Amalgamated Anthro News

19 09 2007

Much to my astonishment, I’ve actually started to receive some news items that people would like me to talk about here on Laelaps, and the past 24 hours or so has been full of anthropology-oriented news.

First up is a talk given by Zeresenay Alemseged, the discoverer of “Selam,” the Australopithecus afarensis child detailed about a year ago in the journal Nature. Brought to us by the Technology, Entertainment, and Design Conference, the talk can be found in either mp4 or zip form (it’s a video) here. The dreaded “March of Progress” rears it’s ugly head, but otherwise it’s an interesting summary if you’re not familiar with the discovery.

I also received notification of a new article in Scientific American (just about the only popular science magazine I don’t presently subscribe to, I think) about “The Trouble With Men.” At first, seeing only the title, I thought I was in for another evolutionary psychology (or “sociobiology”) rant about how inherently evil males of the species Homo sapiens are, but the reality of the article is far more interesting. According to the article, Virpi Lummaa of the University of Sheffield has found that there is something of a higher price to be paid for male offspring in our own species than for daughters, the course of development being more costly on the mother and siblings (both in and out of the womb) than previously suspected. While the data to back up the observations Lummaa has made are still wanting, studies on development in other animals suggest that testosterone has a lot to do with the problems experienced by females, especially if a mother gives birth to opposite-sex twins (the female might even be born sterile as a result of the testosterone influence).

How significant Lummaa’s studies are to modern society is also in question, as she primarily derived her observations from church records from over two centuries ago about premodern mothers among the Sami people of Finland. While such a time period may be slight, the cultural and technological changes have been great, which complicate the application of the data to people living today;

Access to effective birth control, an abundance of food, and low child mortality rates would all obscure the evolutionary influences seen in the preindustrial data. “It’s almost a shock when you realize that 100 to 150 years ago, 40 percent of babies died before they reached adulthood,” even when adulthood was defined as age 15, Lummaa notes.

Still, many, if not most, of the people in the world do not live in an industrialized society, so there is still plenty of opportunity to see if the observed trend still holds. For some reason Scientific American makes no mention (and provides no link) to the study that inspired the article, appearing in the June 26 edition of PNAS and by Lummaa, et al., entitled “Male twins reduce fitness of female co-twins in humans.” From what I can glean from the abstract, the authors argue from an entirely hormonal origin for reduced reproductive success in female twins born with a male brother, even if the brother dies at some point. Societal and cultural values do not seem to make a difference in the group studied, although I am still a bit dubious about the assertion that culture doesn’t compensate and would like to see a similar study undertaken with extant groups of people so more detail can be taken in. Regardless of how accurate the conclusions may or may not be, it is interesting to me personally as I am friends with a family where the mother had two sets of twins, each pair consisting of a boy and a girl.

Still, the idea that males might be favored in one way or another is not so strange an idea, especially since it’s becoming apparent that evolution can work on males in females of the same species in different ways. A study revealed earlier this year about Red Deer seem to show that what makes a successful male deer does not make a successful female deer (and vice versa), and another study involving White Rhinoceros showed that male offspring are favored when it comes to receiving milk from their mothers. The more we learn about species, the more dynamic and interesting things become, and before the study on deer I can’t say that I had considered the idea that an especially successful male deer might produce sub-par female offspring as a result of his prowess (although any sons would gain the benefit of dad’s genes).

Finally, the new issue of Natural History has an article about the skeleton of “Lucy” going on tour in the U.S. by AMNH paleoanthropologist Ian Tattersall. He writes;

Dinosaur bones and many other fossils routinely hit the road, but fossils of extinct hominids tend to be treated as sarcosanct, never allowed to leave their home institutions, let alone their countries of origin. That is regrettable, in part because such fossils are the patrimony of all humankind. Furthermore, paleontology is quintessentially a comparative business: no fossil can be satisfactorily understood in isolation from the wider record.

