lecture is about the connections
and the origins of disease.
My name is Mary Jane West-Eberhard,
and I work for the Smithsonian
Institute in Panama,
while living most of
the time in Costa Rica.
I confess that I am not
a medical researcher.
I am an evolutionary biologist.
My research is primarily field work
on the natural history and behavior
of tropical social wasps.
Observations on these exquisitely
conditioned sensitive organisms
led first to an interest in the
origin of workers and queens.
Which of these two forms, as
developed by an individual female,
is environmentally determined?
From studying these, I got
interested in developmental
plasticity in general.
Developmental plasticity is
simply the responsiveness
of the phenotype to new
inputs from the external
or the internal environment.
It's phenotypic change
without genetic change.
The word phenotype, of course,
refers to all traits of an organism
other than its genes.
This includes molecular
products of genes,
morphology, physiology, and
behavior, including learned traits.
It includes nervous tics,
remembered phone numbers, and spots
on the lung following
a bout with the flu.
That is, phenotypes can be
adaptive or pathological,
permanent or temporary, and
typical or atypical of a species.
plasticity is a broader
concept than phenotypic plasticity.
to the external environment.
to the internal environment.
This means that includes
sensitivity to things
like gene products within cells and
the action of hormones on tissues.
includes modularity of structure.
Have you ever wondered how it can be
that men and women with strikingly
different faces can
mate with each other,
and yet all the
different pieces somehow
fit together in their offspring
to make a coherent face?
This is because the
different pieces of the face
are semi-independently developed,
or modular, as shown in the side.
And there is accommodation among
adjacent bones other tissues.
So modularity is a kind of internal
plasticity during development.
Since my main field of research
is actually on the evolution
of insect social
behavior, I usually try
to avoid extrapolating to humans.
But I don't worry much
about this in the case
of developmental plasticity.
Because it's a universal
property of living things,
almost a defining property of life.