Macro/microevolution

A number of posts have appeared at Uncommon Descent on the topic of macroevolution. Comments here have been appended to other threads, but I thought it an appropriate subject for its own thread.

The posts start here with a link to chemist James M Tour’s blog, on which he posted some personal musings on the creation-evolution debate. Numerous follow-on posts have appeared on UD subsequently, in a rather recursive comments-becoming-posts-spawning-more-comments-that-become-posts manner. I won’t detail them all, but they comprise the bulk of UD threads between 18th and 22nd February.

Tour admits his lack of credentials in the subject, but fundamentally expresses doubts that microevolution (which he accepts) leads to macroevolution. The issue has taken a bizarre turn since, apparently, a couple of UD regulars have offered to stump up costs for Nick Matzke to have lunch with Tour in a meeting that will be witnessed by one of them (it’s his dollar!) but, at Tour’s request, will not be recorded or discussed externally. A personal tutorial. Matzke’s mission, should he choose to accept it, is to prove to Tour’s satisfaction that the extrapolation is justified – that macroevolution is sufficiently explained by iterating the small degrees of microevolution.

I think the problem often boils down to people’s mental construct of one modern group turning into another. A dog could become a fox at a pinch, but a cat … ? Instead, place the forms side by side and draw lines of genetic continuity to a common ancestor. At the node, according to theory, that ancestral population split, not into two families, but into two species. Formally, microevolution is evolution at or below the level of species, while macroevolution deals with broader patterns. This requires a precise understanding of the biological role of species – because a species in sexual forms is not a mere convenience of classification, but is a true biological entity: the breeding population. It also requires an understanding of the role of recombination – in such a population, this enables genes to travel quasi-independently, on units that are smaller than the entire genome. But when recombination between two populations stops, and the barrier has a biological basis, they have become two species, irreversibly. They stop sharing genes, and so drift apart.

At any moment in time, the entire ‘definition’ of a species is held within the genomes of its currently living members. And of course, that is a movable feast. Gene frequencies constantly, unavoidably and often irreversibly shift in a recombining population. The statistical inevitability of this is readily demonstrated mathematically, in computer models, and (over periods unavoidably shorter than the working life of the average scientist) in the wild. Two ends of shifting frequencies are of particular significance: the day a new gene arises, and the day a gene disappears. This could of course be the same day, but with a baseline frequency that can readily be calculated, a proportion of new genes will not be rapidly extinguished, but will ‘sweep to fixation’ – they will become the sole representative at their locus, and it is the existing gene that has been extinguished. Evolution has no ‘memory’, and cannot distinguish old from new. Now, the number of generations in which this is expected to happen typically exceeds the lifetime of a scientist, but if we can demonstrate the idealised behaviour of populations (akin to, and using some of the same maths as, diffusion), and model it in computers, what is it about real populations that renders extrapolation unjustified?

This is, remember, still within the region of change dubbed ‘microevolution’, which Tour accepts. And even ark-friendly Creationists accept that and a little bit more, since proliferation of species – a macroevolutionary pattern – is invoked to explain species numbers. If two populations cannot interbreed, their genes cannot recombine – however recent their ancestry, they have moved into the part of the continuum marked ‘macroevolution’. At its lowest level, then, macroevolution is hardly bigger than microevolution. If populations can change, split populations can diverge. If that divergence is proposed to be limited as a general rule, there needs to be either a clear universal mechanism that stops such change proceeding indefinitely, or definite and widespread discontinuities in the historic pattern we see in fossils or in commonality between modern forms.

One possible ‘anchor’ is that real populations don’t just have a genotype, they have a phenotype. That tends to be the focus of all attention. It is the change in gross form in the fossil record, the morphological divergence among taxonomic classes, that really impresses. And here, it all looks superficially discrete, even to the point where, for some people, that morphology presents a barrier, a drag on indefinite genetic change. While they might accept the logic of iterative genetic amendment multiplying up into major change (think changing a book a letter at a time), the bodies of two current species cannot be connected by a genetic continuum to a common ancestor because there cannot be viable intermediates (think the demand that all ‘transitional’ books must be worth reading). But this amounts to making a judgement about the space of viable organisms, without doing any investigation. Evolutionists are wrong to assume that the space between any two species is fully connected via viable ancestors to a common ancestor, because … well, what? Where do we place the barrier between reasonable and unreasonable extrapolation? We certainly aren’t generally challenged to prove that two individual humans are connected by an audited genetic continuum. Nor that, for example, any two dogs are. Or dogs and foxes. Or dogs and cats? Dogs and rats? Ah well, now … the bigger it gets, the more stringent the demands. Is there nothing we can do to assess the claim of genetic continuity?

Early attempts to investigate the patterns were obliged to concentrate on phenotype. They had little choice; they had no idea how genotype was implemented. Those morphologies converged on nested hierarchies of characters. The perfectly reasonable assumption was that a character resemblance – canine teeth, say – was shared between all dogs because they got it from a common ancestor. And between dogs and wolves because they did also. And between dogs and cats because … well, all of a sudden, some people insist that this explanation be discarded RIGHT NOW … at this remove, extrapolation is a matter of metaphysical bias, not reasonable inference. But no sound rationale is offered to make such a dichotomy between close-branching relationship and more distant ‘common design’ between suppposedly genetically discontinuous groups.

