How I spent another morning at SICB

Everyone can stop now, my brain is full. Seriously, this is a painful meeting: my usual strategy at science meetings is to be picky and see just a few talks in a few sessions, to avoid burnout…but at this one, I go to one session and sit through the whole thing, and at the breaks I look at the program and moan over the concurrent sessions I have to be missing. I have to come to SICB more often, that’s for sure.

I do have one major complaint, though: PowerPoint abuse. The evolution of slides has continued apace since my graduate school days, when one slide was one photograph, developed in a darkroom ourselves, and then carefully labeled with letraset lettering, photographed again on a copy stand with slide film, and then sent off for processing (usually the day before the meeting, so there was no slack for redoing anything.) Now the slides are all huge multipaneled affairs with data packed into tiny little boxes that fade in as the speaker does a tarantella on the keyboard, and it’s getting a little irritating. Most of the talks this morning would, at some point, throw up a gigantic, intricately detailed cladogram with 50 taxa and branch points all labeled and circles and arrows and scary tiny lettering all around. Any one slide legitimately represents something that the speaker could talk about for an hour, no problem, but wham-bam-zoom, they’ll run through 20 of them in 20 minutes. If the information density is going to be this high, they ought to set it up so they can beam these monster slides to our laptops over the wireless network, so we can actually try to absorb it into our heads in some way other than being battered about the cranium with it.

I spent Friday morning at the Key Transitions in Animal Evolution symposium.

  • F. Boero: Cnidarian milestones in metazoan evolution. This talk was a bit thin on the data, but it was presented more as a conceptual overview, so I let it go. The idea was simple: it was an anti-Great Chain of Being talk, pointing out that sponges and especially cnidarians were darned important creatures that ought to be appreciated for the fact that they bear the seeds of everything we consider especially essential to the bilateria. They have bilateral symmetry, many have supporting skeletons, polyp buds have an internal mass that corresponds in many ways to mesoderm, they have body cavities, the modularity of their development has affinities to bilaterian metamery, and most interestingly, cnidarian planula larvae have specialized concentrations of nerve cells that resemble a brain. One weird twist (I love weird twists) was the idea that the cnidocyst was such an incredibly potent adaptation that the cnidaria didn’t need all the elaborate complexity of the bilateria to succeed, and that maybe an important milestone that was a precursor to our evolution was the loss of cnidocysts.

  • B. F. Lang: The evolutionary transition from protists to Metazoa: mitochondrial genome organization and phylogenomic analyses based on nuclear and mitochondrial genes. I was rather far over my head in this talk; it was hardcore phylogenetic analysis of really distant branch points in our evolutionary history—this fellow is trying to puzzle out the branch point between fungi and animals. I mainly just jotted down a few names I’ll have to look up later: the Ichthyosporia, which are fungal-like cells with amoeboid stages, the Nuclearia, which are low on the branch leading to the fungi, the Capsaspora, which similarly lie on a branch leading to the animals, and the Apusozoa, bikont flagellates that have been poorly characterized so far.

  • D.K. Jacobs: Origins of sensory and neural organization in basal metazoa. The cnidarian fan club was out in force in this session. This was a talk on the identification of cnidarian genes usually associated with nervous system and sensory organ development and function, the point being that all of the precursors to our rather more elaborate neural processing system are there in jellyfish. There were a few places where I wondered if he was going a little too far—there’s no reason to assume that finding a gene that is used in the vertebrate brain in a cnidarian means that gene has a similar function there—but still an interesting talk. One cute idea was that the choanocytes of sponges can also be thought of as sensory organs, and also that neural genes seem to share functions with nephridia/kidneys, too, raising the possibility of a primitive link between excretion and the origins of the nervous system. (Watch Fox News, and this possibility will seem even more likely).

  • G. Wagner: Do genome duplications play a role in key transitions? This is the second time I’ve heard this Wagner fellow talk, and he keeps making me think. He brought up a familiar correlation: in vertebrate evolution, we see signs that there are major gene duplications at the same time that we see major radiations. In the vertebrate lineage, for instance, we see two whole genome duplications, and the conceit is that these increases in genetic material provided the substrate for more sophisticated developmental events that were the source of our success; similarly, the even more successful teleosts show signs of a third round of duplications. Wagner objected, pointing out that there are many highly successful groups that did not exhibit these duplications (arthropods, insect, mammals, and birds, for instance), and that others, such as plants and sturgeon, have duplications but no subsequent radiation. He argued that it was an artifact, not evidence of a causal relationship. The rapid expansion of a lineage during an adaptive radiation would act to preserve and propagate any genetic quirks of the founding population. The duplications are neither necessary nor sufficient to instigate a key transition. One point that came up very briefly in the Q&A was that we developmental biologists are a bit obsessive about regulatory genes like the Hox genes and think those are indicative of importance, but that there are also duplications in, for instance, the glyocolytic enzymes that also correspond to the major transitions.

