Phylogenetic trees are essential tools for representing evolutionary relationships. Unfortunately, they are also a major conceptual stumbling block for budding biologists. Anyone who has taught basic evolutionary concepts to college undergrads (and probably high school students as well) has most likely dealt with students struggling to properly read and draw phylogenies.
Lucky for us, there is also a growing body of literature on the most effective ways to teach what has been dubbed “tree-thinking”. I have summarized this literature in a review due to be published in the journal Evolution: Education and Outreach (doi:10.1007/s12052-010-0254-9). The full text of the article is available at that link, and I have reproduced the abstract below.
Evolution is the unifying principle of all biology, and understanding how evolutionary relationships are represented is critical for a complete understanding of evolution. Phylogenetic trees are the most conventional tool for displaying evolutionary relationships, and “tree-thinking” has been coined as a term to describe the ability to conceptualize evolutionary relationships. Students often lack tree-thinking skills, and developing those skills should be a priority of biology curricula. Many common student misconceptions have been described, and a successful instructor needs a suite of tools for correcting those misconceptions. I review the literature on teaching tree-thinking to undergraduate students and suggest how this material can be presented within an inquiry-based framework.
The Great Clade Race, at Evolution 2010 meeting in Portland back in March: link (Quote)
Richard,
Thanks so much for this valuable resource. I will definitely use it to improve my teaching of evolutionary concepts. And thanks for providing the free link as well.
Can’t wait for the creopigeons to come crapping all over this one..
Students just don’t seem to get enough exposure to phylogenies when they take biology courses. I have found that when I lecture on phylogenies to audiences outside of evolutionary biology, they are mystified as to what the branches mean and what the order of tips means. Just having more opportunities to see evolutionary trees and play around with them would help a lot.
I don’t recall ever having had to respond to that question, “If we man evolved from monkeys, why are there still monkeys?”
And I have not encountered anyone who, to my knowledge, has difficulty with tree thinking.
But for those of you who have encountered it, what would be their response to the question, “If we are descended from cousins, why are there still cousins?”?
It seems to me that difficulty with tree thinking points to even deeper issues with reasoning and relationships. Has anyone explored the cognitive development of this ability?
Good paper. I love the “tree-thinking” research.
Really? I’ve hardly met a single creationist who understands that common descent = nested hierarchy tree. I’ve tried explaining dozens of times why the finding of nested characters is huge evidence for common descent, and creationists either have nothing to say, or they don’t think it’s good enough evidence, or they don’t understand that common descent can only ever produce this pattern. Can you believe there are people at UD who think that common descent is still ‘an unsettled issue’ because they don’t understand the tree of life?
I don’t doubt that they exist; they may even exist in my community
I just haven’t dealt with anyone who can’t grasp branching; and I have seen some pretty strange letters to the editor of our local newspaper. None have made that particular argument about descending from monkeys; rather they tend to focus on how evolution turns children into animals who run amok and commit homicide and suicide.
Thus I am curious about the cognitive development, or the impairment of that development, that would lead to an inability of someone to understand branching even as they can see trees all around.
That has to be a rather curious or pathological development with some pretty abnormal antecedents; although not necessarily surprising in some of these fundamentalist churches.
I’ll posit 2 general sources of difficulty. One would be that nested hierarchy thinking is not an obvious or emphasized mode of thinking. Biologists and Object Oriented programmers are the only 2 groups I can think off the top of my head that do this regularly. The second difficulty aside from the novelty of the structure is that typology plays a big role. I’ve never thought to actually do the experiment, but I’d bet given a tree labeled only at the tips, and asked students to describe the creature at each node they would almost certainly pick one of the two species and call it that or some variation. That’s for students who’ve had some exposure to the concept. The notion and ability to articulate that the node represents a population in itself with it’s own genepool and variety of traits. The last is an advanced but absolutely critical piece to realize to actually be using the tree correctly.
To Richard looking at your references, might I recommend Arnold Arons book Teaching Introductory Physics. There is a lot to be said for port his methodology to biology classrooms particularly since I think it helps to address some of the findings of Lederman and his colleagues on helping students understand nature of science.