We now have the luxury undreamt of by the early taxonomists, of direct examination of the molecular basis of phenotype – and more, of genotype that has no apparent phenotype at all beyond existing. Precisely how, in Tour’s ‘chemical’ terms, genotype becomes phenotype is not deeply understood – but that it does cannot be reasonably doubted. And we see no discontinuity. The genetic differences between close branches (accepted as common descent) differ only in degree, not in type, from those among more distant ‘macroevolutionary’ categories. The deeper you go, the more scrambled the relationship signal, but this is hardly at odds with the assumption of steady divergence – it is entirely consistent with it. At the limit, the signal would degrade entirely, even in a true genetic continuum, but even so for the most part, we are somewhere short of that point.

It could be argued that genetic continuity does not prove that the change was unguided – and indeed, it does not. But the process which appears to proceed without guidance now, inexorably changing and diverging populations, you’d expect to be in operation wherever and whenever DNA replication is occurring. All you need in principle to achieve all taxonomic categories above the species (discrete categories that are human constructs, not ‘natural’ groups based upon biological interaction) is a process of bifurcation and continuing divergence beyond the node, and viability of all intermediate forms. The appearance of genetic continuity is either deceit, or it indicates that a branching process has been in operation, and all intermediates must have been viable. We don’t need to know the precise steps, nor the selective environment (with or without Intent), to conclude that macroevolutionary divergence is real, and demands no fundamental source of variation beyond that supplied by generational change. With no evidential support at the genetic or the morphological level for an hypothesis of discontinuity between higher taxa, there is no good reason to adopt one.

94 thoughts on “Macro/microevolution

  1. When I first saw that UD post about Tour, what stood out was that he accepts micro-evolution but does not understand how macro-evolution is possible.  It was immediately clear that Tour has a very poor understanding of evolution — an all too common problem.

    I have occasionally considered posting, perhaps at an evolution/creation debate forum, about micro-tree-growth vs. macro-tree-growth.  Here micro-tree-growth would be the fattening of existing branches due to growth under the bark, and it would also be the growth of small soft-tissue twigs.  And macro-tree-growth would be the growth of whole new branches.  I think of that as a good analogy for the micro-evolution vs. macro-evolution disputes. 

  2. The weirdest thing about Tour’s article is this statement:

    I simply do not understand, chemically, how macroevolution could have happened.

    That’s all he says on the subject.

    What does that even mean? What would a “chemical understanding” of macroevolution look like?

    Tour says he accepts microevolution. Does he have a “chemical understanding” of it? If no, then why does he insist on a “chemical understanding” of macroevolution? If yes, then what does this “chemical understanding” look like, and what is the barrier that prevents Tour from explaining macroevolution in a similar fashion?

  3. Yes, the tree is a pretty easy-to-grasp analogy, provided one does not overemphasise things that are specifically properties of vegetative trees! One of these, I think, is that idea of branches thickening with age. All there ever is is a growing tip – the current population, constantly adding and losing members. The tree into the past is the series of ancestral populations, towards whatever point happens to be the origin of that replicative series. The ‘stuff’ of the tree is a series of eternally equivalent, spindly collectives of contemporary interbreeding individuals.

    Within each stem, microevolution is happening, because the population is in genetic contact. Between them, it’s macro. People commonly think of some kind of ‘dynasty formation’, or the arrival fully-formed of a major organ, but it’s still all steady divergence, on the data.

     

  4. All ID has to do is explain macroevolution. 

    How the designer does it.
    When the designer does it.

    Etc Etc. If they choose they can do this at the chemical level. In fact, any level would be acceptable. 

    “Hence, by my observation, the unfair treatment upon the skeptics of macroevolution has not come from the administration level.”

    It’s easy to pick holes, anybody can do that. When skeptics of macroevolution have something to contribute other then skepticism then perhaps they’ll get somewhere. I.E. some data. 

  5. Yes, Tour’s demand of a chemical explanation did strike me as bizarre. Equally bizarre is the fact that no-one (though I have not looked too closely) has questioned this from the ID side in UD discussions. To me, it’s like asking for the chemical rationale that ensures that two flasks on a bench can have different contents, but not if you mix them. It does betray a particular view of what a ‘higher-taxon’ transition looks like to him – something that should happen suddenly, with a fairly discrete explanation, rather than in a gradual series – a series of weasels (micro) becoming, by some ‘macro’ chemical change, a series of dogs, or something.

  6. As I understand the ID/creationist argument, they seem to think that a new genetic mutation in an individual would leave that individual without any choice of mates because it would be one of a kind (pun not intended); therefore it can’t propagate.

    But in any real population, the genetic variation still allows reproduction; and at any “microscopic” state of the population, it would be other factors – including some emerging phenotype differences; say, in morphology – that would begin to start separating out subpopulations.

    Then other, more drastic separations begin to occur, due to changes in the environment that act on those phenotype differences; but the now-separated populations would still be capable of interbreeding if brought back together. Over time, continuing variations in the separate populations gradually result in the accumulation of enough genetic differences that there comes a point at which the populations can no longer interbreed. But those populations may not have shared a common gene pool for many generations and would already be categorized by human classification schemes as separate species.

