Macroevolution and the argument from ignorance

Let’s think about Creationists (and let you remind you that by creationist I mean those who demand a literal reading of the scriptures as scientific texts–all the LDS members of my Biology Department at BYU believe evolution is the way life on earth emerged, and the way the human body was formed, yet believe in a Creator. However, literalist creationism, where it exists in Mormonism, is a leak from sources other than the Restoration that misunderstands the scriptures’ purpose. More on that in what follows.) Creationists love to talk about ‘macroevolution’ as if it was some mysterious magical thing that is problematic for evolutionary biology—science’s dirty little secret we don’t want you to know about.

Take the Discovery Institute, an evangelical front organization promoting Intelligent Design Creationism (ID), which is attempting to backdoor creationism into the schools. Macroevolution plays a big role in their mythology (is there another word for it?). For example, in their summary The Scientific Controversy Over Whether Microevolution Can Account For Macroevolution, they say,

“The scientific controversy over whether processes observable within existing species and gene pools (microevolution) can account for large-scale changes over geological time (macroevolution) continues to this day.”

That statement is based on either ignorance or deception (a well-established criticism of ID—even in the Dover Trial the judge found them engaging in lies, deception and misdirection (and who was it in the Garden of Eden that used those tactics . . . um it will come back to me).) Of course, to get to this point in the summary, they’ve just used science from the 1930’s. Then they proceed to take a bunch of out of context statements from evolutionary biologists today to make it look like there is a controversy. Macroevolution serves the role of straw man in ID circles. But it’s commonly enough repeated that maybe a closer look is warranted for people who are generally confused by the smoke they are pumping out of their bellowing misinformation machine. For when you boil it down the ID Creationist blathering about macroevolution causing problems for evolutionary theory is an argument from ignorance.

First let’s get at what macroevolution is. Macroevolution in short explores evolutionary patterns discernible over large periods of time. It is not a different kind of process. It’s a difference in scale of interest. But it is completely explainable by micro evolutionary principles. In macroevolution one is looking at larger-scale patterns and asking questions like, ‘What patterns do we see in the major radiation of mammals after the Cretaceous extinction of the dinosaurs?’ ‘How has neural complexity increased over time?” Why did flowering plants, replace ferns, in the Cretaceous?” There is no sense is there some kind of problem in explaining how these emerge from microevolution, but rather the scale of interest is different. Just because one might use areal photography to study the large-scale patterns of forest landscape patches, it does not mean that there is some problem in scaling up from how individual trees grow or are important to explaining how forests expand or shrink.

In fact, it is useful to look at what’s being talked about within science. Here’s the debate from one journal, Evolution. There are many such journals. This is what scientific activity looks like (you won’t find any such thing for ID). Peak into the vibrant research going on with macroevolution. Look at science in action! There are no debates close to what the creationists imagine–that there is some hard problem science isn’t grappling with moving from ‘micro’ evolution to ‘macro.’

Go There. Type macroevolution into the search bar.

What you see is lots of activity. Macroevolutionary models, data, theory, analyses, questions, debates, coming from genetics, embryology, the fossil record, etc.

Why is macroevolution so glommed onto by creationists? Because they reject a priori that species can evolve across ‘kinds.’ It is the archaic idea from antiquity that species represent a “Fullness of Forms” meaning that the species we see are all the species that are possible, and that there are no gaps. Species are fixed in this view and form natural boundaries that cannot be crossed. While the origin of this has its roots in Plato, it really came into its own in the Neo-Platonist writings of Plotinus and from his work into Christianity. There is a wonderful article on this by Sam Brown in the current issue of Dialogue and how it affected Mormon thought, but the basic idea is that species are fixed and immutable and form a hierarchy from high to low with God, angels and men at the top, and beasts below in a great chain of being. It is a particular reading of Genesis that has its origin late in Christian thinking, but became an important doctrine in explaining early attempts at natural history (So if you like your Mormonism mixed with ideas developed in the Medieval ages by all means keep this unsupported notion.).

