Tag: evolution

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Nature

Dazzled and Deceived by Peter Forbes

This is a book about mimicry and camouflage; principally in nature but also in human use — i.e. the military. I heard about it because it won the Warwick Prize for Writing 2011, and the subject sounded interesting, so I thought I’d give it a go.

It’s certainly pretty good, but I wasn’t blown away by it. It didn’t help that I was familiar with many of the examples already.

My other slight gripe is that it spends a lot of time using examples of mimicry and camouflage as a way to shed light on deeper ideas about evolution. Which is, obviously, a valuable exercise, and not in itself a Bad Thing. But I’ve read loads of stuff about evolution already, thank you, and so reading yet another explanation of evo-devo is not enormously exciting. I would much rather have been reading about extra examples of strange and curious animal mimicry.

So, you know, a good book; but I am not its perfect audience. Still, if nothing else it introduced me to the jaw-dropping amazon leaf fish pictured above.

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Nature

Life Ascending by Nick Lane

Full title: Life Ascending: The Ten Great Inventions of Evolution. The ten ‘inventions’ are: The origin of life, DNA, photosynthesis, the complex cell, sex, movement, sight, hot blood, consciousness and death. Lane explains how each of these work and how they evolved, at least as far as current knowledge can take us — which in some cases, like the origin of life, is apparently rather further than I had realised. The consciousness chapter, if you’re wondering, was rather less persuasive.

What sets this book apart from most popular accounts of evolution is that Nick Lane is a biochemist rather than, say, a palaeontologist or an ethologist. So this is a book which focuses on evolution at the micro level: it’s all biochemical pathways and enzymes and the genes which code for them. This is the real nitty gritty of how evolution works, how it actually achieves things; but it’s also the stuff which I generally find is a complete headfuck. No matter how many times I have read accounts of the inner workings of a cell over the years, it just doesn’t stick.

So it is not a small compliment to say I found this book was not just full of new and interesting information, but also managed to be clear, engaging and enjoyable. I still ending up having a long pause halfway through, and I’ve already forgotten a lot of it, but I enjoyed it as I read it.

» The picture is Cytoplasm to vacuole targeting from the Journal of Cell Biology, used under a CC by-nc-sa licence. Picked because it’s a striking image rather than because it’s relevant in any way beyond basic thematic appropriateness.

‘The cytoplasm to vacuole targeting (Cvt) pathway uses Atg11 to direct Atg9-containing membrane from mitochondria (top right) to forming autophagosomes (center) before eventual fusion with the vacuole (bottom right). Original painting by David S. Goodsell, based on the scientific design of Daniel J. Klionsky. (JCB 175(6) TOC1)’

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Nature

Harry’s advent calendar of birds, day 17: Green-tailed Sunbird

Still on the dinosaur thing, because it is genuinely fascinating, I think. Yesterday I picked a bird that looked like a bit like a dinosaur to illustrate the point, but of course they’re all evolved from dinosaurs, even ones like the Long-tailed Tit, or this Green-tailed Sunbird:

And it’s not a distant relationship, in evolutionary terms; birds fit right into the middle of the family tree of dinosaurs. Here’s something I just learnt from Wikipedia, which I don’t think I’d appreciated before: Velociraptor, the predatory dinosaur made famous by Steven Spielberg, had feathers. Indeed it had stiff, quilled ‘wing feathers’ on its arms, although it didn’t use them for flight. It had hollow bones. It brooded its eggs. Some of the smaller species in the same family probably used their feathers for gliding.

However, the other scary predatory dinosaur in Jurassic Park, the Tyrannosaurus rex, did not have these kind of quilled feathers. Which means that Velociraptor shares a common ancestor with modern birds which it does not share with T rex. Velociraptor is more closely related to the Green-tailed Sunbird than it is to Tyrannosaurus.

And Tyrannosaurus, in turn, shares a common ancestor with the sunbird which it does not share with Iguanadon, or Stegosaurus, or Diplodocus.

It’s an extraordinary thought.

» I didn’t want to get too sidetracked because the details are complicated and I’m only getting most of this stuff from Wikipedia myself, but just a couple of pedantic points. Firstly, the velociraptors in the film are much too big, apparently, although there is a larger related species called Deinonychus which is the right sort of size. The real Velociraptor was about turkey sized. Still too big to glide though.

And secondly: it’s true that T rex did not have quilled feathers. But apparently, some of the smaller tyrannosaurids do show signs of having had primitive, downy feathers for insulation. It may be that the only reason T rex doesn’t have these is that it is too big to need insulation, and like elephants, rhinos and hippos, it has lost it. Or maybe the hatchlings were downy but they grew out of it.

Wikipedia has an article about feathered dinosaurs. The whole business is mind-boggling, in the best possible way.

Photo credit: Green-tailed Sunbird (male) – Aethopyga nipalensis is © Mike (NO captive birds) in Thailand and used under the CC by-nc-nd licence.

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