Humans, the other animals, plants and microorganisms are woven into interdependent networks that we, and they, depend on for food, water, clean air, reproduction, and a place to call home. Plants help filter our water and stem erosion; insects pollinate our crops; other animals help to build the soil and control pests. How exactly do these systems work? How is shifting climate affecting plants and animals, their sources of food and their patterns of migration? What are the best ways to protect these ecosystems, or help them adapt, so we can maintain the services that they provide—for each other, and for us?