The immediate manifestation of natural selection is nearly always at the individual level. But the long-term consequences of non-random individual death and reproductive success are manifested in the form of changing gene frequencies in the gene pool.
-- Richard Dowkins The Selfish Gene
This concept is key ingredient to think about genetic diversity and some philosophical problem of the definition of diverse.
*1:The main collection of Python library modules is installed in the directory prefix/lib/pythonX.Y while the platform independent header files (all except pyconfig.h) are stored in prefix/include/pythonX.Y, where X.Y is the version number of Python, for example 3.2.