What portion of all species have scientists identified and named?

Of course, we have no idea exactly what proportion of all species have been classified, named, described or discovered.

Currently there are at least 1 million named insect species, over 50 000 vertebrate species (of which 25 000 are fish, 5000 are mammals, 10 000 are birds, about 10 000 are reptiles and 6000 are amphibians) and 250 000 flowering plant species. What I have mentioned is only a tiny proportion of the number of species already named. The total number of named species probably approaches 2 million.

In South America, insecticide fog was released into a tree's canopy, out of which fell thousands of specimens of insect. 80% of those specimens were of species not yet described.

The number of tree species in the forests is better known than the number of insects (or arthropods in general). One argument took the number of tree species and multiplied it by the average number of insect species found to be specialist (to specific trees) per tree species. This yielded an estimate of undescribed arthropod species at 30 million. Since these seem to be the majority of life on Earth, it may be that the total of all life would in fact round off to this number of species; 30 million.

Still there are estimates of the total number of species up to 100 million. I was conservative in my last thumbsuck-like guess of the total number of species on Earth and guessed 50 million or so. Yet everyone around me was aiming much higher, much closer to 100 million.

2 million species described so far divided by 100 million in total and you can see the proportion of life so far discovered is astonishinly little. You may think we do know at least mostspecies. But then you imagine the undiscovered angler fish and crabs and polychaete worms in the endless depths of the unexplored oceans and the endless leafy heights of the rainforest trees crawling with insects................