At the heart of evolution lies a bewildering paradox. Natural selection favors above all the individual that leaves the most offspring--a superorganism of sorts that Jonathan Silvertown here calls the -Darwinian demon.- But if such a demon existed, this highly successful organism would populate the entire world with its own kind, beating out other species and eventually extinguishing biodiversity as we know it. Why then, if evolution favors this demon, is the world filled with so many different life forms? What keeps this Darwinian demon in check? If humankind is now the greatest threat to...

Everything that lives will die. That's the fundamental fact of life. But not everyone dies at the same age: people vary wildly in their patterns of aging and their life spans--and that variation is nothing compared to what's found in other animal and plant species. A giant fungus found in Michigan has been alive since the Ice Age, while a dragonfly lives but four months, a mayfly half an hour. What accounts for these variations--and what can we learn from them that might help us understand, or better manage, our own aging?
With The Long and the Short of It, biologist and writer...