    I think the issue comes up for ID/creationists only in the context of sexual reproduction in animals. I don’t recall what they say about the far more varied reproductive characteristics of plants.

    Tour seems to be locked into an old fashion reductionist thinking; but reductionism has been passé in physics and chemistry for well over a century. Even water molecules have properties that are not reducible to those of their constituents; and those emergent properties depend sensitively on temperature.

    In the cases of complex systems like organic molecules and living organisms, natural selection does not necessarily act on the properties of the constituents of the system – i.e., the atoms and individual molecules – it acts on emergent properties that are not reducible to the properties of the constituents.

    So Tour’s demand is a fool’s errand.

  7. Leaving aside the issue of Tour’s conditions for a discussion of macroevolution (Nick Matzke will deal with that as discussions about the event go further):

    I think that, among commenters here, I have a unique perspective on the microevolution / macroevolution distinction. My current research is on statistical methods that bring together data from within and between species to see whether the microevolutionary processes predict larger-scale evolution. In fact Steve Arnold (Oregon State University) and I are currently finalizing arrangements for our week-long summer course on Evolutionary Quantitative Genetics. The course, for graduate students, postdoctoral fellows and faculty members, is given yearly at the National Evolutionary Synthesis Center (NESCENT) at Duke University in Durham, NC.  A link to last summer’s course including PDFs of lecture projections and even audio recordings of our lectures will be found here.

    The use of the quantitative genetics machinery from animal and plant breeding to examine differences between species started with the elegant and beautiful pioneering work of Russ Lande in the mid-1970s, and it is undergoing a major upsurge of interest right now.

    Are we assuming that within-species processes can be extrapolated between species?  Yes. Is that circularly self-reinforcing? No, because it’s the null hypothesis. We test how well the processes that we see working today within species can account for the patterns of differences across the evolutionary tree, or whether processes of natural selection were different in the past.

    So this is an active, even “hot” area for evolutionary biologists. We’re trying to quantitate changes within and between species and ask how the evolutionary processes compare. Here is a paper by Uyeda, Hansen, Arnold, and Pienaar in 2011 in the Proceedings of the National Academy of Sciences that addresses this in a sweeping multi-time-scale manner.

    But, by comparison, what do creationists do about all this?  Sit around and make dogmatic declarations of impossibility. 

  8. It is frustrating to see an entire field dismissed as ideology. My own interest is as a layman – my degree is in biochemistry, which has some, if limited, relevance, but for fun I invested in Futuyma’s Evolutionary Biology – 800 dense pages of exhaustive detail upon mathematical expectation, hypothesis proposal and direct testing of the expectations thrown up by the ‘idealised’ mathematical framework, and the rich source of additional data provided by first protein sequence and then DNA sequence.

    Familiarity with the material in at least one undergraduate-level textbook might be a reasonable requirement for a scientist to sign ‘concern documents’ on a field that is not his own. I guess that lets Paul Nelson off the hook, though he, like Tour, routinely confuses macroevolution with macromutation.

  9. As I understand the ID/creationist argument, they seem to think that a new genetic mutation in an individual would leave that individual without any choice of mates because it would be one of a kind (pun not intended); therefore it can’t propagate.

    Anyone who thinks that way may care to try and explain the existence of heterozygosity! I think, again, that people are thinking of macromutations rather than macroevolution in their mental model. Mutations that do render their bearers or offspring dead or infertile are of course dead ends. That leaves all the rest.

    Any reproducing population of any finite size will gradually eliminate variation at any locus, unless there is a particular (and rarely-observed) pattern of selective balance between heterozygotes and the two homozygotes. We should see, overwhelmingly, homozygosity – especially if their ancestors came off the ark!

    We don’t, so something, somewhere, is generating variation. Something else is continually eliminating it, but the variation eliminated is not constrained to be the latest arrival. The net result is a succession of changes that could not all occur in one go.

  10. …he, like Tour, routinely confuses macroevolution with macromutation.

    Worth including in any definition of ID or creationism.

  11. Familiarity with the material in at least one undergraduate-level textbook might be a reasonable requirement for a scientist to sign ‘concern documents’ on a field that is not his own. I guess that lets Paul Nelson off the hook, though he, like Tour, routinely confuses macroevolution with macromutation.

    Zygoisity.

    It has always been the case that ID/creationist “arguments” mangle even the science that one learns in high school. High school AP biology courses cover this stuff.

    It is the same with physics and chemistry. ID/creationist calculations always have the underlying assumption that atoms and molecules are all inert. The AP Physics B high school course also covers concepts in thermodynamics; yet misconceptions about thermodynamics are the foundation of Intelligent Design “Theory.”

    The Institute for Creation Research and Answers in Genesis are both devoted to mangling middle school and high school science. Ken Ham has clearly targeted children. Of course, the Discovery Institute’s Center for (the Renewal of) Science and Culture is basically a strategic political spin-off to court-proof creationist pseudoscience.

    So it is probably no coincidence that mangled middle school and high school science is at the core of ID/creationism. Kids have been the primary focus of ID/creationist politics.

