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Mark Frank’s question on common descent and some responses

[cross posted at TSZ A Question for those that doubt Common Descent]

Mark wrote

Recent posts by Sal remind me that there are some intelligent educated people who doubt Common Descent. What I don’t understand what they think the alternative is. Put simply I take Common Descent as the position that :

* At one time there was only very simple unicellular life on earth (this is not a debate about how that unicellular life originated)

* Complex life forms (eukaryotes) are created by slight modifications from other life forms (which are their parents). We have never observed them being created any other way!

* All complex life forms are the descended from a very small number of simple life forms – quite possibly just one.

The alternatives I can imagine are:

* Complex life descended many different times from simple life forms – so e.g. mammals descended from a different simple life form from fish. This flies in the face of the fossil record and the hierarchical nature of complex life but I can sort of understand it.

* Complex life from time to time gives birth to wholly different species – massively implausible.

* Complex life is created anew by some process never imagined or observed – even more implausible but presumably what Young Earth creationists believe.

But maybe there is another option?

If Sal or someone could explain I would be interested.

[My response (and readers can add theirs).]

Take a look at this graph. I personally fall into the CRS (Creation Research Society) members group. Monophyly means those that accept common descent, and polyphyly means those that accept independent lines of descent.


(image by Paul Nelson: http://www.evolutionnews.org/2007/05/_most_people_including003582.html)

From the polyphyletic column we see two varieties of mechanisms for the independent lineages:

1. special creation by some Creator or intelligent designer
2. independent origin of separate lineages by some naturalistic means

Each has its challenges.

One can always invoke a Creator (like God). God is always a sufficient explanation, but is it a necessary one? Further, God as a mechanism isn’t a repeatable mechanism and hence is outside operational science. Some don’t believe God exists or view His existence irrelevant to the evolution of life. Others would believe if they saw God, but will not invoke a creator until they see Him in operation, so they provisionally invoke naturalistic mechanisms. I respect those objections, but those are views I don’t hold…

Surprisingly there are some naturalistic theories that reject common descent that don’t involve God or some Designer. I don’t necessarily endorse these, but I can appreciate that they exist. Notice Woese and Doolittle are put in the category of non-Design and non common-ancestry (polyphyly). In addition to those two we can add Periannan Senapathy. They accept naturalistic mechanisms of independent (rather than common) descent. They believe in some sort of pool and Horizontal Gene Transfer. I don’t know much about Lamark and Haeckel. These naturalistic theories don’t solve the problem of ORFans.

Why do I accept design and polyphyly (essentially special creation) even though I’ve not witnessed God? Life looks designed, therefore a designer seems reasonable. The designs evidence more capability than humans, so much so the designer seems God-like, and God is postulated as a real entity by some physicists: Quantum Enigma of Consciousness and the Identity of the Intelligent Designer.

Thus if the designer is God, is the evidence more in favor of God using an evolutionary mechanism that evolves all life from one simple cell, or an evolutionary mechanism that evolves life from many complex created kinds? If one believes in a Creator, the latter seems more reasonable. Paraphrasing the way Darwin posed the question: “which way did the Creator choose to diversify life, via common descent or special creations?” Darwin left out the third possibility which Blyth and other creationists allowed for, namely the Creator created many created kinds which diversified over time. I hinted at this here: Deorigination of species by means of reunion..

IMHO, the reason some design theorists sometimes criticize common descent is that evidence of special creation is a sufficient but not necessary condition for demonstrating design. That was the line of reasoning I laid out here: Cocktail: Relevance of YEC to ID, and Cocktail: Astrophysics vs Darwinist paleontology, and Cocktail: C14, DNA, Collagen in dinosaurs, and Cocktail: Falsifying Darwinism by Falsifying the geological column.

