how do we teach students to question what we say? Alison Campbell Mar 14

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This is a re-post of something I’ve written for Talking Teaching. I’ve reproduced it here because I think the notion of teaching things like critical thinking & the nature of science are just as relevant here as they are in a discussion about teaching itself.

I’ve just been reading a post by Tim Kreider, over at Science-Based Medicine. Tim’s talking about the learning experiences of medical students, but a particular phrase caught my eye. I”m reproducing it here because I think it can be applied much more widely: students are in the habit of transcribing and commiting to memory everything uttered by the professors who grade them.

I’ve seen this happen myself. I remember talking with a class about fungi & saying that while most fungi are saprophytes (consuming dead material), some are predatory. And they all (well, all those I could see, anyway) wrote this down unquestioningly. ‘Hang on a minute,’ I said; ‘does this sound likely to you?’ They agreed that no, it didn’t really, it didn’t match with what they already knew about fungi. ‘Well then,’ I said; ‘why didn’t any of you call me on it?’ ‘Because,’ they said, ‘you wouldn’t tell us anything incorrect, would you?’ Which showed a touching faith but also a worrying lack of willingness to question things that didn’t sound right.

(Just as an aside: This was amply demonstrated one year when my class was sitting a lab test. One of the questions asked students to label a section of plant tissue, selecting their labels from a list that I provided. It happened to be April 1st – so I included the word ‘aardvark’ in that list. Rather worringly, about 30% of the class used it for a label – & when asked why they said well, it didn’t sound right, but they just knew I wouldn’t have used a word that didn’t belong… And not one of them questioned it at the time.)

Now, in his SBM post, Tim makes the point that med students in their pre-clinical training have to learn so much content that there isn’t a lot of room for rigorous skepticism (but make no mistake, he’s still arguing of the need to teach critical thinking). And I agree, there is factual content that I want my students to be able to remember (& my colleagues teaching at 2nd-year would like it too!) But at some point we must surely also want our students to develop a healthy skepticism: the ability to think critically about what they’re hearing & learning.  And I certainly don’t like the idea that my science students might regard me as infallible. Not least because that’s not a particularly good model for what science is like. They need to know that scientists can & and do make mistakes, get things wrong, interpret data in ways that subsequently (in the light of further data) turn out to be inaccurate. And they need to feel confident that it’s OK to ask questions. The thing is, how best to get this across?

Speaking for myself, I’m a firm believer in modelling this for my students. If I’m asked a question to which I don’t know the answer, I’ll tell them so, up front. But then I’ll say, but I can hypothesise about this – here’s what the answer might be, & here’s my evidence for thinking this. (If the classroom has web access – & most of ours do these days, we’ll often go on to check what I’ve said on the spot.) If it turns out that I’m wrong (which happens quite a lot, then that’s fine, & we’ve all learned something new.

Plus, I actively encourage questioning during my lectures. (Pop quizzes & concept maps are good for encouraging the sort of conversations that lead to this.) Sure, I mightn’t get through as much content as if I didn’t do this, but the students’ learning experience is surely going to be a better one if they can follow up on things on the spot. And hopefully they learn from this that it really is OK to ask questions :-)

And – I’m all for telling stories. How better to help students learn about the nature of science than to use a narrative approach that lets them see how scientists viewed the world at some past point in time, & how science has led to a change in - or a reaffirmation of – that perspective?

cross-species hanky-panky Alison Campbell Mar 12

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My first-year students & I are currently studying plants. This is actually something of a balancing act from my perspective as a reasonably large proportion of the class didn’t study the ‘diversity in plant structure & function’ standard back in year 12 (or don’t remember doing so), so I’ve got to bring them up to speed without boring the others.

