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The Biology of War. Darwinian Evolution. Evolution by natural selection rests on the following set of assumptions:. There are inheritable variations among the members of a population;. Darwinian Evolution.
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Darwinian Evolution Evolution by natural selection rests on the following set of assumptions: • There are inheritable variations among the members of a population;
Darwinian Evolution • 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 • Individuals with adaptive characteristics are more likely to be selected to reproduce by the environment;
Darwinian Evolution • Gradually, over long periods of time, a population can become well adapted to a particular environment click here for more on naked mole rats
Darwinian Evolution • 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 Freudunderstood 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 • Populations contain genetic variation that arises by random (ie., not adaptively directed) mutation and recombination; • Populations evolve by changes in gene frequency brought about by random genetic drift, gene flow, and especially natural selection
Neo Darwinism • Most adaptive genetic variants have individually slight phenotypic effects so that phenotypic changes are gradual; • Diversification comes by speciation, which normally entails the gradual evolution of reproductive isolation among populations
Neo-Darwinism • 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?