Published online by Cambridge University Press: 04 August 2010
Animals are destructive by nature. They do not build as plants do, by taking simple molecules and making themselves from them. Instead, animals operate by taking complex ready-made structures and breaking them down in their guts. Vertebrates are distinctive in that they are prone to attacking the largest structures. They are, and probably always were, very active organisms, with consequent big energy expenditures, and they evolved teeth and jaws early on to increase the rate of acquisition of these food items. Mammals descended from this line of biological warriors, but they evolved mechanical comminution (chewing) of food particles to precede the chemical comminution in their guts with so as to increase the rate of energy flow. They needed to turn an energy stream into a river so as to fund their all-weather activity cycle, attaining the latter at the immense cost of maintaining an internal body temperature well above their surroundings. We (making the assumption that the reader is human) are super-mammals, having extended this characteristic mechanical and chemical destruction beyond the realm of our bodies to our environment. Probably none of their devastating nature gives animals a good reputation among plants, which have developed an enormous array of defences to try to stop being eaten, and were any readers to be organisms other than human, then they would surely vouch for the exceptionally poor reputation that we currently have with every other species.