  12. I see signs of the classic “I’m very impressed with myself, and because I draw an analogy between what I do and what nature ‘does,’ I conclude that intelligence is manifest in nature.” From the Wikipedia article on Tour:

    I build molecules for a living, I can’t begin to tell you how difficult that job is. I stand in awe of God because of what he has done through his creation. Only a rookie who knows nothing about science would say science takes away from faith. If you really study science, it will bring you closer to God.

    Of course, if he built software for a living, he would join the droves of IDCists who can’t begin to tell us how difficult their jobs are, and who stand in awe of a god who happens to look a lot like them.

  13. microevolution – Small-scale genetic changes, observable in organisms.

    Davis and Kenyon. Of Pandas and People: The Central Question of Biological Origins, Second Edition. 1993.

    microevolution – Small-scale genetic and structural changes in organisms. Microevolution (unlike MACROEVOLUTION) has been observed and produced experimentally.

    Dembski and Wells. The Design of Life: Discovering Signs of Intelligence in Biological Systems. 2008.

    microevolution – Small changes in a population of organisms that do not change the fundamental nature of that organism (color, size, antibiotic resistance).

    Crocker, Caroline. Free To Think: Why Scientific Integrity Matters. 2010.

    microevolution – Change in allele frequencies resulting from mutation, genetic drift, gene flow, and natural selection.

    Starr and Taggart. Biology: The unity and Diversity of Life. 1998.

    microevolution – Changes in the frequencies of alleles of genes in a population

    Tobin & Dushek. Asking About Life. 1998.

  14. macroevolution – The hypothesis of large-scale changes, leading to new levels of complexity.

    Davis and Kenyon. Of Pandas and People: The Central Question of Biological Origins, Second Edition. 1993.

    macroevolution – Large-scale genetic and structural changes in organisms leading to new and higher levels of complexity. Such changes have not been observed within the time scale of recorded human history.

    Dembski and Wells. The Design of Life: Discovering Signs of Intelligence in Biological Systems. 2008.

    macroevolution – Evolution resulting the formation of a new type of organism (with a new morphology or shape). Requires generation of significant amounts of new information.

    Crocker, Caroline. Free To Think: Why Scientific Integrity Matters. 2010.

    macroevolution – The large-scale patterns, trends, and rates of change among families and other more inclusive groups of species.

    Starr and Taggart. Biology: The unity and Diversity of Life. 1998.

    macroevolution – The processes by which species and higher groupings (taxa) of organsism originate, change, and go extinct.

    Tobin & Dushek. Asking About Life. 1998.

  15. I can honestly say I’m no happier with how the “ID” books have defined micro/macro evolution than I am with how Nick defined the terms over at UD, or how these biology text defined them.

    Is there a textbook on “Macroevolutionary Theory” that I can buy?

     

  16. Allan Miller:

    The appearance of genetic continuity is either deceit, or it indicates that a branching process has been in operation, and all intermediates must have been viable. We don’t need to know the precise steps, nor the selective environment (with or without Intent), to conclude that macroevolutionary divergence is real, and demands no fundamental source of variation beyond that supplied by generational change.

    So you seem to be in the “just more microevolution please” camp.

    Your argument seems to be that if common descent is true, macroevolution must likewise be true. But must not macroevolution be true in order for common descent to be true?

  17. Allan Miller:

    It is frustrating to see an entire field dismissed as ideology. My own interest is as a layman – my degree is in biochemistry, which has some, if limited, relevance, but for fun I invested in Futuyma’s Evolutionary Biology – 800 dense pages of exhaustive detail upon mathematical expectation, hypothesis proposal and direct testing of the expectations thrown up by the ‘idealised’ mathematical framework, and the rich source of additional data provided by first protein sequence and then DNA sequence.

    So you’re no more qualified than Tour, but you have no doubts? Why not?

    Or can I find that in the OP?

    I mean, as a biochemist, I would think you would be closer to Tour than to Nick M. Or do you just look at all that goes on at the biochemical level and see in it the explanation for macroevolutionary change? Or do you just tell yourself that the one has nothing to do with the other?

    I’ll ask you the same question I asked Nick over at UD, to which he hasn’t yet responded. How do you explain macroevolution when you’re dealing with single-celled organisms, if not at the biochemical level?

  18. Even I know enough biology to know those are bizarrely foolish questions.  

    They’re bizarrely foolish especially from an ID standpoint.  Your lot are always banging on about how God, erm, the Designer arranged all organisms’ DNA to be “functional” and “complex” and shit.  So you already think that macroevolution is all at the biochemical level.  Yes, you think that if your God, erm Designer, has a wonderful idea for a biological innovation – say, nucleated single cells – that it will implement its wonderful idea by twiddling its microscopic fingers in the existing organism’s DNA to arrange the new, more “functional” more “complex” sequence.  Presto change-o, macroevolution! It’s all biochemistry to you – the biochemical machinery of DNA/RNA replication like a player piano, with your Player causing instant macroevolution by changing the piano-reel. 

     

  19. Even I know enough biology to know those are bizarrely foolish questions.

    But you couldn’t be bothered to say which questions, and why they were foolish and/or bizarre, nor could you tell  us how your level of expertise in biology allowed you to pronounce such judgments.