Over supper this evening, I ran this question by my wife who understands cognitive development far better than I do.
She suggested that the problem may be something like the following:
“If evolution is about survival of the fittest, then why are the unfit still around?”
I think most biology instructors are already acutely aware of this problem. If that is what is really at the heart of the issue, then the problem with understanding trees may not be the real issue at all.
I have distant relatives who are fundamentalists and who also object to evolution along the same lines as what my wife suggested. Yet they do genealogy; so it doesn’t seem likely they are having a problem with “tree thinking.”
I wonder if the example of a partially completed jigsaw puzzle might be even better. Not only are there “nodes” to surmise, but it also requires a certain amount of gestalt to see the “big” picture.
Genealogy can be a double edged pedagogical sword however Mike because it creates the misconception of a single entity at the node instead of a population.
“Mind mapping” software is great for tree thinking. I use Freemind, which is free, for project management (nested tasks), writing (nested ideas), and sometimes for programming (nested objects, as JGB mentioned). I imagine it could also be very helpful for teaching phylogeny.
I have long been interested in misconceptions in physics as well. And this relates to the problems we find among ID/creationists who continue to spread misconceptions despite repeated attempts by the science community to get them to correct these.
I would hazard a guess that there are very strong emotional blocks to constructing trees in biology when lodged in the back of student’s minds is the notion that humans fit somewhere on these trees along with other creatures.
I can see why a fundamentalist would have no problem with genealogy but would have an extreme reluctance to place humans on a tree diagram with other animals.
But there is also that other misconception suggested by my wife – and I see that you mention it in your paper also – that somehow a “lower species” was less fit and therefore should not have survived to be on the tree.
The notion of population is similar to a problem we physicists have in with the notion of an ensemble in statistical mechanics. Now that issue really is a big step for most undergraduates.
I am wondering if a little “cloud” used in place of a node might help with the notion of these various lineages emerging from a population. Since it is unlikely that any particular fossil that represents an intermediary would lie exactly on a line to a given species, lines connecting common ancestors should only enter the cloud but not join at a node.
I think I also saw somewhere in genealogical research that one can infer much about the lives of one’s ancestors by looking at historical pictures or drawings depicting the clothing and other environmental factors in which the ancestors lived. One’s own particular ancestor may not have dressed exactly as depicted or had that particular beard or moustache, but he was probably something like that and he probably had many of the same customs and daily routines.
Oops,Richard Meisel’s paper, not your paper.
“Tree thinking” just doesn’t sound exalted enough.
How about “dendrophrenia”?
Might that lead to schizophrenia? ;-)
just wanted to say how much i appreciated the appearance of the term “boy howdy” … an indispensable tool for mocking gullible and undereducated amazement. i don’t believe mockery is ever the first resort, but some arguments eventually insist upon it. incidentally, boy howdy is also my intended future gay pornstar name
I love the concept of tree-thinking because that thinking led Darwin to think seriously of evolution. It was his moment of euphoria, so to speak, when he sketched a crude phylogenetic tree aboard HMS Beagle as it was sailing back toward England (I think this was while the ship was sailing either in the Indian Ocean or off the coast of Africa.).
Former teacher here. I remember when set theory was introduced and I had to teach it to 10-year-old children. I expected a really hard time, but to my amazement kids grasped and loved it. Since then I’ve been wondering if one should forget about teaching the tree model and start immediately with nested hierarchies.
Another successful outreach is the recent David H Koch Hall of Human Origins at the Smithsonian Natural History Museum. When the curator spoke at a AAAS Dialogue on Science Ethics and Religion colloquium, he noted how it “got through” even to religious audiences. Part of that success includes dealing with tree thinking and the other is the constant refrain “how do we know that”?
