Abstract:
For most of their historical development as distinct fields of biology,
population ecology and population genetics have remained largely separate
(Kingsland 1995, Mueller 1997), even though they have had obvious overlaps as
reflected in Fisher’s (Fisher 1930) equation of the Malthusian parameter of population
growth with Darwinian fitness (henceforth, fitness). The two major areas where
theory in population genetics and population ecology has meaningfully intersected are
the dynamics of age-structured populations (Fisher 1930, Hamilton 1966,
Charlesworth 1970, 1994, Charlesworth & Williamson 1975, Charlesworth and
Hughes 1996) and density-dependent selection (MacArthur 1962, MacArthur &
Wilson 1967, Gadgil & Bossert 1970, Roughgarden 1971, Clarke 1972, Asmussen
1983, Anderson & Arnold 1983). The latter is especially significant, as selection at
high densities is essentially selection for increased competitive ability (Joshi et al
2001), and competition is an important factor shaping not just evolution but also
population dynamics and stability, and community structure, as well as affecting the
ecological and evolutionary outcomes of other species interactions (Arthur 1982, Case
1999, Dey et al 2012). Indeed, competition between organisms was an important
component of Darwin’s conception of the ‘struggle for existence’ (Darwin 1859).
