154
THE BEST STRATEGY
DEPENDS ON WHAT
OTHERS ARE DOING
EVOLUTIONARILY STABLE STATE
T
he field of behavioral
ecology seeks to explain
how the behavior of
animals—what they eat, how they
socialize, and so on—has evolved
to suit their particular environment.
The driving force is natural selection
because the environment favors
individuals with certain genes—
some genes are “better” for certain
situations and not for others—
which are then passed on to
offspring. Because the behavior of
animals is influenced by genes,
behavior must be influenced by
natural selection as well.Adaptive behavior
In 1972, British evolutionary
biologist John Maynard Smith
introduced a theory known as the
evolutionarily stable strategy
(ESS), that helped explain how
behavioral strategies appear by
natural selection. Just as factors
such as food and temperature can
affect animals, so can the behavior
of other species. Maynard Smith
suggested that an ESS adapts to
the behavior of other animals, and
cannot be beaten by competing
strategies, thus giving animals the
best chance to pass on their genes.
He argued that only naturalIN CONTEXT
KEY FIGURE
John Maynard Smith
(1920 –2004)BEFORE
1944 Mathematician John von
Neumann and economist
Oskar Morgenstern use a
theory of games of strategy to
devise a mathematical theory
of economic and social
organization.1964 British biologist W.D.
Hamilton applies game theory
to the evolution of social
behavior in animals.1965 Hamilton uses game
theory to describe the
ecological consequences
of natural selection.1976 Richard Dawkins
popularizes the idea of
evolutionarily stable strategies.AFTER
1982 John Maynard Smith
applies the theory to evolution,
sexual biology, and life cycles.Animals come into
conflict with each other
over food, territory, and
mate selection.They have evolved to
react to the behavior of
other animals in certain
preprogrammed ways.The best strategy
depends on what
others are doing.US_154-155_Evolutionary_stable_state.indd 154 12/11/18 6:25 PM