Anyway, when we get on to talking about flowering plants, one of the topics is adaptations for pollination. Some flowering plants (eg grasses) simply shed their pollen to the wind, but for many successful pollination has required the establishment of a plant-animal relationship. And some of those involve some very kinky activity indeed – the animal ‘vector’ comes to a flower, not for a nectar reward, but because in its eyes the flower looks like a member of the opposite sex…

And thanks to PZ, who always finds these things first!

what makes students stick at science? Alison Campbell Mar 11

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This is a very relevant question in the light of the government’s recent announcement of its intention to tie a proportion of tertiary funding to student completion and retention rates. (This decision is presumably driven, among other things, by relatively low rates of retention and passing papers/courses, which lead to questions about whether we’re getting value for money from our tertiary system.) Speaking personally, I find this a rather blunt instrument for rewarding performance as at least some of the factors affecting this are beyond the institutions’ control (e.g. Zepke et al. 2005). There’s quite a lot of literature around dealing with the whole issue of student retention, but I thought I’d be self-indulgent for once & discuss a study done here, examining the factors affecting completion & retention of students in science & engineering (Otrel-Cass et al., 2009).

This study used a combination of a questionnaire & focus-group interviews with returning 2nd-year students to examine various factors that could influence students’ decisions to stick with their studies. (One immediately obvious flaw is that we’d got no real way to find out why those who didn’t return, chose not to.) The questions we used in the survey were designed to elicit students’ opinions on their ability to cope with the varying demands they faced during their studies. We were interested in time management, learning strategies, how confident they felt at managing their learning in lectures & labs, communication issues surrounding their studies, information available about their programs of study (provided by staff in particular & the institution as a whole) and about assessment.

Rather alarmingly, only around half of the students we surveyed felt particularly confident about managing the workloads associated with tertiary study, while 70% felt that this was a significant issue in deciding to come back to uni. (And remember, these were second-year students, so they’d already managed to cope with the jump from school to university.). So – those of my readers who are intending to enter uni at some point – be aware that you’ll need to develop some strategies to handle the various demands on your time. I feel it’s also important for us to keep an eye on how our students are doing, & offer support when it’s needed, & in fact we’ve developed a system in my Faculty to do just this for first-year students. We need scientists & technologists & engineers, so it makes a lot of sense to support our budding technicians & researchers & teachers through the rocky patches as best we can.

If you’re studying science you’ll be in the lab, writing essays & reports, & using the library. Yet less than 20% of our respondents felt very confident in their ability to do these things well. (This bothered me more than a bit – we should be teaching them how to do these things in first-year! That’s actually one reason we include an essay in the assessment for first-year biology – to help students to learn the conventions of academic writing. And also to help prepare them for the essay-type answers in their end-of-year exams.) 

I mentioned labs – the students we surveyed placed a lot of importance on their lab work, in terms of learning various techniques but also because of the opportunities lab classes offer to interact with teaching staff. You get the chance to ask questions that you might not have wanted to ask during a lecture, and this helps to develop a more personal relationship with your lecturers. In fact, we found that [students] placed high value on the presence of academic staff in practical sessions,(Otrel-Cass et al., 2009), for thiis very reason.

Our respondents (in both the survey & the focus groups) recognised the value of lectures. They were particularly positive when they felt that lecturers valued what they were doing. They also felt strongly that it was easier to engage with a subject when the lecturers were themselves interested and enthusiastic – and when the teaching staff told personal stories in class. While these gave information about future careers, they also increased the students’ motivation. This was obvious in the students’ comments: One of the best [experiences] that I loved was how they give examples. You know, really amazing little things of weird little animals you never even knew about and you can actually go home and tell people, ‘Oh, I learned this today’ and that’s really cool. I always tell at home what I learned and why things happen too. 

Overall, it seemed clear to us that we (uni academics, & institutions) need to give our first-year students the message that we value them & take their educational needs seriously. This has a big impact on their attitudes to continuing with their studies. Letting students see staff as ‘people’ through personalised lectures, having academics (rather than senior students) in lab classes, being available to talk with students, keeping an eye on how students are handling things like workload – all these make students feel part of the uni community. This finding fits in with research findings elsehwere that stress the significance of staff: student relationships. The trick for us, of course, is to balance all this with the other demands on our time in a funding environment that places a high importance on research & attracting external funding. Achieving success is a juggling act for staff as well as for their students :-) But an act that’s rewarding, if we do it well.

