the limit, and this, scientists say, can undermine not only the quality of life, but human sururvival itselflf. we probably don't know the names of about 95% of everything livingng in the ocean. momost of the life in the ocean has neverr been studied by scscientists. >> therere may bee 100 milillion microbial species. there may be a billion. nobody has any idea about that whatsoever. >> most of the world's biological diversity is found in the world's rain forests of the coral reefs and new species continue to be identified. deep ocean environment in particular often -- offer tantalizing prospects for the discovery of a known forms of life. no one knows how many species exist on earth. scientists have named at catalog just over 1 million species. what we do know for certain is that we are losing species at an unprecedented rate. losing species before we even knew they shared our planet. >> at the variety of life is going down quite rapidly. >> its going to change the nature of our culture, our cities, and how we go about our daily lives. >> i in earth's history, there have been five mass extinc