I’m still not entirely sure how I feel about the bones of Lucy going on tour; I would prefer them to stay safe because they do belong to all mankind (and not just my generation or paying customers at various institutions), but I won’t lie and say I will stay home when her remains come to New York. Also, I have heard from many a paleontologist that they wish America was a bit more strict about its fossils and where they can be taken after being discovered. Many countries, while allowing fossils to be taken to various institutions for study for a number of years, want the remains of organisms from their own country returned for storage, study, or display after a certain amount of time, and as far as I am aware the U.S. has not followed suit.

Many thanks to those who notified me of the new articles and videos; I will continue to write about whatever news is sent my way as often as I can, so if you see something that catches your eye and think should get some attention, send it on in. And, before I forget to mention it again, be sure to check out the new look of The Panda’s Thumb.





A snippet from “Tempo and Mode in Evolution”

4 07 2007

I started in on G.G. Simpson’s Tempo and Mode in Evolution tonight (reprint of the first edition, not the revised edition [Major Features in Evolution]). While I haven’t read enough of it yet to share any detailed thoughts of the subject, I did enjoy this bit from Simpson’s original Introduction, which I have seen quoted elsewhere before;

The attempted synthesis of paleontology and genetics, an essential part of the present study, may be particularly surprising and possibly hazardous. Not long ago paleontologists felt that a geneticist was a person who shut himself in a room, pulled down the shades, watched small flies disporting themselves in milk bottles, and thought that he was studying nature. A pursuit so removed from the realities of life, they said, had no significance for the true biologist. On the other hand, the geneticists said that paleontology had no further contributions to make to biology, that its only point had been the completed demonstration of the truth of evolution, and that it was a subject too purely descriptive to merit the name “science.” The paleontologist, they believed, is like a man who undertakes to study the principles of the internal combustion engine by standing on a street corner and watching the motor cars whiz by.

Now paleontologists and geneticists are learning tolerance for each other, if not understanding. As a paleontologist, I confess to inadequate knowledge of genetics, and I have not met a geneticist who has demonstrated much grasp of my subject; but at least we have come to realize that we do have problems in common and to hope that difficulties encountered in each separate type of research may be resolved or alleviated by the discoveries of the other.

Simpson originally wrote that over 80 years ago, and we’ve still got a long way to come. Knowledge in science continues to be specialized, genetic and morphological analysis of evolutionary trees still seemingly at odds, but I honestly don’t see how we’re going to advance our understanding of evolution if scientists who study the history of life focus only on their own field and no others. I don’t know if a new synthesis would do a trick, I don’t even know if it could be done, but no matter how it’s achieved, ecology, ethology, genetics, evodevo, paleontology, anatomy, etc. must all be considered and become more familiar, otherwise each field will be cataloging the minutiae of evolution rather than revealing the “big picture.”





It figures…

5 06 2007

What Science are You?


You’re geology. The science of beer. If people want you to do something, they bring you beer. If someone fails to bring the appropriate beer offering, they have committed a grave social blunder. Other than when people forget the beer, you are laid back and outdoorsy. You get really pumped about rocks. You’re loud, friendly and clumsy by nature. The beer only heightens this condidtion.
Take this quiz!


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The dinosaur one was a bit more anthropomorphic as far as the questions go, but I can’t really complain with what I got;


What Kind of Dinosaur are You?


You are a Deinonychus. You are fiercely loyal to your friends. You are honorable and stealthy. You can be violent. You’re like a Ninja-saur.
Take this quiz!


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(Hat-tip to Bora)





Book Notes; The Science of Jurassic Park and the Lost World

29 05 2007

Despite the busy weekend, I managed to polish-off Rob Desalle & David Lindley’s 1997 book The Science of Jurassic Park and the Lost World or: How to Build a Dinosaur. Spanning only 181 pages, it went fairly quickly, but in the end I wasn’t terribly impressed. While a book like this was certainly needed, it could have been so much more than what it actually was. The rhetorical technique of taking the reader step-by-step through a PCR process works, although the description is a bit dry and runs on long (just like, from what I’m told, running a PCR in real life). The authors also tend to bounce between vignettes from the book and the movie despite the fact that the movies are really quite different from their source material. This isn’t a major issue, but the authors seem to be picking and choosing bits rather than addressing the works as a whole.