K.Otrel-Cass, B.Cowie & A.Campbell (2009) What determines perseverance in studying science? Journal of Institutional Research 14(2): 30-44.

N.Zepke, L.Leach, T.Prebble, A.Campbell, D.Coltman, B.Dewart & M.Gibson (2005) Improving tertiary student outcomes in the first year of study. NZ Council for Education Research report.

writing that essay Alison Campbell Mar 09

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Found this today (while procrastinating…)

funny graphs and charts

Now, while the cartoon is funny, the message is not (& hopefully some of my first-year students are reading this – pay attention, guys!). Leaving an assignment to the last minute is not a good strategy for success – not in science, & not in any other area either.

It means you’ll do a rush job, so your formatting, spelling, grammar & so on are likely to suffer. And these do matter, because you’re essentially attempting to communicate with the reader about your understanding of a topic & how you write is part of that. (I’ve had students use – repeatedly, within an assigment – the wrong technical term in a way that makes me wonder if they actually understand what they’re writing about.)

It means you’ll be last to the library & so may miss out on that crucial book; of course, access to on-line journals has changed that more than a little. But if you’re not confident about what you’re searching for, leaving things until the last minute will make it that much less likely that you’ll find that perfect reference (remembering that you actually have to read them as well!). Wikipedia doesn’t count.

it means you probably won’t proof-read your work properly. So you may not pick up the fact that you haven’t properly cited a reference (or haven’t included that source in your References section). Or that you’ve missed out a whole paragraph that presents the crucial information supporting your argument. Or – eek! – that you haven’t actually answered the question at all.

It means you probably won’t have crafted a really good essay. (Trust me on this – I’ve seen an awful lot of them.

And, when crunch time comes & you haven’t finished writing, going to your teachers & saying ‘I ran out of time’ is unlikley to be viewed with favour… I wouldn’t advise trying the following, either.

a blog for talking teaching Alison Campbell Mar 08

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This is really an advertorial, I guess :-) But Marcus, Fabiana & I have got together to set up a blog for talking about teaching, called – fairly predictably I guess! - Talking Teaching. So for those of my readers who are teachers (secondary, tertiary, whatever) - please feel free to join us there. We’re hoping to get some interesting discussions going, & maybe some sort of on-line teaching community. To give you a bit of background, so you can see where we’re coming from – I’ve got a Trained Teacher Certificate (which has since been eclipsed by the Dip.Tching I think) & both Marcus & Fabiana are working towards a tertiary teaching qualification, & we’re all university lecturers. And science bloggers as well :-)

So maybe we’ll see you there some time soon?

the age of mammals Alison Campbell Mar 06

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The last 65 million years have sometimes been called ‘the Age of Mammals’ (although I’m inclined to think it should be the Age of Insects, or perhaps – as it’s always been – the Age of Bacteria; after all, in terms of sheer number of individuals, bacteria have got to be the dominant life form on the planet…). This gives the impression that mammals are a relatively recent evolutionary novelty.  But just how old is this class of organisms? Just what is the ‘age’ of the mammals?

Mammals began to diversify after the mass extinction event that marks the boundary between two geological ‘periods’ (the Cretaceous & Tertiary) and which carried off a large number of species, most notably the dinosaurs. But they’ve been around for much longer. Much, much longer – the mammal family tree has its roots way back in the Carboniferous, 350-270 million years ago.

Not that those ancestors wandering through the swampy Carboniferous forests would have looked like the mammals of today. Scientists call these ancestral beasts, ’mammal-like reptiles’ ie they were reptiles, but with some mammal-like features, including features of their skulls. Modern mammals, those early mammal-like reptiles, and everything in between, are described as synapsids.

  

Amniote skull types. a) Anapsid eg turtles b) Synapsid eg mammals c) Euryapsid eg ichthyosaurs & plesiosaurs d) Diapsid eg dinosaurs & birds. (NB the ‘amniotes’ are the reptiles, birds, & mammals – all produce an amniotic egg with a number of membranes associated with the yolk & developing embryo.)
 
