episode description
What's the most harmful kind of air pollution? It's the black soot generated by diesel engines found in the durable workhorses of transportation, like trucks, buses and ships. Find out what communities close to major shipping ports around the world are doing to combat the influx of unhealthy emissions. Urban forests are going digital. With laptops and handheld devices, volunteers in San Francisco are creating an online map of every street tree in the city, getting a leg up on keeping the urban landscape healthy and growing. In search of the common ancestor of all mammals, Biomolecular scientist David Haussler is pulling a complete reversal. Instead of investigating fossil remains, he's comparing the genomes of living mammals and constructing a map of our common ancestors' DNA. His technique holds promise for providing a better picture of how life evolved on Earth. A nesting pair of Peregrine Falcons has become an unlikely internet sensation. Watch as their family dramas - from courtship to parenthood - are caught on webcam.
