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Posts Tagged ‘animals’

The Biology of Flowers, Eigil Holm, illustrated by Thomas Bredsdorff and Peter Nielsen (Penguin Nature Guides 1979)

An excellent short introduction to one of the most fascinating areas of biology. Flowers are results of millions of years of interaction between plants and animals. The first animals were insects, the next were birds, and the last so far, at least in nature, were bats. Flight is the important thing, you see, because it allows pollinators to travel far, fast and accurately between individual flowers. To take advantage of wings, plants have evolved to advertise with color, shape and scent, but those advertisements aren’t necessarily honest. Some animals are paid for their services with nectar and pollen, or even with seeds, but others are tricked into cooperating or even turned into drug-addicts.

Helleborines of the genus Epipactis, an orchid named after a plant supposed in ancient times to cure madness, actually induce a kind of madness in the wasps that pollinate them: a wasp sometimes becomes so drunk on Helleborine nectar that “it cannot fly, but walks from flower to flower, covered in pollen clubs” (the helleborine glues a little stick of pollen to the wasp’s head as it drinks the nectar). The wasps can even blunder into spiders’ webs while under the influence or end up too weak to move, caught on the sticky helleborine flower. Apart from bee-orchids, flowers pollinated by bees generally play fair. But bees don’t always play fair back: some flowers are designed for only the heaviest bumblebees to enter, so the lighter “buff-tailed bumble-bee (Bombus terrestris) sometimes steals the nectar by biting holes in the corolla tube” (the base of the flower where nectar is stored).

Talk of “playing fair” is anthropomorphism, of course: selfish genes take whatever advantage they can and if a plant has evolved to feed an animal, it’s because the animal performs some service for it in return. Plants that don’t use animals to reproduce, like the grasses, can seem less interesting at first glance, but if you wait patiently by a field of rye (Secale cereale) in summer, you might change your mind. The dull-looking rye-flowers will be waiting patiently too: for a “sudden lowering of light intensity” caused by a cloud passing in front of the sun, which will trigger the simultaneous opening of thousands of stigmas and a huge cloud of pollen. There’s a lot more to even the dullest-looking flower — and plant — than immediately meets the eye, and this book will give you many mind-expanding examples, beside enriching your understanding of those aspects of flowers that do immediately meet the eye (and nose): their shapes, colors and scents.

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restless-creatures-by-matt-wilkinsonRestless Creatures: The Story of Life in Ten Movements, Matt Wilkinson (Icon 2016)

A fascinating book about a fascinating thing: the movement of plants and animals. It’s also a very familiar thing, but it’s far more complex than we often realize. Human beings have been watching horses gallop for thousands of years, but until the nineteenth century no-one was sure what was happening:

The man usually credited for ushering in the modern study of locomotion is the brilliant photographer Eadweard Muybridge. […] His locomotory calling came in 1872, when railroad tycoon and former California governor Leland Stanford invited him to his stock farm in Palo Alto, supposedly to settle a $25,000 bet that a horse periodically becomes airborne when galloping. (ch. 1, “Just Put One Foot in Front of Another”, pg. 16)

To answer the question, Muybridge used a series of still cameras triggered by trip-wires. And yes, galloping horses do become airborne: “not when the legs were at full stretch, as many had supposed, but when the forelimbs and hindlimbs were at their closest approach.” However, Matt Wilkinson calls another man “the true founding father of the science of locomotion”: the French scientist Étienne-Jules Marey, who had been investigating movement using a stylograph. In fact, it was Marey who first proved that galloping horses become airborne (ch. 1, pg. 19). Muybridge’s photographs were dramatic confirmation and the two men began to collaborate.

Marey also pioneered electromyography, or the recording of the electrical impulses generated by moving muscles. Like the rest of modern science, biokinesiology, as the study of animal movement might be called, depends on instruments that supplement or enhance our fallible senses. It also depends on mathematics: there is a lot of physics in this book. You can’t understand walking, flying or swimming without it. Walking is the most mundane, but also in some ways the most interesting, at least in its human form. Bipedalism isn’t an everyday word, but it’s an everyday sight.

What does it involve? How did it evolve? And how important was it in making us human? Wilkinson looks at all these questions and you’ll suddenly start seeing your legs and feet in a different way. What wonders of bioengineering they are! And what a lot of things happen in the simple process of “just putting one foot in front of another”. Scientists still don’t understand these things properly: for example, they can’t say whether or not sport shoes are dangerous, “lulling us into a false sense of security, causing us to pass dreadful shocks up our legs and spine without our being aware of them” (ch. 1, pg. 29).

