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Archive November 2010

homos*xual necrophilia by a mallard drake Alison Campbell Nov 28

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I’ll bet that got your attention!

A little while ago I was running through a seminar with a colleague. It was an end-of-semester trip through various ‘oddities’ in the biological literature, including things like the amazing corkscrew penises of mallard ducks & the tendency of some tree shrews to use pitcher plants as potties. ‘Hmmm,’ said my colleague, ‘why don’t you include the one about necrophilia by a mallard drake?’ I must have given him a rather funny look because he hastened to assure me that this was totally true & had even won an Ig Nobel award for the scientist who described it.

Now, I know that mallard drakes are randy little devils and that groups of them will harass hapless females for forced copulations, particularly later in the breeding season. But this did sound a bit over the top. So, in the interests of completeness & also to check this story for myself, I went looking. and found…

The first case of homos*xual necrophilia in the mallard Anas platyrhynchos by C.W.Moeliker.

Dr Moeliker works in the Natuurmuseum in Rotterdam. Apparently this building has a all-glass facade – a dangerous thing for the local birdlife, as in certain lights it can act like a giant mirror. It’s not unknown for birds to be flying along, minding their own business, & then bang! they fly into the windows & are killed by the collision, whereupon the scientists inside the building often rush out to pick up the corpse & add it to the institution’s collection.

Anyway, Dr Moeliker tells of hearing yet another large bang! & rushing downstairs to see if the window was damaged (& also to see what could be added to the bird collection). On the sand outside the building lay a very dead mallard drake – and next to it another drake, this one very much alive. After pecking at the dead bird’s head & neck for a couple of minutes, this second bird mounted the corpse & started to vigorously copulate with it (with a couple of brief breaks in activity) for 75 minutes! At this point, Dr Moeliker comments, he ‘disturbed this cruel scene’. This apparently disconcerted the necrophiliac drake, who was rather reluctant to leave off what he was doing and hung around, quacking disconsolately, for a good 10 minutes after the human observer had collected the body & stored it safely in the lab freezer. (It was subsequently stuffed and Dr Moeliker relates how it then joined him on lecture tours in Europe & the US.)

And yes, I did include this tale in my seminar – and even managed to deliver it with a (mostly) straight face (although much of the audience was in stitches!). 

C.W.Moeliker (2001) The first case of homos*xual necrophilia in the mallard Anas platyrhynchos (Aves: Anatidae). DEINSEA 8:243-247

so who are these ‘scientists anonymous’? Alison Campbell Nov 27

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A friend of mine, who happens to be a biology teacher, recedntly forwarded me an e-mail. Quite apart from the fact that the sender had sent it to what looks like every secondary school in the country & didn’t have the courtesy to bcc the mailing list, there are a number of issues around it that give me some soncern.

But first, the e-mail:

TO: Faculty Head of Science / Head of Biology Department

Please find attached a new resource (pp. 12-14) by Dr Jerry Bergman on the left recurrent laryngeal nerve (RLN) for the teaching and learning of Senior Science/Biology (human evolution). [Edit: I've removed the link for 'RLN' as I don't see why I should drive traffic to the ICR website.]
 
•  Much evidence exists that the present design results from developmental constraints.
•  There are indications that this design serves to fine-tune laryngeal functions.
•  The nerve serves to innervate other organs after it branches from the vagus on its way to the larynx.
•  The design provides backup innervation to the larynx in case another nerve is damaged.
•  No evidence exists that the design causes any disadvantage.
 
Freely share this resource with the teaching staff in your faculty/department.
 
Yours sincerely,
Scientists Anonymous (NZ)
 
PRIVACY ACT/DISCLAIMER
Dissemination of extraordinary science resources will be made once or twice a year at the most ().
All replies will be read but not necessarily acknowledged (no-reply policy applies).
The distribution of resources through this mailing system is not by the Publishers.

