Friday, April 13, 2012

Teaching Evolution in Tennessee


The state of Tennessee is about to have a new law that impacts the teaching of science in their public schools. Here's how the National Center for Science Education (NCSE) describes the law.
Nicknamed the "monkey bill," HB 368 would, if enacted, encourage teachers to present the "scientific strengths and scientific weaknesses" of topics that arouse "debate and disputation" such as "biological evolution, the chemical origins of life, global warming, and human cloning."
It doesn't take a mental giant to see where the Tennessee legislators are coming from. They want to support teachers who challenge evolution in the classroom. Most of those teachers will, of course, be creationists of one form or another.

But here's the problem. Those ignorant legislators have been very clever to avoid mentioning religion or creationism. On the surface, the new law looks perfectly reasonable.After all, who wouldn't want students to learn both the scientific strengths and weaknesses of current theories of biological evolution?

The issue has prompted many scientists and teachers to come out against the bill. They hoped that the Governor would veto it. He didn't. A petition signed by thousands of Tennesseans was presented to the Governor Bill Haslam [Governor petitioned to veto "monkey bill"].
Explaining her opposition to the bill, petition organizer Larisa DeSantis, who teaches in the Department of Earth and Environment at Vanderbilt University, told MSNBC, "What it does is bring the political controversy into the classroom, where there is no scientific controversy," adding, "As a science teacher I would say there is no controversy over evolution or climate change in the scientific literature ... Sure, we argue about the details. But these are core ideas … that are not controversial."
This seems typical of the rhetoric over this bill and a similar one that was passed in Louisiana a few years ago. Evolution defenders seem to be committed to the idea that the way evolution is taught in high schools is not controversial and therefore there is no need to discuss any weaknesses. I doubt that this is true.

I don't know what the standards are in Tennessee but I recently had a chance to look at proposed national standards for teaching evolution as advocated by the National Academies in A Framework for K12 Science Education.
Biological evolution explains both the unity and the diversity of species and provides a unifying principle for the history and diversity of life on Earth. Biological evolution is supported by extensive scientific evidence ranging from the fossil record to genetic relationships among species. Researchers continue to use new and different technologies, including DNA and protein sequence analysis, to test and further their understanding of evolutionary relationships. Evolution, which is continuous and ongoing, occurs when natural selection acts on the genetic variation in a population and changes the distribution of traits in that population gradually over multiple generations. Natural selection can act more rapidly after sudden changes in conditions, which can lead to the extinction of species. Through natural selection, traits that provide an individual with an advantage to best meet environmental challenges and reproduce are the ones most likely to be passed on to the next generation. Over multiple generations, this process can lead to the emergence of new species. Evolution thus explains both the similarities of genetic material across all species and the multitude of species existing in diverse conditions on Earth—its biodiversity—which humans depend on for natural resources and other benefits to maintain themselves.
This is a proposal from the leading scientists in the USA. It's reasonable to assume that something similar is in the curriculum standards for Tennesse. For the sake of argument, let's assume that's true.

Let's assume that a knowledgeable high school teacher in Tennessee decides to teach her students that this definition of evolution is incorrect, or at least incomplete. Let's imagine that she points out several weaknesses, including the fact that analysis of DNA sequences shows little support for the idea that natural selection is responsible for the diversity within and between populations/species. What if she teaches her students that random genetic drift, not natural selection, might be behind most speciation events?

That teacher is posing a direct challenge to the standard curriculum that she is required to teach. Shouldn't she be protected from firing?

Do you see the problem? As scientists we can't proclaim that evolution is taught so well in the public schools that there is no legitimate scientific debate over the fundamentals of evolutionary theory. We can be almost certain that evolution is taught poorly in many schools and there's plenty of opportunity for legitimate criticism in the classroom.

Let's think of another example. Imagine a teacher who is really concerned about what the fossil record shows. He teaches his students that the fossil record does not show the gradual transformation of one species into a new species as the curriculum implies. Instead, new species seem to spring into existence in the blink of an eye as demonstrated by Gould and Eldredge over forty years ago. Furthermore, the Cambrian explosion shows that all animals appeared at once in the fossil record. This is not consistent with evolution.

