The writing diary of a well-mellowed science writer who cares about the public understanding of science and knows the ropes. This blog bounces between my curiosity, the daily realities of professional writing, the joy of pursuing nature, and my recycling of ideas that won't be in some book or other as far as I can see, but still needed sharing. I welcome comments and suggestions! Spam will be blocked and reported. For my books, see http://members.ozemail.com.au/~macinnis/writing/index.htm
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Wednesday, 30 August 2017
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
Ant lions are small. I move them with a small paint brush.
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.
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.
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
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
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.
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
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.
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
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.