It’s immediately obvious that this is a thinly-disguised attempt by cdesign proponentsists to get ‘intelligent design’ materials into the classroom. The use of the word ‘design’ is a dead giveaway there. The arrangement of the laryngeal nerves has been noted by biologists as an example of poor ‘design’ as it doesn’t follow a straightforward path to the organs it innervates (& in fact follows an extremely lengthy detour in giraffes!), leading to the question, why would a ‘designer’ use such poor planning? (There’s a good youtube clip on the subject here.) That the ID proponents now seem to be arguing that poor design is actually purposeful & thus still evidence of a designer smacks of grasping at straws. Furthermore, the article that the e-mail originally linked to is mounted on the Institute for Creation Research website – it’s not published in a peer-reviewed journal. So there’s nothing ‘extraordinary’ about this particular ‘resource’.

Of more significance, I think, is the identity of the originators of this message (& I note they promise others in future; at least one can opt out!). ‘Scientists Anonymous’. This is an attempt at an appeal to authority – a bunch of scientists say so, so we should give it some weight.

But we shouldn’t – because we don’t know who they are. No-one’s publically signed their name to this stuff, so why should we accept their authority in this matter? Are there really any practising scientists there? Are any of them biologists? Who knows… but it adds no weight to their proclaimed position on this issue. The only person mentioned by name, Jerry Bergman, is indeed a biologist by training, for whom the first ‘google’ entries are citations by answersingenesis and the creation wiki. Google Scholar indicates that his recent publications are not in the area of biological sciences but promote anti-evolution ideas including the one that Darwin’s writings influenced Hitler’s attitudes to various racial groups (an idea that’s been throroughly debunked elsewhere – here and here, for example).

A search for ‘scientists anonymous’ brings up a students’ Facebook site & a book of the same name about women scientists. So who, exactly, are these ‘Scientists Anonymous’ who are behind the e-mail to schools, and why aren’t they prepared to put their names to the document?

stunning biological image #2 Alison Campbell Nov 26

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I teach a bit of botany, to our first-year students. I really enjoy the subject & hopefully some of that rubs off :) Anyway, I’m always on the lookout for new images to use in my lectures, & tonight I came across this stunning photograph by Eckhard Völcker, who has very kindly given his permission for me to share the image with you.  

While it looks like a lovely piece of lace in contrasting colours, it’s actually a section through a willow shoot, stained with dyes that (for example) highlight the lignified tissues in xylem and the fibre caps on vascular bundles.

You can see more of these beautiful photos here, or visit Herr Völcker’s webpage for more of his work.

(Your turn, Grant!)

Algae & isopods – a unique symbiosis Alison Campbell Nov 24

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When I set essays for my first-year students to write during the semester, I try to give them a scientific paper on each topic to start them off. This means that I need to do some extra bedtime reading as I need to select those papers carefully. Today’s post is based on one of those: a paper about a fascinating mutualistic relationship between marine algae and a species of isopod (the same crustacean group as the more familiar slater).

Symbiotic relationships are fairly common in the oceans — perhaps the best-known example is the relationship between reef-building corals and a group of algae called dinoflagellates (zooxanthellae). The coral animals gain sugars from their algal partners, & may die if the algae leave (which happens if water temperatures get too high, resulting in the coral ‘bleaching’ as at least some of their colour is due to the algae). Another example of such a food-based symbiosis is the one between chemosynthetic bacteria and invertebrate animals at deep-see hot-water vents (Lindquist, Barber & Weisz, 2005). Because many bacteria & algae produce toxic chemicals as a byproduct of their metabolism, it’s been suggested that some microbe-invertebrate relationships also have an element of defence about them. Niels Lindquist & his colleagues investigated this possibility in a species of marine isopod belonging to the genus Santia.

