For the past half-century, Thomas Lovejoy has studied “the shimmering variety of life on Earth” in the Amazon rainforest. The 74-year-old tropical biologist, who teaches at George Mason University, coined the term biological diversity in 1980 to refer to the millions of different species that comprise life on Earth, of which scientists have documented perhaps 10 percent. Unfortunately, countless organisms will vanish before we ever discover them, let alone investigate their potential benefits in fields like medicine, agriculture and genetics. But if we work now to restore ecosystems, Lovejoy argues, we can avoid the worst of these losses — and slow down climate change, too.