Intelligent beings do not behave in ways that are always amenable to repeatability, so I can also accept that hypothesis of creation without repeatability of the creation events in real time. There are many uncertainties in all viewpoints. As nice as it would be to actually have all humanity see God in action as the children of Israel supposedly did in the time of Moses, I follow the old saying, “play the cards you are dealt”. To me, the best play on the data we’ve been dealt is to accept design and polyphyly (special creation), but others will obviously disagree.

NOTES:
1. the above graph conflicts with the way I described Denton in my TSZ response, so I defer to Paul Nelson’s categorization of Denton and provisionally retract my description of Denton. Holye (who believed in Extra Terrestrials and is an ID proponent) is sort of a class of his own.

2. Creationists disagree on how much polyphyly there is. That is the topic of Discontinuity systematics and Baraminology. ORFans and hybridization experiments and taxonomy are of keen interest in these disciplines which are intended to resolve how much polyphyly there is.

3. John Davison would probably argue Berg is in the Design category. Speaking of which Davison would put him self in the design and polyphyly category, but invoke far fewer lineages than most creationists (like Berg did).

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23 Responses to Mark Frank’s question on common descent and some responses

  1. 1
    CentralScrutinizer

    “Paraphrasing the way Darwin posed the question: “which way did the Creator choose to diversify life, via common descent or special creations?” Darwin left out the third possibility which Blyth and other creationists allowed for, namely the Creator created many created kinds which diversified over time.”

    All three can be true. It could be that during the evolutionary history the mutations were precisely controlled at critical points, sometimes just a nudge, other time more than a nudge, and at other times left to “the randomness of nature” (whatever that might be) to acheive a sort of “flourish”. God may be both engineer and experimental artist.

  2. 2
    CentralScrutinizer

    …but this is after “evolution” got started in the first place.

    OOL and protein domains are a “whole different question” and strongly point to the “engineering side of God”, if you will.

    IMO

  3. 3
    CentralScrutinizer

    And to tell ya the truth, I kind of expect for the natural history of life to be “weird”; weird in the sense that, like Quantum Physics, it’s not what we expected.

    God is bizarre…

    …in a good way

  4. If one believes in a Creator, the latter seems more reasonable

    Maybe, where does that leave you when you look at the overwhelming evidence for common descent? With an unreasonable creator?

  5. where does that leave you when you look at the overwhelming evidence for common descent?

    You mean like ORFans, lack of transitionals, lack of believable mechanisms for slow gradual transformations instead of sudden transformations?

    To add to it your supposed narrative of overwhelming evidence is the fact that illegitimate comparisons were advertised to hide the enormity of certain gaps.

    Similarity alone is not a criterion for asserting common descent because even in naturalistic terms we have convergence and HGT.

    I point the reader to the “overwhelming” case you made that humans descended from fish:

    http://www.uncommondescent.com.....e-to-tuna/

  6. Seriously, Sal? You arguments against common descent are (in this post) god wouldn’t’ do it that way and (in the one you link) you personally can’t believe the animals you posted pictures of are related in the way science says they are?

    And something about HGT and convergent evolution (which don’t’ seem the least bit relevant to me).

  7. wd400,

    What is the basis for the claim of common descent except similarity? But similarity doesn’t imply common descent if there is a creator, HGT, and/or convergence.

    The similarity is overwhelming, but that is not the same as common descent.

    If one says, “the only mechanism to similarity is common descent, therefore since there is so much similarity, common descent is true”, then one has resorted to circular reasoning, not science. You can state it as an unproven assumption that you find reasonable and believable, but don’t pretend it’s been proven or that the evidence is overwhelming.

    Creationist Rob Carter put coral genes in fish to make them glow. Does the similarity in genes between the coral and glowing fish imply the Carter’s glowing fish descended from Coral? No! The similarity is evidence of common design, not descent. In theory, Carter could have made the gene from scratch by taking the data of the coral gene and then making the sequence chemically from scratch and then inserting it into the fish. Thus in that case the similarity in the glowing gene cannot in anyway be said to be the result of common descent.

