Sometimes the normal processes of cell growth, death, and regulation get completely deranged. Cells are transformed and begin robbing their neighbors’ blood supply, like vampires. They defy normal limitations on growth, multiply unceasingly, and then invade space reserved for others. They refuse to die on schedule. These are cancer cells, and they are responsible for about two million new cases of various cancers that occur every year in the United States, and over half a million deaths. One out of five people in industrialized countries will die of cancer, most of them from tumors that originated in a lung, breast, prostate gland, colon, or rectum. And except for a few very clear instances such as lung cancer caused by smoking or exposure to certain chemicals and radiation, no one knows exactly why. Unlike smallpox or malaria, cancer is not a distinctive disease with a single cause. It arises from various kinds of mutations in a cell’s DNA. Some mutations occur naturally. In the course of an average human lifetime, billions of trillions of cell divisions take place. Given this huge number of replications, mistakes are bound to happen. They may result in a disadvantageous change for the organism; some may even spawn cancers. More often, mutations and cancers are prompted by external causes.

        When a bee returns from a more distant food source, she does what is called the Schwanzeltanz or the waggle dance. She wags her abdomen as she runs straight a short distance while making a rasping sound with her wings.She makes turns that create a figure-eight design. The movements of the dance indicate to the other bees in the hive where they must fly to find the food. Karl von Frisch was the first to decode the dances of the honeybees. As early as the 1940s, he found that honeybees can communicate the direction, distance, and quality of a food source to members of their hive through elaborate dances. Scientists have also discovered that the bees produce a hive-specific pheromone that they leave at the source of the nectar, helping to direct the other bees to the site. A pheromone is a chemical that is secreted by one individual and acts from a distance on another individual to alter that individual’s behavior. The scout bee also brings back the scent of the nectar itself, which further aids the other bees in locating the food source. So there are several indicators of where the food is located: the “dance,” the pheromone, and the odor of the food.