The event I mentioned above included newly installed director of AAAS DoSER, Jennifer Wiseman. She also has been recently elected as President of the ASA. Our annual meeting starts today in Washington DC. The ASA had a special showing of the Hall of Human Origins last night. Our executive director described it as follows:
Students need to understand the nature of science. A scientific theory is a consistent mathematical framework along with partial empirical verification. While the math must be fully consistent, the verification can never be complete. See “Teaching and Helping Students Think and Do Better” on amazon.
The following is a high-school-level curriculum that was recommended by the NAS in 1998. [Emphasis mine]
http://www.nap.edu/openbook.php?rec[…]&page=81
Another useful web page on this topic is here: http://evolution.berkeley.edu/evosi[…]adders.shtml
In my opinion this is also helpful concept in dealing with popular misconceptions introduced by ID. There is not some great chain of being with the higher end of the chain having more of some ill-defined sense of information. We also don’t come from apes but we both come from a common ancestor. In my opinion it’s imperative that this is taught at the high school level since most people don’t go on to take college-level biology.
Finally, I appreciate the concern of dealing with the concept of populations and all. My concern is that given the necessity for the public to understand this in order to be good citizens that introducing the concept would unnecessarily complicate things. There may be students who might get this but they will probably be going on to being involved with science at a professional level. I want to reach the majority who won’t.
Your definition of a scientific theory would rule out the theory of plate tectonics in the geological sciences and the Modern Synthesis of Evolution in biology, which are, respectively, the grand unifying theories of these sciences:
A number of people who have posted here have Ph. D. and/or master’s degrees (present company included) and have felt no need to advertise their credentials. The most notable person who has posted at this thread is Joe Felsenstein, a highly regarded evolutionary geneticist at the University of Washington. I don’t recall an instance where he referred to himself as Joe Felsenstein, Ph. D..
Of course one does not want to confuse the students by bringing in every conceivable complication, but I am worried about the level of oversimplification in many textbooks and museum displays. It would be ideal if we typically had characters in which we could reliably identify derived (apomorphic) states, and where parallelism and reversal never occurred. The real world is messier, and that is not conveyed to students or museum-goers.
Another problem is the equivocation on whether we are descended from apes. We of course are not descended from present-day apes. But we are apes. I know that I am descended from apes because I am descended from my mother and my father, and, like me, they were apes.
Fifty years ago biologists had (mistakenly) concluded that apes were a clade, a sister group to the human lineage. They then could say that “humans are not descended from apes, but humans and apes had a common ancestor”. This was comforting to many people who would be upset to think that they were descended from apes.
By thirty years ago this phylogeny had been replaced by one in which we were part of the clade of apes, and soon after we were understood to be a sister species to the two species of chimpanzees.
I am worried that we are still encouraging people to believe that the common ancestor of humans and apes was not an ape. It’s convenient, reassuring … and wrong.
Venus Mousetrap -
Actually, I don’t believe that. What I believe is that there are people who are authoritarian and biased in their thinking. They are determined to “fight against” the theory of evolution and common descent. They will will deny any supporting evidence and at least superficially “concur” with any argument against it. All they need to “understand” is that “evolution is the enemy”.
We can prevent them from 1) using taxpayer dollars teach sectarian science denial in public school science class and 2) being the only voice that less-brainwashed, less-authoritarian members of the public hear. As for hopeless, I strongly support their right to deny reality all they want.
Dr Sanford Arnoff -
1. Not every theory is grounded in a simple mathematical framework. That is mainly true of theories in physics.
2. Biological evolution is consistent with and amenable to extensive mathematical analysis and modeling.
What remarkable obtuseness you display, John. To condemn others’ display of credentials while simultaneous plugging your own strikes me as quite hypocritical.
You’re a f**kwit:
I’m not touting my own credentials, jerko. There are several scientists posting here with Ph. D. degrees, including Joe Felstenstein, I might add. Aronoff stops by and wants everyone to know that he is Dr. Aronoff and that he has published - apparently privately published - a book on helping students learn mathematics. That’s touting one’s credentials, asshole:
Malchus: After a while, you get used to it. Sort of.