    If similarity is no evidence of common descent in the case of human designer of glowing fish, how much more of a God-like designer for all of life!

    However, if you accept a creator as working hypothesis (as Darwin did in Origin, and I emphasize working hypothesis, not necessarily that he believed it), then there is no reason to insist in common descent a priori. If one supposes a creator, then which way does the data point? The data points to polyphyly not monophyly.

    If one rejects a creator then one can go ahead and invoke common descent, no matter how implausible the mechanism of transition, no matter how conflicted the phylogenies, no matter how forced fit the data have to be in order to make the narrative, no matter how at variance it is to the fossil record, and possibly no matter how at variance it is to the possibility the fossil record is recent….

    The eye of the octopus is similar to the human eye. Would you then argue because of the similarity, humans descended from octopus?

    So humans have more similarity to some animals than others, does that necessarily mean the two have a common ancestor? On what grounds do you make that insistence especially if their DNA are only 70% similar? They are 70% similar in percentage terms which we can say is overwhelming, but in absolute numbers of nucleotides required to effect the change, possibly close to half a gigabase (3.5 gigabases multiplied by 30% divided by 2) we can say they are sufficiently different to preclude evolution.

    If we assume a creator, one way to identify an independent lineage is ORFans and hybridization and taxonomy. If one rejects a creator, then one is pretty much caged into common descent no matter how the absent the mechanisms are for common descent to be a reality.

    One should not make the argument “similarity can be explained by common descent therefore there is no need of a creator”. The problem is that if the differences in absolute terms (not in percent terms only) is sufficiently substantial, then one cannot make that argument.

    If common descent cannot account for the similarity, then common design is the better explanation. As pointed out here, the phylogenies will permanently conflict if one tries to hypothesize a physical ancestor:
    http://www.uncommondescent.com.....ck-matzke/

    Science has shown the phylogenies conflict, which suggest common descent is the wrong explanation for similarity.

    The time has come for Biology to go beyond the Doctrine of Common Descent.

    Carl Woese

  8. Craig Venter Denies Common Descent – Dawkins Incredulous
    http://www.youtube.com/watch?v=SDZzaYaLhXU

  9. Craig Venter Denies Common Descent – Dawkins Incredulous

    So much for overwhelming evidence of common descent…

  10. Sal

    Thank you for this. A thread with my own name in it! A very specific question.

    … lack of believable mechanisms for slow gradual transformations instead of sudden transformations?

    Do you know of believable mechanisms for sudden transformations?

  11. The evidence for common descent is not in similarity per se, but in shared differences. You really ought to learn a bit more about this topic.

  12. wd400:

    Maybe, where does that leave you when you look at the overwhelming evidence for common descent?

    There isn’t any such thing as “overwhelming evidence for common descent”. No one even knows what makes an organism what it is.

    OK if you accept universal common descent how do you test it to the exclusion of all alternatives?

    How many mutations does it take to get a eukaryote starting with populations of prokaryotes- you can use each alleged symbiotic event as one genetic change/ mutation?

    How many mutations does it take to get a chordate starting with populations of invertabrates?

    How many mutations does it take to get a fish-a-pod starting with populations of fish? What genes are involved? Are any new genes required? If “yes” how many?

    Science says that genes control traits- traits being eye color, hair color, ear-lobe style, etc. What is your evidence that being human is just a collection of traits?

    And the killer question:

    What makes an organism what it is? Without knowing that no one can say one type can evolve into another.

    In his book (English title) “Why is a Fly not a Horse?”, the prominent Italian geneticist Giuseppe Sermonti, tells us the following:

    Chapter VI “Why is a Fly not a horse?” (same as the book’s title)

    ”The scientist enjoys a privilege denied the theologian. To any question, even one central to his theories, he may reply “I’m sorry but I do not know.” This is the only honest answer to the question posed by the title of this chapter. We are fully aware of what makes a flower red rather than white, what it is that prevents a dwarf from growing taller, or what goes wrong in a paraplegic or a thalassemic. But the mystery of species eludes us, and we have made no progress beyond what we already have long known, namely, that a kitty is born because its mother was a she-cat that mated with a tom, and that a fly emerges as a fly larva from a fly egg.”

