This is a wonderful book that describes two of the great events of macroevolution: the emergence of tetrapods from the water and the return of whales to the seas. \Carl Zimmer explains the evolutionary pressures of different ways of life in different ecologies in tracing the probable path of whales to the ocean, using the magnificent series of transitional fossils found in the 80s and 90s. Along the way he explains why whales and seals use their flippers differently, why fish can lose their eyes but octopodes don't, how many lineages of fish have lungs for use out in the open seas, and why the baleen whales developed from toothed whales. He also follows a whole series of transitional fish to four-legged creatures. He shows us how one change in the timing of an embryo's development can change a whole group of characteristics in the adult. And he makes it seem simple!

Forced on me by monado, so I stop pestering her with questions about macro-evolution.