Should this teacher be fired while the other one is protected? It's very difficult to make a law that distinguishes between the correct exposure of weaknesses in the first example and the incorrect criticism in the second example.

The goal should be to create a curriculum that exposes the students to critical thinking while, at the same time, getting the basics correct. Until that happens, we have no right to say there aren't any weaknesses in the way evolution is taught in high schools in Tennessee.


19 comments:

  1. Evolution defenders seem to be committed to the idea that the way evolution is taught in high schools is not controversial and therefore there is no need to discuss any weaknesses. I doubt that this is true.

    Until that happens, we have no right to say there aren't any weaknesses in the way evolution is taught in high schools in Tennessee.

    Strange, I don't recall reading anyone defending the way evolution is taught as perfect. Nor do I recall anyone holding out for the distinct proposition that the Modern Synthesis or modern "consensus," to the extent such a consensus can be said to exist, is without any weaknesses. If the latter were true, why waste time doing research?

    It's very difficult to make a law that distinguishes between the correct exposure of weaknesses in the first example and the incorrect criticism in the second example.

    Really? You think it's that difficult to separate the core idea that evolution took place and is responsible for the diversity of species, from either how effectively it is taught, or whether there are any points of scientific dispute regarding the main biological drivers of the evolutionary process?

    Much more to the point (regarding US law at least), do you think it is qualitatively more difficult than other legal judgments courts are called upon to make, to determine whether laws with a religious purpose and/or effect can be separated from those that do not have such purpose and/or effect?

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  2. Really? You think it's that difficult to separate the core idea that evolution took place and is responsible for the diversity of species, from either how effectively it is taught, or whether there are any points of scientific dispute regarding the main biological drivers of the evolutionary process?

    Yes, it's difficult because you need to define evolution in order to make the case. If you say that evolution is responsible for the diversity of species then doesn't that depend on what you mean by "evolution"?

    Much more to the point (regarding US law at least), do you think it is qualitatively more difficult than other legal judgments courts are called upon to make, to determine whether laws with a religious purpose and/or effect can be separated from those that do not have such purpose and/or effect?

    I don't understand the American law as it applies in these cases. What I do know is that many Supreme Court justices struggle with the problem. That's why none of the relevant rulings have been unanimous.

    Do you think the teacher in my second example would be found guilty of teaching religion in the classroom? What about the first teacher? Would she be found guilty because she challenges the version of evolution promoted by the National Academies?

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    1. What I do know is that many Supreme Court justices struggle with the problem. That's why none of the relevant rulings have been unanimous.

      Very few cases important and controversial enough to get to the Court, which in most instances can choose the cases it takes, are the sorts of disputes amenable to unanimous decisions. :-) But I don't think of this as terribly dissimilar to, for example, finding a research topic sufficiently interesting to make a good thesis subject. If the proposed topic is about something on which there is virtually unanimous agreement among scientists, is it worthwhile recapitulating subject matter that is already well-worn? Yet you wouldn't want a topic so hard it was effectively impossible for the student to come to grips with effectively. Within these constraints, thesis topics are chosen by the thousands every year. Similarly, just because the Court is not unanimous doesn't mean it's impossible to make sense of these cases.

      Do you think the teacher in my second example would be found guilty of teaching religion in the classroom? What about the first teacher? Would she be found guilty because she challenges the version of evolution promoted by the National Academies?

      Well of course the question wouldn't be whether an individual is innocent or guilty of a crime, but whether or not state or local requirements setting out such principles for teaching about evolution would pass Constitutional muster. On that question, a competent lawyer would never take a case to court with as little evidentiary support as the bare facts you've provided. Fortunately, real life provides far more context, such as school board members raising money for favored textbooks from fellow church members, then attempting to lie about it in court; and drafts of the favored textbook containing phrases like "cdesign proponentsists."

      Yes, it's difficult because you need to define evolution in order to make the case. If you say that evolution is responsible for the diversity of species then doesn't that depend on what you mean by "evolution"?

