The central claim of the theory of evolution
as laid out in 1859 by Charles
Darwin in The Origin of Species is
that living species, despite their diversity in
form and way of life, are the products of
descent (with modification) from common
ancestors. To communicate this idea,
Darwin developed the metaphor of the
“tree of life.” In this comparison, living
species trace backward in time to common
ancestors in the same way that separate
twigs on a tree trace back to the same major
branches. Coincident with improved methods
for uncovering evolutionary
relationships, evolutionary trees,
or phylogenies, have become an
essential element of modern biology
(1).