Ever since widespread consensus was reached last decade that a meteorite was at least partially responsible for the extinction of the dinosaurs (among other organisms) at the end of the Cretaceous, it's been en vogue to try to show that meteorite or comet collisions can be linked to all the major mass extinctions. I'm usually very skeptical of such studies, which are often highly speculative and smack more of self-promotion than of good science. That said, it's never worth shooting such hypotheses down without having first heard the evidence used to formulate them. With that in mind, I went to a talk last Friday given by two professors from the anthropology department here at Oregon. It was, in effect, a practice talk in advance of the official presentation of their findings this week at the Geological Society of America's meeting in Acapulco. The research group - which consists of 26 (!) members from representing many different fields - had come across several lines of evidence that seem to suggest that a small meteorite, or more likely a comet, smashed into Michigan 13,000 years ago. These lines of evidence included such things as an iridium spike and nannodiamonds, both of which are generally associated with some type of extraterrestrial impact. I was ready to be a skeptic, but I have to admit, their argument was very compelling. While the impact itself would have been relatively minor, the authors suggest that such an event in an area that was then covered by glaciers would shatter ice dams holding back massive glacial lakes, wreaking havoc on ocean circulation and, by extension, climate.
As anthropologists, the presenters I saw were most interested in how the impact might have affected North American paleoindian society. I was more interested in a topic they touched upon only briefly. For several years, one of the most contentious debates in paleontology has been the argument over whether humans are responsible for the extinction of large "Ice Age" mammals (megafauna). It's been a particularly vitriolic debate, with each side having its share of convincing arguments, bad science, and flat-out name-calling. This comet hypothesis will no doubt light an entirely new fire under a cauldron that's already been boiling for some time. As such, I have no doubt that the findings of this will be debated and subjected to several rigorous geological, anthropological, and paleontological test, and I for one look forward with great interest to seeing how well they hold up under scrutiny.
25 May 2007
24 May 2007
My Own Private Deer Park
22 May 2007
Happy ACD-Day!
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20 May 2007
How to Make a Good Nature Documentary
Today, the Discovery Channel has been airing the BBC series Planet Earth. I had heard about the series before, but I'd been skeptical: it couldn't really be as good as everyone claimed it was, could it? Turns out that yes, it is. Here's why:
- As the narrator is never tired of reminding you, the cinematography in the series is nothing short of stunning. There are gorgeous landscape shots (like a top-down view of Angel Falls and a flyby of a fog-shrouded coastal forest right here in the Northwest), close-ups catching animal behavior "in the act" (like macaques diving for food in Indonesia or the mating display of a bird of paradise), or - best of all - combinations of the two (the most spectacular example being a snow leopard hunt on a sheer cliff face in the Himalayas). The producers also do a great job of using slow-motion footage (of a great white shark leaping to catch a seal, for example) and stop-motion (to show a sunflower sea star chasing brittle stars across the California seafloor).
- Many nature documentaries focus on one individual or group. While this might make for a good story-line, it also opens the door for anthropomorphism and presents logistical problems (one documentary on baboons is notorious for having used five or six other individuals stand-ins for the "main character," of which they just didn't have enough footage). Planet Earth takes a much more holistic approach, with each episode focusing on an entire biome. While much of the documentary is still devoted to animals, other organisms get plenty if air time as well, as does the physical environment itself.
- The producers aren't afraid to show "nature, red in tooth an claw." It's always annoyed me that most documentaries will show only the appealing bits of the natural world, cutting away from footage hunts just before the kill, for example. Planet Earth, on the other hand, doesn't skimp on the carnage, whether it's a chimp cannibalizing an infant from another troop or a parasitic fungus erupting out of the head of an ant (in stop-motion, no less). It may be gruesome to some people's eyes, but a documentary that shows only those aspects of the natural world that they think viewers will want to see are, at best, telling only half the story.
- Many nature documentaries also like to drive home their conservation message with a sledgehammer. I'm as pro-conservation as the next guy, but finger-pointing and guilt-mongering are annoying at best, and more commonly are entirely counterproductive. Planet Earth most certainly has the same goal, but it is much more nuanced and subtle about it. One of the producers stated that the aim of the program was to show people that there are still places out there worth saving, and there can be no doubt that Planet Earth does so masterfully. It would take a truly hard-hearted person to watch this and not be moved on some level, and to paraphrase the old adage, there is no better way to inspire conservation efforts than to first inspire appreciation.
04 May 2007
Happy Darwin's Bulldog Day!
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