This is why you find the Creationists completely disengaged in the actual science of macroevolution and make the claim that it hasn’t been adequately explained. If you dissect their claim, what they are really saying is ‘We haven’t read any books on it (there are many), read any of the papers, engaged in the actual debate, examined the evidence, however, based on our ignorance of the arguments we say it’s a problem and so it is.” Why engage with evidence when you don’t have to heh? In fact, their argument can be boiled to, “I will believe macroevolution when I see it happening. Since no one has seen it in action (an impossibility given the time scales necessary) it isn’t true.” No standard evidence from numerous collaborating stories in every discipline from geology to biology, will be accepted. Confirmations of the grand story of evolution on earth macro and micro are ignored.

The absurdity of their position becomes clear if one looks at galaxy formation and evolution. We cannot watch a galaxy grow age and such. The time scales are too vast. But we know a lot about how they evolve by catching varying stages of formation and piecing together what happens between. So we have very nice sequences from very young galaxies to very old ones that have evolved in various ways. However, there are gaps. We don’t have a continuous sequence. We make inferences from one stage to the next based on what we do have in the sequence. Where we are missing data, we know of no magic that needs to be evoked to get from one to the next.

Just as we do in the fossil record.

ID Creationists are OK with this because there is no implicit idea they are reading back into it of the great chain of being , e.g., that galaxies form an immutable ‘kind’ of galaxy. Therefore it makes sense, even to them, that galaxies evolve into their various kinds from simpler and less developed galaxies.

To biologists species are not immutable. They are formed by DNA and developmental forces that are, in fact very, malleable. There is a large debate going on right now in biology if ‘species’ is even a useful idea. It is clear that any boundary of one species becoming another must be instantiated in the DNA and there just isn’t any. Like the galaxies above we have tons of evidence that macroevolution is not only easy to explain using basic evolutionary theory, but there is a massive amount of evidence supporting it. If you disagree attack the science as it is being produced, don’t run around saying, I won’t believe it until I see it happen in real time. If that’s your goal, hone your skills on galaxy formation. There is way less evidence about that than there is for the macroevolution of life on earth.

The ID notion that macroevolution presents a problem to evolutionary theory is just based on a refusal to confront what actually has been done in the field. An argument from ignorance

Be Sociable, Share!

16 comments to Macroevolution and the argument from ignorance

  • I’ve always wondered what the difference between “macroevolution” (a word which only creationists of one form or another use) and “common descent” (a word which scientists use) is supposed to be? Anyone?

  • Yes, it always bugs me that creationists misuse biological vocabulary, such as microevolution versus macroevolution. Both concepts encompass speciation — because evolution on a big scale emerges from evolution on a small scale.

    Pardon me for promoting: Special Tests of Special Creation.

    Also, I highly recommend: A Molecular Phylogeny of Living Primates, newly published in PLoS GENETICS.

  • [...] SteveP explains why macroevolution isn’t as hard to deal with for evolutionary biologists as some might have you b…. [...]

  • Dave (not Dave C.!)

    So Steve, have I got this right? Macroevolution is evolution over large time scales, wherein species change from one “kind” to another. Creationists do not acknowledge that such changes can occur, in part because no one has ever seen them happen. Do Creationists consider bacteria to be alive?

  • Rich

    Evidence abounds, under creationist’s very noses in fact. They don’t have to look any further than the folks next door (like I have) or down the street who own horses and/or donkeys. The two animals are very similar genetically — obviously have common equine ancestry, as evidenced by the fact that you can still breed horses and donkeys. The resultant offspring are mules. And mules evidence the fact that the parents ARE different species, since mules are sterile. The parents have just “stepped over the macroevolutionary boundary” from each other, so to speak. Close, but not close enough to produce reproductively viable offspring. This is just one example of many (e.g., Napoleon Dynamite’s “Ligers”, seagulls, etc.).

  • And as Dave says, bacteria are another example of species concept breakdown. Some are so promiscuous they’ll exchange DNA with anyone–even vastly different taxa.

  • SteveP

    Thanks S. Faux! I just put your post on the side bar. Great stuff!