    Par for the course.

  20. Tee hee, Mung, you’re so cute when you play the fool.  

    Unless you’re not playing.  

    In which case, you’re just a sad example.   

  21. But must not macroevolution be true in order for common descent to be true?

    Let’s take a simple example: three sparrow species (links are to their Wikipedia pages):

    1. The White-Throated Sparrow (Zonotrichia albicollis)
    2. The Golden-Crowned Sparrow (Zonotrichia atricapilla)
    3. The White-Crowned Sparrow (Zonotrichia leucophrys)

    They are a clade, more closely related to each other than to anything else, so there is common descent of them from their common ancestor (two other Zonotrichia species are a bit less closely related).

    Do these look like they differ in ways that involve major innovations or great changes in complexity? Yet they are three species that have common descent. 

     
    So the answer to the question is “no”.

  22. Mung,
    How does ID “explain” macroevolution? 

    How do you explain macroevolution when you’re dealing with single-celled organisms, if not at the biochemical level?

    How does ID explain macroevoluiton?
    How does ID explain microevolition?

    As it seems to me that ID rejects any explanation then refuses to provide it’s own alternative (and presumably an alternative with more explanatory power otherwise why believe it?) and I’m wondering why that is?

    What is the ID for any kind of evolution at all?  

    On a thread you are taking part in on UD this was posted:

     

    Large Morphological Gaps: Explainable by creationism. Explainable by ID. Not explainable by Darwinian evolutionary. Accommodates only.
    Sudden Appearance: Explainable by creationism. Explainable by ID. Not explainable by Darwinian evolutionary. Accommodates only.
    Convergence: Explainable by creationism. Explainable by ID. Not explainable by Darwinian evolutionary. Accommodates only.
    Lack of clear phylogeny: Explainable by creationism. Explainable by ID. Not explainable by Darwinian evolutionary. Accommodates only. Stasis: Best Explanation: creationism or ID.

    http://www.uncommondescent.com/intelligent-design/ecs2-responds-to-the-same-nick-matzke-he-said-it-clipped-and-commented-on-yesterday/#comment-447765

    Would you be so kind as to ask what those “explanations” actually are? You don’t seem to have asked for that clarification on the thread itself so presumably you already know (being keen on ID and all that) what those explanations actually are. I don’t, and I’m sure many people here would also like to know how ID explains, well anything at all really. 

    Would the ID “explanation” for “sudden appearance” be something like “The designer finished his tea and so had time to make some new animals”?
    Or what? You tell me! It’s your sides claim! Explain it or do the right, intellectually honest thing which would be to ask for that explanation yourself from the people claiming it exists. 

  23. Mung, It has already been pointed out (repeatedly) that the bizarre thing about Tour’s request for an explanation of macro-evolution at the chemical level is that he’s asking for analysis at the wrong level.

    Yes, molecular biology depends on biochemistry, and biochemistry depends on chemistry, but asking for a chemical explanation of evo-devo makes no sense.

    Let me try an analogy, imperfect as they are:

    A theoretical physicist wants to understand why his RAV4 does not corner as well as his brother’s Porsche 997. But he wants the explanation in terms of quantum mechanics. The engineers in his family just look at him with puzzled amusement.

    Thus when you write:

    I mean, as a biochemist, I would think you would be closer to Tour than to Nick M. Or do you just look at all that goes on at the biochemical level and see in it the explanation for macroevolutionary change? Or do you just tell yourself that the one has nothing to do with the other?

    it is analogous to saying “Allan, as a metallurgist, I would think that you would be closer to JMT than NM (who designs cars for a living).” etc.

    Both metallurgists and physicists should know that centre-of-gravity and tire grip are important, and that there are other factors, best explained by a MechE. But some may not grasp this. 

    And your question:

    How do you explain macroevolution when you’re dealing with single-celled organisms, if not at the biochemical level?

    is slightly less incoherent, perhaps equivalent to “How do you explain how bicycles go around corners, if not at the materials science level?”

    Here goes. “Changes in the timing and expression levels of genes that themselves regulate the timing and expression levels of other genes.” The biochemistry of DNA binding and transcriptional activation is quite well understood (although we continue to learn new stuff at that level), but it is at a ‘higher’ level that your question re macroevolution should be addressed. How would you explain (at the “biochemical level”, e.g. what new hydrogen bonds are formed) the effect of a change in ploidy?

    Edit foar typo

  24. I’d like to see an ID advocate explain how the designer know the effects of proposed changes. Not just the immediate biochemical effects, but also the effects of relative reproductive success and relative competitive success in the larger environment.

    How does the designer acquire this knowledge and where does he store all the data? 

  25. petrushka, that’s elementary! The designer is omniscient, i.e., he already knows everything. (The guy must be bored out of his mind!)

  26. Tour seems to know that, but IDiots deny that the designer is god.

    In particular, gpuccio denies that the designer is omniscient. 

  27. Looking back at those decade+ ISCID threads and comments the only thing I’m surprised about is that they are still available. In fact it seems to be broken so you can’t browse the thread list now. 

    It needs to be preserved.