The synapsid skull (b) has a single opening in the external bone layer, behind the eye – these diagrams can be a bit confusing & certainly my students sometimes find them so; it looks like the hole might go through from one side of the skull to the other, but in fact that’s not so.
 
Early synapsid reptiles roamed the Earth from the Carboniferous period until the Jurassic, and at one time were the dominant land animals. Many groups of these early reptiles were not in our direct lineage; one group that was, was the pelycosaurs - which included the fearsome predator Dimetrodon. (The name Dimetrodon means ‘two kinds of teeth’ – this is significant as most reptiles have a single type of teeth in their mouths, while modern mammals have 3-4.) One group of pelycosaurs evolved into the mammal-like  ’therapsids’, a group that included Thrinaxodon, and the therapsids in turn produced a number of descendant groups. One of them, the cynodonts, was on the line to modern mammals (but not, as it turns out, directly linked to them). 
 
By the way, it’s actually rather difficult to define a clear instant at which an animal becomes a ‘mammal’, rather than a ‘mammal-like reptile’! Therapsids have a number of mammal-like features: compared to the sprawling stance of reptiles, they held their legs more underneath the body (making locomotion more efficient); they had a distinct neck; their mouths contained several different types of teeth – something described as heterodonty; the beginnings of a secondary palate began to separate the airway from the mouth; and one of the bones in the lower jaw (the dentary) was enlarged compared to that in reptiles. But they definitely weren’t mammals.
 
Many therapsids became extinct during the mass extinction event that marked the end of the Permian, around 225 mya. (Incidentally, this was one of the greatest mass extinctions in terms of species lost – David Raup & Jack Sepkoski estimated that up to 94% of all species then alive, died in the end-Permian event. On the mammalian side the survivors included cynodonts like the herbivorous dicynodont Lystrosaurus (the distribution of Lystrosaurus fossils provided early evidence in support of the concept of continental drift) and the carnivorous ‘theriodonts’. The latter were similar to wolves in size, with large serrated canine teeth and skull modifications that provided larger jaw muscle attachment points.
 
During the Triassic cynodonts gradually became more & more like ’true’ mammals. Eventually their lower jaws comprised just a single bone (called the ‘dentary’ because it bears the teeth). Along with this came a change in the way the jaw articulated with the skull (& associated changes in the tiny bones of the inner ear). Another feature was the obvious presence of a diaphragm. OK, you say – this is so unlikely to fossilise, so how can you say this? The evidence lies in the lack of ribs attached to the lumbar vertebrae (the ones that form the ’small’ of your back) – in modern mammals the diaphram is attached to the lower edge of the ribcage, & there are no lumbar ribs. The therapsid Thrinaxodon didn’t have lumbar ribs either, so the diaphragm must have been an early evolutionary innovation in the proto-mammal lineage.

And these beasts were probably furry :-)  Cynodont jawbones are perforated by small holes, similar to those which in modern mammals carry nerves and blood vessels to the whiskers, which implies furriness. (Cuddliness would be highly unlikely!) And a wonderful fossil from the Jurassic, Castorocauda, includes direct evidence of fur. Not only this, but a range of features tell us that Castorocauda spent a lot of time in the water. So, an immediate predecessor of modern mammals swam in the streams that T.rex would have splashed through: the earliest evidence yet of an aquatic mammal.

But the origins of ‘true’ (modern) mammals remains a bit murky. This isn’t helped by the fact that many of the early forms are known mainly by their teeth. (I’m sure it’s been said by someone before, but you could jokingly say that the evolution of mammals is traced through the matings of teeth with teeth…).So to get back to that original question: what is the age of the mammals? The answer has to be – it depends on how you define them :-) 

the bca vs simon singh Alison Campbell Mar 05

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Over the last few months many science bloggers have been watching – with considerable interest – a libel case taken agains science writer Simon Singh by the British Chiropractic Association. Singh had used the word ‘bogus’ in describing treatments offered for a range of ailments, including asthma and ear infections. (Similar claims-by-implication are made in NZ.) While the UK’s libel laws allowed the case to proceed (it’s still before the courts), Singh’s view is supported by a number of meta-analyses of availble good-quality studies: for conditions other than musculoskeletal pain (eg asthma, & a range of childhood conditions)  such treatments perform no better than placebo .

