PHOTOGRAPHS BY ROBERT CLARK FOREWORD BY DAVID QUAMMEN
Foreword David Quammen 5 introduction: Darwin, wallace, 9 and the birth of a theory Ancient History 31 modern Birds 52 Reptiles, Amphibians, and fish 85 Seeds and Plants 113 insects 133 some mammals 167 Human origins 193 the evolution of evolution 221 Index 234 photographer s biography 238
4 ancient history
BIRDS The ability to fly has evolved repeatedly during the history of life on Earth: in countless insects; in one of the most widespread groups of mammals (the bats); and, of course, peerlessly, among the birds. (It is possible that amphibians will eventually join them as well; some amphibian species can glide long distances with the aid of skin flaps between their legs and torsos, much as the ancestors of bats likely possessed.) Flight, having evolved so often and independently, is a good illustration of a pair of features of evolution that scientists have identified since Darwin s time. The first is convergent evolution, in which groups that are not closely related (such as mammals and birds) have evolved similar physical characteristics and habits and fill similar ecological niches. For example, hummingbirds and certain bats have both developed the ability to hover before flowers, drinking nectar. Birds also illustrate the phenomenon known as parallel evolution, in which more closely related but geographically remote species evolve to resemble each other and exploit equivalent ecological niches. For example, rheas in South America, ostriches in Africa, and cassowaries in Oceania evolved separately to become huge, mostly vegetarian, and flightless. 9
above and opposite First described in 1773, this beautiful lepidopteran (top: XX, bottom: XX) endemic to Madagascar was first thought to be a kind of swallowtail butterfly. Further research, however, showed that it s actually a day-flying moth in the widespread family Uraniidae. Since it is large, noticeable, diurnal, and migratory, the Madagascan sunset moth would seem to be a prime target for birds and other predators but it has an effective defense: It is toxic, and its bright colors, rather than being an invitation, serve as a warning. The iridescence in the wings of the sunset moth and many other butterflies and moths (as well as some birds) comes not from pigment, but through a form of trickery. Called optical interference, it s a phenomenon in which the microscopic structure of the wings or feathers refracts light in only a certain spectrum. As a result, the sunset moth can flash bright orange and green or a dull gray-brown, depending on the angle at which the light strikes its wing surface. (0004) 10 insects
opposite For thousands of years, humans have been breeding pigeons for food and a wide range of other uses. Clockwise from top left: the Scandaroon (or runt), a favorite of Darwin s and a breed once used for carrying messages; the Oriental Frill, a royal bird once bred for the Ottoman sultans in Turkey; the Nun, a breed that was originally prized for its tumbling aerial displays; and the Hungarian Giant House Pigeon. Despite domestic pigeons significant differences in size, plumage, bill length, and other features, Darwin believed that all were descended from a single common ancestor: the familiar rock pigeon. And he was right. In recent years, the genomes of more than forty pigeon breeds have been mapped, confirming his belief while also pinpointing the specific genetic mutations that cause many of the distinctive physical difference seen among various domestic pigeon breeds. (0027; 0103; 0104; 0254) 16 opposite How do plants propagate their species? One very early, successful step was the development of pollen (here, an example is visible on a dying blossom). Fossil specimens of seed ferns with pollen attached date back to the late Carboniferous Period (about 300 million years ago). The evolution of pollen conferred a dramatic survival advantage: While the spores of more primitive plants required water to spread, pollen could be carried by the wind, a step that opened up vast new areas for colonization. (0236) pages 84 85 Diversity among birds isn t found only in size, shape, habitat, plumage, and behavior. It begins far earlier. This collection of eggs (in the Great North Museum: Hancock, Newcastle upon Tyne, England), demonstrates some of that diversity as well. In nature, birds eggs can range from that of the bee hummingbird (whose eggs are the size of a pea) to the ostrich (which can weigh 2.5 lbs.) From the 1890s through 2009, the Great North Museum was called the Hancock Museum, after the great nineteenth-century British naturalists Albany and John Hancock, friends and supporters of Charles Darwin. (0011) pages 122 123 Flowering plants and trees have evolved a nearly incalculable variety of techniques to aid survival and propagation. The seeds of some orchids, for example, weigh only 1/35,000,000th of an ounce, sailing through the air like dust particles before lodging in the canopies of tropical trees. On the other hand, the seed of the coco de mer palm can weigh up to forty pounds and can float unharmed across vast stretches of ocean waters to colonize new coasts. (0095; 0243) 16 modern birds page 124 Meet the meat-eating Venus flytrap (Dionaea muscipula). Native only to wetlands in North and South Carolina, it