Webinar Follow-Up: Dinosaur Polls and More

By Carl Zimmer | February 25, 2010 4:23 pm

A few questions came up during the webinar this afternoon that we didn’t have a chance to get to.

texas poll1. I talked about a poll of Texans about evolution. Someone asked for the source of the chart I showed. Here it is. I used this poll mainly to illustrate the fact that being a journalist who writes about evolution in the United States is an inherently interesting job. (You get really interesting comments, for example.) But I don’t think that Texas warrants singling out, judging by nationwide polls.

I also get annoyed when pollsters ask questions that demonstrate that they don’t understand evolution very well. Walk into a museum with a good dinosaur exhibit, and you’ll discover that birds are dinosaurs. And so, if someone changed that statement to “Humans and dinosaurs live at the same time,” and asked me if I agreed with it, I’d say, “You betcha!”

2. Another person asked how much space in The Tangled Bank I spend on the mechanisms of evolution, such as epistasis, fitness landscapes, evolvability, modularity, and genotype-phenotype maps. The answer is that I lay out some of the fundamental mechanisms, such as selection and drift, and try to delve into mechanisms that have been investigated more recently–without turning the book into a textbook for biology majors, instead of the non-majors book that it is. So, rather than deriving theorems, I tend to use illustrations, metaphors, and specific biological examples to get the concepts across.

3. A third person mentioned that she does research on the teaching and learning of evolution, and wondered if I would consider writing a book specifically for teachers to help them teach evolution. I’m no expert on pedagogy (which is why I had a board of advisers for The Tangled Bank made up of scientists who not only do important research on evolution but also teach non-majors). Fortunately, there are already lots of resources out there intended specifically for teachers, such as Understanding Evolution. (Full disclosure: I wrote the history sections on the site, and my chapter on evolutionary medicine can be downloaded for free there.)

Thanks again to AIBS, Chris Mooney, and all the people who joined us. It was my first webinar experience, and it was not only painless, but downright enjoyable. And congratulations to the people who won copies of our books!

Update: 8:15 pm. Jamie Vernon left a comment worth replying to at length:

Hi Carl,
I truly respect what you have done for science communication, however I must take exception to your implication that humans walk with dinosaurs. Dinosaurs? Really? “Terrible lizards?” You see, I live and teach in Texas so I see on a regular basis the problems of improper science education. Now, I can appreciate the humor in that statement and the provocative nature of it, but for those who clearly don’t understand evolution, it can be confusing and misleading. I assume when you agree that “humans walk with dinosaurs” meaning birds, you intend to provoke the question, “Really? How? Where?” Unfortunately, not everyone is as inquisitive as you might think. This leaves us, teachers, to clean up the mess. The statement isn’t anymore true than someone who says, “humans descended from chimpanzees.” So, the least you could do is clarify by stating that “humans walk with the descendants of dinosaurs.” Eh?

No, humans walk with dinosaurs.

It would not be true to say that humans walk with other species of dinosaurs, such as Tyrannosaurus rex or Velociraptor. But birds are dinosaurs, too. That is, they belong to the group of species defined as dinosaurs by paleontologists, based on their shared common ancestry. The statement “humans walk with dinosaurs” is not analogous to “humans descended from chimpanzees.” That would be like saying “birds descended from Tyrannosaurus rex.” Birds are dinosaurs in the same way humans are mammals.

This statement is not misleading, nor is it intended merely to provoke. It’s just an accurate depiction of the state of the science today. It problably comes as a surprise to many students, but that makes it–as they say–a teachable moment. The link to the American Museum of Natural History web site I provided above offers some good information to help students understand this statement. It’s also something I discuss in The Tangled Bank. Here’s an evolutionary tree I put together with the help of paleontologists to get this across…TB birds 600

CATEGORIZED UNDER: Evolution, The Tangled Bank

Comments (30)

  1. Greg Peterson

    Carl, I thoroughly enjoyed the presentation–both you and Chris. Thanks for doing this. I received “Tangled Bank” for my birthday in early January and pick away at it a little at a time, between other books. It’s good for that, being rather modular. At any rate, it was a privilege to hear you and your work is much appreciated.

  2. Jelena

    I like people like you saying you can’t write a book for teachers, because you’re no expert on pedagogy. My high school biology teacher never caught my interest and I lost a few years searching for the job I want to spend my life in. After that, I found a book in the local library, that completely changed my direction. It was your book Parasite Rex and it made the difference that made me study biology. It seemed so interesting to me, that I decided to go study parasites and evolution. Now, I’m a graduate student of evolutionary biology and I do research on changes caused by latent toxoplasmosis in human and I really love the stuff. Thank you, and please – teach teachers how to talk about evolution the way students will understand and be interested in it, because you definitely can do that! :)

    [CZ: First off, thanks! I feel gratified (albeit old) when I hear about people being so influenced by reading my book. But having tried my hand at one or two problem sets in the past, I have deep respect for people who are experts on pedagogy.]

