Bacteria are abundant in soil, water, and air as well as in the depths of the Earth's crust, organic matter, and live animals or plants. They are also abundantly social -- among themselves and with others. Not only do they interact with each other but also with their host. Bacillus subtilis and Streptomyces coelicolor are two examples from daily life. The former would be involved with the ropiness of spoiled bread. But the well-known Streptomyces produce the soil's earthy aroma and flavor and the majority of today's antibiotics.

During the past few days, news media has inundated the U.S. public with word that for the first time in 20 years, a government task force has changed course in its recommendations for breast cancer screening.

On the surface, that doesn't seem like an earth-shattering story. Guidelines are routinely revised and updated based on available evidence. But the new recommendations go against entrenched medical practice and advice, and the firestorm the change caused shows no signs of flickering out, and is pitting two government groups against each other.