  10. ItBeMw

    OK The lUCA was a single individual organism which lived at the time time as billions or trillions of other organisms, millions of years after the origin of life. Can we at least get that clear? I realize you don't believe that. But can you at least accept that that is what scientists say? If you don't understand that, can you say what you think evolutionary proposes instead? It does not propose that the first organism that could be called alive was also the LUCA, if that is what you think.

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  11. We all appreciate your efforts Anebo, but trying to explain that to a YEC is the same as trying to explain advanced calculus to all the guys who call themselves Elvis and are locked up in some mental institution.

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  12. pseudoscience: 'a system of theories, assumptions, and methods erroneously regarded as scientific'

    The theory of evolution stands falsified with the falsification of common descent.

    Common descent is falsified by the falsification of the last common ancestor, sometimes called "last universal ancestor." Darwin called it, "one primordial form."

    The last common ancestor is the ancestor "from which all organisms now living on Earth have a common descent." (Wikipedia, Last universal ancestor)

    The last common ancestor was falsified by "Origin of Life" research; which covers everything that's necessary for, and the appearance of, the last common ancestor.

    NASA: 1. Cosmic evolution of biogenic compounds; 2. Prebiotic evolution; 3. Origin and early evolution of Life.

    The last common ancestor is the first existence, and origin, of all life forms on Earth.

    NASA astrobiologist Chris McKay; "The scientific study of the origin of life is still early enough that there's not even a consensus on how to approach the problem..."

    All the previous theories (prebiotic evolution) on the origin of life, the possibility of the last universal ancestor, have been falsified.

    There's currently not a single workable theory to support the possibility of the appearance of the last universal ancestor.

    The last common ancestor "is thought to have been a small, single-cell organism. It likely had a ring-shaped coil of DNA floating freely within the cell, like modern bacteria." (Wikipedia, Last universal ancestor)

    Currently, there's no know scientific process of how this could be possible. "Steve Benner: We have failed in any continuous way to provide a recipe that gets from the simple molecules that we know were present on early Earth to RNA." (http://m.huffpost.com/us/entry/4374373)

    With no workable theories to support the last common ancestor, and all old theories falsified; the theory of evolution stands FALSIFIED, pseudoscience!

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    1. I demand a minimum level of intelligence on my blog. You don't have to agree with me to post comments. In fact, I prefer commenters who disagree.

      However, you have not met the minimum standard. I do not want this blog to turn into a cesspool like many of the creationists blogs.

      Goodbye.

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    2. NASA astrobiologist Chris McKay; "The scientific study of the origin of life is still early enough that there's not even a consensus on how to approach the problem..." (http://www.astrobio.net/exclusive/4835/the-origin-of-life-challenge-searching-for-how-life-began)

      Last common ancestor has been falsified.

      pseudoscience <> intelligence

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    3. LOL, so now it's back to the flock to claim victory? You have been shown that your arguments are flawed, your reasoning is flawed. You're also not willing to learn or perhaps not capable of learning.
      Clearly you have scored a major victory!

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  13. I assume you are a Christian. I assume you know the difference between John the Baptist and John the beloved disciple. How would you respond to someone who kept excitedly shouting at you every few seconds that he had disproved Christianity because John the Baptist and John the beloved disciple are the same person?

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  14. This exchange did make me wonder about one thing; when was the RNA world? As far as I know, all extant creatures (unless you count some viruses) have DNA carrying their genetic information. And all extant creatures have the same, or almost the same, genetic code. (And there isn't, as far as I know, any logical reason why the code should be exactly the way it is; that is, I've never heard any chemical explanation of why any particular codon should necessarily code for the particular amino acid that it does.)
    So, my question is, doesn't that indicate that the RNA world existed after abiogenesis, but before LUCA?
    If that's true, wouldn't it be pretty strong evidence that LUCA had to have lived a long, long time after the abiogenesis event?

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    1. If that's true, wouldn't it be pretty strong evidence that LUCA had to have lived a long, long time after the abiogenesis event?

      Not just that. Comparative reconstruction shows that -- as Anebo pointed out above -- LUCA had a relatively modern genomic structure. The evolutionary precursors of many of the modern superfamilies of proteins were already encoded in its DNA. Which is hardly surprising, since LUCA is the last common ancestor of Bacteria and Archaea, and anything that is homologous between them and not due to horizontal transfer between domains goes back to LUCA. Some features found in one domain but not the other may be primitive too, though they may be impossible to distinguish from features that arose after the split.

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  15. So, my question is, doesn't that indicate that the RNA world existed after abiogenesis, but before LUCA?
    If that's true, wouldn't it be pretty strong evidence that LUCA had to have lived a long, long time after the abiogenesis event?


    The RNA world is one of the candidates that has been discussed for the abiogenesis event. It or any other abiogenesis event would presumably have occurred quite a while prior to LUCA.

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  16. Getting back on topic:

    Professor Moran says: “If, in fact, we discovered modern species that showed no signs of having evolved for millions of years, this would refute modern evolutionary theory."

    The C. milii genome is the slowest evolving of all known vertebrates and appears not to have changed much at all in the last 420 million years!

    http://www.nature.com/nature/journal/v505/n7482/full/nature12826.html

    Let’s presume the data supporting this claim are valid. How would the exceptionality of this particularly slow molecular clock “flatly contradict modern evolutionary theory”?

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    Replies
    1. Larry has already discussed this. Your claim that it "appears not to have changed much at all in the last 420 million years" is false.

      http://sandwalk.blogspot.ca/2014/01/can-some-genomes-evolve-more-slowly.html

      Delete
    2. Tages Harispex says,

      The C. milii genome is the slowest evolving of all known vertebrates and appears not to have changed much at all in the last 420 million years!

      I have a low tolerance for people who post incorrect information on my blog.

      Clean up your act or go somewhere else where your lies might go unnoticed.

      Delete
  17. @ lutesuite

    Thank you for directing my attention to a previous blog of Professor Moran’s that I was unaware of.

    In my defense, I did phrase my query as a hypothetical. “Let’s presume the data supporting this claim are valid.”

    Professor Moran couched his response in interesting terms:

    “The simplest explanation is that the biochemical mutation rate in elephant sharks is lower than in other species.” [my intended point exactly]

    Professor Moran than continues with: “In other words, DNA replication is more accurate in sharks or repair is more efficient. While we can't rule this out, it doesn't seem very likely.”

    Perhaps. I also suspect that more was being read into my response than I intended. Going back to my hypothetical. The elephant shark still seems a far better candidate for “animals that barely evolved” than either the opossum or the platypus. I think we can agree on this.

    The question then becomes, exactly how slow is the elephant shark clock compared to other vertebrates and what are the theoretical implications for evolutionary theory? Professor Moran states (albeit on opposums and platypus): “The evidence shows that they have evolved at the same rate as ALL [emphasis mine] other species.”

    On this point, I thought would need to disagreed, until I read Joe Felsenstein’s and John Harshman’s excellent observations on the earlier blog post. Professor Moran also concluded with: “Species with larger genomes tend to have larger mutation rates.” That was, in fact, going to be my next point; and I am somewhat vexed that Professor Moran already made it for me. I confess that I remained unclear on Professor Moran’s apparently contradictory insistence on clock uniformity, until I continued to read Professor Moran’s clarifying exchange with Professor Felsenstein.

    @ Professor Moran
    It was a pleasure to read your analysis of the Nature paper on elephant sharks. My compliments. That would explain my lingering lurk-mode. For what it’s worth, at least we have gotten this exchange back on topic. My sincerest apologies if I caused offense.

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