  • N.W. Blackstone: Foods-eye view of the transition from basal metazoans to bilaterians. This was another weird talk that came from a completely different perspective and made me think. It might actually be a little too weird, but it’s still provocative and interesting. Blackstone is looking at everything from the perspective of metabolic signaling—he’s clearly one of those crazy people coming out of the bacterial tradition. Cells communicate with one another with the byproducts of metabolism, where the redox state of membrane proteins are read as indicators of the internal state of the cells (he later calls this “honest signaling”, because there aren’t any intermediates between the cell and the expression of its metabolic state). The big innovation in the eukaryotes was to escape volume constraints by folding their chemiosmotic membranes into the interior of the organism, and the major animal innovation was the evolution of the mouth, which allowed specialized acquisition and processing of food patches. Subsequent evolution was to allow the animal to sense and seek out and exploit food patches in an environment where they were dispersed in a non-uniform manner. Another interesting tangent was the question of cancer: long-lived sponges and cnidarians don’t get cancer. His explanation was that it was because their cells use that “honest” metabolic signaling, so that rogue cells don’t have a way to trick the organism into allowing them to use more resources than they actually need; the only way to signal is to exhibit genuine metabolic distress, and cells with metabolic problems will die. Our cells have these indirect, multi-layered signaling mechanisms that allow cancer cells to “lie” to the organism as a whole.

  • P. Cartwright: Rocks and clocks: integrating fossils and molecules to date transitions in early animal evolution. Molecular phylogeny is a useful tool to find patterns, and recognize branch points; this information needs to be integrated with fossil date to calibrate the clock and anchor those events to specific dates. This work was a combined effort to put together a catalog of 18s and 28s trees, and use fossil evidence to constrain the timing of the events in a metazoan cladogram. I wasn’t entirely convinced that they’d overcome the obvious problems—fossils can provide a minimum but not a maximum age—but as an excuse to show lots of pictures of Cambrian and pre-Cambrian fossils, I wasn’t going to complain. In particular, they had some amazing cnidarian fossils from 500 million year old rocks in Utah that were pretty much indistinguishable from modern taxa; jellyfish definitely are in a good niche. In her final table of conclusions (which flew by much too quickly!), she pinned the origin of the metazoa to 950mya, the deuterostomes to 539mya, the lophotrochozoa to 537mya, the ecdysozoa to 541mya, and the placozoa to 61mya (!). The clustering of those significant groups to right around the Cambrian was an indication that the Cambrian explosion was real.

  • M. Q. Martindale: The developmental basis of body plan organization in the Eumetazoa. Uh, Mark can talk really, really fast. My notes are a rather unreadable scrawl as I tried to keep up. A general point: he emphasized that much of what we can expect to see from developmental biologists is going to look like the intricate ‘circuit diagrams’ that Eric Davidson has published, where the fundamental unit is a network of gene interactions that define a cell state. He showed Davidson’s endomesoderm specification kernel for echinoderms, for instance, and then went through each of the genes involved and showed that they are all also present in Nematostella, and that they are almost all involved in endomesoderm specification there, as well. While the network has not been identified in the cnidarian, only the components, I do’t think we’ll be too surprised to see similar interactions appear as the details are worked out.

  • D.J. Miller: Implications of cnidarian gene expression data for the origins of bilaterality: is the glass half full or half empty. Where Martindale was all about the similarities, Miller was all about the differences. He’s working with a cnidarian, too, but a different one, Acropora. He was also explaining the expression of important early patterning genes, but one very interesting difference is that he looked at Emx and Otx, homologs to anterior-posterior genes in the bilateria that are expressed in the anterior end of those animals—but are expressed at opposite ends of the Acropora planula from each other. While some gene functions are conserved, there is no simple correspondence along the body axis.

  • J. Extavour: Urbilaterian reproduction. A different sort of talk: this one was about the nature of Urbilaterian germ cells. She made the case that one of the key steps necessary to the evolution of true multicellularity was the sequestration of a distinct stem cell population that was specialized to minimize mutation with a greatly reduced mitotic rate, reduced transcription, and with mechanisms to reduce the activity of transposable elements. This was part of the process of making the fitness of individual cells take a backseat to the overall fitness of the organism.

