The per capita housing space for urban Chinese was more than tripled in the past two decades, said an official in Beijing on Monday.

For the first time this year, more people will live in cities than anywhere else on the planet. Speaking to a gathering of urban planners at the World Bank in Washington, New York City mayor Michael Bloomberg urged policy makers and the public to confront the challenges of urban life with a new vision.

If you are reading this, chances are that you live in a city – one, perhaps, on its way to becoming a megacity with a population that exceeds 10 million or more. If not, you and most of the world’s population soon will be, according to global population demographics projections.

More than half of humanity – 3.3 billion people – will be living in cities by 2008 and by 2030, some 5 billion will live there, according to a U.N. report set to be released Wednesday.

Urbanization changes landscapes and local environments, which can alter the life histories and traits of the creatures living in and around these areas. Studying European blackbirds (Turdus merula), Jesko Partecke and Eberhard Gwinner (Max Planck Institute for Ornithology) discovered certain adaptive traits, that in the long run, could lead to more offspring.