The doubling time for E.coli bacteria is 20 minutes. With uncontrolled growth, it would take a mere two days for the weight of bacteria to equal the weight of the Earth. What rules determine the actual numbers of bacteria? Why is the world green; why don’t insects eat all the leaves? How does the body maintain homeostasis? What determines the uncontrolled growth of cancers? What happens when you remove natural predators from an ecosystem?
You can find the answers in Sean Carroll’s new book The Serengeti Rules: The Quest to Discover How Life Works and Why It Matters.
Everything is regulated: every kind of molecule, cell, and process in the body is maintained in a specific range and governed by a specific substance or set of substances. Diseases are mostly abnormalities of regulation. Too little insulin = diabetes. Uncontrolled cell multiplication = cancer. To intervene in disease, we need to understand the rules of regulation.
Carroll calls them the Serengeti Rules because of the ecological rules that regulate the predator/prey ratios in Africa. But the same rules apply everywhere, at every level of biology. (more…)