  • P.W.H. Holland: More than one way to make a worm. This talk was fun. He started with the idea of the worm, a flexible, elongated, motile tube, and showed that “worm” was a successful form that one could find scattered across the phyla of the bilateria, and that the urbilaterian was almost certainly a worm. He then raised two questions: are there examples of more derived forms that have secondarily given up features to revert to “wormness” (he gave one example, arguing that the hagfish was basically a chordate worm); and more interestingly, are there any examples of organisms that have independently evolved into a worm? He then showed us a movie of a creature that definitely looked like a worm; on first sight, it looked like a nematode, but rather than undulating and crawling it did a strange corkscrew curl. It’s called Buddenbrockia, and it’s a parasite found inside bryozoans. closer examination showed that it is a sealed hollow tube, completely mouthless and without a gut, and with no sensory organs, and that its interior is lined with 4 blocks of longitudinal muscle. It looked like something from outer space, if you asked me. Inside that tube, though, can be found flagellated spores that look like myxozoans. Molecular phylogeny reveals that it is a myxozoan, and that it is nested within the cnidaria. The idea is that this wormlike animal was built by breaking down a cnidarian and building it up again, and so represents a worm that has evolved independently of the Eubilateria—a worm is apparently a kind of universally basic form to take. Very cool!


  1. says

    Here I am, a complete outsider to biology, just watchin’ the action, and I found this posting fascinating and riveting. Wonderful exposition of really interesting stuff.

  2. says

    Gunther Wagner is a very smart guy. I chetted with him a little bit after the evo-devo session at SICB in Chicago (2000?) and I have read several of his theoretical/philosophical papers.

  3. says

    Thanks for this post, summing things up clearly is a rare thing.
    Oh and one puzzling point… Sorry but :
    “sponges and especially cnidarians were darned important creatures” “They have bilateral symmetry”

    Must have missed something somewhere… bilaterian how?

  4. says

    They both have planula larvae, a kind of very simple tear-drop shaped form; adult cnidarians may not be radially symmetrical as well.

  5. Scott Hatfield says

    PZ: I’m impressed by your ability to give in-depth reportage seemingly on the fly. Did you compose this in fits and spurts during the talks? Good gravy.

  6. Caledonian says

    Perhaps this is a stupid question, but: if cnidocysts were so potent, why did we lose them?

  7. says

    Re “powerpoint abuse” –

    Don’t you get copies of the slides (or the talk itself as a written paper) as part of the conference pack? How about copies of the slides after the talks? If you don’t get them then I think you’ve been robbed.

    There’s always a debate about lecture notes (and/or slides) when it comes to teaching students. Should they be made available in advance so the students can prep for the lecture or will that cause them not to attend at all? Should they be handed out at the start of the lecture (or the lecture course as above) so the students can annotate them rather than having to write full notes from scratch? Or is the writing from scratch a useful part of the learning process? I know of nobody who disputes that the notes should be available to the students after the lectures.

    This debate would seem to be needed for academic conferences as well as lecture courses.

  8. lo says

    The slides are okay, they are not meant to be read directly and entirely, besides the human brain does not cope well with that anyways as we concurrently decode the verbalizations from the speaker and attempt to decode the language on the slides, which itself involves the same neurology for the most part.

    There are great for downloading and review so far one is familiar with the basics of a certain subject.

    And yeah i fully agree with the idea to downstream the slides so one can focus at one point at the slides and another at the presentation, but this would only truly work well if the equipment is pre-provided.

    PS: I know no professor who lectured for several years who messes up his slides entirely, as everyone else does when he is young and creates his first presentations.
    It is not PP abuse it is humans in an evolving IT world, adapt or perish!

  9. says

    Bob Dowling: I took a public speaking course as part of general ed requirements way back when (before Powerpoint took off) and the expert in said matters said handouts should be done at the end, so as not to distract people. Judge this appeal to authority as you wish.

  10. boojieboy says

    Hey PZ:

    It’s funny that you make that comment about the info density of these ppt slides, because I’ve noticed that too. I say it’s funny in the sense that it’s odd: Tufte is one of the major opponents of ppts, and one of his problems with them is that he thinks they tend to encourage LOW info density, making presenters click too quickly through them, inducing to “presentation hypnosis”

    Perhaps presenters at science meetings are discovering that high def video projectors now allow much higher density ppt slides, and presentations are evolving, with speakers now tending to overuse that capacity. If so, it’s actually an encouraging sign (I think) b/c it tells you that ppt and projection equipment may have finally evolved to the point where people are getting close to matching the quality of the traditional slides. In a few years, they’ll learn to scale back the info density, or perhaps something else.

    One thing that Tufte recommends is having high density handouts to accompany talks, constrained to no more than two sides of a single sheet of paper. Did anyone at SICB do that for you? It’s pretty much SOP for posters at the meetings I go to (having a single mini-copy of the poster printed in color on 8.5×11 paper), but I haven’t any speakers doing it as well.