Most marine isopods are either cryptically coloured or only come out at night, when many predators are less active. But this particular Santia species is a bright fluorescent red colour — and spends the day sitting on sponges or corals & basking in the sun, in groups of up to a few thousand individuals. They’re quite big — about 5mm long – & so they’re readily visible to potential predators, which makes their colouration & behaviour particularly interesting.
When the research team examined the animals more carefully, they found that the red colour was due to a carpet of single-celled algae covering the animals’ exoskeletons. At the same time, they never saw fish eating the isopods (despite the fact that fish normally feed quite happily on isopods), which suggested that the Santia sp. were inedible, an hypothesis supported by the isopods’ bright colour and risky sun-bathing behaviour. Linquist & his colleagues decided to see whether the Santia really were unpalatable; whether the epibiont algae caused this unpalatability; just which microbes were living on the animals’ exoskeletons; and how the algae were passed on to new generations of isopods.
For their feeding tests the scientists caught red Santia and also ‘normal’ brown isopods and then released them upstream of schools of reef fishes. This was after releasing isopod-sized food pellets into the same water current — the fish snaffled these up & weren’t put off their meals by the presence of nosey human divers. They were quite happy to eat brown isopods as well. But it was a different story for the red isopods, which were mostly completely ignored. If they were ingested, the fish spat them out again immediately.
To test whether this aversion was due to the carpet of microbes, the researchers kept red isopods in the dark for 2 days. They also extracted pigments from ‘unbleached’ isopods and then carried out feeding trials in which fish were offered: normal food pellets, food pellets with the algal extract, isopods with normal symbionts, and the ‘bleached’ isopods whose algae had lost most of their colour after being kept in the dark. The results: 100% of the food pellets and 80% of bleached Santia were eaten by the fish, while no normal isopods were eaten and only 30% of the treated food pellets, which strongly suggested that the microbes (which turned out to be cyanobacteria, or ‘blue-green algae’) were producing some off-putting chemical that deterred predation by fish. These protective microbes appear to be transmitted vertically, as the scientists observed juvenile Santia — which had just emerged from their mother’s brood pouch — climbing over the mother’s exoskeleton & picking up their own episymbiont populations.
Lindquist et al. concluded that they were looking at a unique symbiosis, one based on both nutrition and defence. Protected by their cyanobacteria, red Santia can be active while it’s daylight, which opens up new niches to them and may mean that they have more chance to feed without competition from other invertebrates. They also eat the microbes, which would certainly be a disadvantage to the individuals consumed. However, overall the cyanobacterial population benefits, because the isopods’ sunbathing habits would maximise opportunities for photosynthesis and hence microbial population growth. The paper concludes:
Although these isopods represent only the second marine example of microbial symbionts producing a chemical defence against host predators, the risk of predation is high in many marine habitats, suggesting that defensive symbioses may be more common in the marine environment than presently believed.
N.Lindquist, P.H.Barber & J.B.Weisz (2005) Episymbiotic microbes as food and defence for marine isopods: unique symbioses in a hostile environment. Proceedings of the Royal Society B (Biological Sciences) 272: 1209-1216. doi: 10.1098/rspb.2005.3082

astrology can help achieve pregnancy? um, really? Alison Campbell Nov 22

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Over at Grant’s, a commenter on one of his posts noted that, in its ‘World News’ pages, the Dominion-Post included an article entitled: “Pioneering’ astrology analysis may help women get pregnant after IVF treatment has failed”. The commenter said he’d nearly choked on his weetbix when he saw that, & I can sympathise.

I’d like to have read the item on the Dom’s website but unfortunately our Waikato Times subscription doesn’t give me access. But – never underestimate the power of the internet! This would have been a syndicated article & there it is on several other ‘news’ pages, including here at The Australian. So, with breakfast out of the way & no coffee anywhere near the keyboard, I pressed on…

Now, the use of the word ‘analysis’ in the headline makes this sound sort of science-y, so maybe there’s something in it, right? But no, this ‘analysis’ hasn’t actually happened yet, so we don’t know if astrology actually has the claimed effect. The article is built upon anecdote: testimonials from two women who had undergone multiple (failed) attempts at pregnancy via IVF before becoming pregnant at times suggested by the astrologer, & a statement by said astrologer that “she has helped many women in Britain and her native Cape Town to conceive.”

Interestingly, she went on to admit that “success may be due to coincidence, a placebo effect, or the power of suggestion.” Of which, coincidence is the most likely. After all, one study of Dutch women who’d had several cycles of IVF found that “1349 of the women (16 per cent) had conceived naturally after stopping IVF treatment (in a maximum timeframe of 13 years). Forty-five per cent of these had conceived within 6 months after their last IVF cycle.” And Cahill et al (2005) report similar odds of natural conception following a series of unsuccessful IVF treatments, commenting that factors such as maternal age and the reasons for infertility affect the likelihood of success.

