Connecting Global Priorities Biodiversity and Human Health

Mushroom Spring in Yosemite National Park. In this sulphurous hot spring was discovered Thermus
aquaticus, the source of Taq polymerase, which serves as the essential cog in the polymerase chain reaction,
arguably the single most important method used in genetic research.
JIM PEACO / US NATIONAL PARK SERVICE
to infections (Petersen and Round 2014). The
microbiome may also shape mood and behaviour
(see also the chapter on microbial biodiversity
and noncommunicable diseases in this volume).
The influence of microorganisms on the larger
life forms they cohabit is not terribly surprising,
given the history of life on earth. Several billion
years elapsed between the appearance of the first
single-celled creatures and multicellular life, and
single-celled creatures appear to have enmeshed
themselves with all their multicellular successors.
4. Future challenges: implications
of biodiversity loss for medical
discovery
In this time of technological advancement,
when the precision of measurement comes at
increasingly diminutive scales such as nanoseconds
or nanometers, and we begin to explore the most
minute forms of life on earth, we have at best a
first approximation of the numbers of organisms
we share the planet with (May 1988; Mora et al.
2011; Costello et al. 2013). About 2 million of an
estimated 10 million species on earth have been
given scientific names (Wilson 2003). For many
of these, we know little more than their names as
they are known from only a single encounter in
which an explorer observed a creature never before
seen. Most of life’s diversity, however, cannot be
seen by the naked eye, and of these microscopic
creatures, we know far less.
Even with this limited view of the life we share
the planet with, we know that each year the
variety of organisms on earth continues to decline
(CBD 2014). Recent scientific estimates indicate
that species are disappearing up to 1000 times
faster than occurred before humanity populated
the planet (CBD 2010). Such statistics are often
difficult for many people to grasp, especially as
most loss of biodiversity goes unnoticed. While
each of us may in our own lifetimes recognize that
one, or even a few, species that were once common
in a place we know have disappeared, far more
often species vanish without notice.
168 Connecting Global Priorities: Biodiversity and Human Health