“Biodiversity” … is the key to the maintenance of the world as we know it. Life in a local site struck down by a passing storm springs back quickly because enough diversity still exists. … This is the assembly of life that took a billion years to evolve. It has eaten the storms—folded them into its genes—and created the world that created us. It holds the world steady.

Biodiversity is our most valuable but least appreciated resource.

Biological diversity is the key to the maintenance of the world as we know it. Life in a local site struck down by a passing storm springs back quickly: opportunistic species rush in to fill the spaces. They entrain the succession that circles back to something resembling the original state of the environment.

Biological diversity is unique in its importance to both developed and developing countries.

Biology is a science of three dimensions. The first is the study of each species across all levels of biological organization, molecule to cell to organism to population to ecosystem. The second dimension is the diversity of all species in the biosphere. The third dimension is the history of each species in turn, comprising both its genetic evolution and the environmental change that drove the evolution. Biology, by growing in all three dimensions, is progressing toward unification and will continue to do so.

No one knows the diversity in the world, not even to the nearest order of magnitude. … We don’t know for sure how many species there are, where they can be found or how fast they’re disappearing. It’s like having astronomy without knowing where the stars are.

Our understanding of the causes of biological diversity is still crude. The science addressing it can be generously put at about the level of physics in the late nineteenth century.

The cutting of primeval forest and other disasters, fueled by the demands of growing human populations, are the overriding threat to biological diversity everywhere. (1992)

The most wonderful mystery of life may well be the means by which it created so much diversity from so little physical matter. The biosphere, all organisms combined, makes up only about one part in ten billion of the earth’s mass. … Yet life has divided into millions of species, the fundamental units, each playing a unique role in relation to the whole.

The rate of extinction is now about 400 times that recorded through recent geological time and is accelerating rapidly. If we continue on this path, the reduction of diversity seems destined to approach that of the great natural catastrophes at the end of the Paleozoic and Mesozoic Eras, in other words, the most extreme for 65 million years. And in at least one respect, this human-made hecatomb is worse than any time in the geological past. In the earlier mass extinctions… most of the plant diversity survived even though animal diversity was severely reduced. Now, for the first time ever, plant diversity too is declining sharply.

The totality of life, known as the biosphere to scientists and creation to theologians, is a membrane of organisms wrapped around Earth so thin it cannot be seen edgewise from a space shuttle, yet so internally complex that most species composing it remain undiscovered. The membrane is seamless. From Everest's peak to the floor of the Mariana Trench, creatures of one kind or another inhabit virtually every square inch of the planetary surface.

The worst thing that will probably happen—in fact is already well underway—is not energy depletion, economic collapse, conventional war, or the expansion of totalitarian governments. As terrible as these catastrophes would be for us, they can be repaired in a few generations. The one process now going on that will take millions of years to correct is loss of genetic and species diversity by the destruction of natural habitats. This is the folly our descendants are least likely to forgive us.

There are three levels of biodiversity that we’re trying to save: ecosystems, then the species in the ecosystems, and then the genes that prescribe traits of the species that make up the ecosystem. And we should decide upon areas to be saved not by the general appearance or what are the main ecosystems in them. We don’t know enough about ecosystems. We should be choosing them according to the number of species that are in each. And particularly the number of endangered species of some kind.