  3. Those stats of Texas scare me – it’s incredible that so many people can not know things that some of us take so much for granted. Then again, if the knowledge doesn’t help them in their daily life, why SHOULD they know?

    Well, I think they should know, but there’s an argument against it.

  4. Hi Carl,
    I truly respect what you have done for science communication, however I must take exception to your implication that humans walk with dinosaurs. Dinosaurs? Really? “Terrible lizards?” You see, I live and teach in Texas so I see on a regular basis the problems of improper science education. Now, I can appreciate the humor in that statement and the provocative nature of it, but for those who clearly don’t understand evolution, it can be confusing and misleading. I assume when you agree that “humans walk with dinosaurs” meaning birds, you intend to provoke the question, “Really? How? Where?” Unfortunately, not everyone is as inquisitive as you might think. This leaves us, teachers, to clean up the mess. The statement isn’t anymore true than someone who says, “humans descended from chimpanzees.” So, the least you could do is clarify by stating that “humans walk with the descendants of dinosaurs.” Eh?

    [CZ: Jamie–Thanks for your comment. I’ve responded in an update to the post.]

  5. Jenz

    * old european facepalm*

    Oh my, you are up against some serious lack of knowledge (not that I would know if it’s better on this side of the atlantic….).

  6. Bobbie

    Is it just my computer? Your internet connectible references are in light tan…. hard to see!

  7. Hi Carl,

    this is a beautiful illustration. Can it be re-used on other blogs? I am writing a short article on the Ruben paper (air sacs in Theropods) that made rounds last year and has been picked up by the creationists as the “final nail in the coffin” of the “ludicrous birds-from-dinosaurs hypothesis”. I wanted to re-use one of my earlier drawings, but your tree is way more exact and beautiful. Do you own the permissions, and if yes, can I reproduce it on my blog?


  8. Carmen Raterman

    I teach 9th grade biology and I did not see your webinar. Is it available for viewing again? I definitely want to read your books this summer! Which one do you recommend I should start with first? Thanks.

  9. Hi Carl!

    Thank you so much for joining us at the virtual book party yesterday. The event was a great success, and your presentation was outstanding. I wanted to share the archive URL for the webinar, so that any of your blog readers can hear your presentation if they missed it.

    Glad to hear it was a painless experience ;). Hope we have a chance to work together again sometime soon!

    Sheri Potter
    American Institute of Biological Sciences

  10. Chuckwalla

    It is disturbing to see how many people agree with the author’s points, but then criticize him for saying “birds are dinosaurs.” Yes folks, birds ARE dinosaurs, just as birds are reptiles. This is a basic concepts of evolutionary relationships (called monophyly). Birds originated within the group Dinosauria so, by definition, they are dinosaurs. Saying birds are not dinosaurs is like saying primates are not mammals.

  11. Chuckwalla

    Say, sorry Carl Z.; I used almost the exact same analogy as you (“birds are dinosaurs in the same way humans are mammals”). In my defense, I posted my comment before reading your update. Call it convergence (or great minds…)

  12. Thanks, Carl, for clarifying. I appreciate the detailed explanation. Now, I am armed with the facts!

  13. Thank you for this, Carl. I share the same frustration. There seems to be some reticence about identifying birds as living dinosaurs or even recognizing that many dinosaurs were covered with feathers (or other body coverings as in Psittacosaurus and Tianyulong).

    Maybe it has something to do with the old “five classes of vertebrates” trope we all learned back in elementary school. That system (fish-amphibians-reptiles-birds-mammals) emphasizes disparity along a graded chain of “lower” to “higher.” We know it is wrong, but it stays entrenched, and it makes discussing evolutionary transitions/connections all the more difficult. Feathered dinosaurs, with all their bird-like characteristics, don’t fit neatly into one category or another, and maybe that makes it easier for some to ignore what we have learned about them in the last 15 years.

    And (pardon the shameless plug) anyone who wants to catch up on some of the latest research confirming that birds are dinosaurs can check out the “birds are dinosaurs” tag on Smithsonian’s “Dinosaur Tracking” blog (which I write): http://blogs.smithsonianmag.com/dinosaur/category/birds-are-dinosaurs/

  14. Trevor

    birds are dinosaurs in the same way humans are reptile or even fish.
    scientifically correct in terms of nomenclature/clades but inconsistent with how those dinosaur/reptile/fish terms are commonly understood. To say “birds are dinosaurs” is correct but the intention would be to provoke, bringing out the point birds descend from dinosaurs.