    No matter how many leaks Darwin’s Titanic springs, you’ll blithely keep asserting, “Steady as she goes.” And down she will.

    ” 

    This ship is taking over a decade to sink Dr Dr Dembski! How very strange!

  28. Mung

    So you’re no more qualified than Tour, but you have no doubts? Why not?

    Or can I find that in the OP?

    I mean, as a biochemist, I would think you would be closer to Tour than to Nick M.

    I’m not playing a ‘qualification game’. Nonetheless, as a biochemist, I have a fair grasp of the molecular biology of the cell, especially DNA replication and expression. That just keeps ticking away, imperfectly, ad infinitum. As part of my undergrad education, I did a year’s general biology and a year’s botany, (plus a year’s geology) … I’ve also educated myself about evolutionary biology (Futuyma’s Evolutionary Biology, Maynard Smith’s Evolutionary Genetics). As a keen naturalist, I have been familliar with the Linnaean system since the age of 11. And I have a particular amateur interest in the role of sex and recombination in populations.

    None of which makes my opinion worth a damn. But it is the reason why I am much further from Tour than you might think – because I’ve studied the subject from several different angles.

    As I point out in the OP, Macroevolution is simply that portion of change that occurs once the gene-swapping ties of interbreeding have been severed. As such, it is strictly a phenomenon of sexual organisms only. Of course, things aren’t quite that simple in biology, and most organisms are asexual – mostly single-celled prokaryotes.

    But the things that people think ‘can’t evolve’ – whales, people, giraffes etc – are phenomena of the sexual world, so I won’t worry unduly about the difficulty of exporting terminology outside it.  

    The reason I point to common descent in this regard is that the principal difference between clades at the genetic level relates to the degree of change that has accumulated between lineages, not its type, as revealed by comparative genetics. Deeper branches – higher taxonomic categories – are not typically more different, adjusting for divergence time, than recent ones. So there is no apparent difference between the process along a stem (anagenesis) and that between two branched stems (cladogenesis followed by two sets of anagenesis).

    In microevolution, change is only visible while in train – as polymorphism. Once a change is fixed, we cannot see the ancestral state. But speciation provides a means of ‘freezing’ a population state. Of course, because both lineages can change subsequently, it takes multiple branches to fully resolve a sequence. But at no point do we see something that is inconsistent with a process of increasing divergence, powered by microevolution in each stem.  

    Imagine two 3/4 pipes running side by side in contact. Dye injected into one will end up in the other. Downstream, they seal and diverge, and contact ceases. Now, dyestuffs injected at various points travel into descendant pipes only. When you sample the pipe ends, you can determine any hierarchic branching pattern from the dyes (using a little chromatography). But at no point does some new kind of flow come into it. Fluid molecules still make their way in tiny steps, in tiny subdivisions of time. Asking for the chemical basis for macroevolution is like asking for the chemical basis for the branching, or the pattern of dyes at the pipe ends. 

    The fundamental isolating mechanism – the point where microevolution in one lineage becomes microevolution in two (ie: macroevolution) is the permanent impossibility of successful meiosis between genes in the two populations. It can have a chemical basis, of sorts, but I’m betting that’s not what Tour is thinking of.

  29. I suppose Macroevolution could be considered a large increase in the FSCO/I present. 

    As such I find it interesting that KF has this to say:

     

     

    Joe: it most definitely is possible to produce tests that FSCO/I and IC can and have been produced by blind watchmaker, Mt Improbable incrementalist mechanisms, or by wider blinde chance and necessity mechanisms. Remember, a reasonable threshold is 500 bits of functionally specific info, about 250 base pairs of D/RNA worth of storage. What I think is the real challenge is that to date, the only empirically credible, observed source of such, is design. So, Evo mat advocates, unlike design theorists, are not in a position to argue “like causes like.” Indeed, a lot of the objecting rhetoric I have seen is designed to distract from or dismiss that very cogent appeal. And, ironically, if they were to succeed, all they would then be able to show is that such features can be produced by BOTH blind mechanisms and design. So, this cannot be where the decision would be made. And that is a best case they have not been able to deliver on, with the earliest challenge being Cicero’s c. 50 BC. That’s a mighty long time to be drilling away obsessively at a dry hole! KF

    I for one would like to see these tests that KF mentions. The bolded line says to me that:
    A) The specific amount of FSCO/I can be determined.
    B) The source of that FSCO/I can be determined.  

    Yet only a short time ago we went around that roundabout with Gpuccio and it went nowhere.

    KF, would it be possible for you to demonstrate the tests that definitely exist that FSCO/I and IC can and have been produced by blind watchmaker, Mt Improbable incrementalist mechanisms, or by wider blinde chance and necessity mechanisms?

    http://www.uncommondescent.com/intelligent-design/ecs2-responds-to-the-same-nick-matzke-he-said-it-clipped-and-commented-on-yesterday/#comment-448107 

  30. Oh, I know. I was George L Farquar on UD during the Weasel era. Even after video evidence was available his contortions were amazing to witness. 

    But it also speaks to other commentators like Mung who objected when I pointed out that he uncritically accepts ID claims whereas he demands standards of evidence for evolution that he does not apply to ID. 

