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So, which is it? A mantis? Or a fly?

(Image by kind permission of Daniel Llavaneras)

In fact, the creature shown in this gorgeous image by Daniel Llavaneras is neither mantis nor true (Dipteran) fly, although its common name is 'mantis fly'. Instead, it belongs to the insect family Mantispidae (a group that includes lacewings and antlions). Like real praying mantids, matis flies walk on 4 legs, with the front pair folded as shown, and the head is somewhat mantis-like. The adults hunt as mantids do, shooting out those raptorial front legs to catch small insects, while the larval diets vary: some are also active predators, while others consume wasp & beetle larve, or spider eggs (later pupating in the spider's egg sac). In adult form & behaviour, the mantis flies are an excellent example of convergent evolution.

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Seeing this image of a fish with 2 mouths reminded me that I needed to finish writing about Frankenlouie, a janus-headed (diprosopic) cat. It's funny how the mind works, because the fish definitely isn't a janus-fish: that would require the mouths to be side-by-side rather than one above the other. (While this is a rather unsightly mutation, the fish seems to have survived in the wild until a fisherman hauled it out.)

Two-mouthed bream

Photo: Garry Warrick)

So - on to Frank'n'Louie. 

Frank'n'Louie was (were?) described as a 'janus cat' because he had two faces that looked in different directions, like the Roman god Janus (as opposed to that fish, which has two mouths one atop the other). Many people would have found him rather hard to look at, as he had 3 eyes, the middle one of which was blind; two noses; two mouths; and but a single brain. The fact of that single brain means, I suppose, that this really was one, strange-looking, individual cat, rather than the two distinct individuals seen in dicephalic parapagous conjoined twins such as the Hensel sisters. Despite being expected to die soon after birth, Frank'n'Louie attained the ripe old age of 15 years before succumbing to cancer in 2014.

R.I.P.: 'Frankenlouie', the world's oldest Janus cat - a feline with two faces - died at the age of 15 on Thursday, Dec. 4, 2014. The Guinness World Record holder passed away at the Cummings School of Veterinary Medicine at Tuft's University in Grafton, Mass. according to owner Martha "Marty" Stevens of Worcester, Mass. (AP Photo/Worcester Telegram & Gazette, Jim Collins)

Frankenlouie's features are the result of craniofacial duplication, or diprosopus: an individual with a single body and normal limbs, but a greater or lesser degree of duplication of the face. (He was lucky to survive so long as many janus individuals also have neural tube defects, including - at their most severe - anencephaly, or the absence of a brain, and die very young). When I first saw a picture of this cat I wondered if his features had something to do with conjoined twinning, and apparently that's often put down as the underlying cause if the organism has two complete faces.

However, another possible cause is a mutation in the gene responsible for the Sonic Hedgehog protein (SHH), which among other roles is involved in the control of craniofacial development. Too much of that protein (overexpression of the mutant form of the gene) results in craniofacial duplication; too little can cause cyclopia, where there is just a single eye. (Infants with cyclopia die soon after birth as the condition is associated with severe brain abnormalities, so the Cyclops of the Ulysses stories would not have been modelled on an actual adult with the condition.)

In fact, SHH plays a crucial role in embryonic development, as this description on the National Institutes of Health gene database makes clear:

It has been implicated as the key inductive signal in patterning of the ventral neural tube, the anterior-posterior limb axis, and the ventral somites.

This means that mutations in the gene coding for SHH can have far-reaching impacts on the development of the brain and nerve cord, limbs, and body segments, while a mutation in one of the enhancer regions (an enhancer is a region on a chromosome that affects transcription of a particular DNA sequence) results in duplication of the thumb.

But there's more: Sonic Hedgehog is one of a group of 'evolutionarily conserved' genes (others in this gene family include 'Desert Hedgehog' (!) and Indian Hedgehog) found in vertebrates, so SHH is involved in the patterning of embryo development in all vertebrates, not just in mammals like Frankenlouie. These 'conserved' regions of DNA tend to play crucial roles in development and functioning of an organism, and so are relatively unchanged over time: any significant alterations in their sequence, and so in their products, would probably be subject to strong negative selection.  And Sonic Hedgehog's gene family is in turn related to the hedgehog gene that is involved in proper formation of body segments in Drosophila. So the chromosomal region that's most likely to be implicated in Frankenlouie's particular birth defect is one with a very long evolutionary history indeed, one that extends back beyond the split between invertebrate and vertebrate lineages.

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And if the Stuff story here is correct, then I can understand why parents might choose that route, particularly as they seem to have exhausted other options.

NZ state primary schools can offer 'religious education', and under the Education Act parents have the ability to withdraw their children from those classes. (Personally I think it should be a case of opt-in, with opted-out the default setting, but that's not how the legislation was drafted.) The classes can't actually be offered in school time; this is usually circumvented by 'closing' the school for the 30 or so minutes each session takes.

