Not content with hosting endless tribute bands and seaside-postcard revues, the End of the Pier Show goes all upmarket by hosting the latest Carnival of Evolution. So, roll up! Roll up! Get yer tickets ‘ere for a plethoric phantasmagoria of the peerless presentations of the natural Universe, like wot she is spoke, notwithstanding inasmuch as which a panjandrum of phylogenetical perorations sent in by enthusiasts from all over the world, and elsewhere.
The Books! The Books!
Let’s start with something general – and you can hardly get more general than the structure of evolutionary biology itself – viz, and to whit, does biology have ‘laws’? Surely you jest: biology treasures its exceptions. Biology wouldn’t be biology if it didn’t get all messy round the edges, rather like Crox Minima’s bedroom. But soft – here is a book review at Kele’s Science Blog of a terse, 150-page work by McShea and Brandon entitled Biology’s First Law: The Tendency for Diversity and Complexity to Increase in Evolutionary Systems. Is this just Steve Gould’s Full House all over again?
Shirley Surely, things can only get more complex if you always start with something simple? This is clearly a book that I should read for myself.
But enough of such japery – what about specific examples of complexity? Becky Ward, for it is she (and, Becky, it has indeed been a long time!) draws our collective attention to Clumping is good; controlled clumping is better posted at It Takes 30, on research showing how cells of Vibrio cholerae, the water-borne bacteria and agents of cholera, maximize their fitness benefits by producing extracellular polysaccharides and therefore clumping together to create biofilms. Becky nods to yet more recent research on the subject, this time highlighted by Elizabeth Preston. Yeast Show Humans Why It’s Better to Be a Clump, posted at Inkfish, shows that in some circumstances, yeast cells that form clumps with their daughters, rather than separating, thrive in conditions of famine that prove too harsh for cells going it alone. These examples could put some exemplary flesh on the theoretical bones offered by McShea and Brandon. Over at BEACON Researchers at Work, Mitch Day looks at the practical problems of treating bacteria as species, or even as Operational Taxonomic Units. Given that bacteria are so free with their DNA, it makes more sense in many cases to treat them as communities, each one a sample of a larger pangenome. Multicellularity, it seems, has very deep roots indeed.
Moving only a little way along the bookshelves, Chris Reynolds presents Babel’s Dawn and the Evolution of Vocalisation posted at Trapped by the Box, saying, “I got this book in the post from Amazon a couple of days ago and this may be the first independent online review, Just in time for the September Carnival.” The book is by Edmund Bolles and is emtitled Babel’s Dawn, A Natural History of the Origins of Speech, which tells the ‘fascinating story of how humanity has developed from just being a great ape over the last six million years’. Cripes – what with Homo floresiensis, the Denisovans and all, the world and its dog is writing books about humanity and what makes it special. Not to be left out, I’m also having a go (this week’s working title: The Beowulf Effect: Fossils, Evolution and the Human Condition.) Chris has mixed feelings about this book. As for me? What with McShea and Brandon, I feel an Amazon order coming on.
The Birds! The Birds!
Yes, there’s still a lot of reaction to the publication in Your Favorite Professional Weekly Science Magazine Beginning with N of the theropod Xiaotingia, and the consequent and rather rude dethronement of Archaeopteryx from its perch and title of ‘earliest known bird’ (something concerning which I have also mused.) At 10,000 Birds Greg Laden compares the episode to the sudden announcement that Atlantis has been discovered. And there was I, thinking that Plato was a brand of washing-up liquid. Elsewhere Greg urges birders to embrace evolution more actively than he thinks they do at present. He’d like field guides to group birds together based on their phylogeny as well as their phenotype – if they don’t, I guess, birding becomes obsessed with quasi-philatelic detail and less with the Big Picture.
Tempo, Mode and the Tangled Bank
Questions of the tempo and mode of evolution continue to fascinate. Kevin Zelnio notes (I use the term advisedly) that the terms also relate to music. His post at EvoEcoLab considers evolution in the slow lane: molto adagio, even cantabile. Jeremy Fox, in contrast, comes over all presto agitato with this spirited critique of Gould and Lewontin’s now-legendary ‘Spandrels of San Marco’ paper (one of my favorites, as a graduate student), posted on the Oikos Blog. Another Young Turk eager to kick over the traces is Scott Bartlett who argues at BATSHITE that evolution isn’t the same thing as improvement: ‘it means becoming better suited to one’s environment’. This is a message that strikes me as important, mainly because I am writing about it at the moment. The public and the media tend to see evolution in terms of progressive improvement – a Haeckelian distortion of Darwin – rather than the Darwinian ‘tangled bank’ model in which natural selection only happens in the here-and-now, with neither memory nor foresight. (On the subject of our favorite Dead White Guy, Heather Scoville presents 5 Interesting Facts About Charles Darwin, at About.com Evolution. I knew that Mr Darwin married his devout cousin Emma – but their interest in Buddhism was news to me.)
