All we can say is there are most certainly a lot and no one has any idea of how many. Close to two million have actually been collected, studied and undergone some taxonomic classification. Deciding where they fit and giving them a scientific description and a Latin name. Various biologists, naturalists and environmentalists estimate there could be up to 100 million species -- with obviuously 98% ofthem therefore still waiting to be discovered. Most will be bacteria, fungi, insects, beetles, etc. Plus totally weird things we've just been finding in last two decades -- the deep seabed life around volcanic vents thriving without sunlight and oxygen. Bacteria and perhaps lichens living underneath ice sheets. And of course scientists are still discovering entirely new species of birds and large mammals -- which were all thought to have been discovered as recently as 25 years ago. Even in a place so explored as the US the Ivory-billed Woodpecker MAY still exist. However a lot of the philosophy behind the hundred million theory is based on tropical Brazil field work by the Smithsonian's Dr. TerryErwin -- a noted entomologist. In tropical rain forests all sorts of species -- even birds -- have extremely small and local ranges Bird species may live only on one mountain top in the Andes jungles. With totallly different species replacing them on mountain tops you can see just across the valley. And with insects you have species that live on only one group of a certain sort of flowering tree in the jungles -- and the next place maybe a few miles away the same sort of trees will have totally different insects. Anyway, Erwin did his census and species estimation work by finding a gigantic towering tropical forest tree and then surrounding it with sheeting on the ground, so that sheeting extended out from trunk to past furthest branch tips. Then took insecticide fogging machines and sprayed directly upwards through all the foliage. And then started gathering the rain of insects and critters that came pouring down onto the sheeting. They were almost all new and they tried to classify them. Then they would move a quarter mile away and do another tree and found a whole new insect fauna, etc. Then after doing X number of those they tried to extrapolate how many new species/forms they found around each giant tree which might cover half an acre or whatever -- by the total size of the Amazon jungle. And came up with 100 million species. Other conservation biologists have told me that one big caveat was that they didn't really know what all they were getting with all the stuff that rained down on them. As you know insects go through a lot of life stages. Butterfly eggs hatch out as caterpillers or larvae which grow considerably in size, then they pupate and a chrysalis develops, and then a butterfly emerges from that. Each of those stages is an instar. Many tropical insects apparently go though numerous instar stages. And each of them would be unknown to collectors moving through the jungles. And collectors could easily think everything they found was a separate species. However, they could easily have seven or x different unknown instars of just one unknown new species. So the entire Erwin thesis could be off by a very substantial factor. And for the doomsayers and grant seekers the more species on the planet, then the greater number of species that will go extinct by evil civilization and capitlism if they also make unsupportable estimates that X percent of all the species will be estinct by 20xx or whatever. It's hard to find honest scientists anywhere any longer. Science has been completely corrupted by being politicized, by poltical correctness, and by government funding. And often industry scientists are just as susceptible as Green scientists. Alas. Is there anything the government doesn't screw up?