There are many species on Earth. Many types of living beings we know, and many more than not.
At least we can deduce it from the last studies. Every year we discover new species on Earth of different types and in different regions. And, despite the fact that the methods of discovery have improved and that there are more and more groups of researchers dedicated to it, we are still very far from reality.
So far that, according to a new study of the biologists of the Indiana University published in Proceedings of the National Academy of Sciences, right now so we only know one thousandth of 1% of the existing species on our planet (about 10 million species or more on the entire planet Earth). Their data indicates that this, in comparative terms to reality, is hardly a drop of water from all the ocean that make up the different species on Earth.
There are more species on Earth than stars in the Milky Way
In other words, and according to these researchers, there will be around a billion different species on planet Earth, more than all the known stars in our galaxy, the Milky Way (which are around 100-400 billion).
Their estimation has taken into account data analyzes that have taken into account not only the best known biological complexity, the mammals, but also the microbial level. At our scale there is little biodiversity in comparison, but in the world of bacteria numbers can be exorbitant. Currently, with the data in hand, more than 5.6 million species are known on Earth, adding up both the large species and the microscopic world; according to data from 35,000 places on the planet (except Antarctica).
After analyzing all this maremagnum data, it was found that many previous estimates of biodiversity had underestimated the value of microorganisms, which have been studied in greater depth in recent years.
The problem of trying to count all species on Earth
Obviously try counting each and every species on Earth is a complicated and almost impossible task that requires applying different laws of biological scale. In addition, as we mentioned earlier, each year many new species are described and many others become extinct. Still, biologists at Indiana University have attempted to use all available data to develop a trend in species form and abundance, taking into account the number of individual organisms per species and using scales of biodiversity.
Their data augurs that it is possible that on Earth there are a billion microbial species, something striking if we consider that less than 10 million microorganisms have been identified today, and about 10,000 of these microorganisms have been cultivated in the laboratory; and another 100,000 still have not been classified by scientists. Imagine what it would cost to sort the (alleged) remaining 999 million missing species, according to your calculations.