  • raedyohed

    Jeff,

    If I were pressed to define macroevolution, which I think is not a very useful term anyway, I’d have to say that it seeks to define the patterns of differentiation and divergence between sister species after they have become genetically isolated from one another. So in a sense common descent, or in other words the sharing of a gene pool, the subsequent emergence of an incipient species, followed by genetic isolation and differing regimens of selection all precede what is studies at a macroevolutionary scale.

    Alternately, we could define macroevolution as the study of the development of present day traits from their earliest homologous features. The development of the eye from the earliest photoreceptors for instance, would be a topic that falls under macroevolution if used in this sense. We can use common descent as a framework onto which we overlay a history of trait modification. Under both definitions common descent is a built-in assumption.

    I think this is part of the confusion, since the patterns of divergence observed at large time-scales are sometimes pointed to as “evidence” for “macroevolution.” I think this has it backwards. Forensics (the parsimonious correlation of paleontological, geological, and genetic data) is where the bulk of the evidence for common descent is. Common descent is then used as the deductive framework for elucidating the patterns of diversification or modification over large time scales. Just my POV. Others’ mileage may vary.

  • I am not a creationist nor am I an IDer. I am a good old run of the mill skeptic with a background in the philosophy of science who thinks that moving an idea beyond theory status to law status requires firm empirical evidence, the kind that arises from controlled crucial experimentation. IMO, such evidence is lacking in macroevolutionary research, hence this theory has not achieved factual/law status.

    As professor Peck has eloquently pointed out, “macroevolution in short explores evolutionary patterns discernible over large periods of time…[that are] completely explainable by micro evolutionary principles.” Certainly there is nothing wrong when evolutionary science claims that macro is just micro over long periods of time, but such explanations do not make a theory into law, no matter how much factual microevolutionary evidence is gathered to support the macro hypothesis.

    Macroevolutionary researchers need to demonstrate change across life forms via microevolutionary processes in a controlled study. The experiment needs to be set up so that the theory being tested has a chance to either pass or fail. In short, frame a testable hypothesis that posits moving from one life form to another across generations via natural selection acting on random mutations. This is not good old fashion “moving the goal posts”, this is good old fashion philosophy of science. (Lest readers think of me as being one sided, I wish to point out that an inability to carry out crucial experiments is also a major limitation of ID.) Demonstrable, crucial evidence is lacking.

    Does not being able to frame and carryout crucial experiments mean that macroevolution is not scientific? No. It is scientific. Contrary to what Karl Popper taught in his landmark book “Conjectures and Refutations,” a theory need not be subject to falsification via hypothetico-deductive testing to be called scientific. The inductive mode of science (i.e., collecting observations and building theories) is every bit as scientific as the deductive, justification mode of science. It’s just that inductive methods are great for building and developing a theory – they are not so good at justifying a theory, and that, my friends, is where macroevolutionary research is at today.

    Go ahead and believe that mankind evolved all you want; there is plenty of inductive evidence leading to this conclusion. But realize that the theory lacks crucial experimental evidence.

  • Dave

    Not only do bacteria exchange genes with unrelated organisms, they do it amazingly quickly and often, so that we get new “kinds” regularly. I guess my point is that no one needs to argue that we need very large time periods to see macroevolution. Microbes are “macroevolving” in real time.

  • “theory lacks crucial experimental evidence”

    Dave you may want to update your philosophy of science a bit. While I find your view of theory and experiment endearing, in a nostalgic sort of way, you might want to come up to at least the 1950′s with Duhem’s The Aim and Structure of Physical Theory (1954) and especially the section, “A ‘Crucial Experiment’ is Impossible in Physics.” The second half of the second century pretty much makes every thing you said passe. You may want to explore how philosophy of science is done today, and if you are going to talk about philosophy of biology, you especially may want to find out in which ways its turned from the 1960′s on. Science has grown not only in content, but in how it is done. While I don’t have time to dismantle all your misunderstandings of science this post provides an overview.

  • Dusty R.

    >>I am not a creationist nor am I an IDer.

    Really. Is this not you? –> http://www.mormonsandscience.com/1/post/2009/1/expelled-exposed-exposed.html

    http://www.mormontimes.com/article/8928/Make-room-for-God-in-the-sciences—-again

    You always seem to be fighting for that side, Dave. Just sayin’. You seem to work really hard at trying to *appear* neutral, though.

