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October 2012 Archives

One of the catchphrases of Intelligent Design creationism is 'irreducible complexity' - the idea that in some complex biological systems, it's impossible to remove any one part without causing the whole system to fail. Supposedly this means that such systems could not have evolved but must be the product of a 'designer'. The term - in its most recent incarnation - was proposed by biochemist Michael Behe, but it's effectively the same as William Paley's 19th century concept of the watchmaker.

Behe used to be fond of using the ordinary, bog-standard, everyday mousetrap as an example. I have always found this just a tad unimaginative of him, as while removing (say) the spring would render the mousetrap incapable of doing its current job, this is not the same as saying that the remaining parts do not (& cannot) have some other function. (In a better, biological, example various constituent parts of the so-called 'irreducibly complex' flagellum bacteria** do actually have other functions, including adhesion to other cells.) I could, for example, throw the wooden platform of our old mousetrap*** at a mouse. Occasionally I might even hit it.

There are other possibilities for mousetrap evolution, described rather amusingly here (& hat-tip to Peter Bowditch of the Millenium Project).

 

** Incidentally, there is no such thing as 'the' bacterial flagellum.

*** I say 'old' because we haven't used it for a while. These days the fat (6kg) furry ginger monster does the job quite satisfactorily. He probably falls on them.

 

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 While away on holiday (gloat!) I got the opportunity for uninterrupted listening to podcasts :) One of these was a July episode of the Skeptics Guide to the Universe, which included a discussion of the (in)famous Kennewick Man remains. These 9,000-years-old bones have been the focus of considerable controversy in the US, where they were claimed by Native American tribe as being an ancestor's bones & so not available for scientific study. However, this belief was overruled in 2004 by a US Court of Appeals Judge, allowing scientists to continue studying the surprisingly complete skeleton. 

Unfortunately, that study has had to focus on anatomy: an attempt to obtain and amplify DNA from the bones concluded that

No DNA suitable for PCR amplification could be extracted from the Kennewick samples studied. Thus, no conclusion regarding its ethnic ancestry or cultural affiliation based on DNA can be made.

While some sequences were found, these matched DNA from individuals involved in the analysis & so were most likely modern contamination. This means that data from - among other things - analyses of cranial and facial morphology have been used to try to determine the likely origins of Kennewick Man. As the fearless investigative team at Riddled, Inc. report, these analyses have been used to justify some rather shaky conclusions, including a rather tenuous link to New Zealand. One cannot better the Riddled team's take on this one :)

 

 
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 Grant's talked quite a bit about TED talks. This one's a cracker: Melissa Marshall talking about science communication. Important point for scientists: clear, careful explanations of what we're doing =/= 'dumbing it down'!

 And thanks, Annette, for passing it on :)

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 ... because today the Significant Other & I are heading off for a week in balmier climes. Oh all right, in Rarotonga. So apart from a little something I prepared earlier, I won't be blogging for a bit.

Also, I'm not sure what my internet access will be like & so I may not be able to approve comments. So please be patient - I haven't forgotten you!

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Next week my first-year biology students will be doing an appraisal of this semester's paper, & of those academic staff involved in teaching it. They're asked about the perceived difficulty of the paper, the amount of work they're expected to do for it, whether they've been intellectually stimulated, the amount of feedback they receive on their work, how approachable staff are, & much else besides. (The feedback one was always my worst scoring attribute - until I asked the students what they thought 'feedback' met. It turned out that they felt this described one-to-one verbal communication. We had a discussion about all the other ways in which staff can give feedback - & the scores went up.) The results are always extremely useful, as not only to we find out what's working, but we also discover what's not (or at least, what the students perceive as not working) & so may need further attention.

Anyway, my friend Annette has just drawn my attention to a lengthy post in The Atlantic, by Amanda Ridley. It made fascinating reading.

In towns around the country this past school year, a quarter-million students took a special survey designed to capture what they thought of their teachers and their classroom culture. Unlike the vast majority of surveys in human history, this one had been carefully field-tested. That research had shown something remarkable: if you asked kids the right questions, they could identify, with uncanny accuracy, their most - and least - effective teachers.

Ridley, reporting for the Atlantic, was able to follow a 4-month pilot project that was run in 6 schools in the District of Colombia. She notes that about half the states in the US use student test data to evaluate how teachers are doing.