Be that as it may they do a good job at describing how, at nearly every level, the park couldn’t have worked and the dinosaurs would have been nearly impossible to create (at least in any form resembling a dinosaur). The closing chapters on the simple logistics of the park, predator/prey interaction, and the issue of having enough space for the dinosaurs successfully takes down Crichton’s fantasy islands, although I wish a little more time was spent on these issues and as well as a little more scientific fact. I have no doubt their conclusions were correct in that, i.e. there was not enough space or food for all the herbivores and carnivores said to inhabit Site B, but they didn’t seem to put in as much effort explaining this as refuting the notion of getting dinosaur DNA from blood inside an amber-entrapped mosquito (although that is the bigger issue at stake).

Perhaps my favorite chapter, however, deals with Jurassic Park’s “conscience,” Ian Malcolm. While Malcolm seems to be able to predict that the system will fail and that the dinosaurs will escape with some accuracy, he never really explains his computations or thought processes to achieve these conclusions. Much is said of “Chaos Theory,” but it is never really explained and does not seem to hold up to scrutiny when looked at closely. Indeed, Malcolm is much like the book Crichton wrote; fun fiction, but no more scientific than Godzilla or Frankenstein. That very reason is why The Science of Jurassic Park and the Lost World is important; it’s easy to throw assertions about DNA, cloning, and dinosaurs around and seem scientific, but is it really anything of the sort? Hardly. This isn’t to say that I didn’t enjoy reading the fantasy-laden Crichton novels or the high-tech films, but there is a difference between regarding them as science fiction and scientific possibility, and the idea that a real-life Jurassic Park might be possible someday soon was a notion that seems to have been supported by the filmmakers.

In any event, if you’re already familiar with the process of obtaining, processing, and studying DNA this book probably doesn’t have much new information for you. I was overall unfamiliar with the PCR process so I learned a few things there, but otherwise it’s a fairly easy read that doesn’t didn’t excite me or bore me. While there are certainly things that could have been improved (and some rather painful, obvious mistakes like calling Maiasaura “Maiasaurus”), it’d be a good read for anyone who is altogether unfamiliar with basic science dealing with finding, extracting, and studying genetic material and has an interest in dinosaurs. In the end though, I shouldn’t complain too much; I bought it for a penny and I certainly got the author’s two cents.





And the T. rex goes… cock-a-doodle-do?

13 04 2007

I’m sure everyone remembers the Mary Schweitzer’s huge discovery of tissueinside a Tyrannosaurus rex thighbone (and how creationists tried to hijack the study to support their own ideas, and still are), and now some of the organic material from that bone has been analyzed. The conclusion; Tyrannosaurus rex may be most closely related to chickens, with frogs and newts being the runners-up. But wait, why would extant amphibians show a closer relationship than, say, crocodiles or other birds? Are chickens meant to represent birds in general or just chickens? The USA Today article (and most news reports I’ve seen) have had fun calling the dinosaur thighbone a “drumstick” and seem to want to drive the point home, but until more independant studies are completed the findings should be considered carefully.

What put me off most about the article, however, was this quote from Hans Larsson of McGill University;

Dinosaurs will enter the field of molecular biology and really slingshot paleontology into the modern world.

Yes, yes, paleontologists are still running around a-fussin’ and a-feudin’ like Cope and Marsh, content to stay in their dusty labs measuring fossils like Cuvier and Owen did ages ago. In the past few decades paleontology has utilized various tools like computer programs, CAT scanners, advanced microscopy, innovative reconstruction techniques, and others, so I hardly think paleontology is still stuck in the early 1900’s. While it is certainly amazing that organic material has been preserved, we also must ask the question of how well such material is preserved. Will we be able to study such material with enough accuracy to really use it to determine relationships? I don’t know much about genetics and microbiology (unfortunately) but I am a little skeptical, and it seems that these days microbiology trumps other sources of information (at least that’s the way it is sometimes treated).