    >>I am a good old run of the mill skeptic with a background in the philosophy of science…

    To clarify, is that your professional background or a hobbyist background? I seem to remember you having a professional background in something else from the above link…

    “A Brigham Young University and Salt Lake Community College professor of *psychology and statistics*, Collingridge said a few movements are responsible for rendering science “Godless and God-hostile.”

    >>…who thinks that moving an idea beyond theory status to law status requires firm empirical evidence, the kind that arises from controlled crucial experimentation. IMO, such evidence is lacking in macroevolutionary research, hence this theory has not achieved factual/law status.

    You continue to (erroneously) think that scientific theories graduate into laws or ‘facts’.

    A scientific theory is different from the ordinary usage of the word theory (i.e. it’s often used to mean a “haphazard guess”). In the scientific sense of the word, a theory is weightier — and has more explanatory power — than a fact, law, observation, hypothesis, or prediction.

    The Theory of Evolution and speciation is accepted and now unquestioned in the scientific community. There are other scientific theories that are also unquestioned as to their overall validity. For example:

    The Cell Theory of Organisms (organisms are made of cells)
    The Germ Theory of Disease (a theory that proposes that microorganisms are the cause of many diseases)
    Atomic Theory (nothing has refuted the fact that all matter is composed of atoms)
    Heliocentric Theory (the earth orbits around the sun)

    Think about those abovementioned theories for a second. Do you question them? So, why this notion of “it’s only a theory”?

    If you do question them, you’re free to write up a scientific paper on why they’re not valid…if you can convince academically minded people, you will win the Nobel Prize, hands down. If you don’t win (and even if you do), be ready for the crushing questions you’re sure to receive as a response.

    I’d recommend reading this, Dave –> http://chemistry.about.com/od/chemistry101/a/lawtheory.htm

    >>Go ahead and believe that mankind evolved all you want…. But realize that the theory lacks crucial experimental evidence.

    Now we come to it. It’s funny that when someone has a real problem with evolution, it’s not really all of the side-stepping ID talking points (like macroevolution, etc, or even really that any other organisms evolved) — it’s that they have a fundamentally, personal religious problem with humans having evolved. Not a scientific problem with it.

    There are nearly countless ways that evolution has been and is being tested. If you have a hypothesis that two species are closely related/sister taxa, then you can test that hypothesis through many different fields of study and many different tools and methods. Let’s take humans and chimps for an example. Not because I know that this example will get your ire up the most (though that is tempting), but because it’s one of the best studied examples.

    *First, you can test the hypothesis by comparing behavior. Let’s take tool and weapon use. Of all animals, humans use tools and weapons the most, but of all the animals, chimps and great apes, by far come in second place, using tiny twigs to catch termites and larger ones to kill prey and enemies. This is exactly what your hypothesis and evolution theory would predict.

    What about parental care behavior? Maybe you could look among all of the animals and see which ones have two breasts and cradle their infants while sitting upright.

    http://pubpages.unh.edu/~jel/images/bonobo_mom_baby.jpg

    Okay, we could go on and on in testing the behavioral department and find further confirmation, so let’s move on to another method of inquiry.

    *Second, you can test the hypothesis by comparing morphology between humans and all other animals and seeing which one(s) share the most synapomorphies with humans. Out of millions of types of organisms, it turns out that chimpanzees win again.

    *Third, you can test the hypothesis by comparing biogeography. Closely related species should have their origins in similar parts of the world. All of our closest living relatives, chimps, bonobos, and gorillas come from Africa. As for humans, it turns out that the Out of Africa hypothesis has been supported by testing, since nearly all hominids come from that region too.

    *To boot, population genetics tells us that the most diverse populations will be the place where the lineage came from. It has been confirmed that humans are more diverse in genetic makeup in Africa than in any other place in the world. This also happens to be the place where great apes are the most diverse. So, even more evidence from comparative biogeography.