    KF has made a claim, that FSCI/I can be tested for it’s source. Until Mung challenges him on that and asks for that demonstration, my claim stands. 

    After all, ID stands or falls (like everything else) on if it can support it’s claims. It’s in Mung’s interest to get KF to support KF’s claims, not mine as I’m not the ID supporter in this equation.  

  31. There are repeated claims from UD people that CSI (or FSI) cannot be produced by any methods other than Design. When asked what proves that, they don’t provide any proof. Instead sometimes they argue instead that this is an empirical observation. Simple models of natural selection can be constructed that show that CSI can come to be in the genome by natural selection, so that this Design Inference is really a design-or-natural-selection inference.

    There originally was a supposed proof by William Dembski, but this was subsequently shown to be (a) unproven, and (b) not to be in the right form to accomplish the task, even if the theorem could be proven.

    However the “fact” that CSI must be the result of Design has entered the culture over at UD. The usual way it appears is in the form of the Design Inference flow chart. The chart is totally bogus, but no amount of logic seems to make any impression on the people who repeatedly post it.

  32. a reasonable threshold is 500 bits of functionally specific info, about 250 base pairs of D/RNA worth of storage. What I think is the real challenge is that to date, the only empirically credible, observed source of such, is design.

    About 83 amino acid residues. And yet random longer peptides from combinatorial libraries – ie, single-step – produce a variety of functions. The overall space is admittedly frequently constrained, by a patterning algorithm to ensure folding. Nonetheless, the algorithms are not tightly specified, and typically consist of 10-15aa sequences with only a binary rule at each site, multiplied up into the longer peptide. It would be a stretch to call them ‘designed’ in the 500-bit sense.

    And anyone who can’t see how a not-that-improbable 10-acid sequence can become a 100-acid repeat of the same pattern by ‘natural mechanisms’ may be lacking some basic biology.

  33. Mike: As I understand the ID/creationist argument, they seem to think that a new genetic mutation in an individual would leave that individual without any choice of mates because it would be one of a kind (pun not intended); therefore it can’t propagate.

    I think in many cases it is a far more simplistic misunderstanding. The creationists I’ve encountered merely argue that they can’t imagine how an ant could ever give birth to an aardvark. I’ve actually encountered a number of folk – some really smart – who think this is what evolution implies. Of course, creationists have the added agenda that humans can’t be related to any other life on this planet because we’re “special” and really all life is specifically created because that’s what the good book says, but you get the above if press the issue. The fact is, there are a lot of people who think that evolution means that given enough time, birds can beget whales and hydrogen can become humans. They really, fundamentally, do not understand the details.

    Keep in mind too, the vast majority of people really don’t know that much about the natural world around them. Most people, for instance, picture three, maybe four, species of ants for the group concept “ants”. They really are not familiar with – and cannot grasp – the diversity across the ant family. For example, few people have any real concept of the close relationship between ants and wasps. Is it any wonder they can’t begin to imagine the related across all other insects, to say nothing of the relatedness between insects and crustaceans?

    Basically, it seems they ascribe to evolution an instant characteristic generation capability that doesn’t actually exist.

     

  34. Yep. I’ve found the best way to grasp this is by starting with the creationist model – that everything around us got poofed just the way it is now, and that it happened recently. “Evolution”, therefore, necessarily becomes a codeword that denotes “anything and everything that this model disallows”. Everything from biological history to constant lightspeed to the big bang. In creationism, there IS NO PAST, no deep time, no long history.

    So any discussion of common ancestry simply does not fit. Nothing has ever changed. Evolution says things change, which can ONLY mean that some current critter suddenly morphs into some other current critter. Current critters are all the model allows. There can’t be any common ancestry, because there were no ancestors!

    Creationists often complain that the concept of species is undefined, or has multiple definitions, which is easily explained by the fact that scientists are trying to cram organisms into a model they don’t fit. Try explaining that if species were NOT a fuzzy category, evolution couldn’t happen. Just try! Talk about being hopelessly separated by a common language.

    Creationists look at the often bogglingly complex Rube Goldberg relationships in life, with hundreds of interrelated organisms and structures right down to the internals of individual cells, and demand an explanation of how anything that bizarre and byzantine could have happened by accident. The notion that such ornate systems are the inevitable result of the evolutionary process, that the creationist has identified some of the strongest evidence FOR evolution, is simply not comprehensible. At all.

    But design isn’t a conclusion based on ignorance of the process, but rather a doctrine which defends itself against knowledge of the process. And so every discussion devolves to the same point: To the scientist, evidence is what is used to build explanations. To the creationist, evidence is whatever fits foregone conclusions. If it does not fit, it’s not evidence.       

  35. I would expect KF to define microevolution as any change below the hypothetical 500 bit threshold of CSI, and macroevoltion (intelligent design) for anything above.

  36. I recommend Why Evolution Is True by Jerry Coyne.  (Of course, it does assume some familiarity with physical reality, eg that the reader realizes the Earth was not created 6000-10000 years ago but rather that it is about 4.6 billion years old.)

    Almost the entire book is about macroevolution, that is, change at or above species level.  Interestingly, the word “macroevolution” appears only twice in the index.  If it weren’t for Creationists and IDists harping on their foolery that they believe in “microevolution” but not “macroevolution”, it probably would not have been necessary for Dr. Coyne to use the word even once.  