  11. says

    No, no handouts.

    I suspect Tufte would still frown on the way the information density is displayed, though: in many cases, it’s more a matter of making a giant montage, packing what was once on ten pp slides into one.

  12. David Marjanović says

    Usually what scientists present at congresses is their unpublished research. If the editors of the journals they want to submit that research to found out the research has already been made available to the public, they’d refuse acceptance of the paper, and in a “publish or perish” world, that’s, well, bad. Besides, it would make plagiarism a lot easier.

    The Society of Vertebrate Paleontology meetings, for example, have a strict policy: except for the published abstracts, you are not allowed to document or report what was presented at such a congress.

  13. David Marjanović says

    Usually what scientists present at congresses is their unpublished research. If the editors of the journals they want to submit that research to found out the research has already been made available to the public, they’d refuse acceptance of the paper, and in a “publish or perish” world, that’s, well, bad. Besides, it would make plagiarism a lot easier.

    The Society of Vertebrate Paleontology meetings, for example, have a strict policy: except for the published abstracts, you are not allowed to document or report what was presented at such a congress.

  14. ppt god says

    Some general slide preparation guidlines:

    Use Arial or Helvetica font

    all text = 18pts or larger

    don’t use all caps

    small room = dark letters/light background

    large room = light letters/dark background

    avoid red/green

    view slides in grayscale to ensure proper contrast

    every slide should have a heading

    use sentences, if possible, to make a statement

    limit text blocks to no more than 2 lines

    lists should contain max of 3 items

    avoid sublists

    be generous with empty space

    try to include a simple image on every slide

    each slide should make one or two points

    figures/images: explain them or get rid of them

    don’t use facy transitions between slides

    start broad, get specific, end broad (refers to talk, not slides per se)

    design and introduce a “home slide” that you will come back to at each major transition in talk

    think of your talk as consisting of episodes

    broad, specific, home slide, specific, home slide, etc.. conclusions, summary, broad significance

    ***these points were provided to me by my post-doc PI, she got them from a presentation at a Pew meeting; i.e., their not my ideas, but I don’t know the source to cite

  15. Scott says

    Did you mean that placozoa was 61 or 61x (610?) my old. 61 would be quite the finding? Also, was the tree resolved with placozoans branching lateer than sponges? If so, wasn’t there some evidence to the contrary presented at the meeting?

  16. llewelly says

    There’s always a debate about lecture notes (and/or slides) when it comes to teaching students. Should they be made available in advance so the students can prep for the lecture or will that cause them not to attend at all? Should they be handed out at the start of the lecture (or the lecture course as above) so the students can annotate them rather than having to write full notes from scratch? Or is the writing from scratch a useful part of the learning process? I know of nobody who disputes that the notes should be available to the students after the lectures.

    Making lecture notes available in advance is much like making the reading requirements available in advance: it panders to the good students, as they will read the material at their first opportunity, and come to the lecture with a bit more familiarity of the topic. I found that having the lecture notes available in advance enabled me to write my questions down and prepare them in advance, resulting in more and better questions (from me, as a student) than if I’d had to think them up while taking notes and listening to the lecture.
    Making lecture notes available only after the lecture panders to the bad students, ensuring they needn’t compete with people who read lecture notes before class.
    Finally, making lecture notes available in advance is quite helpful to students who must miss a lecture for a doctors appt, an employer or interviewer who won’t budge, etc.

  17. says

    OK, my two cents on handing out lecture notes to students.

    There is no good way. Whatever way you do it you simply have to make the necessary adjustments. If you make the students take notes and don’t give them anything, then don’t test them on specifics mainly covered in lecture. If you do as I have sometimes done, give out some version of your presentation slides as handouts, then you can expect fairly detailed recall.

    The most important thing to do, in any event, is to have a regular and frank conversation with the students about it. You need to tell them, because many will have a very different idea about this, that there is no one way to do this that is best for all classes. Many student are unsatisfied because they figure a certain method is “best” (for some reason having to do with their own experience). You’ve got to let them know that you are doing what you are doing for a reason, with a plan, and that it is OK that it may not be what they are used to.

    It is especially important to make sure the students know that you are being very careful and thoughtful during semesters when you are pretty much making it up as you go along….

  18. says

    Oh, I want to add in support of what llewelly says

    Making the notes available in SOME form or another is probably always good. In large classes you will need to do this anyway (for disabilities services, etc.). But there are many ways to handle how the students get them (in advance, etc.)

    Last time I taught a very large intro class, I actually included about half my notes with a lab book the students were getting, three hole punched (as was the textbook), and later handed out a few batches of additional notes.

    Almost every method I’ve used has been good for some and bad for others.