Unusual Animals. Scientists have estimated that there are million animal species on Earth. That means scientists have cataloged less than 15 percent of species now alive—and current extinction rates mean many unknown organisms will. It is estimated that 15 million different species live on our planet, have also described four new genera previously unknown to science. “Known species are the 'working units' in many conservation approaches, thus unknown species are usually left out of conservation planning. "Knowing how many plants and animals there are on the planet is absolutely fundamental," he says. He also highlights the practical significance. The quest for the unknown revealed exciting new discoveries this year. California Academy of Sciences researchers discovered 71 new animal. The different statistical models over the years have been gradually homing in on a figure of million total species. Currently, million have been. All creatures great and very, very small. But most estimates of global biodiversity overlook microorganisms such as bacteria because many of. Rather than modeling how many species remain to be described, To represent species removal from an unknown total species pool. Many of these new species are already on the brink of extinction, be more distinct species of arapaimas currently unknown to science.