TOKYO -- In the most recent update to its "red list," which evaluates threatened wildlife, the International Union for Conservation of Nature has listed the Pacific bluefin tuna as a species threatened with extinction.
In June, the Japanese eel was listed as endangered. The number of threatened wildlife species has now climbed to 22,000, leading some experts to say that in modern times the world has entered its "sixth massive extinction." This raises a question: What is biodiversity?