My apologies to Dr. Arnoff for misspelling his name:
I’d watch my words, MrG. Have two Elton John/Bernie Taupin songs that would be especially relevant to you:
Since this is an audio-only file, here’s some visuals of some of the multiple lines of evidence for the law of human evolution that Rick presented last night:
http://humanorigins.si.edu/evidence
If you play the m4a file in iTunes you can see Dr. Potts’ slides.
Reposting to make clear who said what.
Casey told our executive director that he enjoyed the talk and thought it was great but didn’t go into any details beyond that. I plan on presenting this with this endorsement. Time will tell if the pattern of ID telling us one thing, laypeople another, and the court a third still holds.
One thing I think Casey will find “interesting” is whom Rick considers partners for the conversation. Rick concluded his talk with, “if not the ASA who?” He also dismissed as not parties to the conversation those who would redefine science. I wonder who that is?
It would be helpful here to define what is meant by conversation. It does not, for example, mean agreement. It does mean a commitment to integrity where the other side is not misrepresented along with a commitment to listening and understanding. Casey Luskin and ID could be parties to this conversation if they merely stipulate that what Rick presented was an accurate description of the science. They don’t have to agree with it and they are free to advocate for intelligent design. But I can guarantee that if I played the lecture with the comment that Casey Luskin found it “great”, jaws would drop in my church.
You realize of course that Casey and his fellow Dishonesty Institute mendacious intellectual pornographers which to redefine the very definition of science so that it could encompass the “study” of supernatural phenomena. This is essentially the admission which lead plaintiff attorney Eric Rothschild forced out of DI Senior Fellow Michael Behe during the 2005 Kitzmiller vs. Dover Area School District trial:
I don’t think anybody missed Rick’s point here save possibly Mr. Luskin.
He’s going with the tell different things to different crowds chameleon approach. This is the gist of what he told us this morning. Evolution is good. Teach it. Common descent? Fine. Methodological naturalism? OK Just need that little extra. ID completes the picture.
That’s Casey Luskin talking to us. Casey Luskin talking to the lay folk:
http://www.discovery.org/a/10651
Yep, exactly the high-pitched whining tone I expect from the Luskito. I can no longer even LOOK at EVOLUTION NEWS & VIEWS. My brain rebels and refuses to parse the text.
I have to force myself to read it, just to see their latest mendacious intellectual pornography, which I do read, since I subscribe to their “newsletter” Nota Bene:
Rock star wannabe Casey (He ought to join the Katy Perry Band IMHO as a second string guitarist.) earned a MS degree in the geological sciences from the University of California, San Diego, a noted center for plate tectonics research. Much of his same simplistic reasoning could be applied to plate tectonics. So in plain English, if he really believes this garbage, he might as well had back his MS diploma:
And he has his reasoning completely backward. It is the similarities observed within anatomical, molecular, behavioral (and where it applies, paleobiological) data that implies common descent NOT THE OTHER WAY AROUND.
Luskin pontificated thusly:
“Some of these ad hoc rationalizations may appear reasonable — horizontal gene transfer, convergent evolution, differing rates of evolution (rapid evolution is conveniently said to muddy any phylogenetic signal), fusion of genomes — but at the end of the day, we must call them what they are: ad hoc rationalizations designed to save a theory that has already been falsified. Because it is taken as an assumption, evolutionists effectively treat common ancestry in an unfalsifiable and unscientific fashion, where any data that contradicts the expectations of common descent is simply explained away via one of the above ad hoc rationalizations. But if we treat common descent as it ought to be treated — as a testable hypothesis — then it contradicts much data.”
Right. Look dude, it’s a complicated theory. It has to account for all of the evidence, all of it. That means that we must discover what actually happened, no matter how complicated it was.
As for horizontal gene transfer, convergent evolution, differing rates of evolution (rapid evolution is conveniently said to muddy any phylogenetic signal), fusion of genomes, etc. all of these thing are well documented. None of them calls into question the idea of descent with modification. All of them are completely consistent with the tree of life. Man this is like saying that if you have evidence for endosymbiosis then evolution can’t be true! Or perhaps Luskin has an alternative explanation for the nested hierarchy of genetic similarities and all of the other lines of independent evidence. Perhaps he has a better explanation of how ID predicts or even explains the things? Thought not.
