Urban humans have lost much of their ability to digest plants
John Timmer writes: Cellulose is the primary component of the cell walls of plants, making it the most common polymer on Earth. It’s responsible for the properties of materials like wood and cotton and is the primary component of dietary fiber, so it’s hard to overstate its importance to humanity. Given its ubiquity and the fact that it’s composed of a bunch of sugar molecules linked together, its toughness makes it very difficult to use as a food source. The…