Tag: evolution

Not about dinosaurs. Honest.

Because pterosaurs aren’t dinosaurs. What they have been, though, is a puzzle, at least in terms of how the later, classic pterodactyl form evolved from earlier long-tailed pterosaurs. There are so many differences between them – from the pterodactyl’s characteristic skull (and the number of openings in it) and much shorter tail, to differences in ribs and a second flight membrane between the legs – that it’s hard to tell what path that evolution took.

But once again, it’s Chinese fossils to the rescue, as a new species – another transitional form, Creationists! – has been discovered. As published this week by the Royal Society, Darwinopterus modularis (“Darwin-wing”…er…”modular”) is the kind of transition that makes things obvious – it has all the skull and neck characteristics of a pterodactyloid, but the rest of its body is old-school, long-tailed pterosaur. It’s as though a mid-Jurassic pterosaur had a new haircut and the new ‘do was such a big hit that it eventually changed it’s whole wardrobe to match…

The exciting thing is that this doesn’t just help explain how one form changed into another, but is also evidence of modular evolution. Normally we think of evolution in terms of an individual trait changing over generations – a tail getting longer, teeth getting sharper, colouration getting brighter. In modular evolution, though, sets of complementary features evolve together at the same time – in this case, D. modularis doesn’t just have a head closer to that of a pterodactyl; it’s evolved all the numerous head and neck features of pterodactyls, while the rest of its body retains the characteristics of an earlier pterosaur. It hasn’t just had a haircut, it’s gone in for some piercings and facial tatts as well, but it’s still wearing the stodgy old business suit.

This story is also interesting in the way that some news outlets have done better with it than others. The Independent did quite well, but fell into a common misconception: “Carbon dating has shown that the fossils fall in the middle of the age range from 220 million to 65 million years ago”. The erroneous word here is “Carbon”; Carbon dating is useless for anything more than around 60,000 years old, and palaeontologists – certainly those working with dinosaurs – use other methods to determine the age of their finds. To the author and paper’s credit, this little error and several others have now been cleaned up; to even greater credit, they added a comment in the story to let readers know! (Probably because bloggers with quicker trigger fingers than mine had already been pointing to it…)

On the other hand, The Australian were much worse; they ran with a headline about “Flying Dinosaurs” – pterosaurs are flying reptiles, not dinosaurs – but then go one better by reporting that the fossil was “baptised” with its scientific name. Baptised? Really? I mean, christened, sure; that has currency as a synonym for “named”. But “baptised”? I expected the article to conclude with a social item inviting the reader to Darwinopterus‘ confirmation… The article lists Agence France-Presse as the source, but somehow I’m not sure this translation is entirely their fault…

I never get tired of dinosaurs

…and just to prove it, here are a couple of cool dinosaur finds reported in the last week or so.

Tiny Tyrannosaurus – not actually a Tyrannosaurus, of course, since they’re pretty big, but the smallest Tyrannosauroid found so far. At around the height of a human and up to three metres long from head to tail, it’s not really all that tiny, but Raptorex kriegsteini is, as the name suggests, an excellent suggestion of how Tyrannosaurids – with their defining features of tiny arms and massive head – evolved from smaller theropods. As pointed out in the linked article, it’s unlikely to be a direct ancestor of T. rex, but still, it shows us what their ancestor probably looked like, and how they diverged from smaller predators before getting bigger. No transitional fossils my arse, Creationists.

Oh, and Raptorex isn’t just a portmanteau – it means “King of Thieves”. Yes: this is the Autolycus, and thus the Bruce Campbell, of dinosaurs. Kriegstein is the name of the person who donated the fossil, though it’s actually in honour of his father, a Holocaust survivor.

As a side note, check out Raptorex paper author Paul Sereno’s web site. It’s pretty awesome; among other things, he rents out and sells replicas of his fossil finds, and on his postings page you can be disabused of the notion that the scientific community is one big, happy family. This is why is pays to delve into the links given on any science story!)

Earliest feathered dinosaur – Raptorex might have had feathers, but Anchiornis huxleyi is particularly significant because it pre-dates even Archeopteryx, usually acknowledged as the earliest bird. The genus name means “near bird”, but the type species honours Darwin’s bulldog, Thomas Henry Huxley. It even had two different kinds of feathers. Dinosaurs are awesome.

A day for birthdays

I just got home from a lovely little birthday party thrown for one of my Anarchist Guild Social Committee castmates, and I had been so intent on getting the fairy bread right and excited that we used electrostatic charge to stick some of the party balloons to a curtain that I almost forgot who else was born on February 12: Abraham Lincoln.

Yes, it’s true: America’s tallest president turns 200 today, and I’d like to take the opportunity to talk about variation in the human population…nah. I’m kidding! I want to talk about Charles Erasmus Darwin, because he’s 200 today as well.

What to say about Charles Darwin? He studied medicine, but didn’t complete the course because – according to various sources – he both found it boring and was afraid of blood. He came up with one of the most powerful scientific ideas of all time, but delayed publishing it for twenty years to study barnacles in infinite detail. (If you find that intriguing, I recommend Rebecca Stott’s Darwin and the Barnacle, probably the finest book written about Darwin.) He possessed a gentle nature, and detested all forms of cruelty to man and animal alike; he once tried to have a man freed from an asylum when a letter written by the patient came into his possession and seemed rational, though even the man himself latter admitted he was insane when he wrote it. And he greatly opposed vivisection, writing in a letter in 1871 that it was “a subject that makes me sick with horror” and cutting the discussion short “else I shall not sleep to-night.”

