Life dies at the end

Reading Henry Gee’s A (Very) Short History of Life on Earth for the Times, 23 October 2021

The story of life on Earth is around 4.6 billion years long. We’re here to witness the most interesting bit (of course we are; our presence makes it interesting) and once we’re gone (wiped out in an eyeblink, or maybe, just maybe, speciated out of all recognition) the story will run on, and run down, for about another billion years, before the Sun incinerates the Earth.

It’s an epic story, and like most epic stories, it cries out for a good editor. In Henry Gee, a British palaeontologist and senior editor of the scientific journal Nature, it has found one. But Gee has his work cut out. The story doesn’t really get going until the end. The first two thirds are about slime. And once there are living things worth looking at, they keep keeling over. All the interesting species burn up and vanish like candles lit at both ends. Humans (the only animal we know of that’s even aware that this story exists) will last no time at all. And the five extinction events this planet has so far undergone might make you seriously wonder why life bothered in the first place.

We are told, for example, how two magma plumes in the late Permian killed this story just as it got going, wiping out nineteen of every species in the sea, and one out of every ten on land. It would take humans another 500 years of doing exactly what they’ve been doing since the Industrial Revolution to cause anything like that kind of damage.

A word about this: we have form in wiping things out and then regretting their loss (mammoths, dodos, passenger pigeons). And we really must stop mucking about with the chemistry of the air. But we’re not planet-killers. “It is not the Sixth Extinction,” Henry Gee reassures us. “At least, not yet.”

It’s perhaps a little bit belittling to cast Gee’s achievement here as mere “editing”. Gee’s a marvellously engaging writer, juggling humour, precision, polemic and poetry to enrich his impossibly telescoped account. His description of the lycopod forests that are the source of nearly all our coal — and whose trees grew only to reproduce, exploding into a crown of spore-bearing branches — brings to mind a battlefield of the First World War, a “craterscape of hollow stumps, filled with a refuse of water and death… rising from a mire of decay.” A little later a Lystrosaurus (a distant ancestor of mammals, and the most successful land animal ever) is sketched as having “the body of a pig, the uncompromising attitude toward food of a golden retriever, and the head of an electric can opener”.

Gee’s book is full of such dazzling walk-on parts, but most impressive are the elegant numbers he traces across evolutionary time. Here’s one: dinosaurs, unlike mammals, evolved a highly efficient one-way system for breathing that involved passing spent air through sacs distributed inside their bodies. They were air-cooled, which meant they could get very big without cooking themselves. They were lighter than they looked, literally full of hot air, and these advantages — lightweight structure, fast-running metabolism, air cooling — made their evolution into birds possible.

Here’s another tale: the make-up of our teeth — enamel over dentine over bone — is the same as you’d find in the armoured skin of the earliest fishes.

To braid such interconnected wonders into a book the size of a modest novel is essentially an exercise in precis, and a bravura demonstration of the editor’s art. Though the book (whose virtue is its brevity) is not illustrated, there six timelines to guide us through the scalar shifts necessary to comprehend the staggering longueurs involved in bringing a planet to life. Life was entirely stationary and mostly slimy until only about 600 million years ago. Just ten million years ago, grasses evolved, and with them, grazing animals and their predators, some of whom, the primates, were on their way to making us. The earliest Sapiens appeared just over half a million years ago. Only when sea levels fell, around 120,000 years ago, did Sapiens get to migrate around the planet.

As one reads Gee’s “(very) short history”, one feels time slowing down and growing more granular. This deceleration gives Gee the space he needs to depict the burgeoning complexity of life as it spreads and evolves. It’s a scalar game that’s reminiscent of Charles and Ray Eames’s 1967 films *Powers of Ten*, which depicted the relative scale of the Universe by zooming in (through the atom) and out (through the cosmos) at logarithmic speed. It’s a dizzying and exhilarating technique which, for all that, makes clear sense out of very complex narratives.

Eventually — and long after we are gone — life will retreat beneath the earth as the swelling sun makes conditions on the planet’s surface impossible. The distinctions between things will fall away as life, struggling to live, becomes colossal, colonial and homogenous. Imagine vast subterranean figs, populated by evolved, worm-like insects…

Then, your mind reeling, try and work out what on earth people mean when they say that humans have conquered and/or despoiled the planet.

Our planet deserves our care, for sure, because we have to live here. But the planet has yet to register our existence, and probably never will. We are, Gee explains, just two and a half million years into a series of ice ages that will last for tens of millions of years more. Our species’ story extends not much beyond one of these hundreds of cycles. The human-induced injection of carbon dioxide “will set back the date of the next glacial advance” — and that is all. 250 million years hence, any future prospectors (and they won’t be human), armed with equipment “of the most refined sensitivity”, might — just might — be able to detect that, a short way through the Cenozoic Ice Age, *something happened*, “but they might be unable to say precisely what.”

