This is a follow up to Mammal Body Size 1.
Looking at the average mass of extinct and extant species overall is useful, but
there are lots of different processes that could cause size-biased extinctions
so it’s not as informative as we might like. However, if we see the exact same
pattern on each of the different continents that might really tell us
something. Repeat the analysis in
Mammal Body Size 1, but this time compare the
mean masses within each of the different continents. Export your results to a
csv file where the first entry on each line is the continent, the second entry
is the average mass of the extant species on that continent, the third entry is
the average mass of the extinct species on that continent, and the forth entry
is the difference between the average extant and average extinct masses. Call
the file continent_mass_differences.csv. If you notice anything
strange think about what’s going on and present the final data in the way that
makes the most sense to you.