Even 100 years ago, scientists gathered to celebrate his contributions, and when he died in 1882, he was buried in Westminster Abbey a few feet from the grave of Isaac Newton. A century later in the age of genetics, molecular biology, and even the resurgence of not-quite-Lamarckism via epigenetics, his name is synonymous – for better or worse – with his legacy, the theory of evolution via natural selection. And now, 150 years after the publication of Origin of Species, his name and deeds are being discussed in hundreds if not thousands of blogs across the globe.

Not bad for a life’s work, eh?

February 12 is also – unofficially – “National Freedom to Marry Day” in the United States, which has been celebrated for a decade today. It’s tempting to think that the date was chosen on purpose, as a refutation to all those neo-conservatives who argue that homosexuality is “unnatural” (and who, in the States at least, are pretty likely to consider evolution pretty unnatural too) – but of course, with only 365 days to choose from, I’m sure there are plenty of other reasons. Probably it was convenient to make it coincide with an official holiday – Lincoln’s Birthday.

Whatever you did today, I hope you can take a moment to think about Charles Darwin, the man, as admirable a scientist and human being as ever there was. But spare a thought for Alfred Wallace while you’re at it; if it weren’t for his famous generosity, Darwin might be no more than a blip on the scientific radar, and in 2023 we’d be celebrating his 200th birthday instead.

The ginger science alliance

It’s not often you get to see a redheaded comedian speak about the beauty of the universe, and pictures from the Hubble space telescope in particular, and even less often that the person in question isn’t me. So it was lovely to be in the audience tonight to see Rod Quantock at the Ian Potter Gallery in Federation Square do just that.

If you don’t know who Rod is then I can only assume you’re either under the age of 20, you have no interest in the Australian comedy scene, or both. He recently did a show titled “First Man Standing” and it’s not much of a stretch to imagine he was one of the first stand-up comedians, at least in the modern sense, in Australia. If you’re my age or older, you’ll probably remember him from The Big Gig, Australia: You’re Standing In It, or possibly (and I apologise in advance, Rod) the Cap’n Snooze advertisements of the eighties.

Now, Rod being Rod, he didn’t exactly stay on topic; his style may be best described as lovingly rambly. But it was a grand half hour that featured, among other things, a model of the history of the universe contructed using only four human beings, one of whom played a dinosaur. (That might have been me, but I swear it was all Rod’s idea.) One thing he did mention, however, when sketching out his plan for establishing equilibrium in the ecologically disastrous times ahead,  was that humans are made of 80% water, and, perhaps inspired by Rod and Dr Karl, I’m going to go off on a tangent about that.

Like just about all living things of which we’re aware, we are made largely of water. There’s a lot of fluid in our bodies: blood, lymph, saliva, bile…all mostly water. Our cells are full of it, with anything up to 90% of their mass accounted for by H2O. That varies, of course; you or I have a large though uncertain number of cells in our bodies (it’s in the millions of millions), and they come in about 200 different types.

Interestingly, fat cells have a hugely lower water content than other cells: they’re only about 14% water, which is less even than bone, which is about 22% (“dry as a bone”, indeed!). This explains why in adult humans, the actual percentage of water is around 55%-65%, with men at the top of the range and women at the bottom. This varies quite a bit depending on body shape, size, health, fitness and how much you’ve had to drink. (There’s a pretty good breakdown of all this in the Wikipedia article on body water.)

Now, water is obviously pretty exciting and important for all of us, and when I say us, I mean “living things”. The Earth is in what’s known as the “habitable zone”, the narrow band in which a planet orbiting a star can have water in all three states: vapor, liquid and solid. The habitable zone varies quite a lot, depending on the size and temperature of a star; for hotter stars the zone is further away, for cooler stars it’s closer. Over a star’s lifetime the habitable zone will change, but since stars have long lives, there’s no reason to suppose life won’t usually have time to kick off and develop into complex forms. You know: like us.

The nice thing about all this rambling is that next year is both the International Year of Astronomy (much as 2005 was the Einstein International Year of Phsyics), and the 150th anniversary of the publication of The Origin of Species (not to mention the 200th birthday of Charles Darwin). Aside from Moby’s refrain that “we are all made of stars” (the elements heavier than Hydrogen – i.e. all of ’em – which are created via nuclear fusion in stars), physics and biology are, like all sciences, inextricably linked. It’s a bold time of exploration both inside and outside of ourselves; as Rod pointed out, not only will the successor to the Hubble space telescope, the James Webb Space Telescope, be launched, but we’re also learning more every year about genetics and also neurology. While I don’t think humans will run out of things to investigate any time soon, in the next decade or so we’re going to find out some very exciting stuff.

How sad, Rod pointed out, that we’ve managed this only at the precise time we’re all likely to die out…

Here’s an experiment you can try at home.

Just to show me they appreciate their starring role in my show, a bunch of microorganisms have decided to swarm and multiply in my throat, first making their presence felt at 5am on the morning I left for Adelaide. I’m booked in to see a doctor today; we’ll see how the little rascals do trying to evolve their way around some antibiotics…

The problem is, of course, that some bacteria have evolved resistance to antibiotics. Remember, these microscopic villains reproduce incredibly quickly; even though some species do not reproduce sexually (and therefore lack the sophisticated variation of those who do), they still have more than enough variation through simple mutation over the millions of individual organisms and hundreds or thousands of generations that are currently living inside me to have a fair crack at it.

But never fear; the Man in the Lab Coat’s mighty constitution (at least 14, for the D&D nerds out there) is up to the task of battling these foul invaders, even if medical science isn’t. The corpuscles are massing, indeed the offensive has already begun, and come Friday my sweet voice shall be unadulterated by germs.

See you all at the show!