- There are an estimated 4–6 x 10^30 prokaryotes on, below, and above planet earth and about an order of magnitude more viruses..
- There are an estimated 10^16 prokaryotes/tonne of soil. Compared to 10^11 stars in the milky way.
- 1 g of soil yields an average of 10^7 unique “species”. The number of cells in just 1 tsp. exceeds the entire current human population of the continent of Africa.
- More than 50% of the biomass of earth is prokaryotic even though prokaryotic cells are just 1/10 the diameter of eukaryotic cells (the cells of plants and animals), and 1/1000th the volume.
- In the oceans they make up more than 90% of the biomass and the number (~10^28) is about 100 million times more than the estimated number of stars in the universe.
*Facts borrowed (stolen) from a very good recent book, Philosophy of Microbiology. 2014. Maureen O’Malley. Cambridge University Press. Pgs. 3–5.