Along with nuclear proliferation and the deteriorating condition of the natural environment, human population growth has become an issue of significant public concern during the past century. With the global population increasing at an ever-accelerating rate, how can the world continue to support its freight of humanity?
The common bumblebee is a familiar visitor to European gardens. At first sight there's nothing particularly remarkable about this small furry interloper, but it has been a source of mathematical controversy for nearly a century.
Some birds, including sparrows and herring gulls, lay their eggs so that the last one to come out is a shade or two lighter than the others. You might suppose that laying eggs requires some effort and that the colour of the last egg is a sign of an exhausted mother. But this practice might be of evolutionary advantage.
Earlier this year, a group of scientists at Bell Labs announced that they had succeeded in observing the effects of "dark matter" - invisible matter that can be detected only by its gravitational effects.