      True, you've caught me leaping (saltating?) from "a process that results in heritable changes in a population spread over many generations" to issues of speciation. Still - aren't heritable changes in a population spread over generations a minimum requirement for speciation? Split one population into two, wait however many generations you like, and if no evolution, no speciation, it seems to me. Change the environment of a single population as radically as you like, wait as many generations as you wish, and again, if no heritable changes over time, no speciation. So if you change my original statement to describe a role for evolution in speciation along the lines of evolution being necessary for speciation, and involved in all the natural speciation that has taken place on earth...? Or if that has problems, then I still have confidence something relatively satisfactory would not be insuperably difficult for legions of scientists and educators to formulate.

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  3. This law turns the clock back nearly 100 years here in the seemingly unprogressive South and is simply embarrassing. There is no argument against the Theory of Evolution other than that of religious doctrine. The Monkey Law only opens the door for fanatic Christianity to creep its way back into our classrooms. You can see my visual response as a Tennessean to this absurd law on my artist’s blog at http://dregstudiosart.blogspot.com/2012/04/pulpit-in-classroom-biblical-agenda-in.html with some evolutionary art and a little bit of simple logic.

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    1. This law turns the clock back nearly 100 years here in the seemingly unprogressive South and is simply embarrassing.

      Absolutely. If it weren't for the fact that ultimately the abolition of slavery hung in the balance, I'd happily go back in time and tell Lincoln, "Nah, let 'em go... trust me; the REAL United States will THANK you one day." It sucks that the price of the 13th, 14th, and 15th Amendments was hanging onto these people and their 15th century conception of reality.

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  4. If evolution is defined as common descent, there is no controversy, AFAIK. The problems that Prof. Moran is raising have to do with the mechanisms of evolution, e.g. the relative importance of natural selection, genetic drift, and possibly other mechanisms. Here there is genuine disagreement between evolutionary biologists, e.g Richard Dawkins and Larry Moran don't see eye to eye.

    What I think should be taught relative to mechanisms in high school biology classes is descriptions of, at least natural selection and genetic drift with a statement that scientists differ as to their relative importance. I suspect that the text being utilized will probably have a bias one way other, e.g. Larry Moran's book probably doesn't agree with Ken Miller's book on this issue. This is not an issue that is going to be resolved anytime soon and high school biology classes have too much material to cover to spend inordinate amounts of time on unsettled issues like this one.

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    1. So, you agree that there are important controversies in evolution and they should be taught in high school?

      If you are correct then what do you think of those who attack the Tennessee law by saying there are no "weaknesses" or arguments about the theory of evolution? (See comment above by Brandt Hardin.)

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    2. I don't know; is it far to call differences of opinion on emphases "weaknesses"? They don't risk disestablishing evolution's reality--but that's what it amounts to in the eyes (or is it "lies"?) of creationists. To illustrate, if everyone agrees, say, beans, hamburger, chilis, and a tomato bases of some kind are the fundamental ingredients of chili con carne, is quibbling over their relative proportions a "weakness"? One way or another, you still end up with chili con carne. But let's be honest here... these people want to use such minutiae to convince people that chili therefore doesn't really exist at all... and I think that's fiendishly dishonest.

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    3. AFAIK, there are no arguments and there is no controversy about common descent in general, any more then there is a controversy about the inverse square law of gravity. Apes and humans had a common ancestor. Not even Michael Behe, based on his Dover testimony, rejects common descent. As I stated, there are arguments as to the mechanisms that drive evolution, although the fantasies of the IDiots are not among them.

      I go along with Ernst Mayr, as to the 5 elements of evolution, namely old earth/universe, extinction, most living animals not present millions of years ago (crocs are an exception), common descent, and mechanisms. There isn't time in a high school biology course to get into lengthy discussion of mechanisms. Given the breadth of the subject and the amount of material to be covered, teachers would be fortunate to spend as much as 1 class period, if that, on mechanisms in a 1 year high school biology course. As I recall from my high school physics courses, there was only time to cover the basics of mechanics, electromagnetism, and optics. There was certainly not time to get into specific areas such as elementary particle physics, solid state physics, low temperature physics, etc., etc. and the same must be true for biology.