We’re told that a group of IVF clinics in the US is going to test the astrologer’s ‘abilities’, providing her with the birth dates of clients, asking her to calculate the best dates for them to attempt to get pregnant, and comparing these with actual dates of conception. Given that other studies of astrology have found that it failed to perform at a level better than chance, I hope that the researchers will be allowing for the impact of coincidence in analysing their results.

D.J.Cahill, J.Meadowcroft, V.A.Akande & E.Corrigan (2005) Likelihood of natural conception following treatment by IVF. Journal of Assisted Reproduction and Genetics 22(11/12): 401-405. doi: 10.1007/s10815-005-6655-y  

‘the uncertainty of it all – understanding the nature of science’ Alison Campbell Nov 18

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With the implementation of the 2007 NZ Curriculum comes the need for teachers to think about how best to help their students to develop an understanding of the nature of science.

The Nature of Science is the overarching unifying strand. Through it, students learn what science is and how scientists work. They develop the skills, attitudes, and values to build a foundation for understanding the world. They come to appreciate that while scientific knowledge is durable, it is also constantly re-evaluated in the light of new evidence. They learn how scientists carry out investigations, and they come to see science as a socially valuable knowledge system. They learn how science ideas are communicated and to make links between scientific knowledge and everyday decisions and actions. (from the NZ Curriculum, 2007

But to do this, teachers need resources. From time to time a colleague & I had tossed around the idea of writing a book for just this purpose, looking at how scientific ideas have developed over time and the relationship between science & society. Well, I’ve just finished reading through the book I’d have liked to write: The uncertainty of it all: understanding the nature of science, by Jane Young (2010).

(At this point I need to let you know that I could be a biased observer, having seen an earlier, draft, version of this book and its accompanying CD-ROM.)

Jane decided to write this book after her experiences with a Year 9 class who “had issues with science” and were quite hostile to her attempts to lead them to engage with topics such as evolution and global warming. “Scientists,” they said, “don’t know what they’re talking about.” This seemed to be a reflection of a wider lack of understanding of what science is all about: that it’s evidence-based, & that scientists’ understanding of the world is thus subject to change if the evidence demands this.

So,The uncertainty of it all begins with a chapter on what science is & what it’s not. (Apparently Ernest Rutherford once said that “science is what scientists do”, which isn’t particularly helpful when you’re trying to nail the idea for a bunch of young teenagers!) Next is a section on the history and development of science, before we move on to the language of science as distinct from pseudoscience (which is generally untestable, not particularly logical, lacks plausible mechanisms – homeopathy, anyone?, disregards or ignores existing data and theories, and often claims that its finds are ignored by ‘the Establishment’).

The section on how science works includes ‘What are scientists really like?” This includes some of my own favourite examples, including the eccentric Henry Cavendish & also Beatrix Potter, who besides being a popular & successful author of stories for children was an accomplishd botanist. They’re mostly no more weird than anyone else, they don’t all wear white coats - and they get things wrong: the great physicist Lord Kelvin, for example, commented that ”X-rays will prove to be a hoax.” And the paths to scientific discovery are many and varied. While careful observation, experimentation and analysis are important, insight and plain old good luck have their place.

And I was happy to see “science and statistics” receive several pages :) A reasonably large number of students come into my first-year biology classes with no statistical knowledge (& sometimes no maths), which presents a few problems when they get into experimentation and data analysis. But even more importantly, students who’ve been exposed to experimental design & the concept of probability are better equipped to think critically about the multiplicity of pseudoscientific claims they’ll encounter over the years.

The final chapters of the book deal with people and science: ‘A love-hate relationship” begins by noting that while we use the outputs of science and technology on a daily basis, our human need for certainty doesn’t always sit well with the potential for change that is part of good science. What’s  more, science can challenge comfortable beliefs; it “asks people to see things as they are and not as they believe or feel them to be.” Jane then goes on to look at criticisms of science before dealing with the interplay between science, morals and ethics, using examples (the infamous Tuskegee study and our own ‘unfortunate experiment, among others) that should be good starting points for productive classroom discussion.

