The Great Extinctions : What Causes Them and How They Shape Life

A fascinating history of species extinctions, their causes and the looming "sixth extinction".

It is the central issue for this generation. Respected journals and popular publications worldwide pose the question, call the warning: "Are we in the middle of a sixth mass extinction?" (Science), "Multitude of species face climate threat" (The New York Times), "The sixth great extinction: a silent extermination" (National Geographic).

Of the 1-3 billion species estimated to have appeared during Earth's history, only 12.5 million exist today. Geologists know that species extinction is as natural a process as species evolution. They also know that the rate of extinction in the geological past has not been constant. On at least five occasions in Earth's history, extinction intensities have spiked well above the normal level.

For over a century, geologists have tried to conclusively identify and understand the processes responsible for the complex, fluctuating history of species extinction through the millennia. This has become even more important over the last decade as human populations and technology may now rival sea-level change, volcanic eruptions and asteroid impacts as an extinction mechanism. Will there be a sixth Extinction? When? What will cause it?

The Great Extinctions explores the history of this search, its subjects, its controversies, its current conclusions, and their implications for our efforts to preserve Earth's biodiversity. It explains what extinction is, what causes it and whether it is preventable, and by comparing past geological extinction events, it aims to predict what will happen in the future.

Author Norman MacLeod covers this compelling topic in a concise, easy-to-read style with illustrations and diagrams throughout. He examines a controversial subject with universal implications, which will fascinate a wide readership with interests in geology, prehistory, the environment, endangered species, conservation, wildlife, biodiversity, climate change, zoology, botany, invasive species and more. The Great Extinctions is an essential choice for an informed contemporary readership.

Norman MacLeod is Keeper of Palaeontology at the Natural History Museum, London. He studies the origin and maintenance of form in fossil and modern organisms using mathematical models of shape variation. He also creates new mathematical tools for studying plant and animal form and develops systems for automating the identification of species.