Saving the Earth

Biodiversity

This Earth is teeming with Life – from single-cell organisms to blue whales and giant redwoods. Somewhere in the middle, size-wise, is humanity – the most destructive species ever to live on this planet.

Biodiversity is the cumulative variety of life forms within a given ecosystem, and is a measure of the health and vitality of that ecosystem. Richness of biodiversity offers depth and breadth of gene pool and speciation, conferring the benefits of lowered vulnerability to catastrophic loss through mass extinctions; greater variety of food, medicine and industrial raw material; higher resistance to disease and epidemic; and stronger crop varietals.

The biodiversity found on Earth today is the result of 4 billion years of evolution. Until 600 million years ago, all life consisted of bacteria and single-celled organisms. During the Cambrian explosion, beginning some 540 million years ago, nearly every phylum of multicellular organisms first appeared.

The last few million years include the period of greatest biodiversity in the Earth's history. Estimates of present global species diversity vary from 2 million to 100 million species, with a best estimate of somewhere near 10 million.

Biologists think that the period since the emergence of humans is part of a new mass extinction, the Holocene extinction event, caused primarily by the destructive impact humans are having on the environment.

Overpopulation, deforestation, air and water pollution, soil contamination and global warming - driven by human activity – are now contributing to habitat loss and species extinction at a rate greater than at any time in human history. The extinction of species and loss of biodiversity ensures that the entire ecosystem decreases in complexity and stability.

The books recommended in this section celebrate the breathtaking extent and diversity of life on Earth. They explore the mysteries of evolution, the challenges of stemming extinctions, the creative adaptions that organisms make to changing habitats, and the science of maintaining biodiversity.

David Yarian, Ph.D.