 ”A human endeavour” also offers these starters, covering misunderstandings about science, examples of using the scientific toolkit as a basis for making informed decisions (are cell phones implicated in cancer? does chelation therapy help ‘cure’ autism?), and highlighting some of the astounding achievements that science has made over the last few hundred years

 Jane’s hope for her book is that it will help “to communicate… both the excitement and the uncertainty of the human endeavour that is science.” I think it succeeds :)

Jane Young (2010) The Uncertainty of it all: understanding the nature of science. Triple Helix Resources Ltd www.biologyresources.co.nz

bats and exam questions Alison Campbell Nov 15

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The third question in last year’s Schol Bio paper was about bats – specifically, the ecology, behaviour, and evolution of New Zealand’s only two extant native land mammals, the lesser short-tailed bat & the long-tailed bat (Mystacina tuberculata & Chalinolobus tuberculata respectively).

The long-tailed bat is a relatively new immigrant, arriving from Australia ‘just’ a million years ago or thereabouts. It’s a ‘typical’ bat, catching food (mozzies, moths & beetles) on the wing. The short-tailed bat, on the other hand, has been here at least 35 million years, with its ancestor arriving from what is now Queensland. M.tuberculata lives in dense forests and, the examiner tells us,

… are unusual bats because although they are capable of rapid, darting flight they, unlike their Australian ancestors, spend a lot of time on the forest floor searching for food. The ability to fold their wings and use them as legs allows them to scurry along the ground. Their diet consists of insects and other small invertebrates, as well as pollen, fruits and nectar of flowering plants. They are the main natural pollinator of the ground-dwelling wood rose plant. The short-tailed bat has sometimes been described ecologically as doing the job of mice.

(Remember, you can expect quite a lot of background information with some questions – make sure that you read it carefully and use it in your answers. This particular question was accompanied by quite a lot of data, from a 2006 paper by Colin O’Donnell and colleagues Jennifer Christie & Warren Simpson – and the examiner expressed some concern that many students didn’t make adequate use of all this.)

O’Donnell & his co-workers studied habitat use and nocturnal activity of the two bat species, using automatic bat detectors set up in Fiordland beech forests. These were set along transects that passed through five habitat types: red beech forest (>200m from the edge of the forest); silver beech (<100m of the forest edge); roads through the forest; on the margin between forest and grassland; and in the open grassland. Their results were presented in several graphs, some of which the examiner included – in modified form – in the exam.

 bats - activity in different habitat types II.png

 View larger imagebats - activity vs hours after sunset.png

View larger imagebats - emergence from roosts.png

View larger image

The examiner adds that “long-tailed bats were much less active in the winter months than the short-tailed bats”, and then asks the question:

Discuss: the evolutionary processes that have resulted in the present-day niche of the lesser short-tailed bat in New Zealand, AND the factors that allow the co-existence of these two species of bat in New Zealand. Support your answer using data from the resource material [my emphasis - do take care to use the relevant information in your answer].

Okay – now, it’s just the short-tailed bat you’re focusing on to begin with. When that ancestral population arrived here, there’d have been no other mammalian competitors around ie vacant ecological niches. And they’d have been isolated from other bats by the Tasman sea, which sets up conditions for allopatric speciation: an isolated gene pool with no gene flow. Natural selection on advantageous mutations, plus the impact of genetic drift on this small isolated population, would have seen its gene pool diverge from that of its Australian relatives, with the potential for favourable alleles to spread rapidly. One or more of those mutations must have allowed some individuals to fold their wings to some degree in a way that allowed the animals to use them as legs when on the ground, and although these days – with so many mammalian predators around – crawling around on the ground is likely to put a small bat at a disadvantage, 30+ million years ago this wasn’t an issue. Those bats that were able to utilise this new habitat would have been able to sample a more varied diet (fallen fruit, pollen of ground-living plants), plus there would have been energy savings due to a reduction in flight: energy that could be put into growth & reproduction. The end result would be for the favourable alleles that allowed this (such as those underlying the anatomical changes allowing wing-folding) to become more common.

The relationship with the wood rose (Dactylanthus) is worth mentioning too. This is an example of co-evolution, with both members of this mutualistic relationship benefiting. The wood rose is pollinated by this little bat, which in turn gains a high-energy food supply in the form of the plant’s nectar. (The relationship is at risk due to browsing by possums, particularly in the North Island, & also to damage by rats.)