  15. marcel

    A bit late to the party. I hope Chuckwalla or Carl see this.

    Chuckwalla wrote:

    Birds originated within the group Dinosauria so, by definition, they are dinosaurs. Saying birds are not dinosaurs is like saying primates are not mammals.

    Reptiles and mammals descended from, so by this logic, it seems that repitiles and mammals are also fish. At some point, this becomes silly. There are animals around today that we call fish and distinguish from birds and from mammals and from reptiles. Saying that mammals are fish, and as far as I can tell this is equally true, equally accurate as saying that birds are dinosaurs, does not usefully convey information to anyone but an expert. What sense does it make to say that birds are dinosaurs? Isn’t more information conveyed by saying that birds are descended, or evolved, from dinosaurs, or better yet, that the immediate ancestor of (all) birds was a dinosaur?

    I guess this is addressed to Laelaps as well.

    I imagine the issue may be Linnaean taxonomy vs. cladistics. According to Wikipedia (yeah, I know, but…) birds are a class while dinosaurs are a collection of genera, I guess an order. Cladistics doesn’t make this distinction I guess, so the later twigs are always members of the earlier ones. For scientific classifications and organizing knowledge, this may be appropriate, but I think for the way most of us operate on a day to day basis, it is likely more useful to say ‘Birds descended from a certain type of dinosaur (and are their only currently existing descendants)” than that “Birds are dinosaurs”, just as it is more useful to say “Mammals (and reptiles) descended from a certain type of fish” rather than to say “Mammals (and reptiles) are fish”.

  16. Dani

    Hi Carl,

    I am a spanish student of biology. I enjoy very much with your blog every day, and really wanted to congratulate you. However, I would like to add a comment related with this discussion between you and Jamie Vernon. The cladistic point of view considers only monophyletic groups. So, birds are dinosaurs just as we (i. e. mammals) are reptiles, or fishes. Of course, some of this classifications could be useful, but others are not. This is what evolutionary taxonomists claim. Thus, we may also consider paraphyletic groups. From this point of view, birds are just birds, but not reptiles, just like we are not fishes.

    Nowadays, both of you can be right. You think dinosaurs are defined by a monophyletic group, but Jamie (and most of general public) thinks dinosaurs are paraphyletic. Maybe it might be positive to talk about the different interpretations of taxonomy in another topic (even more this year: the year of biodiversity!)

    (I have just realised that some comments say the same as mine. I am sorry for this repetition. However, I still wanted to thank you for your daily efforts and your terribly interesting work. You make us learn and get fun. -By the way, could it be possible that you come to Valencia and visit our University in a near future? :)-)

  17. I’m even later to the party than marcel, but I’d like to add my two cents. To the people who used the primate to mammal analogy, I think a more fitting analogy is that birds are dinosaurs in the same way that bats are mammals, or that whales are mammals. Bats and whales both have methods of locomotion pretty different from the rest of mammals, but we don’t hesitate to include them in that group. Why should it be any different for birds being dinosaurs?

  18. David Bofinger

    I think to say humans walk with dinosaurs, while conceivably true in some sense, is misleading for at least two reasons. Whether or not it’s good science, it’s bad science communication.

    First, as remarked by others, it’s using a monophyletic definition where the scientific world uses a paraphyletic definition. We are after all trying to communicate with people who are not paleontologists. It’s not like saying humans are mammals, because biologists and ordinary people pretty much agree on what a mammal is, at least as far as extant species are concerned. It’s more like saying humans are monkeys, or giraffes are fish, or sparrows are amphibians.

    Second, there are some true statements it’s misleading to make because the natural interpretation of their intent differs from any interpretation justified by the science. An example of this is “Black people are descended from monkeys.” Yes, it’s true – all humans are descended from monkeys, or if you’re in a monophyletic frame of mind are monkeys – but the implied intent is misleading.

    Would you really be comfortable saying “a dolphin is a kind of fish” or “a duck is a kind of amphibian”? This way lies madness.

    CZ: The statement humans walk with dinosaurs is true. But I’m not saying that people should should shout, “Birds are dinosaurs!” and then run off without another word. Of course many people will find that surprising–of course some may have a “natural interpretation” of that statement that’s wrong. But that’s an opportunity to explain what scientists understand about the relationship of birds to other animals, and how they evolved into their unique form.

