Eocene, some 90 million years later. The
implication is that the highly sophisti-
cated social system of present-day insect
species was not enough in itself to result
in the success we see in these groups.
Without the fossil evidence, we could
easily and erroneously assume social
complexity was the single causal factor.
One of the great benefits of the way
that this book is written is that it follows
a path like that of a good class in insect
systematics. First it leads the reader
through sections on basic and broad con-
cepts that underlie scientists' under-
standing of insect evolution. Grimaldi
and Engel briefly lay out their ideas on
important issues such as homology,
species, and phylogeny reconstruction.
These areas of systematics remain steeped