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Wednesday, 30 August 2017

Darwin's error

This is a small excerpt from a new book, probably to be called Background to Science. Drawing on a lifetime of writing essays, articles and talks about matters of science, I am repurposing a lot of old prose, 405,000 words at the last count.  It should be released on Kindle, later this year. I am rewriting most of it, and all so filling in some of the gaps.

It is that work which has led to the lack of posts here. Sorry!

While I always say Darwin’s work has never been shown to be false, there were a few minor errors in some of his examples, mistakes which don’t affect his overall correctness. There was also one major error in his thinking, which also made no difference in the long run, but it has to do with one of my favourite animals, the ant lion, so it gets a quick run here.

In Australia, ant lions are the carnivorous larval stage of lacewings. They make little pit traps in sandy soil and catch ants and other insects (I have seen one catch a small weevil). Their prey fall into the pits the ant lions make, and they are sucked dry.
Ant lions are small. I move them with a small paint brush.

Because there is some rather marvellous physics involved in the way they make their pits, I have often used these animals in teaching and in books, so I know quite a bit about keeping and feeding them.

In the early days of 1836, a young man called Charles Darwin slipped into Sydney on HMS Beagle. Nobody really noticed him, as he rode out to Lithgow, stayed for a while, saw a few animals, returned to Sydney, slipped aboard his ship, and departed.

Temporary guest ant lions.
He left, though, with the key idea that started him thinking about evolution, because he had seen ant lion pits of two sizes, and started musing on variation. Two species, two sizes of pit, he thought, and that was, legend tells us, the start of the whole evolution-by-natural-selection saga.

Jump forward now to the 21st century, when a film maker was planning a doco on the Darwin story. The producer came across the ant lion story, and thought it would be neat to recreate this, but where does one find an ant lion wrangler at short notice?

Because I had written a book on the Darwin story (Mr Darwin’s Incredible Shrinking World, still available as a e-book), a researcher contacted me to see if I had any idea of where a wrangler might be found, able to take ant lions to a suitable site, and get them making their pits.

I said modestly that I was probably just about the best bet they could find, and then explained a few of the realities. The researcher said that all they wanted was the two sizes of pit, and I said that was easy: the photograph at the head of this section shows that much.

But, I said, it was my firm opinion that the two sizes of pit were made by the same species, and would be the result of two lots of eggs being laid in the sand: the older and larger ant lions make larger pits, and the younger and smaller ant lions made the lesser pits.

In short, Darwin had been inspired to think about variation after a false inference. It made no difference to the validity of his later thinking, but it would be difficult to get this across in a short documentary. I offered to help with the wording.

The result was that the producer had a melt-down, followed by a hissy fit, and the whole sequence ended up on the cutting-room floor, even before it was shot.

In this way, I missed out on the chance to feature “ant lion wrangler” on my CV, but at least we side-stepped the risk of giving cherry-picking idiots the chance to shout “Look! Darwin got it wrong, so logically, evolution is wrong!”, all the while ignoring the many other valid examples of variation within a species that might have got him started.

The secret behind evolution is genetic variability that can be passed on to offspring. Fair-haired people mostly have fair-haired children, dark-haired people mostly have dark-haired children, but they are all humans, all part of the same species.

That was the part that Darwin got right, and that was the part that mattered.

Now here's a tip if you are keeping them: ants added as food have an annoying habit of escaping. The outer tub here has water in it, so the ants can't escape.

Wednesday, 16 August 2017

Wattle Day

Traditionally, Wattle Day in New South Wales has always been August 1.  A few years ago, the Canberra bureaucracy changed it to September 1, but the true believers, here in New South Wales, will stay with August 1.  By September, most of Sydney's best wattle flowers have died away, and most of the wattles are dropping their seed on the day that some people call the first day of our southern spring.  No matter, there are almost always one or two species in flower.

Wildflowers are normal, the whole Sydney year around.  We have no home-grown deciduous trees in Australia, but we do have flowers all the year around, because our ‘climates’ are less extreme.  In early August, there are easily 40 species in bloom in the Sydney bush, with many more in bud.  At the lowest point in our ‘autumn’ — April and May, there are always between fifteen and twenty species flowering on any given hillside, but if the truth be known, we do not have real seasons, except in south-western Western Australia.