Now it seems that the case appears to have sparked somethng of a backlash in the UK, with chiropractors advised by their professional body to remove from their websites & other publicity material any claims of the ability to treat conditions such as whiplash and colic. This is interesting given that the BCA had previously released what it described as a ‘plethora’ of evidence supporting those claims. However, as Edzard Ernst has noted, of the 19 references included in that list, it seems that 4 didn’t even contain data relating to chiropractic treatment. A further 8 are not based on controlled clinical trials, and the remaining 7 are flawed in methodology or conclusion – for example, a lack of double-blinding that doesn’t allow us to rule out the placebo effect, in a comparison of chiropractic vs an anti-colic drug.  (Ernst also points out that several robust, rigorous trials of chiropractic interventions, that don’t show any effect better than placebo, aren’t included in the BCA list.)

If the BCA is now advising that claims concerning ailments other than back pain should not be made, where to next for the case against Singh?

evolution supressed in new zealand? i think not Alison Campbell Mar 02

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While searching for some background on another post, I happened across this headline on the Herald site: University denies author’s PhD claim. I went on to read the story, as it’s always a bit of a concern to see people claiming credentials and the supposed awarding institution denying that this is the case. And a statement from the person making the claims caught my eye.

“During a period in which ‘evolution’ became a bad word [in New Zealand] punishable by revocation of credentials and confiscation of property [the 1980's], I refused an order from a department chairman to withdraw my books Darwin’s Universe and Time Gate from press,” he told a contemporary writers’ website.

Really? I have to say, that was news to me. The history of attitudes to teaching evolution in NZ has been quite well documented, most notably in works by Numbers & Stenhouse (2000), McGeorge (1992), & Peddie (1995), & it’s an area I’ve followed with interest.. Way bac,k in the 1880s there was an attempt by local creationists to get an Otago academic removed from his post for daring to mention evolution in his lectures (to no avail), and in the 1940s the creationist lobby was successful in getting a radio program for schools that talked about the evolution of life, taken off the air.

But to claim, as this person has done, that in the 1980s you could lose your credentials or even have property confiscated for mentioning the ‘e’ word?! This was the same time that I was teaching evolutionary biology to impressionable young minds in Palmerston North high schools – and I wasn’t run out of town or tarred & feathered ;-) Mind you, the fact that evolution wasn’t taught until the last couple of years of high school, thus exposing the smallest possible number of of impressionable young minds to this dangerous idea of Darwin’s, may have had something to do with that :-) Similar claims have been made in the US, around the infamous movie Expelled. And they’ve been shown to be similarly without substance. (Unless, in some alternate universe…)

Don’t get me wrong – there are problems associated with teaching evolution, particularly in some parts of NZ, as Peddie documented in his 1995 thesis. But they don’t manifest in people being pilloried or losing their belongings. Instead, as Peddie found, teachers may face pressure to skip that part of the curriculum (perhaps made easier to do by the fact that schools don’t have to offer the full number of achievement standards in a subject). Hopefully the fact that evolution is so prominent in the new science curriculum (beginning in primary schools) – being implemented this year, along with all the other curriculum areas – will make it that much harder to avoid teaching about this key biological concept, in state schools anyway.

But as for the claim that began this post? Pure fantasy.

 

 

C McGeorge  (1992) Evolution in the Primary School Curriculum. History of Education 21(2): 205-218

RL Numbers &  J Stenhouse (2000) Antievolutionism in the Antipodes: from protesting evolution to promoting creationism in New Zealand. The British Journal for the History of Science 33: 335-350

WS Peddie  (1995). Alienated by Evolution: the educational implications of creationist and social Darwinist reactions in New Zealand to the Darwinian theory of evolution. Unpublished PhD thesis, University of Auckland.