    As for your “that way lies madness” argument, it’s based on a flawed premise. Of course I would be uncomfortable saying humans are monkeys or a duck is a kind of amphibian”–because they’re not true. The term “monkey” refers to two separate lineage of primates–New World monkeys and Old World Monkeys. Humans belong to neither lineage. Humans are anthropoids, humans are primates (so are monkeys), humans are mammals, humans are lobe-fins (so are dinosaurs), humans are vertebrates, humans are animals, humans are eukaryotes. The same goes for ducks and amphibians. Amphibia is a separate branch, not the branch that includes frogs and ducks. For more information along these lines, you can check out a site like the Tree of Life. I understand your concern, but the reaction should not be to shy away from science.

    It’s fascinating to me that this post has gotten such a strong response. It must be because birds can fly. But, then again, think about bats. Is it dangerously misleading to say that bats are mammals? Bats evolved from non-flying mammals about 60 million years ago, and mammals are a lineage that arose about 230 million years ago. Birds evolved from non-flying dinosaurs about 160 million years ago, and dinosaurs first arose about 250 million years ago. Bats are united with other mammals by lots of traits, despite having wings. The same goes for birds and other dinosaurs.

  19. Hugh

    Isn’t it more like saying ‘humans are cavemen’? I think it’s great to remind people that birds are the living descendants of dinosaurs, and what we know about the one informs what we know about the other. But let’s not lose sight of the fact that birds have become marvelous creatures in their own right, with a whole host of attributes that simply don’t characterize the rest of the dinosaurs.

    CZ: What happens if I rephrase what you said like this: “I think it’s great to remind people that birds BATS are the living descendants of dinosaurs MAMMALS, and what we know about the one informs what we know about the other. But let’s not lose sight of the fact that birds BATS have become marvelous creatures in their own right, with a whole host of attributes that simply don’t characterize the rest of the dinosaurs MAMMALS.”

    The two statements are logically equivalent. For some reason, however, the bat one doesn’t sound as weird. The claim that birds are the only living dinosaur lineage doesn’t change the issue. If all mammals but bats became extinct this afternoon, bats would still remain mammals.

  20. Stephen Hampshire

    Isn’t this just a debate about semantics, really?

    It seems to me that the fundamental point is Darwin’s insight that all species are descended from a common ancestor (hence the tree of life). We attach labels to various trunks, branches and twigs of that tree to help us understand it, but to some extent the way we classify things into box A or box B can be pretty arbitrary (and I mean no disrespect to cladists – that’s what makes it interesting!).

    The way you’re using the word “dinosaur” is different to the way people who object are using “dinosaur”. For instance – I wonder how those people would classify pterosaurs?

  21. Tyro

    While I agree that, when speaking with a certain group of educated people or you have a couple minutes to explain yourself this is true, it’s also not something I’d blurt out as a yes/no answer.

    Consider that by the same cladistic standards, ‘fish’ could be ‘chordates’ making us a fish. Once a fish always a fish, right? While saying that your dog is a fish would provoke questions and discussion, what if you said that dolphins and whales are fish? People would jump to the wrong conclusion, just like you know they’d jump to the wrong conclusion if you said that humans and dinosaurs live(d) together at the same time.

    There’s just too much pseudo-science, cryptobiology and ignorance to say things like that without a lot of clarification.

  22. Tyro–Show me a phylogeny where the clade the includes humans and trout is labeled FISH. It’s a straw man argument.

  23. Tyro

    Sarcopterygii is labelled as “lobe finned fish” (http://en.wikipedia.org/wiki/Lobe_finned_fish) and is the parent of Tetrapods. On PNAS, a paper about the “fish clade” uses Vertebrata (http://www.pnas.org/content/106/34/14456.abstract). If you are only considering monophylytic groups as you appear to be arguing for, then why aren’t tetrapods still fish? And if tetrapods are no longer fish, then whatever process you used to remove them could be used to remove birds from ‘dinosaurs’, couldn’t it?

    Of course I picked the example because it was uncommon but I don’t know why it was a strawman. I’m addressing the question of whether birds can change sufficiently to be no longer considered a part of their parent clade which surely is relevant to fish::tetrapods.

    A more common debate is whether humans are apes or monkeys – I’ve seen evolutionary biologists of all stripes pick different sides on this issue. No doubt they all agree on the biology and cladograms but language is a funny thing.

    CZ: With all due respect to Wikipedia, I would rely instead on a more authoritative work, such as The Tree of Life: A Phylogenetic Classification (Harvard University Press Reference Library). There is no “fish” clade there. As for humans being apes or monkeys, I know of no current arguments for humans belonging to a “monkey” clade. It is abundantly clear from DNA studies that humans are apes–i.e., they belong to a group that includes chimpanzees, bonobos, gorillas, orangutans, and gibbons.

