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GENETIC FITNESS IN A COLONIZING HUMAN POPULATION
D. F. ROBERTS
Vol. 40, No. 4 (December, 1968), pp. 494-507
Published by: Wayne State University Press
Stable URL: http://www.jstor.org/stable/41448931
Page Count: 14
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From the data on individual fertilities, mortality and survival that are available for the population of Tristan da Cunha since its foundation, it is possible to calculate genetic fitness, as measured by the intrinsic rate of natural increase, and examine its secular variation. The intrinsic rate of increase was calculated for each sex separately by birth date cohorts from the founders to the last decadal group for which fertility is complete. The results are compared with those for other populations. The fitness of the founders was remarkably high. There has been a general secular diminution due to changed patterns of fertility and reproduction. On two critical occasions during the population's history the intrinsic rates of increase declined to a negative level, illustrating the precarious demographic situation of this particular colonizing group. Reasons for the secular variations in the intrinsic rate of increase are discussed.
Human Biology © 1968 Wayne State University Press