In the Stuff article it's stated that despite the parents indicating that their daughter was not to attend her state primary school's religious education classes, she was "repeatedly put back in". The whole issue isn't new, either, as this 2012 article in the NZ Herald demonstrates. This surely indicates a failure of process at the school end, and the parents are right to be frustrated by it. 

But wait, there's more. From the article: 

One of the Bible class teachers from Life in Focus Trust1, a volunteer who was not a qualified teacher, said parents did not need to be notified because the classes were "history lessons" as the Bible was factually correct.

Seriously? (There's no evidence for the exodus in contemporary Egyptian documents, for example.)

I think it would be great if students learned about comparative religions (if there's room in the already crowded curriculum). But the fact that a document revered by one particular faith is being presented in this school, at least, as an 'historical document' suggests that other religions aren't getting a look-in - and also raises questions about how the Genesis stories, for example, might be taught. Because those are certainly not 'history' (the comments thread to the Stuff article is quite... .... interesting).

1 Having had a look at the Life in Focus website, I can see that its classes are mapped onto the NZ Curriculum document. Since the various outcomes & attributes the program lists are already intended to be delivered in classrooms I'm not clear on why additional people, not all of whom are qualified teachers, would need to be involved, and why myths and stories from only one faith would be used in developing universal attributes in multicultural classrooms.

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Critical thinking is a necessary tool for understanding the world we live in. And I don't believe we teach it particularly well. I know that students in high school science classes learn how to assess the validity/reliability of a source, for example, and that's great, but on top of that we need to get students really thinking about the information and arguments that they'll come across on pretty much a daily basis.

And for that, something like this (found, as is often the case, via Facebook) would be a useful resource: 

For example, you'll often see someone advocating for science-based medicine described as a 'shill'. (Apparently all of us on Making Sense of Fluoride are shills. All I can say is, if the cheque's in the mail, it's a long time coming.) This is an ad hominem attack that does nothing to address the person's arguments. In fact, I'd add another: the argument from authority eg Prof X says so, therefore it's true. (We get that a lot.) You'll find some more examples of these rules to work by, here.

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And at the end, there weren't many of those.

One of the things we talk about in biology class is the importance of decomposers. Most students think in terms of bacteria when this topic's raised, & maybe things like fungi. But there is more to the breakdown of a body than those microorganisms. 

Think worms, for example. In his final bookA, Charles Darwin highlighted the significant role played by earthworms in breaking down 'vegetable matter' (eg leaves) to produce what he called 'vegetable mould'. 

And of course there are ants. While we may think of them as those irritating little critters that overrun the kitchen if they find a food source, & produce anthillsB of sand in the cracks in paving, they also act as what could be called macro-decomposers. As this video demonstrates: 

A  "The Formation of Vegetable Mould, through the Action of Worms"

B Those with small children (&/or a fondness for kinetic sand!) might enjoy this blog post about ants, kinetic sand, & learning opportunities :)

 

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Lizards, like us, are chordates. One of the defining characteristics that all chordates share at some point in their development is the presence of a notochord: a stiff rod of tissue that runs along the dorsal side of the animal, just beneath the hollow dorsal nerve cord. (Yes, hollow. This is the result of its origins in the neural tube that forms early in chordates' embryonic development.) In most vertebrates the notochord's replaced by the spinal column. Another chordate feature is the presence of pharyngeal pouches (homologous to gills in fish, and to structures in the jaw and inner ear in mammals), and there's also the tail. A tail that extends beyond the anus. And it's that last fact that sets lizards & scorpions apart, when it comes to losing their tails.

This ability to shed the tail is known as autotomy, and it seems to have evolved in response to predator pressure: the tail may even continue to wriggle for a while, which would help to distract a carnivore long enough for the lizard to escape and to live another day.

And that longer-term survival post-autotomy has much to do with the fact that a chordate's tail is 'post-anal'. For when a lizard (eg a gecko, or a skink) loses its tail, the animal's gut remains intact; it can continue to take food in at one end & pass faeces out the other.

Scorpions are arachnids, related to spiders and mites. As a paper published earlier this year in PLoS ONE notes (Mattoni et al, 2015), scientists have known about autotomy in arachnids, but up until now they'd only observed the voluntary loss of legs. However, Mattoni & his co-workers augmented data from the field, and from museum specimens, with some (very careful!) experiments on live animals to demonstrate that at least some species of scorpions are able to detatch their tails.

As for lizards, a tail (more correctly, a 'metasoma') continues to wriggle for a while after it's detatched, and may also act as a distractor to allow the animal to escape a predator. There is, however, a drawback - with its tail the scorpion also loses its anus and the penultimate portion of its digestive tract. And neither metasoma nor gut regenerates.

