Wednesday, 5 August 2009

Darwin's Descendents - The Exhibition


Charles and Emma Darwin had ten kids, but this exhibition isn’t about them, or his great-great-grandchildren. It’s about Charles’ scientific descendents – thousands of scientists working around the world on what I like to describe as the Great Adventure. Here are some notes from a speech I gave at the opening of the exhibition on Monday. What I can't provide is a transcript of Charles Darwin, in person, talking to four of our enthusiastic scientists...or Robyn Williams, both funny and smart, as always.

In short, Charles Darwin made sense of life on earth. Before Darwin, and Alfred Wallace, life was unexplained, and through this celebratory year (see plenty of postings below) I’m become more impressed by the man and his science, not less.

Natalie Angier in her book ‘The Cannon - The Beautiful Basics of Science’ – laments that we use the word Theory for his great discovery. In common parlance a theory is mere conjecture. In science, it’s about as close as we get to an indisputable fact.

What we do today is fine-tune the theory – just as we do with the Big Bang, Plate Tectonics, Climate Change….Capitalism?

Darwin spent most of his life experimenting, observing – before and after he published his theory. There was much more he wanted to check to resolve, he knew there were details to sort out.

One of those details was DNA. Another was to find more of the leaves on the tree of life (the variety of life on earth today) as well as the many more leafless branches – 99% of the tree – (the dead-ends, some of them preserved fossils).

What you can see around us today is the continuation of the great adventure started by Darwin. I know that when I dip my hand into freezing water in south-west Tasmania or the clear blue streams of Kakadu, I am entering a new world. When I return to the lab the discovery continues and each new collection adds to the story, the theory, the fact…

But my collecting has been pretty tame, except for a few crocodiles (which were mostly in my mind only). In our exhibition you’ll hear about head-butting a grey nurse shark, being covered from head to foot in ticks and parking the four-wheel drive on top of a critical specimen (haven’t we all done that, or discovered something new when relieving one’s self behind a tree…). Mind you, the exhibition doesn’t include the dangers of pipettes, or the reputed internet addiction (listen to recent episodes of Robyn William’s Science Show on Radio National).

Everyone in this exhibition is collecting, accumulating information, building up the picture. The scientists are finding new things, constructing new branches, fine-tuning the tree of life.

Perhaps 95% of fungi (150-250K, 5K described) are still to discovered, described and named; 20% of algae (12,000, 10,000 described); and 10-15% of green plants (21,000, 18,000 described), and some very serious trimming and grafting to do in all groups as we track down their DNA history.

In the exhibition we have three Trees of Life in the exhibition.

Firstly the original version drawn by Charles Darwin - which our PR Manager Kerry Brown describes as like a small piece of seaweed washed up on the beach

Then Ernst Haekel’s version drawn a decade later that looks more like a brown kelp growing on the sea floor, again thanks Kerry…

And thirdly a recent version by David Hillis (see image above) that could be a town plan for Canberra. Kerry points out humans are one shelf in one house in one street on the outskirts of that town. Try and find humans – you’ll need to use our magnifying glass if you look at the enlarged version of this ‘wheel of life’ in our exhibition. (Just one point of clarification though. About 3000 organisms are dotted around the edge of this tree/wheel and there is a disproportionate number from groups such as the green plants – the greatest diversity at higher taxonomic levels are in the protist and bacterial groups, the micro-organisms. Remember the quote I’ve used before: life to a first approximation is unicellular.)

And what does the real tree of life look like? More like the last, but more complicated still, with interconnections particularly back in the early years of algal evolution. And maybe there is another tree elsewhere in the universe, or as Paul Davies has pointed out, in some difficult to collect place on earth like a volcano or in the upper atmosphere. Now there will be some dangerous and interesting field trips, and a truly great adventure.


"Darwins Descendents: 200 years of scientific adventures", Monday 3 August – 24 November, Weekdays 10 am – 4pm. Red Box Gallery, National Herbarium of NSW, Mrs Macquaries Road, Sydney. Enquiries: 9231 8111. Entry is free.


Image: David M. Hillis, Derrick Zwickl, and Robin Gutell, University of Texas. http://www.zo.utexas.edu/faculty/antisense/DownloadfilesToL.html

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