But there’s much more here than horse and human locomotion: Wilkinson discusses everything from eels, whales, pterodactyls, bats and cheetahs to amoebas, annelid worms, fruit-flies, zombified ants and the “gliding seed of the Javan cucumber Alsomitra macrocarpa”. He also discusses the nervous systems, genes and evolution behind all those different kinds of movement. This book is both fascinating and fun, but I have one criticism: its prose doesn’t always move as lightly and gracefully as some of its subjects do. Wilkinson mentions both Stephen Jay Gould and Richard Dawkins. I wish he’d written more like the latter and less like the former. If he had, a good book would have become even better.

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Life: Extraordinary Animals, Extreme Behaviour, Martha Holmes and Michael Gunton (BBC Books 2009)

Probably the best BBC book I’ve seen: the beautiful photographs and the enlightening text complement each other perfectly. It’s not advanced biology, with equations and game theory, and it doesn’t give scientific names. But it does include some recent discoveries, like the rehabilitation of the Komodo dragon. If that’s the word:

The tissue damage from the bite is not enough to kill. Until recently, it was thought that bacteria in the dragon’s saliva poisoned its prey. But it has been shown now that the dragon, like some snakes, has venom, making it the world’s largest venomous animal. (ch. 5, “Frogs, Serpents and Dragons”, pg. 134)

The Komodo dragon has become more frightening. And also more interesting. But the book isn’t only about big and frightening: it’s also about strange and beautiful, like:

A tall Gersemia soft coral bending over to sweep tiny animals from the sediment. It does this when there isn’t enough food in the water for its polyps to trap. Once it has consumed everyting in a circle around itself, it will detach from whatever it is holding onto and crawl to a new spot. (ch. 1, “Extraordinary Sea Creatures”, pg. 39)

Germesia soft coral
That’s in very cold water under “the ice in McMurdo Sound, in Antarctica’s Ross Sea”, as part of an “ancient, isolated and utterly unique community” of marine life: there are also sponges, starfish, proboscis worms and sea-urchins. The Gersemia looks both beautiful and graceful, bowing to the sediment like a jewelled and mobile tree, but those are human terms for an organism that probably isn’t even conscious. And all of those organisms that are conscious, like the mammals in the final three chapters, aren’t aware of how they look to us. Natural beauty – and its absence – aren’t designed for us, but the aesthetics of animals is an interesting topic.

Television wants powerful images and this book reproduces them from the series, like the “lioness charging across a river in the Okavango” on page 228. But I think the static image must be more powerful than the mobile one: the photograph freezes the chaos of splashing water and the pale gold perfection of the lioness herself. She wears a look of immense concentration and purpose and I’ve rarely seen a better example of the power and beauty of the big cats. On page 219, there’s an image of one of the big cats’ greatest enemies. It’s also powerful, but in a different way: “a yawning spotted hyena revealing a perfect set of teeth, specialized for cutting, tearing and grinding.” Hyenas are interesting but not attractive. Big cats are both, from the charging lioness to the cheetahs on pages 231-5 and the alert lynx on page 237.

So why is the cat-family, big and small, generally much more attractive than the dog-family? And why are bats often so grotesque? The bulldog bat sweeping up a fish on pages 242-3 has a flat snarling face, ginger fur, taut, veined wings, hook-like hind claws and what looks like a small dangling penis. Birds are often very attractive. Why not bats? Their hairiness and leathery wings are part of it, as are their faces, which are adapted for sonar and eating, not for appealing to human beings.

And then we come to the primates in the final chapter. Now we’re getting closer to home. The faces of each species has a distinct effect on humans, from the endearing spectral tarsier to the choleric red uakari and the melancholy macaque. And chimpanzees look more intelligent than gorillas. Their faces haven’t evolved for our eyes, but they trigger mechanisms in our minds all the same.

So do the insects, birds and fish earlier in the book. And the plants in the single chapter devoted to them, like the bamboo and the dragon’s-blood tree. Colour and line: beautiful and ugly, attractive and repulsive. But all of this bio-aesthetics is interesting and all of it’s governed by natural and sexual selection. And behind it all is Mathematica Magistra Mundi, Mathematics Mistress of the World, from the circle swept by a soft coral on the floor of an icy ocean to the pattern of veins in a bat’s wing and the stripes in a tiger’s pelt.

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