    The bottom line is people accept universal common descent for personal, not scientific, reasons. And the comments will bear that out.

  13. Do you know of believable mechanisms for sudden transformations?

    Yes, sort of. Consider a monarch butterfly. Consider the stages where it starts out as a crawling caterpillar, then enters a cocoon and dissolves itself into a liquid, and emerges as a butterfly. The shape of the body changes, the proteins change (a completely different proteome!), the diet changes, the means of propulsion, etc. It is analogous to macro evolution except it happens all in one generation in the same creature.

    The above graphic by Paul Nelson referred to Leo Berg. Berg (1876-1950). Berg was Dobzhansky’s mentor (Dobzhansky made the famous statement “nothing in biology make sense except in the light of evolution”). Berg hypothesized that macro evolution takes place by developmental mechanisms such as those seen in the butterfly stages.

    He viewed biological development and evolution as following laws like the laws physics, so he wasn’t aware of DNA and the mechanisms we know of today. John Davison took Berg’s ideas and tried to find mechanisms in light of modern biology that would create macro evolution from a few independent lineages. Berg reversed Haeckel’s claim of “ontogeny recapitulates phylogeny” to “phylogeny recapitulates ontogeny”.

    Some ID proponents view macro evolution as some sort of pre-programmed sudden transformation like the stages of a butterfly except that it happens to the offspring — hopeful monsters. I personally find that hard to believe. If one insists on no creator and designer, the hopeful monster hypothesis solves some problems, but invites others as you stated in another thread (the problem of sudden transformation). Complete gradualism on the other hand has its problems because of the problem of functional transitionals.

    If one postulates a creator, the question then is how much polyphyly there is. When it seems that existing (extant) organisms would be hard pressed to evolve certain features, then special creation is provisionally invoked for that lineage. Each of these provisional created kinds can be falsified via hybridization or study of ORFans or some other means.

    To be fair, the hypothesis of a creator cannot be proven, in fact the Creator as a mechanism has not even been observed nor is there expectation he will ever appear in the normal course of human events. So some will exclude the Creator as a mechanism on those grounds. I respect that, but at a personal level, the impression of ID and a designer is far stronger than what I perceive in Mount Rushmore…

    But the hypothesis of creator can be falsified if we find adequate mechanisms for OOL and macroevolution. Common descent can explain some patterns of life, but imho, it presumes there are credible mechanisms to effect common descent (like evolving a fish into a bird). Even though Behe accepts common descent, his IC arguments are actually invoked by creationists to criticize common descent.

    So we have an impasse, the creationists postulate a mechanism that will be adequate, but that mechanism has not been directly observed or might never be by modern man. On the other hand, mechanisms we have in evidence today seem inadequate. There is the third possibility of a mechanism not in evidence today, but is not like a creator.

  14. But the hypothesis of creator can be falsified if we find adequate mechanisms for OOL and macroevolution.

    Not true. I can point you to all sorts of people who think OOL and macro-evolution are a consequence of the initial boundary conditions and because/in spite of this believe in a creator. And then there are some who believe in a creator and believe we are just a happenstance of the creation process.

  15. There is the third possibility of a mechanism not in evidence today, but is not like a creator.

    This is part of how I express the issue. There is a possibility of an unknown mechanism but until such is found, the only answer is “it is a mystery.” This should be the position in the biology textbooks. If this was done, there would be more than a tsunami that would hit the biological world.

  16. It is apparent that most here have not read Meyer’s new book. The most dramatically different thing in the book is that the genome might be a sideshow. All the really complicated stuff is somewhere else in the zygote and this is what determines form more than anything. Proteins are just the building blocks but the architect’s blueprint is not in the genome but somewhere else in the cell.