    By definition, a bird cannot evolve its way out of being a dinosaur. It’s a matter of common ancestry–in other words, it was all set in the past. We humans have lost most of our hair, a lot of babies don’t get milk when they’re young, we walk around on two legs, etc. etc.–but as weird as we are, we are still mammals.

  24. Tyro

    Carl – Okay, tolweb then: http://tolweb.org/Sarcopterygii/14922

    Sarcopterygii is described as “The lobe-finned fishes & terrestrial vertebrates”. Whatever the ‘fish’ clade might be, we’re deep inside by now and yet we find terrestrial vertebrates.

    If there was a fish clade, what would it be? Chordata or Vertebrata, I’d guess. Colloquially ‘fish’ is polyphyletic I agree so maybe you’ll tell me it isn’t a clade but ‘dinosaur’ is also polyphyletic so we’re back in the same boat. If polyphyletic groups are fine for fish, why not accept them for dinosaurs and if you want to talk clades or monophyletic groups for dinos then surely we must to the same for fish.

    Do you agree that our ancestors were fish? If so, why aren’t we still fish?

  25. Tyro

    Judging by tolweb, celocanths and other lobe-finned fish are more closely related to dogs than to salmon, and salmon are more closely related to dogs than to lampreys. If celocanth, salmon and lamprey are fish, how did terrestrial vertebrates “evolve their way out” as you put it?

  26. Lindsay


    I am forever impressed with your writing. Not just that it is wonderfully entertaining, but because you have a masterful grasp of the science that you describe. Thanks for taking the time to get it right!

    And I can tell everyone, when you get to graduate school in biology and the Univ. of California, Berkeley, they’ll tell you:

    Birds are dinosaurs!

  27. The more I think about this, the more I think that Tyro has an interesting point about the names of classifications — although he’s stretching it, since “fish” is not a cladistic term.

    I agree with Stephen (#22) that the point is essentially semantic. (Do we need to bring Ben in here?) Let’s start with those fish. We’re Sarcopterygians, sure, because we are in the class Sarcopterygii. Of course, “Sarcopterygian” doesn’t mean much to most people, so we fall back on a descriptive phrase to translate it: “The lobe-finned fishes & terrestrial vertebrates” (per tolweb; I might have said, “the lobe-finned fishes and tetrapods”). This is a good English descriptor of the clade. It is not, of course, an accurate translation of the Greek, but that’s fine — etymology is not destiny. Does it make us fish? No, we are either “lobed-finned fishes [or] tetrapods”. (Most of us, the latter.)

    We, and bats, are in the class Mammalia. There is a convenient English translation of this Latin word, so we understand that we are mammals, and the meaning of the colloquial English word “mammal” is identical to the scientific meaning of the classification “Mammalia” (see, for example, the They Might Be Giants song).

    Birds are in the superorder Dinosauria, of which the English word “dinosaur” is an obvious translation. If we use the English word “dinosaur” to identify the superorder, birds are indubitably dinosaurs. However, tolweb calls that superorder “Dinosaurs including birds”. That implies that birds are not dinosaurs. Is that a more accurate understanding of the name “Dinosauria”? In fact, the *colloquial* use of the word “dinosaur” has not, historically, included birds — as is demonstrated clearly by tolweb’s own English name for the superorder.

    So whether birds are dinosaurs depends on what “dinosaur” means (obviously), and, coming from the other directions, on how you translate “Dinosauria”. If the superorder is described as “dinosaurs”, then birds are dinosaurs. If the superorder is “dinosaurs including birds”, then maybe they’re just birds. Of course, birds are always Dinosauria, just as bats are Mammalia, but then, there isn’t any question about the colloquial meaning of “mammal”.

    The question is really about the translation of the scientific name into colloquial English. In fact, it’s a perfect analogy to the Pluto problem. In each case, us nerdy types are using a widely-understood word (“planet”; “dinosaur”) in terms in scientific usage that is more technically accurate but less colloquially recognizable (“does not include dwarf planets”; “includes birds”). Eventually, people will catch on, and accept the translation of “Dinosauria” — which includes birds! — as “dinosaur”. But I think we must admit that that’s not how most people, including the authors of tolweb, think of it now.

  28. Citizen,Scientician- that was very well put!
    i think you summed up the debate very well.


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The Loom

A blog about life, past and future. Written by DISCOVER contributing editor and columnist Carl Zimmer.

About Carl Zimmer

Carl Zimmer writes about science regularly for The New York Times and magazines such as DISCOVER, which also hosts his blog, The LoomHe is the author of 12 books, the most recent of which is Science Ink: Tattoos of the Science Obsessed.


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