Draw in a long, steady breath. Then gently release it. With every inhalation, you’re pulling in oxygen produced by the plants around you. Once in your lungs, that oxygen travels through your bloodstream, where it’s traded for carbon dioxide. Each time you exhale, you send carbon dioxide back into the air—the very ingredient plants require for photosynthesis. What we breathe out, plants take in. What plants release, we take in. The air entering your lungs is the shared breath of countless other beings. You are immersed in the world, and the world is immersed in you. Your body is home to an astonishing variety of life; up to a thousand different species live on your skin, in your mouth, and throughout your gut. Only about 10 percent of your cells contain the human genome; the other 90 percent carry the genetic material of bacteria, viruses, fungi, and other microbes. This multispecies community—your microbiome—sustains you by supporting digestion, metabolism, immunity, brain function, and many other essential processes. On an even finer scale, your body contains roughly seven octillion atoms, each billions of years old, forged in the heart of an ancient star before eventually becoming part of you. This is likely what naturalist John Muir was pointing to when he wrote that “when we try to pick out anything by itself, we find it hitched to everything else in the universe.” Yet our usual picture of evolution rarely captures this deep interdependence. And our view of evolution, in turn, shapes how we…