Our local ecosystems have evolved to cope with this lack of true annual seasons.  It gets warmer around Christmas and cooler around June to August, but that is about it.  Tim Flannery, says in his excellent book book The Future Eaters, that Australian farmers should not be made to pay their bills annually to the banks.  Rather, they and their accounts should be tied to the El NiƱo Southern Oscillation, for our plants and animals, like our present and future economy, are driven by forces far greater than mere seasons.

Because our plants can flower right through the mild year, they do.

This makes evolutionary sense, because the combined plants can then support a rich variety of pollinating insects and birds.  They take it in turn to use the resident pollinators' services, the pollinators stay around all year, and everything gains.  July and August are the time for the wattles to dominate the Australian bushland.  These are similar to the better-known mimosas of the northern hemisphere, though some of the French ‘mimosas’, grown for the perfume industry, are really our Australian wattles.

The name comes from the early colonists' building practices.  Putting up a timber frame, they filled in the gaps with ‘wattle and daub’, interwoven sticks and twigs, smeared with mud and whitewashed to make the whole water-proof.

If you wonder how this would look, think of the ‘Tudor’ style of house so favoured in Hollywood reconstructions, for Tudor architecture was also wattle and daub, usually with willow twigs under the whitewash.  Other trees provided the timbers in Australia, but the abundant wattle shrubs provided the twigs.

Nowadays we value our wattles for their flowers, golden or cream puffballs with leaves that can be a rich dark green or a bright silvery blue-green, leaves which may take the shape of delicate feathers, neat coin-sized circles, or broad straps.  Australia's national sporting colors are green and gold, representing the classic wattle, as you can see if you watch out for the Australians at the Olympics.

The wattle has long been a national symbol: here is part of a poem by Henry Lawson in 1891.  This was a time of social upheaval in Australia, as the trade unions and the Australian Labor Party came into being, and Lawson was looking back to the Eureka Stockade, some forty years earlier, when gold miners at Ballarat took up arms against an unjust government.
So we must fly a rebel flag
As others did before us,
And we must sing a rebel song
And join in rebel chorus.
We'll make the tyrants feel the sting
O' those that they would throttle;
They needn't say the fault is ours
If blood should stain the wattle.

There is more to Freedom on the Wallaby, but that will give you a feel for it.  Cruder Australians have a different chant that they offer up in adoration of the wattle.  It requires a group to stand in a circle, facing in, and holding aloft sprigs of wattle as we chant:
This here is the wattle,
The symbol of our land,
Yer can stick it in a bottle,
Yer can hold it in yer hand.

Well, nobody ever said that Australians had to be easy to understand . . . or couth.

But even if you ignore the cultural significance, the nationalistic symbolism of the Australian wattle, the bush is a delight to look on in August.  Many of the other flowers are small, delicate, and insignificant, but the wattles stand out as golden masses on the hillsides, crowding the roadside edges in country that barely a year and a half ago was a fire-blackened and ash-covered ruin. 

The wattle is an Acacia, a relative of the peas.  This means the fluffy golden flower produces a pod which later splits open, flinging seeds in all directions.  By October, when we start to see the first small bushfires that herald the approaching high summer, the wattle seeds will already be deep in the leaf litter, or blown under fallen logs, waiting for fire to trigger their germination.  Maybe that is why they flower so early.  Everything here is fire-adapted, for our landscape is shaped by fire, and many wattle seeds will not shoot until a fire has passed over them.

Around the world, there are some 900 species of wattle, with 75 in the Sydney region, and more than 700 across Australia.  All of them have roots which make a home for nitrogen-fixing bacteria, and a delicate perfume that many people miss altogether.  Some produce edible seeds, and some of our most delicious biscuits are made with wattle seeds.  Some people even make fritters from the flowers!

Botanically, the wattles are remarkable for the number of leafless species.  While we have no deciduous trees, we have a number of trees which have done away with true leaves altogether, relying on phyllodes, leaf-like stems, to carry out the same task that leaves usually perform, the wattles being among them.

Dry climates make plants do funny things sometimes, and it seems that phyllodes are more efficient in dry areas than the traditional leaf.  The trees with large dark-green strap-like ‘leaves’ are really equipped with phyllodes instead.

Many Australian gardens, and almost all bush areas feature a wattle tree or five.  As often as not, this will be the Cootamundra wattle, but in 1991, I was told that the people who came to Sydney for the Olympics would look in vain for that one around the Olympics site.

The consulting botanist there told me that the Cootamundra wattle is proving to be a nasty weed, away from its home territory, and so it has been banned.