It’s worth quoting Mr. D. here, from the final paragraph of his best-known work, My Favorite Bathtime Gurgles:
It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us.
Note the phrase ‘dependent upon each other in so complex a manner’. Life on the Tangled Bank can get complicated. Jeremy B. Yoder writes on Denim and Tweed about red spider mites that react to the defenses of plants such as tomatoes by switching them off, rather like a burglar switching off an alarm system before defenestrating your dojo. The problem is that this strategy leaves a plant open to attack by other herbivores … which the mites cunningly trap in their webs. Because of the Tangledness of the Bank, the race doesn’t always go to the strong. With many forms interacting in all kinds of ways, the ‘fittest’ doesn’t always mean the the one who can solve the Times crossword in under 12 minutes, nor the strongman who can tear a telephone directory in half with his bare hands. This goes right down to the molecular level: as Stephen Matheson shows at Quintessence of Dust, the function of a protein can be ‘improved’ by ‘weakening’ it. Meanwhile, and once again over at BEACON researchers at work, Joshua Nahum talks about lab-based evolution systems in which the meek inherit the Earth – which is nice, as they’d been having a terrible time. Not everything is ‘fit’ that has to go up to eleven. Another BEACON researcher, Mike Wiser, discusses Richard Lenski’s famous Long-Term Evolution Experiment, which has bred (so far), 50,000 generations of bacteria. Wiser shows how this system can be used to measure fitness in a truly evolutionary context.
The Tangled Bank means that predators will ever hunt for prey – which will discover ever more elaborate ways of avoiding the snare. Quite literally, in the case of nematodes trying not to be snared by fungi, as Zen Faulkes describes at NeuroDojo. On the subject of nematodes, Suzanne Elvidge writes at Genome Engineering on how different species of nematode have convergently evolved the capacity not to assume their usual resting phase (or ‘dauer’) when times are tough.
Suzanne Elvidge also looks at another aspect of the Tangled Bank: interactions are not always between species, or between predators and prey, but between siblings, and siblings and their parents. She asks why twins tend to run in families, given that bearing twins is much riskier than having singletons, and twins (as individuals) are smaller and lighter (and presumably less healthy) than singletons. It turns out that women who have twins also tend to have heavier single babies, perhaps as a kind of evolutionary consolation prize – an advantage, then, for twinning, albeit indirect. Heavens to Betsy, that Bank sure is Tangled.
More maternity news just in from The Panda’s Thumb: to Mrs Plesiosaur, the gift of babies (aw, bless) while, elsewhere in the ancient abyss, the incomparable Carl Zimmer, for it is he, writes at The Loom about Janjucetus, an extinct toothy relative of modern baleen whales. Elsewhere on his blog, Carl discusses a problem on a much larger scale, but with much smaller creatures – whether the giant ‘mimiviruses’ comprise a fourth domain of life, alongside archaea, bacteria and … er … the other one. The jury is still out. But – what’s this? – a third post from Mr Zimmer, on the current debate on the environments in which early hominins (members of the human family) evolved. Zimmer has a work rate comparable with that of Prince, or even John Mayall’s Bluesbreakers. He’ll go far, that boy.
Genes and Jumpers
When Bathtime Gurgles was published in 1859 (and, as William Bell observes from the Ben Fry blog, it evolved considerably between the first and sixth editions) most ire was directed at the supposed social consequences of Darwin’s ideas, rather than at its flaw – that without a mechanism to explain the generation of variation, natural selection couldn’t work. In what promises to be a series of posts at The Mermaid’s Tale, Anne Buchanan shows that Darwin was well aware of the problem; goes into the details of Mendelian inheritance; and shows how Mendelism and Darwinism were eventually reconciled. Turning from genes to jumpers, or at least the genes of jumpers, Suzanne Elvidge discusses the sequencing of the genome of the tammar wallaby (posted at Genome Engineering). The creature (Macropus eugenii) is the smallest and arguably the cutest species of wallaby, but don’t be fooled by the fluffy exterior. This baby packs twin thymuses under the hood, together with a thoroughly intriguing immune system and (it sez ‘ere) incomplete X-chromosome inactivation. Who knew? Sometimes, then, the genomic landscape of a creature seems entirely different from what one would expect from its external appearance. For example, I’m always amazed that my axolotl, Squirty Benson Wilberforce III, has a genome ten times the size of mine.
