1.3.2 Understanding the present
If we were to take a perspective to the biology of modern
humans that neglects evolutionary history, what might we
predict about the genetic diversity of our species, the
significance of our phenotypic differences and the prevalence
of disease-causing mutations?
First, we would be struck by the huge numbers of
humans, especially when compared to other animals of
similar body size. We might reasonably think that this should
be mirrored by a correspondingly greater genetic diversity.
Second, we might be struck by the clustered distribution of
phenotypic diversity among modern human groups and
might expect this to be matched by a similar structuring of
genetic diversity. Third, we might expect that diseasecausing
mutations would be specific to different continental
groups, in a similar manner to some of their easily observable
‘normal’ phenotypes. As we shall see in this book, all of these
conclusions would be wrong.
To understand why this is so, we must comprehend that
the past is not simply something that happened, and is
packaged up and studied for its own sake, but is more
properly considered as the source of the present. The present
should only be seen as another small step in shaping this past.
If we are to improve our present circumstances, we must take
account of how that present has come to be. An evolutionary
perspective does not just answer the question ‘What
happened in the past?’ but also the question ‘Why is the
present like it is?’.
Once we understand that the obvious differences between
peoples’ appearances can be unreliable indicators of
biological origins, we start to appreciate the other factors that
have shaped and continue to shape human biology. The
interaction of humans and their environments comes to the
fore, as does an understanding of human adaptability in the
face of huge variability in inhabited environments