Tuesday, 28 April 2009

More on that first flower

Nothing like the first flowering plant (it's a brown alga) but the kind of thing we might be displaying in the Royal Botanic Gardens if sea levels rise as much as predicted (this arrived on a king tide a few month's back).

Well wouldn't you know it. As soon as I make an attempt to sort out this 'abominable mystery' I find a far more scholarly, and illuminating, account in the journal Science. It's on p. 28 of volume 324, called 'On the Origin of Flowering Plants' by Elizabeth Penisi, if you're interested.

Just a few quotations from that article will give you the general idea.

'In 1879, Charles Darwin penned a letter to British botanist Joseph Dalton Hooker, lamenting an 'abominable mystery' that threw a wrench into his theory of evolution: how did flowering plants diversify and spread so rapidly across the globe?' So that's where the quote came from.

Michael Donoghue from Yale University is quoted "We're a bit mystified. It doesn't appear that we can locate a close relative of the flowering plants". So, yes, it's still a wee bit of a mystery.

'It's one of "the most similar living flower[s]" to the world's first flower, says James Doyle of the University of California.' This is the kind of tangled language we get into talking about Amborella - see my last post.

And what about Archaefructus you ask (see my last post...). 'In one sense Archaefructus wasn't much to look at. "It's a flowering plant before there were flowers" says David Dilcher from Florida Museum of Natural History. But Pennisi goes on to say that 'Archaefructus's distinction was short-lived...Within months, better dating of the sediments...yielded younger dates, putting this first flower squarely with other early fossil flower parts...'.

In the evolutionary tree of life provided, Amborella branches off before this previoulsy purported 'first flowering plant'. Amborella also turns out to have evolved before plants start to duplicate their chromosomes, a process called polyploidy, and one that is thought to have driven the amazing array of flowers we see today. I apologise for this is getting so complicated, but it is.

The story continues with lines like "The nonangiosperm ancestor just isn't there" says paleobotanist William Crepet of Cornwell. "I'm starting ot worry that weill never know..."

But never fear, the article ends with a quote from Crepet saying "We are liess likely to go around in circles in the next 10 years. I believe a solution to the problem is within reach...The mystery is solvable."

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