An exploration of how “just as there are molecular rules that regulate the numbers of different kinds of molecules and cells in the body, there are ecological rules that regulate the numbers and kinds of animals and plants in a given place.”
Carroll (Molecular Biology and Genetics/Univ. of Wisconsin; Brave Genius: A Scientist, a Philosopher, and Their Daring Adventures from the French Resistance to the Nobel Prize, 2013, etc.) describes Tanzania's Serengeti National Park as “an unending canvas containing mammals of many sizes, shapes, and colors,” each with its own place in the food chain. In the 1920s, Charles Elton discovered the role of the food chain in regulating the numbers of animals that can be supported in a given region, a discovery that Carroll compares to the contributions of Darwin. While he was still a student at Oxford, Elton joined an expedition to the Arctic, where he observed a pyramid of life, beginning at the bottom with plankton and fish. These were eaten by seabirds, which, in turn, provided food for the arctic foxes and seals that, in turn, became sustenance for the polar bears. Elton recognized that the different species functioned as a community of predators and prey, with their populations regulated by their relative positions in the food chain. Predators play important roles in ecological sustainability by limiting the numbers of the species on which they prey. This is exemplified by the recent necessity of reintroducing wolves to Yellowstone Park because the unchecked population of deer and elk were overgrazing the vegetation. Another analogy is the way in which water pollution creates massive growth in algae. Carroll compares this to a failure in the body's regulatory system, which causes excessive cell multiplication and leads to the development of metastatic cancers. He warns that by failing to protect the environment with appropriate regulations, we face “an ecological cancer.”
A thought-provoking challenge to complacency.