    *Fifth, you can test the hypothesis by comparing human DNA with the DNA of other organisms and seeing which one most resembles that of humans. Chimps again! (Since DNA comparisons test evolutionary distance, i.e. that I’m 100% related to myself, that I’m less related to my sister, and even less related to my cousin, it should also show that distance between species, and guess what, it does. When molecular biology/comparing DNA tests was discovered, this was the thing that could have blown the Theory of Evolution to smithereens, but it has stood up, and has been confirmed in even greater detail. Very cool.)

    *Sixth, you can test it by comparing karyotype (or number of chromosomes). Evolution theory predicts that closely related species will have similar/close numbers of chromosomes.

    For example, Mules and Hinnies have 63 chromosomes, a mixture of the horse’s 64 and the donkey’s 62.

    In 1925, the evolutionary relatedness of ratsnakes was tested by comparing morphology. This led to a conclusion that Baja Ratsnakes and Trans-Pecos Ratsnakes (both were included within the genus Elaphe at the time) were each others’ closest living relatives, in other words, that they shared a Most Recent Common Ancestor, more recent than either of those two species do with any other snake species. This conclusion would predict that they would also share a closer number of chromosomes than they would with any other species. In 1985, this was confirmed when it was learned that Baja Ratsnakes have 38 chromosome pairs while Trans-Pecos Rats have 40. All of the other members of their tribe — many species in several genera — have 36.

    Getting back to humans and chimpanzees, humans have 23 pairs while chimpanzees have 24. See a pattern here? Not only that, but karyotype morphology should leave fossil-like evidence of its past. Evolution/common descent would predict that you could find that extra 24th chromosome buried somewhere in our karyotype. And it was right. That 24th chromosome, which chimps have, was fused to our human chromosome #2, making one big chromosome from two smaller ones attached at the telomeres. The hypothesis was tested and confirmed again.

    http://upload.wikimedia.org/wikipedia/commons/7/71/Chromosome2_merge.png

    This is all very commonly known stuff in the field of biology (see here http://en.wikipedia.org/wiki/Chromosome_2_(human)#Evolution).

    I have shown you several ways to test this hypothesis of common descent across a more-or-less “macro” resolution. There are many other ways, and new studies, experiments, and tests confirm this hypothesis constantly in laboratories and field studies throughout the world’s many institutions of higher learning. These findings are published in journals on a constant basis. No offense, but evolutionary biologists get really tired of pointing the willfully ignorant to the very accessible watering hole of information. (Most of this stuff is on wikipedia, for crying out loud.) Sticking your fingers in your ears and covering your eyes doesn’t mean that the music isn’t playing, my friend.

  • SteveP, how can we possibly be buddies if you are not on Facebook anymore??

  • This is off topic, but could you guys recommend a reading list of up-to-date books that would take me from Bio 100 to knowing something real about the current state of research into evolution? I have an advanced graduate school background (ABD), but not in the sciences (linguistics and public policy).

  • Dusty R.

    Owen,

    Here are some good, quick paperbacks on the subject:

    “Why Evolution is True” by Jerry Coyne (a great overview of evo bio, as a whole)

    “Relics of Eden” by Dan Fairbanks (molecular bio evidence for human evolution, written by the BYU Dean of Undergrad Studies)

    “Your Inner Fish” by Neil Shubin (a cool story of the science of finding transitional species or “missing links”)

  • Craig F

    DAVE C “Macroevolutionary researchers need to demonstrate change across life forms via microevolutionary processes in a controlled study….
    Go ahead and believe that mankind evolved all you want; there is plenty of inductive evidence leading to this conclusion. But realize that the theory lacks crucial experimental evidence.”

    What is Dave C suggesting? That we take an ape and observe it till it evolves into a homo sapien. Please. Prof. Peck is right…get with the times. I am just finishing up an undergrad in biology and even I understand the power of a theory even without what you define as “crucial experimental evidence”. And thank you Rusty for your explanation. It was very informative.

    I love this blog…it is refreshing to know that there are like minded individuals regarding many of these topics (although I would not presume to be nearly on the same informed or intellectual level as most of you… i enjoy your help in understanding these issues.

Leave a Reply

  

  

  

* Copy this password:

* Type or paste password here:

98,681 Spam Comments Blocked so far by Spam Free Wordpress

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>