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May 2014 Archives

... unless you've been following this blog for a while, in which case you may already have read about the sarcastic fringeheads (who are not members of a rock band, despite the wonderful name!).

The dumbo octopus, the pacu (a fish with teeth like nutcrackers, an attribute that has given rise to an urban myth guaranteed to alarm men), the pink fairy armadillo - yes, really! - visit the IFLS webpage and read all about them!

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On Monday I was lucky enough to attend a lecture by Alan Cooper, director of the Australian Centre for Ancient DNA and one of the authors on a very recent paper that provides a new view of kiwi evolution (Mitchell et al., 2014). It was a fascinating & wide-ranging talk that started with a bit of a travelogue, as Cooper told his audience about some of the places he's visited on his search for ancient DNA (aDNA).

To do their aDNA work, he & team use well-preserved organic material - usually found  in rather cold dry places. One of these was Mylodon Cave in Patagonia, named for the extinct ground sloth, Mylodon, whose remains littered the cave - in fact, much of the floor of the cave is apparently covered with balls of ground sloth dung! In the images we saw, much of the cave looked like a bomb site: it seems this impression was close to the mark as in the past local farmers had used dynamite to excavate fossils for sale to museums.

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A paper just out by Broadbent et al (2014) describes research which used data from a 38-year-long longitudinal study of Dunedin children to examine claims that exposure to fluoride in childhood has a negative effect on children's IQ. The paper found these claims wanting, and thus - quite predictably - it's now subject to attack by antifluoride activists, both on twitter and via press release. 

And so on twitter (among many other scurrilous tweets) we get this: "@JayMan471 @OpenParachute A longitudinal study? This is hilarious. [The] twit has little concept of science."

Which is hilarious, all right, but only in that it clearly shows that the tweeter has no idea how a longitudinal study works.

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At least, that's how it sounds in this Waikato Times report on the first day of presentations relating to submissions on Hamilton City Council's draft annual plan. One of those submitting was quoted as saying 

The democratic argument is flawed in this instance. Sometimes democracy is not enough, we need wise leadership.

Democracy is a dangerous game when the community is so uninformed.

There is, of course, an alternative possibility: that those who voteda for the resumption of community water fluoridation (CWF) in Hamilton are actually well-informed, and rejected the misinformationb put out there by many of those opposed to fluoridation.  

 

2/3 of those who voted, and given the sample size, this is a good representation of the population as a whole.

b Something that I see is continuing apace, in the wake of this research paperc that clearly demonstrates no negative impact from CWF on children's IQs. For example, Fluoride Free NZ's Mary Byrne has claimed that the study lacks 'integrity' as she believed that 

...they have included children taking fluoride tablets in the already much smaller sample of children drinking unfluoridated water. Children taking fluoride tablets would have a similar dose of fluoride than the children drinking fluoridated water.

However, the lead author has said that the research included a control for the use of fluoride tablets. 

What's more, 

Ms Byrne said Dr Broadbent's public advocacy of fluoride's oral health benefits meant the findings carried less weight.

Is she suggesting (in a comment that sails pretty close to the wind) that not only was Dr Broadbent likely to be biased in his approach, but also that this applied to all other researchers and to the reviewers of this paper?

cThere's an interesting commentary here on Ars Technica, and another review by Steven Novella on the NeuroLogica blog.

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This is something originally written for the Talking Teaching blog, following a discussion (on FB - where else?) about social media & student learning.

Some of my readers here and on Sciblogs will probably have realised that I quite like Facebook - not least because it's a good source of gorgeous images and quirky facts that can start me thinking about a new science blog post. Also, it's fun keeping in contact with friends & participating in various discussion groups.

One of those groups was set up by the biological sciences students at my institution, and it's used mainly for sharing biology articles and images, the occasional in-joke :) , and alerting other students to upcoming events that their committee has organised. This particular page sees a bit more student activity than some of our paper-specific moodle pages, so for a while now I've wondered about the potential of a good Facebook page to be more than 'just' a place to hang out and share pictures & stories.