It takes a long time to bring complex life to a planet, and complex life, once it runs out of wriggle room, collapses in an instant. Humans already labour under a considerable “extinction debt” since they have made their habitat (“nothing less than the entire Earth”) progressively less habitable. Most everything that ever went extinct fell into the same trap. What makes our case tragic is that we’re conscious of what we’ve done; we’re trying to do something about it; and we know that, in the long run, it will never be enough.

Gee’s final masterstroke as editor is to make human sense, and real tragedy, from his unwieldy story’s glaring spoiler: that Life dies at the end.


Reading Sentient by Jackie Higgins for the Times, 19 June 2021

In May 1971 a young man from Portsmouth, Ian Waterman, lost all sense of his body. He wasn’t just numb. A person has a sense of the position of their body in space. In Waterman, that sense fell away, mysteriously and permanently.

Waterman, now in his seventies, has learned to operate his body rather as the rest of us operate a car. He has executive control over his movements, but no very intimate sense of what his flesh is up to.

What must this be like?

In a late chapter of her epic account of how the senses make sense, and exhibiting the kind of left-field thinking that makes for great TV documentaries, writer-director-producer Jackie Higgins goes looking for answers among the octopuses.

The octopus’s brain, you see, has no fine control over its arms. They pretty much do their own thing. They do, though, respond to the occasional high-level executive order. “Tally-ho!” cries the brain, and the arms gallop off, the brain in no more (or less) control of its transport system than a girl on a pony at a gymkhana.

Is being Ian Waterman anything like being an octopus? Attempts to imagine our way into other animals’ experiences — or other people’s experience, for that matter — have for a long time fallen under the shadow of an essay written in 1974 by American philosopher Thomas Nagel.

“What Is It Like to Be a Bat?” wasn’t about bats so much as to do with consciousness (continuity of). I can, with enough tequila inside me) imagine what it would be like for me to be a bat. But that’s not the same as knowing what’s it’s like for a bat to be a bat.

Nagel’s lesson in gloomy solipsism is all very well in philosophy. Applied to natural history, though — where even a vague notion of what a bat feels like might help a naturalist towards a moment of insight — it merely sticks the perfect in the way of the good. Every sparky natural history writer cocks a snook at poor Nagel whenever the opportunity arises.

Advances in media technology over the last twenty years (including, for birds, tiny monitor-stuffed backpacks) have deluged us in fine-grained information about how animals behave. We now have a much better idea of what (and how) they feel.

Now, you can take this sort of thing only so far. The mantis shrimp (not a shrimp; a scampi) has up to sixteen kinds of narrow-band photoreceptor, each tuned to a different wavelength of light! Humans only have three. Does this mean that the mantis shrimp enjoys better colour vision than we do?

Nope. The mantis shrimp is blind to colour, in the human sense of the word, perceiving only wavelengths. The human brain meanwhile, by processing the relative intensities of those three wavelengths of colour vision, distinguishes between millions of colours. (Some women have four colour receptors, which is why you should never argue with a woman about which curtains match the sofa.)

What about the star-nosed mole, whose octopus-like head is a mass of feelers? (Relax: it’s otherwise quite cute, and only about 2cm long.) Its weird nose is sensitive: it gathers the same amount of information about what it touches, as a regular rodent’s eye gathers about what it sees. This makes the star-nosed mole the fastest hunter we know of, identifying and capturing prey (worms) in literally less than an eyeblink.

What can such a creature tell us about our own senses? A fair bit, actually. That nose is so sensitive, the mole’s visual cortex is used the process the information. It literally sees through its nose.

But that turns out not to be so very strange: Braille readers, for example, really do read through their fingertips, harnessing their visual cortex to the task. One veteran researcher, Paul Bach-y-Rita, has been building prosthetic eyes since the 1970s, using glorified pin-art machines to (literally) impress the visual world upon his volunteers’ backs, chests, even their tongues.

From touch to sound: in the course of learning about bats, I learned here that blind people have been using echolocation for years, especially when it rains (more auditory information, you see); researchers are only now getting a measure of their abilities.

How many senses are there that we might not have noticed? Over thirty, it seems, all served by dedicated receptors, and many of them elude our consciousness entirely. (We may even share the magnetic sense enjoyed by migrating birds! But don’t get too excited. Most mammals seem to have this sense. Your pet dog almost always pees with its head facing magnetic north.)

This embarrassment of riches leaves Higgins having to decide what to include and what to leave out. There’s a cracking chapter here on how animals sense time, and some exciting details about a sense of touch common to social mammals: one that responds specifically to cuddling.