    If this is true, then the entire debate will move elsewhere. Just where and how is the form of the butterfly determined?

  17. #13 Sal

    So for example a reptile suddenly one off forms a sort of chrysalis thing and out of it springs a mammal?

    It is massively implausible as a physical transformation but also to survive many organisms need a whole environment largely provided by its parents .E.g. a mammal needs a mother to provide milk, a mate, often a nest or burrow, experienced adults to learn from etc.

    Isn’t it much more plausible to suppose a series of gradual transformations?

  18. Mark Frank:

    Isn’t it much more plausible to suppose a series of gradual transformations?

    How is THAT plausible?

    Sure if imagination was evidence…

    E.g. a mammal needs a mother to provide milk,…

    And just how did that evolve? Did giving milk evolve before it was required?

  19. wd400:

    The evidence for common descent is not in similarity per se, but in shared differences. You really ought to learn a bit more about this topic.

    According to Theobald’s “29+ evidences…” it is BOTH similarity and shared differences. YOU really ought to learn a bit more about this topic.

    BTW shared differences ARE similarities…

  20. Isn’t it much more plausible to suppose a series of gradual transformations?

    We discussed this on the other thread. There is a problem with gradual transformations that was pointed out to you. In order for your point to be taken seriously, all these problems should be recognized. If you do not believe they are problems, then you should say why. Until such an admission takes place, the discussion just runs in circles.

  21. #13 Sal

    So for example a reptile suddenly one off forms a sort of chrysalis thing and out of it springs a mammal?

    It is massively implausible as a physical transformation but also to survive many organisms need a whole environment largely provided by its parents .E.g. a mammal needs a mother to provide milk, a mate, often a nest or burrow, experienced adults to learn from etc.

    Isn’t it much more plausible to suppose a series of gradual transformations?

    Hard to say as both evolutionary scenarios seem difficult to accept. Sorry I can give a straight answer, because I don’t have one. It’s like asking whether a square circle is more plausible than an triangular circle…

    Gradualism seems superficially more plausible until we examine the details. But if I were defending Common Descent I would argue for non-universal mechanisms and an infinite number of specialized ad-hoc mechanisms. At least a “hexagonal circle” is more believable than a triangular circle. :-)

    The hopeful monster debate still rages among non-creationists as evidence by this 2010 article in the prestigious scientific journal Nature:

    http://courses.biology.utah.ed.....Nature.pdf

    Large effect or small, evolution begins to look like an endless list of special cases, each a new challenge to Fisherian models.

    I presume Fisherian models refers to Darwinian gradualism.

    Numerous specialized cases rather than a universal mechanism is the route I would go if I were not a creationist. Drop the notion of a universal mechanism and appeal to endless number of unrepeatable specialized mechanisms…you’ll be able then to make a very defensible theory that even evolutionists, creationists, and ID proponents would simultaneously criticize and praise. :-)

    PS
    As an aside, in that same article, Lenski did make an interesting comment:

    Gaining the ability to use citrate must have been like the
    colonization of land by proto-tetrapods.

    Lenski

    I find the comment outrageous, but its sort of a hopeful monster argument.

  22. It is massively implausible as a physical transformation but also to survive many organisms need a whole environment largely provided by its parents .E.g. a mammal needs a mother to provide milk, a mate, often a nest or burrow, experienced adults to learn from etc.

    Isn’t it much more plausible to suppose a series of gradual transformations?

    Short answer, “yes” for this particular case, but I still don’t believe in gradualism, I believe in a miraculous unrepeatable supernatural event (not all ID proponents share that view).

  23. The evidence for common descent is not in similarity per se, but in shared differences. You really ought to learn a bit more about this topic.

    Species A cannot fly to the moon.

    Species B cannot fly to the moon.

    Obviously Species A is more closely related to Species B than to homo sapiens due to this shared difference.

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