 

 

today’s big earthquake in chile Alison Campbell Feb 28

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Friends rang us in great excitement this morning to ask if we were following the news about the big earthquake in Chile, and of tsunami alerts that had been issued for coastal areas around NZ. (The answer was actually ‘no’; I’d just got in from a walk with the puppy & hadn’t turned the radio on.)

Anyway, the Science Media Centre has some very good commentary & resources centred on this seismic event, & I thought that those teachers with students who’ll be working on ‘Planet Earth’ standards this year might find them extremely useful. There’s a media briefing here, and a post by Peter Griffin, that includes a presentation by Victoria University’s Dr John Townsend, here.

Big quakes are not uncommon in Chile, given that it sits above the boundary of two big tectonic plates. Charles Darwin wrote about the aftermath of one such event in his Beagle diary, and it’s still worth a read today. He also complained, in a letter to his sister Catherine, about how he’d experienced ‘just’ one little earthquake himself – he almost sounds disappointed! Those looking for some other reading material might enjoy Perils of a restless planet by Ernest Zebrowski. I found it fascinating, although my Significant Other laments that there a are no colour pictures (hardly surprising when you consider that the book covers past events, some of which occurred well & truly before cameras were invented, much less colour film!)

the oversized naughty bits of female spotted hyenas Alison Campbell Feb 24

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When I visited Pharyngula today I saw that PZ had posted a video about spotted hyenas. Female spotted hyenas. And that reminded me of one of the late Stephen Jay Gould’s wonderful essays on the same subject. (Gould remains one of my favourite science writers -although, having said that, I do find some of his later work rather overblown – and you can find examples of his work at The Unofficial Stephen Jay Gould Archive.)

If you watch that video you’ll find out that female spotted hyenas look rather like males, especially when they’re aroused. They have a greatly enlarged clitoris that looks just like a penis. (Apparently early European observers didn’t recognise them as female at all.) The females are also large, heavily muscled, highly aggressive & dominant over any males they encounter. A group of spotted hyenas consists largely of females, with a few males hanging around at the periphery. The clan leader is the dominant female, who will pass on her rank to her pups. Females lead the hunt, & once the prey’s been caught, it’s the females who eat first. Social interactions involve much sniffing – and licking – of the dangling appendages.

All of this - the size, aggression, dominance & enormous clitoris - can be put down to the fact that hyenas are exposed to very high levels of testosterone while in the womb. The clitoral enlargement may be a secondary side effect; the heavily muscled bodies & bone-crushing jaws that result from the high doses of testosterone could well have been selected for, carrying the clitoris along with them. (I have to object to the slant – & the possible explanations – put on this by the video’s narrator, who asks why the females ‘put themselves through this’ – of course, they don’t! What we see is the outcome of a long series of selecction events over thousands of years, not a process driven by the needs or desires of female hyenas.) Giving artifically-high doses of testosterone to pre-natal rat & dog female foetuses has the same masculinising effect: larger size & muscle mass, higher aggression – & external genitals that look like those of the males.

The female hyena’s masculine appearance doesn’t stop at the faux penis: at the base of this structure she has a swollen ’scrotal’ sac filled with fat. The apparent penis incorporates not only the clitoris but also the joined labia – and this has what must be an extremely painful consequence for all female spotteds: they urinate, mate, & give birth through a single small opening on the underside of this structure. I remember my eyes watering when I first read Gould’s essay, & they watered again on seeing this video! Apparently up to 20% of females die giving birth to their first pups – this also suggests that there’s some strong adaptive significance to the high levels of testosterone that produced the apparently maladaptive clitoris in the first place.

And the effects of the testosterone exposure extend to the behaviour of the pups themselves. These are no blind, helpless, mewling little softies. Spotted hyena pups come into the world with their eyes open, teeth in their jaws, & a heap of aggression of their own, sorting out their own dominance hierarchy by fighting. Apparently, while they don’t often kill their sibling directly, the subordinate is so scared of the dominant pup that it hides away in the birth tunnel (taken over from other burrowing animals), too scared to approach its mother to feed while the other pup is present – and eventually starves to death.

Disney Planet this isn’t.

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