Indeed, I haven’t seen the actual paper and I don’t know if I’d be able to make sense of it if I did, but I am a little skeptical. There is no doubt that birds evolved from dinosaurs, but why would the closest relatives of a Tyrannosaurus rex be chickens, frogs, and newts? It’s likely that the USA Today article oversimplified things and I still think there is a lot of misunderstanding about what Mary Schweitzer actually found in the first place because of mass media, but as with anything else these days I think it’s going to take a lot of further study before we can safely say we’ve got this all sorted out.





Things sure have changed… GG Simpson & the “historian of life”

3 04 2007

Yesterday I received a yellowing copy of George Gaylord Simpson’s The Meaning of Evolution (3rd Edition, 1950), and although I am only about 50 pages into it, it is absolutely amazing how much things have changed in the last half century when it comes to evolution. In the book, Simpson notes that the oldest rocks we have are about 2,000,000,000 years old, there are about 1,000,000 extant species, there was some sort of extinction near the end-Permian (although it was largely a mystery), there were few fossils from before the Cambrian (although he rightly notes that the Cambrian “explosion” that creationists cite as proof against evolution is not true), and dinosaurs are still dragging their tails and looking more like big, grumpy lizards. Indeed, on page 30 there is a chart showing the radiation of “significant” phyla through time, Chordates seemingly more diverse than arthropods and even molluscs during the present, at least according to the chart. While Simpson notes that there are likely more arthropods than currently recognized, it is still interesting to consider that not long ago the whole of our understanding of life’s diversity didn’t even scratch the surface.

A piece from the Prologue is also interesting, not only because it notes the professional bias of the time, but because it perhaps reflects my own interest in paleontology & evolution in more “traditional” fields of study;

There are many ways of studying the history of life. The geneticist, raising tiny fruit flies in bottles, and the well driller, piercing thousands of feet of the earth’s crust in search of oil, are both contributing to this study. One way of pursuing the study, the most direct way and the one around which all other contributions need to be organized to articulate the whole history, is that of the paleontologist. In his most immediate and narrow occupation, the paleontologist is a student of fossils, the preserved remains of ancient life. He seeks these in the rocks throughout all the lands of the earth, takes them to his laboratory, cleans them for study, compares them with each other, identifies and names their kinds, determines their ages, and finally sets up their associations and historical sequences. As with any other sort of worker, the paleontologist’s day-by-day attention is mostly focused on the concrete and more or less routine details of the jab in hand rather than on the broad whole of which this job is a small part. When he does turn to these broader aspects, the paleontologist becomes not merely a student of fossils but a historian of life. The historian of life takes not only knowledge of fossils but also a tremendous array of pertinent facts from other fields of earth sciences and of life sciences and weaves them all into an integral interpretation of what the world of life is like and how it came to be so. Finally, he is bound to reflect still more deeply and to face the riddles of the meaning and nature of life and of man as well as problems of human values and conduct. The history of life certainly bears directly on all these riddles and problems, and realization of its own value demands investigation of this bearing.

Sounds awfully lofty, doesn’t it? I especially find this passage interesting in that over the past week, science bloggers have been abuzz about a new study that used genetic data to try and determine what happened in mammalian evolution, the science of genetics having considerably more reach and power than it did in Simpson’s time. As a child, however, I didn’t grow up knowing anything about genetics; if you wanted to understand evolution and life’s history, paleontology is the way to go. Indeed, it is clear that in Simpson’s writing that while he does not write genetics off as unimportant, it only merely contributes to understanding gained from paleontology, the field which allows for scientific and well as (according to the last few sentences, at least) philosophical understanding of life and its history. I wonder what Simpson would say today, with genetic studies and paleontology-based studies sometimes at odds with each other, many people choosing one over the other. As with the new mammal diversification study, many of those who work in genetics and related fields heralded it as doing away with an old paradigm, whereas others (like myself) believed that it was a bit over-hyped and did not say what many ascribed to it (that there was no mammal proliferation following the K/T extinction). Hopefully, paleontologists and geneticists will work together in the future to help our understanding of evolution and extinction, but for my own part I still largely fall into the paleontology camp; I grew up wanting to be the “historian of life” that Simpson writes of.