On the other hand there’s very little about our extremely rare ability to smell what we eat while we eat it. This retronasal olfaction gives us a palate unrivalled in the animal kingdom, capable of discriminating between nearly two trillion savours: and ability which has all kinds of implications for memory and behaviour.

Is this a problem? Not at all. For all that it’s stuffed with entertaining oddities, Sentient is not a book about oddities, and Higgins’s argument, though colourful, is rigorous and focused. Over 400 exhilarating pages, she leads us to adopt an entirely unfamiliar way of thinking about the senses.

Because their mechanics are fascinating and to some degree reproduceable (the human eye is, mechanically speaking, very much like a camera) we grow up thinking of the senses as mechanical outputs.

Looking at our senses this way, however, is rather like studying fungi but only looking at the pretty fruiting bodies. The real magic of fungi is their networks. And the real magic of our senses is the more than 100 billion nerve cells in each human nervous system — greater, Higgins says, than the number of stars in the Milky Way.

And that vast complexity — adapting to reflect and organise the world, not just over evolutionary time but also over the course of an individual life — gives rise to all kinds of surprises. In some humans, the ability to see with sound. In vampire bats (who can sense the location of individual veins to sink their little fangs into), the ability to detect heat using receptors that in most other mammals are used to detect acute pain.

In De Anima, the ancient philosopher Aristotle really let the side down in listing just five senses. No one expects him to have spotted exotica like cuddlesomeness and where-to-face-when-you-pee. But what about pain? What about balance? What about proprioception?

Aristotle’s restrictive and mechanistic list left him, and generations after him, with little purchase on the subject. Insights have been hard to come by.

Aristotle himself took one look at the octopus and declared it stupid.

Let’s see him driving a car with eight legs.

Come on, Baggy, get with the beat!

Reading The Evolving Animal Orchestra: In search of what makes us musical by Henkjan Honing for New Scientist, 6 April 2019

The perception, if not the enjoyment, of musical cadences and of rhythm,” wrote Darwin in his 1871 book The Descent of Man, “is probably common to all animals.”

Henkjan Honing has tested this eminently reasonable idea, and in his book, The Evolving Animal Orchestra, he reports back. He details his disappointment, frustration and downright failure with such wit, humility and a love of the chase that any young person reading it will surely want to run away to become a cognitive scientist.

No culture has yet been found that doesn’t have music, and all music shares certain universal characteristics: melodies composed of seven or fewer discrete pitches; a regular beat; a limited sequence of rhythmic patterns. All this would suggest a biological basis for musicality.

A bird flies with regular beats of its wings. Animals walk with a particular rhythm. So you might expect beat perception to be present in everything that doesn’t want to falter when moving. But it isn’t. Honing describes experiments that demonstrate conclusively that we are the only primates with a sense of rhythm, possibly deriving from advanced beat perception.

Only strongly social animals, he writes, from songbirds and parrots to elephants and humans, have beat perception. What if musicality was acquired by all prosocial species through a process of convergent evolution? Like some other cognitive scientists, Honing now wonders whether language might derive from music, in a similar way to how reading uses much older neural structures that recognise contrast and sharp corners.

Honing must now test this exciting hypothesis. And if The Evolving Animal Orchestra is how he responds to disappointment, I can’t wait to see what he makes of success.

D’Arcy Wentworth Thompson, the man who shaped biology and art

Biomorphic portrait of D'Arcy Thompson

For New Scientist, 1 February 2017

In a small, windowless corner of the University of Dundee, UK, Caroline Erolin of the Centre for Anatomy & Human Identification is ironing a fossilised pterodactyl.

At least, that’s what she appears to be doing. In fact, Erolin’s “iron” is a handheld 3D scanner, and her digitised animals are now being used as teaching aids worldwide. Her enthusiasm for the work (which she has to squeeze between research into medical visualisation and haptics) is palpable. She is not just bringing animals back from the dead, but helping to bring a great collection back to life.

In 1884, the biologist and classicist D’Arcy Wentworth Thompson began assembling a teaching and research museum in Dundee. An energetic philanthropist and a natural diplomat, Thompson had a broad network of friends and contacts – among them members of Dundee’s own whaling community, who provided him with extraordinary, then-unique specimens of Arctic fauna.

In 1956, the building that housed the University of Dundee’s natural history department was scheduled for demolition and Thompson’s collection, created as part of his work there, was dispersed. Scholars have been scrambling to recover its treasures ever since. Asked whether it can in fact be reassembled, Erolin laughs and gestures at the confines in which the surviving items are (rather artfully) squeezed. “It’s a question of space. We’re already sitting on an entire elephant skeleton. Where on earth would we put that?”


inRead invented by Teads
It’s largely not a genuine problem though, in part because advances in digitisation are changing the priorities of collections worldwide. Even more importantly, it is generally acknowledged that Thompson has outgrown Dundee: he belongs to the world. Together with Charles Darwin, Thompson, who died in 1948, is the most culturally influential English-speaking biologist in history.