    What do fossil sequences show us? Evolution (macroevolution, that is).  What does biogeography show us? Evolution (yep, macroevolution).  What do vestigial traits show us? Evolution (macroevolution, again).  What do speciation events, observed both in the field and in labs, show us? Evolution in action (macroevolution, duh).

    What does evolutionary bad design – such as the recurrent laryngal nerve – show us?  That if the Creotards and IDiots are correct that each organism is specially designed by an “intelligent designer”, then their putative designer is a colossal failure at its day job, and anything but intelligent.  But that’s a subject for another book … 

  37.  

    Who said anything about evo-devo?

    ID-advocates typically cite the ‘Cambrian Explosion’ or the ‘appearance of new body plans’ as examples of macro-evolution that they find incredible: see posts 9, 30, 59, 115, 120, 128, 132, 170, 195, 207, and 208 in the thread where you reference the appearance of feathers as an example of macroevolution.

    I did concede that your question

    How do you explain macroevolution when you’re dealing with single-celled organisms, if not at the biochemical level?

    was slightly less incoherent. And I answered it.

     

     

  38. Oh, it wasn’t a rhetorical question? You could start with a textbook on evolutionary theory. Macroevolution is, naturally, a subtopic within that. I’d also rather humbly hoped I’d covered macroevolution in my OP, but I guess not. 

    Macroevolution = evolutionary trends above the species level, where a species (in an evolutionary sense) is an interbreeding group. Reproductive isolation of parts of such a set can lead to speciation and ongoing divergence – macroevolution. Think of the letter Y. Microevolution takes place up the stem, and along each arm, but macroevolution relates to the processes operating at the node and the subsequent divergence and possible further branching between the arms. 

    It can also be applied to long-term trends in the basic generational process, where microevolution again arises out of the simple begetting process in the population and macroevolution the cumulative change between, say, the base of the Y and the tip of one arm. There doesn’t have to be a node for this usage – it’s long-term anagenesis (qv), not cladogenesis (qv) + relative anagenesis. Take your pick, as long as you’re clear about your intended meaning.

  39. My mental image is of looking at a tree with one’s thumb held up, such that only the tips of the branches are visible. The tree consists, as far as they can tell, of nothing but buds and a few minor branches, clustered in bunches but with no visible means of support. Morphological and molecular investigation reveals this to be a false, or certainly unsupported, picture, but no amount of data will persuade people to lower their thumb. They will, instead, point to the odd inconsistent phylogeny as full justification for their stance.

  40. Mung

    Your argument seems to be that if common descent is true, macroevolution must likewise be true. But must not macroevolution be true in order for common descent to be true?

    No. It is not necessary that organisms ever be reproductively isolated (the ‘node’ of a macroevolutionary divergence) in order for common descent to be true, though interbreeding messes up the tree. But that’s how paternity tests and crime-scene DNA work. Common descent within a species is non-controversial. And that between closely related species. But the data goes further, and supports both common descent throughout the biosphere and (mostly) genetic isolation. If anything could interbreed with anything, common descent would still be true, but the tree would be a bit of a mess. You and your cousins could still have the same toadstool grandfather, but some of them would also be part-fly.

    IDists draw some arbitrary line in taxonomy where common descent data is no longer admissible. But given that we are clearly reproductively isolated from most of the biosphere, and yet we appear to be commonly descended, our ancestry must trace back to a time when our lineage and any given other were not reproductively isolated – they descend from the same species. At the time, macroevolution would have been an unremarkable split of one population into two, followed by the macroevolutionary processes of divergence and radiation. 

  41. Macroevolution = A large change in the FSCO/I of an organism. 

    If you want more go ask KF. He has:

    tests that FSCO/I and IC can and have been produced by blind watchmaker, Mt Improbable incrementalist mechanisms, or by wider blinde chance and necessity mechanisms

  42. Extrapolation, Extrapolation, Extrapolation!
    Micro equals macro is just a line of reasoning.
    A line of reasoning is being persuasive to evolutionists as making macro evolution possible.
    So a line of reasoning is only needed to make it impossible.  

    if evolutionists say WHY NOT micro=macro then creationists just need to say WHY NOT NOT.
    There is no reason to think the fantastic differences between kinds of biology can be breached by observation of minor breaching within kinds.
    Being so different easily suggests too different to cross boundaries however flexible boundaries are crossed within kinds.

    Then the question also DID it happen and wheres the evidence.
    evolution, led by chuck Darwin, has been running on lines of reasoning/or hypothesis without biological evidence being the fuel.
     

  43. Robert Byers: ” Micro equals macro is just a line of reasoning.”

    It is the ID side that has promoted the concept that biology can be reduced to “information” that can be presented as a bit-form digital string.

    If as Upright BiPed suggests, this information is “arbitrary”, then it follows that any 1 bit change is not restricted or constrained in any way and thus can accumulate from generation to generation eventually leading to total bit changes in excess of the UPB within 500 generations.

    If however you are right, then Upright BiPed is wrong when he tries to reduce biology to a simple computer model.

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