What about the co-existence of short-tailed and long-tailed bats? Well, their niches are quite different, which would reduce/minimise competition between these two species. They use their habitat in different ways (Fig. 1b): the short-tailed bat prefers beech forest while the long-tailed species is much more active along the forest margins. This alone would reduce competition for food, but (as noted in the additional information) the diets of the two bats are different. The short-tailed bat is a ground-feeding omnivore while its long-tailed cousin is an aerial insectivore. The potential for competition is reduced still further by marked differences in activity patterns ( Figs 2 & 3 above). Long-tailed bats leave their roosts to hunt about half an hour after sunset & their activity declines markedly as the night draws on, while the short-tailed species emerges 1.5 hours after the sun goes down & there’s another peak of activity near dawn ie it is ‘crepuscular’.  Plus short-tailed bats are more active in winter, presumably because they’re able to make use of ground-based food sources that aren’t available to C.tuberculatus.

These differences do have implications for the conservation of lesser short-tailed bats, which are currently listed as ‘endangered’. O’Donnell et al. point out that because M.tuberculata makes little use of forest margins and open grassland, the species would not adapt successfully to fragmented habitats. This has consequences for designing reserves and managing the species – not something that you needed to comment on in answering the question, but definitely something to think about if you have an interest in conserving our native biodiversity.

[edit: I should make the point, though, that this sort of additional consideration would meet the requirement for 'perception' that the examiner's looking for in recognising 'outstanding' scholarship performance!]

C.F.J.O’Donnell, J.E.Christie & W.Simpson (2006) Habitat use and nocturnal activity of lesser short-tailed bats (Mystacina tuberculata) in comparison with long-tailed bats (Chalinolobus tuberculatus) in temperate rainforest. NZJ Zoology 33: 113-124

mount st helens as a model for the grand canyon? somehow i don’t think so Alison Campbell Nov 12

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Recently our local paper ran an article on Mt St Helens, which hit the headlines with a violent eruption back in 1980. The words ‘big bang’ were mentioned in the title. This seems to have struck a chord with one reader…

This mountain’s big bang, and the subsequent rapid remodelling of the area, ironically casts doubt on “the big bang”, which we have been taught is what brought about our own origin over supposedly billions of years.

I quote the writer: “One of the largest landslides in recorded history ensued.”

Yet this event was just a small reminder of how the Earth’s present surface was formed – by a rapid and catastrophic event. Mount St Helen’s eruption created a small version of the Grand Canyon in just a few hours. Therefore, significantly, what we see around us is not evidence for a slow and gradual evolution. An interesting book which discusses parallels to the Grand Canyon and Mount St Helens is available in the Hamilton Llibrary. It’s called “Footprints in the Ash”, by John Morris and Steven Austin. You owe yourself a look at it.

(At the beginning of the third paragraph I was thinking, Young Earth Creationism, or YEC, and mention of John Morris & Steve Austin confirmed it.)

Although by no means the largest eruption in recent history, Mt St Helens was the largest for a considerable period of time in North America. It released around 24 megatons of thermal energy & its lateral blast produced a path of destruction that reached around 27km from the mountain. And it did result in ‘the largest landslide in recorded history’ when a debris-laden lahar travelling at up to 240kph rushed down the mountainside, filling the Touttle river valley with up to 180m of rock, gravel and ash. (There’s a good source of images here on the US Geological Service website.) After the eruption the ash and mud fields surrounding the remants of Mt St Helens’ cone were carved and eroded by rainfall to produce features like this:

 [DSC_4757.jpg]

Image source: Lance Wilson’s blog Mt St Helens Watch

This is ‘Step Canyon’. Steve Austin has called this ‘Little Grand Canyon’ although the formation hardly merits the name as it’s about 20m deep compared to the 1.5km of the real Grand Canyon :) Leading into it is ‘Engineers Canyon’, which Wilson notes was formed rapidly by engineers pumping water out of a lahar-dammed lake further upstream. Austin, Morris & other creationists claim that because these two formations were produced so rapidly by erosive forces, this ‘proves’ that the Grand Canyon itself formed extremely fast & thus supports the idea of a young Earth (6,000 years or so old) with its geological features formed by the Noachian flood.