      By the way, the relative importance of natural selection and genetic drift is not a "weakness". It's an unsolved problem. Just like quantum gravity is an unsolved problem in cosmology. Doesn't mean that general relativity and quantum mechanics have weaknesses. They just don't explain everything as we sit here today

      I am not a biologist and have never taken a course in biology. I took a 1 semester course in what was called life science in junior high school a million years ago and evolution was not mentioned. On the other hand, I have read numerous books on evolution by Mayr, Gould, Miller, Coyne, Dawkins, and Ayala. so I think I have a fair layman's feel for the subject. I am certainly totally unqualified to comment on the relative importance of natural selection vs genetic drift and will not do so.

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  5. If the entire section on evolution in the high school curriculum was confined to one hour then it's quite possible to make statements that all scientists could agree with. But you'd have to be very careful.

    Under those circumstances, you could attack the bill on the grounds that there is no controversy and evolution is taught correctly. (Assuming that the curriculum was properly designed.)

    However, if that were truly the situation then there would be no time to discuss any other weaknesses and the bill is pointless.

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    1. One hour would be totally inadequate to discuss the 5 items identified by Mayr which constitute evolution. I would allocate 1 hour just to discuss mechanisms, and probably a week to discuss all 5.

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  6. Come on, Dr. Moran. Surely you realize that this bill is not about protecting poor persecuted teachers who are only trying to discuss legitimate scientific disputes. The bill specifically says:

    "The teaching of some scientific subjects, including, but not limited to, biological evolution, the chemical origins of life, global warming, and human cloning, can cause controversy;"

    Not that there are scientific controversies within these subjects, but that merely teaching these subjects can cause controversy. And note the examples given: evolution, chemical origins of life, global warming, and human cloning. These are all topics that are controversial for religious, ideological, and/or ethical reasons. Sure, there are scientific controversies in these fields as well, but the Tennessee legislators couldn't care less about that.

    I'm quite certain that there are weaknesses in how evolution is taught in Tennessee high schools, and undoubtedly in the vast majority of US high schools. I'm also quite certain there are weaknesses in how enzyme theory, atomic theory, chemical bonding theory, and every other theory is taught in high school science class. Yet no one ever worries about the poor teachers who want to discuss the strengths and weakness of those theories. Why do you suppose that is? Why do we only ever hear about the 'strengths and weaknesses of evolution, chemical origins of life, and global warming?' (Rhetorical question.)

    Of course, it's entirely legitimate to discuss strengths and weaknesses of every scientific theory. The problem is that evolution is being singled out. What message does it send when students get taught topic after scientific topic as if it's settled fact, but then when they get to evolution, suddenly there's a "strengths and weaknesses" session? I'd be happy if strengths and weaknesses were covered for every topic, but that's not how it will be.

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    1. I think you're missing the point. The creationists have been very clever in promoting "academic freedom" and avoiding any direct mention of religion. They know full well that our side will have trouble opposing goals such as critical thinking and presenting both sides of the issue.

      However, their clever strategy has reaped even more rewards than they could have imagined because some of our allies are defending what is currently being taught as beyond reproach. This sort of dogmatism plays right into their hand and puts our allies in the position of being opposed to critical thinking.

      What we should be doing is to admit that teaching evolution is fraught with problems because many of the topics are difficult for the average high school teacher with no scientific background. We should admit that there are many topics where there is legitimate scientific controversy but they are being taught as though they were scientific facts.

      Our goal should be to develop a curriculum where only the genuine scientific consensus is being taught. We should also encourage the teaching of legitimate scientific controversies, such as the significance of evolutionary psychology, in order to promote critical thinking.

      What we should NOT do is pretend that evolution, or any other topic, is written ins stone. That sort of stance is more typical of Christians than scientists.

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  7. Help keep Oklahoma from becoming the third state to adopt an ‘academic freedom act’!! We have mounted as many messages as we can to the entire Senate asking that they remove the amendment to HB 2341. The Senate floor amendment by Sen. Steve Russell takes the entirety of HB 1551 (copied from the LA law) Non-residents might help as well, but if you do – be respectful. One can send one message to the entire Oklahoma Senate by copying the entire address list and pasting into the ‘TO’ block, mentioning opposition to amendment to HB 2341 and add just a few sentences in the body; a long message not needed – we just need NUMBERS in opposition. We appreciate the help readers of this blog may provide!
    More information and the addresses of the Oklahoma Senate are on the OESE web site ( http://www.oklascience.org/ )

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  8. Larry, I think you're missing the point here in order to be pendantic.