Next time you catch Luskin agreeing to any audience about the basics of evolutionary biology, tape it. Then play it for the audience that he denies these things to. The duplicity is astounding.
I believe that this was recorded. The most blatant “pro evolution” statements were during the Q&A so they might not as well recorded.
Of course the basic fraud is that, though evolutionary theory continues to “evolve”, as it always has, as we learn more about the mind-boggling complexities of life – it gives less and less cause for hope that “unseen agency” is part of the structure. It becomes an ever more tangled bank that looks ever less like a Design. The complexities simply give the Luskins of the world more opportunity to spread confusion.
The damage the Luskins of the World have done goes far beyond the particulars. They’ve created an expectation that things should be simple when they can get complicated and because of this they can sit in judgment of any true expert without any training or preparation. It’s also epistemologically corrosive. Conduits of DI such as Focus on the Family’s “Truth Project” claim to support absolute truth. In reality, they promote the most extreme form of relativism and post-modernism, even nihilism.
As John Kwok and Rick Potts noted (and Michael Behe was forced to admit when under oath) ID seeks to redefine science. The reason why they redefine science is they cannot compete otherwise. From someone on the inside of the religious community I want to challenge the concept that this is because they reject ontological naturalism. Many scientists also reject that the material is all there is and yet stay within the confines of science. The difference between these two groups is that ID is incompetent and is forced to resort to rhetorical tricks such as redefining and slandering science to defend its position.
A detail that Rick Potts noted is also important. It’s those who claim to be inside science that redefine science that are the problem. Because the oversimplifiers claim to be real scientists my friends think they also can think simply and easily dismiss what the scientific community has to say without little or no thought. That intellectual laziness has produced a decay in the social fabric that is now obvious where any long-term, difficult, problem is answered with bumper-sticker slogans or just plain no.
Am in complete agreement here, Rich:
The reason why Ken Miller has observed in his “Only A Theory: Evolution and the Battle for America’s Soul” and elsewhere that Intelligent Design is far more dangerous than other forms of creationism is because its advocates - including, for example Behe - wish to rewrite the very rules under which science has operated for centuries. They wish to supplant the scientific method - methdological naturalism - with something that would include a “serious” attempt at stuyding supernatural phenomena, which is exactly what Michael Behe was forced to admit under oath during the 2005 Kitzmiler vs. Dover Area School District trial. And these “scientists” like Behe want you to believe what they are doing is right simply because they have the right credentials. Just ignore the sad, and inconvenient, facts that they opted to forsake science the moment they felt it necessary to reject the scientific method and credible science like modern evolutionary biology.
I crib heavily from Ken Miller in general and that book in particular. The reason I quoted Rick Potts rather than Ken Miller is to show that moderates like Rick and myself:
1. Agree with Ken Miller here.
2. And more importantly are not fooled by the song and dance. Unfortunately, it appears a necessary condition to not being fooled is to be a professional in the sciences. (I’m talking about the evangelical community here.) Because the ASA is a professional society it’s that characteristic that makes it an ideal partner for Rick’s efforts. It’s not because it’s dominated by TEs. We’re dominated by TEs because we are a professional society. Because the obfuscation has been so successful, however, all our outreach to non-scientist evangelicals has been met with universal failure. I do think, though, that even non-specialists understand saying different things to different audiences is indicative of a lie. (This is why even conservative judges consistently rule against ID.) The evangelicals that I know really want to live lives of integrity and if they understand how ID has stolen their honor from them, then I think it just might break the “spell”.
Don’t worry about cribbing from Ken. Yours is for an honorable reason and I am sure he would concur. But let me add too that I hope yours isn’t a Sisyphean task in trying to reach out to your fellow Evangelicals who’ve been swayed by the Dishonesty Institute and its pathetic band of mendacious intellectual pornographers:
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