Unfortunately for this idea the authors aren’t comparing like with like. The debris fields around Mt St Helens are made up of rocks & gravels, ash & mud, & the remains of pyroclastic flows, sitting loosely atop each other – they’re not compacted or consolidated. All this is sitting on steep slopes, pretty much unprotected by any plant cover (particularly immediately after the eruption sequence), and in an area where the average annual rainfall is about 3m for year – a recipe for some pretty impressive erosion. The Grand Canyon is different.

This significant geological feature cuts through layers of limestone, sandstone, shale and metamorphic granite, a mile down to the Colorado River, arranged as shown in the following image from the TalkOrigins website

 Idealized and simplified diagram of the Grand Canyon - from TalkOrigins
Grand Canyon figure

These rocks are much more resistant to erosion than the unconsolidated debris fields of Mt St Helens, and their rates of erosion are much too slow to allow for the Canyon’s formation in the very short timespan of the YEC model. On the basis of radiometic dating those recent (Cenozoic) lava flows at the very top are around 1.3 million years old – because they flow over the lip of the Canyon they must have been laid down after it formed. Uranium-lead isotope measurements suggest that the Canyon is at least 6 million years old and was cut at rates of between 55 and 400 metres per million years

So we really are looking at a ‘slow and gradual’ event, and indeed, it was Lyell’s and Hutton’s documented evidence of slow, gradual changes in the Earth’s surface (subsequently validated by radiometric dating) that gave Darwin the time needed for the evolution of life to occur.

a little exercise in critical thinking Alison Campbell Nov 11

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Grant‘s just sent me a piece that a recent Sciblog commenter posted on a US website. (Oh, all right, it was the Huffington Post. Not a place to go for good science coverage, but anyway…)

I knew a New Zealand dairy farmer who told me that her 9-year-old daughter had been growing breasts and pubic hair. Somewhat alarmed, she and her husband tried to figure out what caused the problem. It turned out that the vet had injected a few cows in ther herd which had not become pregnant in the first round of artificial insemination with a powerful hormone to induce ovulation, in the hope to impregnate them this time. The milk from these cows, along with the milk from all the pregnant cows, had been going into the tank from which the milk was collected by a milk tanker in the morning. The family had used some milk from the tank for their daughter’s breakfast every morning. Once they realised what the problem was, they stopped using the milk and their daughter reverted back to normal. So much for “100% Pure New Zealand”!

 

Let’s just sit back & have a look at the many misconceptions that this piece contains :)

Quite by coincidence there was a piece in the newspaper just a few days ago (similar to this one) about the lowering in the age at which children begin to enter puberty, over the last few decades, to the point that for many girls the related physical changes begin from about 9&1/2 years of age. The on-line encyclopaedia Te Ara tells us that “[in] 2000 puberty occurred three years earlier on average than it did in most western societies a century earlier — probably largely because of improved nutrition.” (Now, this brings with it a number of attendant problems – not least, the need to look at the sort of s*x education children receive and when they receive it; however, that’s not something I want to get into at this point.) More recently, it’s possible that increasing levels of obesity have an impact, because body fat is a source of oestrogen. (See work by Sir Peter Gluckman, for example.) And some people have also raised concerns about the amount of oestrogen and other related hormones in the environment. So it’s not completely unlikely that this apocryphal farmer’s daughter might have been entering puberty as part of the normal run of things, and that the milk she was drinking had nothing to do with it. Correlation does not equal causation.

Since dairy farmers need their cows to be pregnant and subsequently lactating, injecting hormones that induce ovulation (such as luteinising and follicle-stimulating hormones) into cows that haven’t become pregnant is a common management practice, and there’s a reasonable amount of literature on the best way to manage this (here, for example). But the hormone treatment (& the vet’s time) is going to cost money, so that it’s extremely unlikely that the family described by the HuffPo’s correspondent would be unaware that the vet had treated some of their herd in this way. Good herd managers are going to be very much aware of what’s going on with their cattle.

