Is there more competition or cooperation in nature?

When Charles Darwin and Alfred Wallace promulgated the theory of evolution, a debate began among biologists: is nature dominated by competition or cooperation? After all, both can significantly affect the evolutionary trajectories of organisms. Today we know that the line between the two can sometimes be very blurry. A researcher of parasite-host interactions and a scholar of the evolution of cooperation and symbiosis will talk about how complex and multidimensional the relationships in nature are – and how they often escape our simple categories.