One of the biggest hurdles in protecting the world's rich biodiversity is that much of it still remains unknown. Environmental activists, scientists and other experts alone simply cannot document all the earth's natural treasures even though that is key to preserving the planet's diversity of species. In a bid to do that, scientists are now teaming up with ordinary people to crunch the numbers. One particularly ingenious project that soon hopes to involve citizens is underway in a national park in southwestern Brazil as our reporter Michael Wetzel found out in his video report. In our background article, Elizabeth Owuor takes a broader look at measuring biodiversity by roping in ordinary citizens and takes us back 150 years to the man who first came up with the very concept of biodiversity – Charles Darwin.