The Fundamentals of Cancer

Cancer, we now know, is a disease caused by the uncontrolled growth of a single cell. This growth is unleashed by mutations—changes in DNA that specifically affect genes that incite unlimited cell growth. In a normal cell, powerful genetic circuits regulate cell division and cell death. In a cancer cell, these circuits have been broken, unleashing a cell that cannot stop growing. That this seemingly simple mechanism—cell growth without barriers—can lie at the heart of this grotesque and mult...

 The Wonder of Birds Flocking

What is remarkable about the starlings' behaviour is that, despite all appearances, there is no choreographer and, as far as we know, no leader. Each individual bird is just following local rules. The numbers of individual birds in these flocks can run into thousands, yet they almost literally never collide. That is just as well for, given the speed at which they fly, any such impact would severely injure them. Often the whole flock seems to behave as a single individual, wheeling and turnin...