It seems that even a national symbol, a cultural icon, even one that is a botanical oddity, must mind its manners or face banishment.

Soon, though, it will be time for the waratahs.

Thursday, 3 August 2017

A fishy tale

Frank Buckland (Wikimedia Commons)
   Get me down my filling knife,
   Get me down my stock
   Get me down my filling knife,
   We've a big job in the lock,
   — Dominic Behan, Get me down my filling knife.

I'm working on a big job myself, at the moment, so I shall draw on its pages for a bit of amusement (without saying what the job is).   Today's case for treatment is Francis (Frank) Trevelyan Buckland (1826 - 1880).

Science in the 19th century was the play space of the gifted and curious amateur – and “curious” sometimes took on more than one meaning. Frank Buckland is a prime example.

The son of a clergyman, he was ordained as a priest, but became an academic and practical geologist, the first Reader in Geology at Oxford, where his father, William Buckland, had presented a close argument for the way geology demonstrated Biblical truths in 1820.

William was one of those who regarded all fossils as relics of Noah’s flood. Later, the father was swayed by Agassiz’ theories on Ice Ages and modified his stance, but he remained opposed to the idea of evolution, up to his death in 1856.

Frank was memorable, among other things, for eating all sorts of animals: zebra, snake, earwig, puppy, sea slug and even a bluebottle, though he declared mole the most disgusting thing he had ever consumed.

Frank may (or may not, but legend says he did) have eaten the dried heart of King Louis XIV, but on his honeymoon, he identified some bones said to be those of St Rosalia as goat bones, and he investigated the alleged blood of a saint, which appeared fresh on a cathedral floor each morning. He lay on the floor, tasted it, and declared it to be bat urine (with which we assume he was familiar).

They don’t make scientists like that any more, but if he were alive today, Frank Buckland would surely be a leading television raconteur of science, with his own Youtube channel. Gilbert White would today be an environmental blogger, but White is another story for another day.

Here, before I start rabbiting on about  bestiaries and herbals, is the tale of the sturgeon, in his own words:

On Tuesday evening, at 5pm, Messrs Grove, of Bond Street, sent word that they had a very fine sturgeon on their slab. Of course, I went down at once to see it. The fish weighed, I was informed, 212 lbs [95 kilograms]; it measured 9 feet in length [nearly three metres]. I was anxious to make a cast of this fine fellow, but I confess the size and weight rather frightened me; however, they offered me the fish for the night; he must be back in the shop the next morning by 10 am.

Determined not to lose the chance, I called a cab, and we tried to get the sturgeon on the top of it, but he was “too much” for us, and we were obliged to give up all idea of this mode of conveyance of our huge friend from Bond Street to Albany Street.

Messrs. Grove then kindly sent him up in a cart, and we got him out of the cart easily enough on his arrival at my door, but it was with the greatest difficulty we hauled him up the doorsteps. We then thought of pitching him headlong over the railings into the area below, and thus getting him into the little front kitchen, which, though terribly small, I use as a casting-room; but his back was so slippery and his scales so sharp to the hands, that Master Sturgeon beat us again. However, I was determined to get him down into the kitchen somehow; so, tying a rope to his tail, I let him slide down the stone stairs by his own weight.

He started all right, but, “getting way” on him, I could hold the rope no more, and away he went sliding headlong down the stairs, like an avalanche from Mont Blanc. At the bottom of the stairs is the kitchen door; the sturgeon came against it “nose on” like an iron battering ram; he smashed the door open in a moment with his snout and slid right into the kitchen, gliding easily along the oil-cloth till at last he brought himself to an anchor under the kitchen table.

This sudden and unexpected appearance of the armour-clad sea-monster, bursting open the door — shut purposely to keep out the sight of “the master’s horrid great fish “ — instantly created a sensation scene, and great and dire was the commotion.

The cook screamed, the housemaid nearly fainted; the cat jumped on the dresser, upsetting the best crockery; the little dog Danny, with tail between his legs, made a precipitate retreat under the copper and barked furiously; the monkeys went mad with fright, and screamed “Murder” in monkey language; the sedate parrot’s nerves were terribly shaken, and it has never spoken a word since; and all this bother, because a poor harmless dead sturgeon burst open the kitchen door, and took up his position under the kitchen table.

— George Cox Bompas, The Life of Frank Buckland, London: Smith Elder and Co., 1886, p. 200.