DK Smithsonian. Animal The Definitive Visual Guide

DK Publishing, 2017. — 634 p. — ISBN 978-1-4654-6410-1.Editors-in-Chief David Burnie and Don E. Wilson.
The first man-made object was sent into a low orbit around the earth in 1957, just three years after I was born. I was a schoolboy when the first humans walked on the surface of the moon. Since then the exploration of space has continued steadily and instruments of increasing complexity have been launched into space. One of these, Voyager 1, has even left our solar system. The information gathered has revolutionized our understanding of space, the birth and death of stars, and has widened our horizons to the point where we have proved the existence of many planets that might be similar to earth, orbiting stars in far-flung galaxies. It is hard not be impressed at what we have achieved in such a short
time. For a little over 400 years since Galileo first saw the moons of Jupiter, we have been looking outward—but in my lifetime we have been able to look back at ourselves. For me, one single image from all this monumental effort stands out and it is not one of a Martian landscape or the icy surface of a comet, but the now famous “blue marble” photograph of the earth, taken on December 7th, 1972, by the crew of the Apollo 17 spacecraft, at a distance of about 45,000 kilometers. It shows us how small our home really is and, more importantly, that it is finite. We know a lot about the physical composition of the earth and through studying rocks and the fossil record we have been able to piece together the history of life. We know that evolution has produced, as Darwin eloquently put it, “endless forms most beautiful and most wonderful,” but we are still a very long way off putting a number on exactly how many species we share the earth with. What we do know for sure is that relatively few of them, just shy of 3 percent, have a backbone. Most species and the majority of animals are invertebrates with 3 or more pairs of legsinsects, spiders, and crustaceans. Some estimates of global species numbers have been set as high as 30 million or more, but a general consensus view is that it may be somewhere between 8 and 12 million species. Despite our increasing mastery of biology, from discovering and deciphering the code of life to the making of synthetic organisms, it is very unlikely that we will ever name and catalog the full extent of life on our planet. We must, therefore, get used to the idea that the majority of species will come and go without us ever knowing they existed at all. When I was born, the world human population stood at a little over 2.7 billion. In the time I have been alive it has increased to over 7.2 billion and there is no doubt that this dramatic increase has caused the web of life to fray considerably. Wilderness areas have reduced by almost half, and many species are now threatened. Not just the countless tiny creatures that live in the undergrowth, but primates like us, 50 percent of which are already in danger. Anxiety about species losses is rightly growing, but consider the bigger picture. The norm for any species on our planet is extinction and it has been estimated that only about 1 percent of all species that have ever lived are alive today. The evolution of life on earth has been shaped over thousands of millions of years by numerous extinction events, some so large that relatively few species survived them. We and all other species are descendants of those survivors. But now the earth faces an extinction event caused primarily by human numbers and activities. Unchecked, the loss of natural habitat may lead to the extinction of one third of all living species in the next hundred years. We are now asking questions that I never imagined would be asked when I was studying Zoology—which species to save and which species we can let go. It’s a bit like saying—there are 200 species of owls but we may have to lose half of them. How do you choose which ones we need to look after and which ones we can let slip into oblivion? We might try to conserve “one-of–a-kind” species, organisms that are so unique and genetically different from everything else that they deserve special treatment. Or you could take a different approach and concentrate on preserving the species that have an intrinsic value to us—the ones that provide us with food and materials. The trouble is we know so little about the complexities of ecosystems that we might very well get it wrong. Surely it would be much better to try to save as much of the natural habitat that remains as we possibly can. Studying the natural world is one of the most absorbing and satisfying things anyone can do and if I had my life over again I would still want to spend it getting to know some of the animals I might encounter.With almost 2 million speciesidentified to date, and even more than that awaiting discovery, animals are the most varied living things on the planet. For over a billion years, they have adapted to the changing world around them, developing a vast array of different lifestyles in the struggle to survive. At one extreme, animals include fast-moving predators, such as sharks, big cats, and birds of prey; at the other, there are the inconspicuous sorters and sifters of the animal world’s leftovers, living unseen in the soil or on the deep seabed. Together, they make up the animal kingdom—a vast collection of living things that are linked by a shared biology and that occupy a dominant place in life on Earth.