> I've read arguments that evoltution has no direction, does not result in
> increased complexity. Surely muli celled organisms are more complex than
> single celled organisms. In mammals, evolution seems to have resulted in
an
> increasingly complex central nervous system, culminating in the complexity
> of human consciousness.
In chemistry and biology, "complexity" is often expressed in terms of
structural organization. Enzymes are more complex than amino acids because
enzymes are made of amino acids that then create a three-dimensional object
that possesses catalytic power. A reaction pathway is more complex than an
enzyme because it is made of several enzymes that use the product of one as
their own substrate then pass their own product on to another that uses it as
a substrate. A metabolic system is more complex than a single pathway
because several pathways interconnect to form an integrated, cooperative
network. Eukaryotes are more complex than prokaryotes because eukaryotes
have internal compartmentalization and organize their DNA into compact
structures. Multicellular organisms are more complex than unicellular
organisms because the conjoined cells must communicate with each other in an
integrated fashion to function as a unit. And so on. Yet despite
appearances, it is difficult to justify the claim that increased structural
organization represents progress. Sometimes the simpler approach is more
efficient, more beneficial. Increased structural organization does make for
greater diversity and greater versitility, which an organism needs if it is
to survive competition or environmental challenges. However, simply having a
complex structure with a larger number of units is not in and of itself
progress.
Kevin L. O'Brien