Common cuttlefish (Image by Magnefl via Wikimedia Commons, CC-BY-SA 3.0)
After ethical concerns excluded all vertebrates from the UK school experiments, the only animals to observe are invertebrates e.g. stick insects and snails.
We buy garden snails and students sketch them and feed them various foodstuffs. Apparently, snails like cucumber or bread and don’t like tomato or carrot. We also abandoned giving them sugar as one of the tutors swears that “snails crazy on a sugar rush”.
The same tutor had collected snails and decided to keep them until needed for experiments. She keeps them in an aquarium with moss on the floor and they are so happy that they have laid eggs. Snails need calcium to maintain their shells. My colleagues had a discussion about the best source of calcium – crashed egg shells or ‘cuttlefish bones’.
The upper side of cuttlebone – not a bone but a shell. It’s comparable to a length and width of your hand. (Image by Mariko GODA via Wikimedia Commons, CC-BY-SA 3.0)
Cuttlefish bones? I was surprised. Cuttlefish is a relative of octopus, a mollusk, it shouldn’t have bones. However, all mollusks used to have a shell made of calcium carbonate, it just been lost in snail evolution. But they have a remnant inside their body called ‘cuttlebone’. I was even more surprised to learn that cuttlebone is not a useless atavism but its chambers are filled with gas and used for buoyancy.
See also: Wikipedia article about cuttlebone contains nice images made by industrial micro-computed tomography.
Nautilus. The ancestor of cuttlefish looked like it, notice the tentacles. (Image by J. Baecker via Wikimedia Commons)
Literature: Rexfort, A.; Mutterlose, J. (2006). “Stable isotope records from Sepia officinalis—a key to understanding the ecology of belemnites?”. Earth and Planetary Science Letters. 247 (3–4): 212–212.
Starling murmuration – an example of metachronal wave (Image by Fæ, via wikimedia Commons, CC-BY)
The world’s most renowned TV naturalist, Sir David Attenborough, stands in a tropical forest. It’s dark. Suddenly a pinpoint of green light flashes underneath him, in the grass. Another flash, and another until they become too numerous to count. And then a pattern emerges – instead of random light flashes, which would create a steady background, like individual drops of rain create steady rain noise, the flashing fireflies synchronise. They create a rhythm, not unlike flashing traffic lights – or a lighthouse.
The synchronising of rhythms of individual insects is not limited to the fireflies. Perhaps less surprisingly, bees, the notorious collective, do it. Not the torch-like flashing but they shimmer in response to hornet approach. So do starlings and fish that create mesmerising collective movements.
This type of movement is called metachronal rhythm or metachronal wave. It’s produced by the sequential action (as opposed to synchronized) of structures such as cilia, segments of worms or legs. These movements produce the appearance of a travelling wave.
A Mexican wave in Brazil. (Image by Danilo Borges via Wikimedia Commons, CC-BY 3.0)
It’s made by reacting and repeating the movement of your neighbours be it cilia in a single cell organism or a human. West Ham football supporters (and all the rest of them) succumb to a metachronal rhythm during a Mexican wave.
My article in Medium about a sharing economy site
“An Experiment on a Bird in an Airpump” (1768). Joseph Wright.
Unlike his self-explanatory “Alchemist discovering phosphorus,” another painting of Joseph Wright of Derby, “An Experiment on a Bird in an Airpump” (right) is an enigma for a 21st-century viewer. Who are people surrounding the table? Why is the parrot in a glass bowl?
What is an air pump?
I don’t think I need to convince you that air has pressure and you can remove air from a vessel leaving a vacuum – or more likely thin gas – inside. But for people in pre-scientific time air was something indivisible like other elements – fire, earth, and water.
The air pump, which can suck the air out of a vessel, was invented by Otto von Guericke in 1650. One of the lucky first possessors of the air pump was “the first modern chemist” Robert Boyle. You may remember him from Boyle’s Law. Boyle conducted experiments with the pump and published a book about it in 1660. One of the experiments describes air removal effect on a bird:
1. Walking fish
Shuttles hopfish and its son (Image by Alpsdake/Wikimedia Commons)
Remember that Guinness ad where the evolution goes back: men devolve into cavemen, birds into dinosaurs? It ends with two little fish walking to water and expressing disgust at its taste. These fish do exist. The fish from the advert is close to mudskipper – an Australian fish.
2. Living on land fish
The Kiss (on the right) is one of the most frequent pictures in student rooms. Female students that is. The gold, the flowers, the gently undulating figure of a red-haired and pink woman being embraced and kissed by an angular and darker man – what’s not to like?
But the early 20th-century Austrian painter Gustav Klimt wasn’t always a crowd pleaser. In 1899 he won a commission for three paintings for the ceiling of the University of Vienna’s Great Hall. But his depictions of the goddesses of Philosophy, Medicine, and Jurisprudence caused an uproar of university establishment and were never displayed. They were later looted by Nazis and destroyed in by the fire in 1945, so we have only a fragment in colour and black-and-white reproductions of the rest.
Even from the ghost of the paintings, we can see that Klimt combined his strands of his cash-cow ornate female portraits with his post-Great Hall allegorical groups, as in “award-winning” Death and Life. (If you are ever in Vienna, do visit Leopold Museum for Klimt’s works if nothing else. “Death and Life” is mesmerizing, it’s 2m x 2m but feels like five times that.)
Why were his Great Hall paintings called ‘pornography’ and ‘perverted excess”? Not because the educated people at the end of the 19th century didn’t see nude figures on paintings. On the contrary, classical paintings of this period were full of nudes – relaxing in languorous poses, plump and pink. Klimt’s nudes are emaciated, twisted – and have visible pubic hair and genitals, hence pornography accusation. They also don’t suffer heroically as the heroes of classical paintings do, but depicted being in despair, viscerally – “in excess”.
Reading this book is like having a conversation with an intelligent, wise*, interesting, very open person. A conversation, because some of the things the author says resonate despite our differences in age, upbringing, and nationality. For example, she describes how while falling asleep she imagines herself drifting on a raft at a dark sea. For me, it is a canoe and a large, Amazon-like river at night.
But the book of an octogenarian author, who became famous in her seventies about life and death is better than a conversation because a dialogue is fleeting like a rainbow, but the book remains – to be shared. The prose is beautiful as well as befits to a long time editor.
I wish my local library had more books by Diana Athill.