I know that if I am ever to truly understand evolution, I cannot overlook genetics or developmental studies; ecology, paleontology, anatomy, etc. do not in of themselves constitute the whole picture. There is something that I find enthralling about bushwhacking through the forest in order to get a better idea of the life history of an organism, or peeling away layers of rock to reveal an organism that once was alive and has a story of its own to tell. There must be a psychological component (likely Jungian) to my love for these outdoor studies of the individual or population and my aversion to laboratory work, which I sometimes think of as sterile and boring. This is not to say that I find such work unimportant, but rather that I am not cut out to do it and I must overcome my own bias. If I cannot, if I simply regard my own narrow field as work as the field that illuminates science, I will be doing a disservice to myself and those who may agree with me.





Oodles of confusion, part II

30 03 2007

Yesterday I posted about a new paper in Nature which, through phylogenetic study, suggests that modern mammal lineages diversified earlier than once thought and the extinction of non-avian dinosaurs did not increase the lineages diversity. PZ, Larry Moran, and Mike Dunford have all covered this story as well, but there is one important facet of the study that I think is missing from many of the discussions about it popping up around the blogosphere. If the paper does accurately reflect what occurred to lineages that would lead to modern monotreme, marsupial, and placental mammal groups, this does not mean that there was no diversification of mammals after non-avian dinosaurs went extinct. Indeed, the paper itself states the following;

The supertree therefore contains no evidence that the diversification rate of the extant mammalian lineages increased soon after non-avian dinosaurs went extinct. Although there is strong palaeontological evidence that mammalian diversity, driven by a massively elevated rate of speciation, generally rose rapidly immediately after the K/T boundary, there is in fact no conflict between the palaeontological and neontological interpretations of the known facts. Most diversifications immediately after the K/T boundary were in groups such as multituberculates, plesiadapiforms and ‘archaic’ ungulates, as plots of the numbers of genera known in each sub-epoch indicate. These groups declined or went extinct early in the Cenozoic era and so are barely, if at all, represented in the phylogeny of living species. The continuing low rates of extant mammalian diversification through this period imply that the dearth of Palaeocene crown-group fossils is a real reflection of the low diversity of those clades. The low rates are also consistent with (but not direct evidence for) the hypothesis that extant lineages were inhibited in some manner by the diversity of the predominantly Palaeocene groups, and only started to diversify with the decline of the latter. However, like most other proposed competitive exclusion scenarios (for example, see refs 24, 25), this conjecture is based purely on the negative correlation of taxon diversities rather than direct evidence of exclusion.

While this may be a “minor” theme of the paper, I find this aspect of it particularly exciting. If the study is correct, then extant mammal lineages diversified once before the K/T extinction, but did not do so again until later when many of the other “archaic” mammal groups became extinct. Indeed, it almost seems like modern mammal groups could not catch a break, and if this holds up it would be extremely interesting to find out why now-extinct mammal groups were so successful while extant groups were not, and what caused such a reversal in fortune. Even forgetting about the K/T extinction for a moment, if mammals diversified long before the extinction, what led to this diversification? These are questions that certainly beg answers.

While the idea that extant mammals like opossums crawled out of the ash a little after the K/T extinction and led an unstoppable march of progress towards you and I is preposterous, I can’t see how the extinction of many groups of animals would not “set the stage” for further diversity and evolution. The process was likely more chaotic than previously thought, but it seems apparent that some (now extinct) mammal groups did diversify in the wake of the K/T extinction, although the reasons for this will require further investigation. I’m sure that there will be some debate over this paper for a long time to come, but hopefully paleontologists, paleoecologists, and those undertaking phylogenetic studies will be able to communicate each other to make sense of the fossil and genetic data. Either way, the extinction of the dinosaurs did mark a major landmark for mammals, and how all members of that group responded to the changes around them is something that will require much more study to ascertain.

References:
Bininda-Emonds ORP, Cardillo M, Jones KE, MacPhee RDE, Beck RMD, Grenyer R, Price SA, Vos RA, Gittleman JL, Purvis A (2007) The delayed rise of present-day mammals. Nature 446:507-511.