Good one. If anyone else is curious, analyses like these usually bring in multiple types of data together, but often rely primarily on cluster sampling. Botanis

Good one. If anyone else is curious, analyses like these usually bring in multiple types of data together, but often rely primarily on cluster sampling. Botanists will go to a specific plot of land and very thoroughly count the number of species (amongst many other metrics). These data points are abstracted (while taking into account factors like biome types of course) to obtain an distribution of expected species in different areas worldwide. We then take this figure and compare it with how many species we currently have documented Accounting for all the different factors is obviously much more complex than what I described, but that's the gist of it