Transcript The Biology of War

The Biology of War
Darwinian Evolution
Evolution by
natural selection
rests on the
following set of
assumptions:
1. There are inheritable
variations among the
members of a population;
Darwinian Evolution
2.
Many more individuals are
produced each generation than
can survive and reproduce. This
statement is based on Malthus'
observation
that
populations
can increase
geometrically (1-2-4-8-16) while
the food supply can increase only
arithmetically (1-2-3-4-5);
Darwinian Evolution
3.
Individuals with
adaptive
characteristics are
more likely to be
selected to
reproduce by the
environment;
Darwinian Evolution
4. Gradually, over long periods of
time, a population can become
well adapted to a particular
environment
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Darwinian Evolution
5. The end result of
organic evolution
is many different
species, each
adapted to specific
environments
Neo-Darwinism
• Although Gregor Mendel’s work with
genetics was published (in a relatively
obscure journal), Darwin was
unfamiliar with it or its implications
• Darwin had no explanation for the
transmission of these traits
•Beginning in the 1930s, a
synthesis between molecular
biology and Darwinian
evolution produced a theory
and mechanism for
transmission
Neo-Darwinism
• Likewise, Freud had no
underlying explanation for the
sources of the instincts and
drives he postulated
• Both Darwin and Freud
understood that there was a
biological basis, but
were unable
to identify that basis
Neo-Darwinism
• The modern synthesis of evolution is
based on the following ideas and makes
significant modification to Darwin’s view
in its understanding of the causes
contributing to evolution, to whit:
Neo-Darwinism
1.
Populations contain
genetic variation that
arises by random (ie.,
not adaptively
directed) mutation and
recombination;
2. Populations evolve by
changes in gene
frequency brought
about by random
genetic drift, gene flow,
and especially natural
selection
Neo Darwinism
3. Most adaptive genetic variants have
individually slight phenotypic effects
so that phenotypic changes are
gradual;
4. Diversification comes by speciation,
which normally entails the gradual
evolution of reproductive isolation
among populations
Neo-Darwinism
5. These processes, continued for
sufficiently long time periods, give
rise to changes of such great
magnitude as to warrant the
designation of higher taxonomic
levels (genera, families, etc.)
Human Evolution
• Human beings possess particular
species-specific psychological
dispositions
• These dispositions arose because in
ancestral populations selection favored
certain variants of each mechanism
over the available alternatives
•Genes for each
psychological disposition
became established in the
human gene pool
Human Evolution
• Note, this is not to say that we have
genes for specific behaviors (with the
exception of species-typical
movements)
• In other words, evolution has shaped
the basic psychological substrate of
the species
Freud
• So the underlying question is:
Does the human species have a
psychological predispostion for
violence and warfare?