Wednesday, August 27, 2008

Why I'm glad I don't teach high school biology in this country!

Because I don't have to worry about adhering to some "science standard" set by the whims of uneducated but elected school-board members, rather than the well-established and thoroughly peer-reviewed knowledge accumulated by my scientist colleagues over the past century and a half since Darwin published his Origin! This story in the NYT over the weekend, about a Florida school teacher's struggle to teach Evolution properly in his classroom, is another reason why I respect educators like Mr. David Campbell, and my local friend Scott Hatfield. I'm not sure I'd have the patience or perseverance to keep at it if I was constantly being discouraged from mentioning the e-word by my bosses, challenged by ignorant parents who would rather have me re-affirm their kids' beliefs than teach them the best knowledge in science, and showed up by my own fellow biology teachers teaching creationism down the hall from my classroom!! I don't know how they do it, but these schoolteachers are real heroes of the embattled enlightenment in this country, and my hat is off to them. again. If it were me, I'd have given up long ago and headed back home to India, where this issue never came up throughout my education!


And those of you students taking my classes this semester, please do read the entire NYT article. And watch the accompanying video. I am aware that there are at least some high school biology teachers right here in the Fresno-Clovis school districts, and elsewhere in the central valley, who dance around California's science standards and avoid teaching evolution as much as they can. While I'm happy to provide remedial education if you suffered under such a teacher, I also hope such teachers didn't kill your scientific curiosity and critical thinking abilities entirely! You will certainly need to switch those on to make the most of my classes.



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Holy magnetic cow!!

ResearchBlogging.orgFile this one under the "who woulda thunk it?", or "why didn't I think of this?" or simply "whaaa...?!" categories! Quick, can you tell which way is north in this picture?



Do you think of asking the cow for directions? Why not? For it seems that cow probably knows which way north is!



You know, these big dumb-seeming large mammals you pass by every day, these big walking, grazing cheese-producing happy cows dotting the picturesque landscapes of California's grassy hillsdes, or their scrawnier but holier cousins clogging up traffic throughout India? Well, there is more to them than meets the eye - in fact this curious tidbit about their natural history seems to have escaped notice from even the keenest cowboy, cattle-herder, animal husband (I'm not sure if that's what one calls someone practicing animal husbandry - is it?), or drunken late night cow-tipper, throughout history.


It took some creative but fairly straightforward analysis by German scientists of satellite imagery now available via Google Earth to discover that cows, while grazing or resting, chewing cud tend to orient their bodies along the magnetic north-south axis!! And its not just cows, deer also appear to do the same! How cool, and odd, and curious is that?! And what a clever application of Google Earth imagery? This team simply measured the orientation of 8510 cows in satellite images of 308 pastures across the globe, and found that over two-thirds of the animals orient themselves along a north-south axis!! Apart from simply asking the question (who woulda thunk?), the analysis was careful enough to account for local variation in magnetic fields, and shows that the animals orient according to the local field, not geographic north!


Which raises all kinds of interesting questions worth following up on, some of which you can read about in the original PNAS paper published in an early online edition this week, and in this Los Angeles Times article covering it. Here's the abstract from PNAS:



Magnetic alignment in grazing and resting cattle and deer


Sabine Begall, Jaroslav Červený, Julia Neef, Oldřich Vojtčch, and Hynek Burda


Abstract


We demonstrate by means of simple, noninvasive methods (analysis of satellite images, field observations, and measuring “deer beds” in snow) that domestic cattle (n = 8,510 in 308 pastures) across the globe, and grazing and resting red and roe deer (n = 2,974 at 241 localities), align their body axes in roughly a north–south direction. Direct observations of roe deer revealed that animals orient their heads northward when grazing or resting. Amazingly, this ubiquitous phenomenon does not seem to have been noticed by herdsmen, ranchers, or hunters. Because wind and light conditions could be excluded as a common denominator determining the body axis orientation, magnetic alignment is the most parsimonious explanation. To test the hypothesis that cattle orient their body axes along the field lines of the Earth's magnetic field, we analyzed the body orientation of cattle from localities with high magnetic declination. Here, magnetic north was a better predictor than geographic north. This study reveals the magnetic alignment in large mammals based on statistically sufficient sample sizes. Our findings open horizons for the study of magnetoreception in general and are of potential significance for applied ethology (husbandry, animal welfare). They challenge neuroscientists and biophysics to explain the proximate mechanisms.



So what's the underlying mechanism cows use to sense the magnetic field? Do they also have magnetic particles in their brains like many better studied migratory species known to orient magnetically? Why do they do this? Domestic cows are not, of course, migratory any more (at least not on their own), so what might they gain by orienting magnetically? Or is this simply a vestige of their evolutionary history, from ancestors who actually put that magnet to use? And do they prefer to point their heads north or their behinds? The satellite photos are not sharp enough to tell apparently, so answering that may require some ground-truthing! Opens up a whole new line of research, doesn't it?


And as for why so many humans who have spent much time with cows failed to notice this uncanny magnetism, here's a priceless quote from the LA Times, from a dairy farmer right here in the Central Valley, no less:


Asked whether he had ever observed such behavior in cows, dairy farmer Rob Fletcher of Tulare, Calif., said, "Absolutely not." But, he added, "I don't spend a lot of time worrying about stuff like that."


I suspect, however, that the last laugh belongs to the cows, as only Gary Larson could have guessed! Remember this from his insightful pen?


FarSideCownCar.gif


That's why it took satellites to notice this particular behavior! What else have the cows been up to then?


Reference:


Begall, S., Cerveny, J., Neef, J., Vojtcch, O., Burda, H. (2008). Magnetic alignment in grazing and resting cattle and deer. Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0803650105



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Monday, August 25, 2008

Welcome, Evolution class of Fall 2008!

dragonflies in loveHere we go again! Actually, I guess its just me going again - but all you new students of BIOL 105 are embarking on a brand new journey through Evolution, right? I hope you are excited! Especially since you are the first class of the Sesquicentennial Year of Natural Selection!


This blog will be our secondary channel of communication (the classroom being the primary one). I use this medium to share any cool evolutionary discoveries I read about, outside of the textbook. There are also bits of not entirely relevant, but hopefully enjoyable fluff scattered about. And you students too will have opportunities to share your own readings and writings through this blog during the course of this semester. Feel free to poke around here, look through the archives, and see what your predecessors in this class wrote about.


Welcome back to the new academic year! I'll see you in class soon.



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