The title of this lecture
is "Major Transitions
in the History of Life",
and I am Neil Blackstone at
Northern Illinois University.
When we think of the vast
sweep of geological time
and the massive changes
that life on Earth and Earth
itself have undergone,
it seems impossible
that anything about
the history of life
could exhibit a simple
Yet as remarkable as this may seem,
it may also be the case.
Indeed, the history of life consists
of a series of major transitions
in which lower-level
cooperatively banded together to
form higher-level biological units.
First groups of molecules, then
molecules within simple cells,
then simple cells
within complex cells,
complex cells within multicellular
organisms, and even in some cases,
In the process of these transitions,
life became increasingly complex.
While there is the simplicity
in the repeating pattern,
these major transitions themselves
were not necessarily simple.
In fact, they were
perhaps the greatest
achievements of organic evolution.
In each case, the major
obstacle impeding the transition
was evolutionary conflict.
As lower-level units band
together, conflicts arise.
Some units free ride using group
resources without contributing
their fair share.
These conflicts must be mediated
if a higher-level unit is to emerge.