Our planet is, so far as we know, the only asteroid in the universe to feature life. And it is life in forms so abundant that we have next to no idea how abundant it is. We send costly space probes to Mars to see if there ever was life there, and if we found anything it would almost certainly be a primitive slime mould or something equally rudimentary. Yet here on Earth we have millions of species that are so advanced that we have little grasp of just how advanced they are. Yes, millions of them.
Nobody has more than a vague clue.
Estimates range from 2 million to 100 million, with 'informed estimates' centring on 8-15 million. It is a scandal of modern science that we do not know within an order of magnitude how numerous and multiformed is this super-exceptional phenomenon. In physics we can measure the distance from the Earth to the Moon with an accuracy of half a centimetre. By comparison, the science of biodiversity is still in its Stone Age. Despite our grandscale indifference to species and their numbers, we benefit from the many environmental services they supply to us, and do it free.