Now, this approach is fraught with difficulty. It doesn't tell you why children aren't learning something, for example (or why they do, which is just as interesting). And it puts huge pressure on teachers to 'teach to the test' (although Ridley says that in fact "most [American] teachers still do not teach the subjects or grade levels covered by mandatory standardized tests"). It ignores the fact that student learning success can be influenced by a wide range of factors, some of which are outside the schools' control. (And it makes me wonder how I'd have done, back when I was teaching a high school 'home room' class in Palmerston North. Those students made a fair bit of progress, and we all learned a lot, but they would likely not have done too well on a standardised test of academic learning, applied across the board in the way that National Standards are now.)

So, the survey. It grew out of a project on effective teaching funded by the Bill & Melinda Gates Foundation, which found that the top 5 questions - in terms of correlation with student learning - were

  1. Students in this class treat the teacher with respect.
  2. My classmates behave the way my teacher wants them to.
  3. Our class stays busy and doesn't waste time.
  4. In this class, we learn a lot almost every day.
  5. In this class, we learn to correct our mistakes.

and the version used with high school students in the survey Ridley writes about contained 127 questions. That sounds an awful lot, to me, but apparently most kids soldiered on & answered them all. Nor did they simply choose the same answer for each & every question, or try to skew the results:

Students who don't read the questions might give the same response to every item. But when Ferguson [one of the researchers] recently examined 199,000 surveys, he found that less than one-half of 1 percent of students did so in the first 10 questions. Kids, he believes, find the questions interesting, so they tend to pay attention. And the 'right' answer is not always apparent, so even kids who want to skew the results would not necessarily know how to do it.

OK - kids (asked the right questions) can indicate is a good, effective teacher. What use is made of these results, in the US? The researchers say that they shouldn't be given too much weighting, in assessing teachers - 20-30% - & only after multiple runs through the instrument, though at present few schools actually use them that way. This is important - no appraisal system should rely on just one tool.

That's only part of it, of course, because the results are sent through to teachers themselves, just as I get appraisal results back each semester. So the potential's there for the survey results to provide the basis of considerable reflective learning, given the desire to do so, & time to do it in. Yet only 1/3 of teachers involved in this project even looked at them.

This is a problem in the NZ tertiary system too, & I know it's something that staff in our own Teaching Development Unit grapple with. Is it the way the results are presented? Would it be useful to be given a summary with key findings highlighted? Do we need a guide in how to interpret them? Do people avoid possibly being upset by the personal comments that can creep into responses (something that can be avoided/minimised by explaining in advance the value of constructive criticism - and by being seen to pay attention to what students have to say)?

Overall, this is an interesting study & one whose results may well inform our own continuing debate on how best to identify excellent teaching practice. What we need to avoid is wholesale duplication and implementation in our own school system without first considering what such surveys can & can't tell us, and how they may be incorporated as one part of a reliable, transparent system of professional development and goal-setting. And that, of course, is going to require discussion with and support from all parties concerned - not implementation from above.

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 A topic that gets quite a frequent airing in our tearoom is the decline in the number of students taking physics. This issue isn't peculiar to my institution - a quick look at the literature indicates that it's a global problem**. The question is, what can be done about this? It's a question that Pey-Tee Oon & R.Subramaniam (2010) set out to answer.

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I've just found a new blog that is a must-follow: Becky Crew's Running Ponies.

Run, don't walk, over there - and read wondrous posts such as her discussion of a study that found chocolate** appears to enhance snails' ability to form lasting memories. I wonder what will happen to chocolate sales at the uni shop, when I share this one with my students...

Also, boogie-woogie aphids!

** actually, a chemical found in chocolate; the poor snails missed out on the whole mouthfeel side of the experience :)

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Via a family member's blog, I discovered a physics story with this wonderful beginning:

It's the rare scientific mind that has the pure intellectual chutzpah to tackle a problem that has troubled boffinry since the discovery of cryogenics - namely, "What happens if you combine liquid nitrogen with 1,500 ping-pong balls?"

I wanna be in Roy Lowry's physics class! Talk about getting students' attention - one hopes for long enough that the underlying physics explanation for what they've observed can be generated.

My only complaint is that Someone Has Taken Down the Video at that link! But I know how to google & here we are anyway:

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