    In the absence of this law, there have been exactly zero cases of a teacher being fired, censored, reprimanded, or otherwise scolded for teaching about the open questions in evolutionary theory. So what is the purpose of this law? Is it to protect those teachers advocating for such a law because they were worried about never before occurring issues with teaching the weight of genetic drift versus natural selection on speciation? Extremely unlikely, but if you have evidence to the existence of such a group of teachers and the issues they had, I will happily change my stance. Barring that evidence, the law, like the plethora of laws that predate it, serve to provide a toehold to allow Christian creationism to be introduced as an equal weight scientific explanation to explain the diversity of life.

    FYI The standards also note that RNA is composed of 4 nucleic acids. I don't see the state of TN trying to pass a law protecting teachers who want to point out that other rare nucleic acids can be found, like inosine in tRNA.

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    1. Larry, I think you're missing the point here in order to be pendantic

      No I think it's you who is missing the point.

      This is a political battle but we (evolution defenders) are being steered into a position that we can't defend. It's true that the creationists have been very clever but it's our fellow scientists who are willingly painting themselves into a corner.

      We all know that this is not really about protecting teachers who deviate from the curriculum. Those teachers are often the best teachers and they should be encouraged. I am not comfortable with those who say that teachers should stick to the proscribed curriculum because it's always correct.

      We should actually be embracing the controversies in evolution since it's a very effective way of teaching critical thinking. The real problem here is that our side has little confidence in the teachers. That's why we want to restrict them to teaching only the "scientific facts" that are in the curriculum. If our side really believed that all the teachers would teach evolution correctly then what's the problem?

      I can't imagine that such a law would ever be passed in Ontario since most of our high school teachers already teach about creationism in their science class. They point out how ridiculous it is to believe that all species sprung into existence 6000 years ago and how impossible it is to get seven billion people from Noah's family only 4500 years ago. Wouldn't it be wonderful if the new Tennessee law permitted teachers to say this in class?

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    2. Mr. Lorax has described the situation accurately.

      The folks who voted for this bill and the creationists behind them have not the slightest interest in the relative importance of genetic drift vs natural selection (they don't believe in either of them). They have no interest in real scientific controversies. To them, the notion of a 4.5 billion year old earth is controversial as they insist on a 6000 year old earth. To them extinction occurred via the global flood. Chimps and humans having a common ancestor, not a bit of it. They insist that chimps, humans and every other animal on the planet were specially created. Protecting the teaching of nonsense like this is the purpose of these laws.

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  9. Dr. Moran, you wrote:

    "This is a political battle but we (evolution defenders) are being steered into a position that we can't defend. It's true that the creationists have been very clever but it's our fellow scientists who are willingly painting themselves into a corner."

    I agree it's a political battle, but where is the evidence that our fellow scientists are painting us all in a corner?

    You quote Larisa DeSantis as follows:

    "As a science teacher I would say there is no controversy over evolution or climate change in the scientific literature ... Sure, we argue about the details. But these are core ideas … that are not controversial."

    She's not claiming there are no controversies within evolution. She openly states there are arguments about the details. And she certainly doesn't claim that there are no weakness in the way evolution is currently taught. It's perfectly clear to me that she's saying there is no scientific controversy over the existence of evolution and climate change.

    And again, that's what this is all about. As I noted previously, the Tennessee bill doesn't say anything about controversies within evolution. It says that simply teaching evolution is controversial.

    I agree it would be a mistake to claim there are no weakness in the way evolution is taught. I just don't see any evidence that anyone is making that claim. The quote from DeSantis certainly doesn't, nor does the national standard you quoted (even though I agree it's flawed). If you have better evidence that this is happening, I'd like to see it.

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  10. By the way, there are good arguments that most speciation, at least in sexually reproducing species, is indeed caused by natural selection. Have you read Coyne & Orr's book Speciation?

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