Diversity metrics use sampling to estimate the number of species present.
In this app, there is a sample landscape (World). A circle there represents an individual.
Different colors and sizes are from different species.
White squares on the world are sample areas. The number of species in a
square adds a point to the plot. If there are three samples of area 10
on the world display, there are three points stacked at Sample Area 10 on the plot.
Try different worlds and different metrics.
Hint: Select "Custom" world and try all 5 settings on "abundance".