The other thing is, these hormones don’t last indefinitely in the body. They’re produced (injected), initiate changes, and disappear: the half-life of luteinising hormone in the human body, for example is around a couple of hours. So because the treated cows are not going to be continually expressing these hormones in their milk, it’s hard to see how this child would have been receiving a regular titre in the milk on her breakfast cereal. And if she was, then in all probability so was the rest of the family — was no-one else affected? Plus there’s the matter of dilution factors, as the milk from the few treated cows would be considerably diluted by admixture with the milk from the rest of the herd. And the principles of homeopathy apply here about as much as they do anywhere else i.e. not at all :)

seven signs of bogus science Alison Campbell Nov 09

3 Comments

Over at Sciblogs there’s a lengthy comments thread on vaccination, following an excellent post by Darcy on some myths about vaccines. I hesitate to call the thread a ‘debate’ because, frankly, it’s impossible to actually debate someone who practices what evolutionary biologists would call the ‘Gish gallop’ – firing off so many factoids that you might manage to correct one or two in the time available, but too late! they’ll have already moved on to the next set.

On the other hand, this sort of thing can be educational, on several fronts. First up, there’s the hope that any undecided lurkers might be swayed by your arguments (which is why both sides continue to engage, I guess). But also – what a rich mine of examples of bogus science!

We have: information being presented via the popular media, rather than offered up for peer review. I use ‘popular media’ in the broadest sense to include a range of websites. I’m afraid that using ‘whale.to’ as a source of information to support an argument will immediately win a whole heap of demerit points. There’s a big difference between information that’s been tested and reviewed, and informaton (or mis-information) that simply represents a particular point of view.

We have: conspiracy theories. Oh boy, do we what! On the Skepticon thread one commenter in particular is big on conspiracies. Vaccines are apparently the result of a government/’big pharma’ conspiracy to make us all sick so that the companies can then make even more money selling products to help us get better… For example, our commenter uses the argument from authority in quoting a doctor to support his particular conspiracy-focused view:

’My final conclusion after forty years or more in this business is that the unofficial policy of the World Health Organisation and the unofficial policy of ‘Save the Children’s Fund and almost all those organisations is one of murder and genocide. They want to make it appear as if they are saving these kids, but in actual fact they don’t. I am talking of those at the very top. Beneath that level is another level of doctors and health workers, like myself, who don’t really understand what they are doing. But I cannot see any other possible explanation: It is murder and it is genocide.’

 

… and adds his own coda:

He was obviously referring to the genocidal nature of WHO policy, meaning the WHO is out to kill people — not unsafe needle practices.

 

You actually have to watch out for logical fallacies like the ‘argument from authority’. It’s easy to pull together a list of names, with PhD or MD after them, to support an argument. With the PhDs, in particular, one could well ask, what is their field of expertise? Darcy’s commenter provides such a list: “Dr Eva Snead MD, Dr G Lanctot MD, Dr Kalokerinos, Dr Kris Gaublomme MD, Dr med G Buchwald, Dr J Loibner, Dr H Buttram, Dr R Blaylock MD, Dr R Mendelsohn MD, Dr V Scheibner PhD”.

The last on the list, Dr Scheibner, is a retired palaeontologist ie someone with no expertise in vaccine-related science. Dr Loibner appears to be a homeopathic physician who promotes the use of homeopathic vaccines… (Two others appear to be supporters of rather distasteful attempts to see shaken-baby syndrome reinvented as being the result of vaccinations.) Dr Kalokerinos is the source so approvingly quoted by our commenter (above), which rather makes one wonder about his ability to view evidence dispassionately and – as far as possible – without being biased by his own preconceptions.

(Before anyone jumps in – no, I’m not an expert in vaccine-related science either. Which is why I check credentials like this. I need to know that the information I’m using to come to an informed decision is science-based, & for that I need to know something about who’s providing me with that information. Not all sources are equally reliable in that regard.)

We have: anecdotes, rather than evidence. But unfortunately the plural of anecdote is not data, it’s anecdotes. Humans are pattern-seeking animals & we do have a tendency to see non-existent correlations where in fact we are looking at coincidences. For example, a child may develop a fever a day after receiving a vaccination. But without knowing how many non-vaccinated children also developed a fever on that particular day, it’s not actually possible to say that there’s a causal link between the two.

I’m still waiting on natural laws, & the wisdom of centuries (ancient being every so much better than modern…)

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