Take a long, deep breath in. Now slowly let it out. Each time you inhale, you’re drawing in oxygen from the plants around you. Once in your lungs, oxygen navigates the bloodstream, where it gets exchanged for carbon dioxide. With each exhale, you fill the air with carbon dioxide, the very substance that all these plants need for photosynthesis. What we breathe out, plants breathe in. What plants breathe out, we breathe in. The air you breathe is the collective breath of other living beings. You are immersed in the world. And the world is immersed in you. Your body hosts a remarkable diversity of life; as many as one thousand different species dwell on your skin, in your mouth, and in your gut. Only about 10 percent of your cells carry the human genome, while the remaining 90 percent harbor genomes from bacteria, viruses, fungi, and other microorganisms. This multispecies collective (also known as the microbiome) keeps you alive—it facilitates digestion, metabolism, immunity, neurological function, and other vital processes. Delving deeper, seven octillion atoms exist in your body, each billions of years old, forged in the core of an ancestral star before eventually becoming part of you. That is, perhaps, what the naturalist John Muir meant in observing that “when we try to pick out anything by itself, we find it hitched to everything else in the universe.” But the way we typically understand evolution doesn’t reflect this interconnectedness. And the way we see evolution shapes the way we…
