A reader asks: Will scientists ever be able to catalog all the species on Earth? Is that even possible?
Until recently, it might have seemed impossible. Some scientists estimate that 90 percent of Earth’s species have not yet been identified; you’d need an enormous army of well-equipped biologists working night and day to even make a dent in that figure. But evolutionary biologist Paul Hebert of the University of Guelph in Ontario believes that he has found a way of accelerating the process. He has discovered a “bar code” embedded in the DNA of all animal life, from bacteria to monkeys, that functions like a fingerprint.