We have one book to thank for that: On Growth and Form, first published in 1917 – an event commemorated by an exhibition, A Sketch of the Universe: Art, science and the influence of D’Arcy Thompson, at the Edinburgh City Art Centre.

“Thompson described his landmark book as all preface”

In neither the first edition nor the revised and expanded 1942 version does Thompson talk much about Darwin, and even in the 1940s he considered genetics hardly more than a distraction. Thompson was pursuing an entirely different line: the way in which physical constraints and the initial conditions of life shape the development of plants and animals.

Thompson was fascinated by tiny, single-celled shelled organisms such as foraminifera and radiolaria. He was convinced (rightly) that their wildly diverse shell shapes play no evolutionary role: they arise at random, their beauty emerging from the self-organising properties of matter, not from any biological code.

Even as geneticists like Ernst Mayr and Theodosius Dobzhansky were revealing the genetic mechanisms that constrain how living things evolve, Thompson was revealing the constraints and opportunities afforded to living things by physics and chemistry. Crudely put, genetics explains why dogs, say, look like other dogs. Thompson did something different: he glimpsed why dogs look the way they do.

Most of Thompson’s contemporaries were caught up in a genetic revolution, synthesising the seemingly incompatible demands of chromosomal genetics and Darwinian selection theory. No one ever seriously doubted Thompson’s importance – his book has always been a classic text – but at the same time, few have ever quite known what to do with him.

Portrait of D'Arcy Thompson by Darren McFarlane
Darren McFarlane, Scarus, Pomacanthus, 2012, oil on canvas. (University of Dundee Museum Services © the artist)

Thompson himself (pictured above as morphed by artist Darren McFarlane) understood the problem; he described his landmark book as “all preface”: the sketch of a territory he lacked the mathematical skill to penetrate. What the arguments in On Growth and Form really needed is a computer, and a big one at that (which makes Thompson a character who might have dropped straight out of the pages of Tom Stoppard’s play Arcadia).

Artists, on the other hand, from Henry Moore to Richard Hamilton to Eduardo Paolozzi, knew exactly what to do – and the Edinburgh exhibition combines the University of Dundee’s own collection of biomorphic, Thompsonesque art with new commissions. Several stand-out pieces are by artists who were students at Dundee’s own Duncan of Jordanstone College of Art and Design.

To its credit, Thompson’s alma mater has not been slow to exploit the way his meticulous and beautiful work straddles art and science: it supports a dedicated art-science crossover gallery called LifeSpace, as well as offering degrees in animation, medical art and medical imaging, connecting digital processes with traditional illustration. They are making the most of On Growth and Form‘s centenary, but the influence of Thompson on the university is deep and abiding.

That is as well. For all our anxious predictions about genetic engineering, for all the hype surrounding synthetic biology, and all the many hundreds of graduate design shows stuffed with “imaginary animals”, we have barely begun to explore let alone exploit the spaces Thompson’s vision revealed to us.

Read more:

Colour and Vision at London’s Natural History Museum


for New Scientist, 3 August, 2016

TAKE time over Liz West’s captivating neon artwork in the foyer of London’s Natural History Museum, because darkness awaits at Colour and Vision, its latest exhibition. It’s not that the sun didn’t shine 550 million years ago, where this story begins – just back then there were no eyes to see.

The basic chemical and structural components of vision existed long before it evolved. Something happened to make eyes viable, although the exact nature of that innovation remains mysterious. But once visual information meant something, there was no stopping it – or life. For with vision comes locomotion, predation, complex behaviour, and, ultimately, consciousness.

Colour and Vision does a great job of explaining colour’s role in this story, although sometimes the curators bite off more than they can chew, as when they try to explain the difference between half a dozen kinds of compound vision.

The best insights come from the objects themselves. A sample card of dyed wools reminds us just how hard it has been for humans to extract colours from their environment. For most of our history we have used a dead-leaf palette. In contrast, Gouldian finches boast heads of different colours (black, red, yellow), cowries wrap their bodies around colourful shells, and molluscs lay down iridescent nacre – one of nature’s most beautiful materials – simply to strengthen their shells.

We, however, need an entire industrial base before we can say with any honesty, as the exhibition does, that “we are the only species with the power to choose what colour means for us”. Even then we are constantly reminded that our colour vision is a relatively recent acquisition, and that it’s a mess genetically. This means that there’s a world of variety, beauty and meaning out there humans simply can’t see.

Visit this exhibition, and brush up against it. It’s an uncanny trip.