Anyway, recently I had a conversation (on FB, lol) with my friend Kelly Pender and another Academy colleague about this potential. It turns out that they both use FB quite extensively in their teaching lives and gave me a lot of helpful hints - along with a very recent paper on this very subject (Dougherty & Andercheck, 2014).

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This post's title comes from Something Fishy where, talking about sea cucumbers, Illya wrote "But there's something else they can do. Something reassuringly disgusting. Something totally Sea Cucumber." I was mildly let down to find he was talking about bioluminescence, & not self-evisceration.

Yes, that's right. When threatened (or repeatedly prodded by some uncouth human in a wetsuit), some types of sea cucumber can forcibly expel part of their gut (& other organs) through the body wall - not the cloaca, but various points on the body wall. I knew that the self-evisceration happened, but not how it happened. For that, I went to the most excellent echinoblog, and you should too, for not only is there an excellent explanation but there are pictures

And so I have learned that holothurians have got this really weird connective tissue that they can soften very quickly indeed, so that the gut's normal connections to other internal bits & pieces is weakened, fast. At the same time regions of the body wall also weaken, and then strong muscle contractions expel parts of the body that would normally never see the light. 

The adaptive significance of all this? (You might regard the practice as a fast track to evolutionary oblivion, but these extraordinary animals are able to regenerate the missing bits.) The 'standard' explanation has been that it's a defence against predators, but echinoblog offers another option: that it's a means of getting rid of excretory byproducts that would otherwise build up to harmful levels in the body. This is borne out by the observation that some sea cucumbers expel their innards - & regenerate them - on an annual basis.

There's the potential to learn a lot from these unusual creatures.

 

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I saw this little critter a while back, over on Pharyngula, & put it on the list of Things To Blog About. Somehow, it took me a while to actually get onto it, but we've got there in the end :)

Image credit: Laurence Madin, Woods Hole Oceanographic Institution/CMarZ, Census of Marine Life

I was a bit puzzled when first I saw this picture - the animal has a vague flavour of jellyfish to it, but I knew it couldn't be one due to its tubular gut. (Jellyfish and their relatives have a sac-like gastrovascular cavity, where a single opening serves as both mouth and anus). So I read on, and found out that it's actually a sea cucumber, in the same phylum as starfish, sea urchins, brittle stars, and the less-familiar feather stars and sea lilies.  It belongs to the genus Enypniastes, but has been dubbed the 'headless chicken fish' in this most entertaining blog over at Something Fishy.

I was surprised to find that Enypniastes is able to swim (although apparently this behaviour isn't all that unusual), something it does v-e-r-y s-l-o-w-l-y using the cape of tentacles at its anterior end. It feeds on detritus in the deep ocean, and like all sea cucumbers, the contents of its digestive tract exit the body through a cloaca, a 'multipurpose' structure. In the case of the holothuroids, this multipurposing includes gas exchange, using complex 'respiratory trees branching off from the cloaca. A while back I wrote more about these structures, which may also serve as both anti-predator devices and homes for small fish...

I think perhaps I should add the see-through Enypniastes to the list of creatures for my next talk on the weird and the wonderful :)

 

 

 

 

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Recent Comments

  • Alison Campbell: Thank you! read more
  • Nic : Great to see rational thinking in action. Well done Alison. read more
  • Angela: I've seen the book "Modern Essentials 5th edition" list cinnamon read more
  • Pinya: I got my own moment of eureka when my masters read more
  • Alison Campbell: Yup. Maybe those protofeathers functioned in insulation; maybe in display read more
  • ifthethunderdontgetya™³²®©: So dinosaurs didn't grow feathers to fly. They grew feathers read more
  • Alison Campbell: During the 1918 Spanish flu epidemic Cinnamon in powder form read more
  • Cinnamon Vogue : For further discussion I would like to bring up these read more
  • herr doktor bimler: One has so few opportunities to use the word "chrism". read more
  • Alison Campbell: yes, but... WHY??? read more