On This Green Earth, Nell and Chris talk with author and National Geographic magazine contributor, Doug Chadwick.
Chadwick's new book is titled, Four-Fifths a Grizzly - A New Perspective on Nature that Just Might Save Us All. The book takes a close look at our place in the natural world from a scientific angle, with the underlying message that humans aren't that much different from other creatures.
He shows us the surprisingly close relationship between humans and grizzly bears, with whom we share 80 percent of our DNA. Moreover, he reveals that we are 60 percent similar to a salmon and 40 percent the same as many insects.