s famous as one of the few carnivorous plants that uses sudden movements to trap its prey. As if this isn t striking enough, researchers have recently made another remarkable discovery: Venus flytraps can count. An open trap will not close unless its trigger hairs are touched twice within twenty seconds. And even once it closes, the trap will not secrete the enzymes it uses to digest its prey until it is triggered a third time. Beyond that, the number of times the hairs are triggered corresponds with the amount of digestive enzymes released. From start to finish, this is an extraordinary story of evolutionary adaptation. (0107) page 125 A sundew (family Drosera), one of nearly 200 species of carnivorous plants that occur on every continent except Antarctica. Like the Venus flytrap, sundews need more nutrients than the poor soil of their wetland habitats can provide, and have evolved an innovative way to augment their diet. Their leaves come equipped with tentacle-like glands that produce a sweet, sticky fluid called a mucilage. When an insect, drawn to what seems like a feast, touches one of the tentacles, the leaf curls to ensnare the prey in more of the mucilage. The trapped insect soon dies of exhaustion or asphyxiation, and is digested by enzymes secreted by the sundew. (0238) BOOK SPECIFICATION Binding: Hardback Format: 254 x 190 mm Extent: 240 pp Number of images: 200 col. Word count: 20,000 ISBN: 978 0 7148 7118 9 Stunning images from award-winning photographer Robert Clark reawaken us to the scientific process that drives the amazing diversity of life on earth Clark s photographs are known around the world. Among other projects, he has contributed 40 stories Phaidon Press Limited Regent s Wharf All Saints Street London N1 9PA to National Geographic including over a dozen Phaidon Press 65 Bleecker Street New York, NY 10012 This is a refreshing, beautiful, and provocative display covers. He has 523,000 avid followers on Instagram SEEDS AND PLANTS of the diverse world we live in; one that encourages the reader to stop, marvel, and ask questions 2016 Phaidon Press Limited phaidon.com Informative captions and enlightening text by Joseph Wallace explain every step along the way above How did the Mexican blind cavefish (Astyanax mexicanus) lose not only its vision, but its eyes, when adapting to life in pitch-black caves, while its close relatives on the surface maintained perfect vision? Researchers have found that cryptic or standing genetic variations in the cavefish variations that caused no changes in sighted fish over generations were unmasked after the fish moved into caves where eyes were not needed. The unmasked gene allowed either bigger or smaller eyes to appear in individual fish. Then natural selection took over, selecting more energy-efficient fish with ever-smaller eyes. The ultimate result: the eyeless fish found today. (0102) 16 reptiles, amphibians, and fish opposite Eels are among the most adaptable and well-known fish, with hundreds of species occupying oceans, marshes, rivers and other bodies of water (fresh and salt) worldwide. Yet until recently, the evolutionary history of two familiar species the European and American eels confounded scientists. These eels, which breed in the same area of the Sargasso Sea, once comprised just a single species. How did they split in two? When the land we now call Panama emerged about 3.5 million years ago, it separated the Atlantic and Pacific Oceans and the eel population as well. One group remained near North America, while another was carried by currents to Europe, where it eventually evolved into a separate species. Yet old habits die hard, and even today, the entire European population migrates more than three thousand miles to spawn in the Sargasso. (0008) The book includes a foreword by David Quammen of whom the New York Times has said he is not just among our best science writers but among our best writers, period that underlines the importance of understanding the theory of evolution to every reader today SEEDS AND PLANTS While plants have rarely numbered among the best-known examples of evolution, their history (and especially that of angiosperms, or flowering plants) has been replete with examples of survival against harsh challenges. Since they first moved from aquatic environments onto land about 450 million years ago, plants ability to spread to evolve extraordinary means of spreading effectively has been one of the great stories of adaptation. Consider the act of pollination. Unlike almost every other form of life, individual plants have practically no ability to move in order to find a mate yet in most plants pollination is as crucial to producing offspring as direct, one-on-one fertilization is to animals. Plants have responded to this challenge through the evolution of a breathtaking array of techniques, including temptation, trickery, transportation, and others. The same mix of approaches holds true with the output of successful pollination: the seed, which often can best ensure the survival of a species if dispersed far from the parent plant. Meanwhile, the additional strategies that plants have evolved to survive in a world filled with hungry herbivores ranging from mimicry to the manufacture of toxins of extraordinary complexity are just as eye-opening. 16