On the face of it, you have to wonder why caudal autotomy (the ability to voluntarily shed the tail) would ever have been selected for in scorpions. They're unable to sting ever again, which would leave them with a much-reduced ability to defend themselves or to kill large prey items. And once the open end of the intestine is closed by scar tissue - which takes about 5 days - they can no longer pass faeces from the gut, which must put a dampener on their ability to take food in at the other end - a case of enforced constipation? (The authors note that in at least some cases, the pressure of accumulating poo may trigger another autotomic event, when the animal loses the segment at the 'new' end of the tail.)

However, for the scorpions, all was not lost. The researchers' lab experiments showed that the tail-less arachnids still managed to survive for up to 8 months post-amputation, occasionally eating small prey items. Which would be irrelevant if they were unable to pass their genes on - but the animals were also able to reproduce. In mating experiments, tail-less males were nonetheless able to court and mate with females on multiple occasions. This means that tail-shedding may still provide a selective advantage, in that it allows animals to escape predation and go on to reproduce.

You should also read Ed Yong's take on how the scorpion lost its tail :)

C.I.Mattoni, S.Garcia-Hernandez, R.Botero-Trujillo, J.A.Ochoa, A.A.Ojanguren-Affilastro, R.Pinto-da-Rocha,& L.Prendini (2015) Scorpion sheds 'tail' to escape: consequences and implications of autotomy in scorpions (Buthidae: Ananteris) PLoS ONE. doi: 10.1371/journal.pone.0116639

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A lot of my friends seem to like owls, if their tendency to post photos of adorable fluffy feathered faces on Facebook is anything to go by. I rather like them too; we live close to a gully & it's lovely hearing the moreporks calling at night. Once or twice one has sat in a tree just outside our window - very special!

Of course, behind the beauty lies a fierce, predatory nature, and that is well captured (in a most humorous way) in this video from the wonderful 'True Facts' series: 

I do not remember reading any fairy tales involving the ripping off of small persons' faces by an owl. I'm sure he just made that bit up!

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I suppose one of the benefits of e-readers & 'paperless' offices (haha) is a reduction in the risks of paper cuts. Because those cuts jolly well hurt! Part of that may just be because they usually involve fingers & those are in use so much that our attention is constantly drawn to the afflicted part. But there's more to it than that, and this video from Scientific American explains why:

The comments thread over on youtube is rather fun!

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One of the big stories on my Facebook feed at the moment alerted me to Food Matters Aortearoa and its upcoming Wellington conference. The program for this conference has certainly generated a lot of interest among my friends.

The focus of that interest lies in the line-up of speakers & the agenda of their tour – something my friend & blog-buddy Grant has also written about. The blurb for the Christchurch event pretty much sets the scene: the speakers there (Seralini & Douzelet)

will reveal their experiences with the health problems that chemically grown food can generate

Er, ‘chemically grown food’??? All our food is comprised of chemicals! 

But what of the speakers? As Grant notes, Dr Gilles Seralini is perhaps best-known in scientific circles for a now infamous study on the toxicity both of the herbicide Roundup and of maize treated with it. The original paper was retracted but subsequently re-published (seemingly, without any further peer review), without any real attempt to address any of the issues that led to the retraction: the small sample size and the appalling lack of ethical treatment of the study animals (which were allowed to live with extremely large tumours rather than being euthanized at an early stage of tumour development), among others. 

Dr Vandana Shiva has done some admirable work around conservation and supporting women farmers in India. However, she has also made some highly questionable claims, including the incorrect but oft-quoted statement that the use of GM cotton led to a marked increase in suicides among Indian farmers. While people may oppose the use of GM technology for a variety of reasons, using demonstrably incorrect information doesn't bolster their case. There's an interesting article on Dr Shiva on the New Yorker website, and a discussion on ResearchGate links to a number of valuable resources that look at other claims (for example, the patenting of seeds pre-dates GM technology by some decades).

Similarly, the other major international speaker, Dr Huber, also opposes the use of GM technology & of genetically-modified organisms. I have to say that I continue to be puzzled to the opposition from some quarters to the use of modern genetic modification techniques, while the effects of other tools such as mutation breeding are ignored. Yet the first involves one to a few genes and is well-tested and highly regulated, while the second - which is not regulated in any way - is completely unpredictable and can affect a very large number of gene loci. (A 2008 study found that mutation breeding produced far more genetic change than did transgenesis, & concluded that "the safety assessment of improved plant varieties should be carried out on a case-by-case basis and not simply restricted to foods obtained through genetic engineering.")

On the face of it, this conference and the associated publicity could offer the opportunity to have some valuable discussion on issues such as the future of agriculture in a time of climbing global population and widespread environmental change, and the safety of GMOs and the various techniques used to produce them. However, since the conference appears to have a strong anti-GMO slant, I doubt this will happen - although I'm prepared to be pleasantly surprised.

 

 

 

 

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I do enjoy asapSCIENCE - their videos are quirky, entertaining, & informative, and can provide some great talking points for science classes. But for this one, add poignant to the adjectives.

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