Iddo Friedberg goes into the question in Of Mice and Men or: Revisiting the Ortholog Conjecture posted at Byte Size Biology, showing that the function of a gene is dictated as much by its current milieu as its individual phylogenetic history. It’s all about context, you see. Context is everything.
One Species Or Two?
A big issue in evolutionary biology is the problem of speciation. How do new species get going, so that they are distinct from ancestral or sibling populations? A related issue is whether two species can form ‘sympatrically’ – that is, in a small area, with no discernible geographical or ecological separation. As Jerry Coyne shows at Why Evolution Is True, you can test this by searching for sibling species living in a small area, such as an island. Most research shows that no sibling species of animals coexist on the same island, suggesting that sympatric speciation is unlikely. Not so, though, for plants, at least for sibling species of palm on remote Lord Howe island, which offer a rare glimpse of sympatric speciation in action. Elsewhere on his blog, Jerry ponders why people are actually nicer to one another than you might believe, and the genetics of the remarkable ‘spirit’ bears of British Columbia, and what their genetics has in common with that of mammoths.
The Brain! The Brain!
The spurious conceit of improvement as lambasted by Scott Bartlett (above) would have it that the apotheosis of the zenith for us lofty humans is our large
brians brains, the implication being that creatures with smaller or less complex brains must therefore have smaller and less complex thoughts. Anne Buchanan exposes this idea with a report on ants, posted at The Mermaid’s Tale. It’s assumed that ants, which have very tiny brains indeed, behave more or less as chemical automata. Some, though, seem to be able to identify and defer to colleagues better able to make executive decisions. If only human management structures were so reliable. Perhaps we’ve swapped our brains for MBAs?
One side-effect of having a big brain is depression, or so I assume (I mean, do axolotls get depressed? Do ants?) Over at the Neo-Darwinian Enlightenment Blog and Forum, K. D. Korastky looks critically at some results showing that people in rich countries are more depressed than those in poor countries, and this might be related to income disparity. Koratsky is scathing – it all depends on what you mean by ‘rich’, ‘poor’, ‘disparity’ and – crucially – ‘depression’.
And yet, and yet, there is still space for us to wonder what – if anything – it’s all for, as Andrew Bernardin muses at 360 Degree Skeptic. Is the ‘purpose’ of consciousness to ‘know God’? If not, why is it there? Is it an epiphenomenon of the complexity of a brain evolved ‘for’ other things? When Crox Minor was three, she had a habit of approaching people at random, sighing as if afflicted with terminal Weltschmerz, and saying “what’s it all about?” People have mulled over that question since time began, and they will keep on discussing it, presumably because (a) there is no answer (b) ‘it’ isn’t about anything. Me? I don’t think consciousness really exists, but hey, I live in Norfolk, so that’s understandable.
Well, that’s about it for this month – thanks as always go to everyone who wrote and sent in suggestions. Without you folks – and without the controlling intelligence of Bjørn Østman – to whom I’d like to offer thanks for letting me host the Carnival here at the End of the Pier – there’s be no carnival. The evolutionary festivities will continue elsewhere, however, more specifically at Kevin Zelnio’s salon: submit blog posts (yours or anyone else’s) to the next edition of carnival of evolution using this handy cut-out-and-keep carnival submission form. Past posts and future hosts can be found on this useful blog carnival index page. Bjørn also reminds me of the CoE blog, and that you can follow mini-carnivals on twitter (@CarnyEvolution).
Next month at the End of the Pier, in contrast, we look forward to a production, for one week only, of The Plurdling of the Grummet-Tinker’s Scrode, a musical based on the songs of Rambling Syd Rumpo, staged by the Little Nadgerley Amateur Dramatic and Choral Society – and a display by the Red Arrows formation flying team (in the Town Hall, if wet.)
The public may leave at the end of each performance by all the exit doors and all such doors must at that time be open. All gangways passages and staircases must be kept entirely free from chairs or any other obstructions.
Would the last person to leave please switch off the lights?