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No Death Without Birth: The Implications of English Mortality in the Early Modern Period
Published in Roy Porter, Andrew Wear, Problems and Methods in the History of Medicine, 2018
It is obvious that for most of human history fertility and mortality must have been at closely similar levels. For the former to have fallen short of the latter consistently would have meant extinction, while the opposite case could not have long continued because of the impossibility of increasing food supplies other than very slowly.1 Man is a slow-breeding animal and, therefore, human mortality was always at a far lower level than in most other animals. There is no reason to suppose that crude birth rates in any large population consistently exceeded about 50 per 1000. Equally, there can be no reason to believe that crude death rates ever significantly exceeded this level. In individual years and in exceptional circumstances far higher death rates occurred, but even when such mortality surges occurred the usual situation must have been very different. This in turn implies that expectation of life at birth can seldom have been much less than 20 years at birth, and that where this was so, the gross reproduction rate was in the range 3.0–3.5. Those women who survived to the end of the child-bearing period bore about seven children on average.2
Mortality, Fertility, and the Status of Women in India, 1881-1931
Published in Tim Dyson, India's Historical Demography, 1989
The measure of fertility used is the gross reproduction rate (GRR), which is the number of female births per reproductive-age woman in the population. This measure is estimated by regression, in three sets, for each region and decade. These are the GRR estimates that are implied by each of the three sets of life tables, each having its own life expectancy and age structure effects. The estimated female GRRs are presented in Table 1 along with each life table. (Male GRRs were also estimated for each life table, but are not presented here. They were useful, as were the female GRRs, in the computation of the crisis life tables, for which the criterion of minimizing fertility results was employed.)
Introduction: History and cultural anthropology
Published in Angus McLaren, Reproductive Rituals, 2020
A population revolution did occur in England between 1750 and 1850, but until recently the great increase in numbers was attributed to a fall in the death rate, not to any surge in the birth rate. The argument ran that fertility was consistently high through the seventeenth and eighteenth centuries.31 A more recent account – E. A. Wrigley and R. S. Schofield’s The Population History of England, 1541–1871 – has overthrown the old interpretation and re-emphasized the role of fertility. Wrigley and Schofield found that in fact fertility fell in the seventeenth century from its sixteenth-century level. The gross reproduction rate in the 1500s of 2.8 declined to 1.9 by 1650, swung back to 2.3 in 1756 and only climbed to 3.06 in 1816. As a result, England’s population of 5.058 million in 1701 was actually smaller than the 5.092 million of 1641. It was between 1741 and 1801 when the old constraints on fertility were loosened that the population surged from 5.576 to 8.664 million. Wrigley and Schofield attribute these eighteenth-century gains in fertility primarily to a reduction in the age of marriage.32 Wrigley argued in an earlier article, however, that when explaining ultimate family size the employment or non-employment of birth control techniques had also to be taken into account. David Levine, Keith Wrightson and Daniel Scott Smith have advanced evidence which indicates that age of marriage was not the sole regulator of fertility.33 M. W. Flinn has likewise argued that detailed research into the demographic statistics of seventeenth- and eighteenth-century England reveals a significant drop in the age of the mother at the time of the birth of her last child – a positive sign of the employment of fertility-controlling strategies.34 In short, quantifiers now agree that fertility was variable in early modern England and not wholly biologically determined.
Impact of temperature and prey type on biology and life-table parameters of Cheyletus malaccensis Oudemans (Acari: Cheyletidae)
Published in Egyptian Journal of Basic and Applied Sciences, 2022
Ashraf S. Elhalawany, Hosnia A. Afifi, Eman L. Ayad
The maximum intrinsic rate of natural increase (rm) when the difference between birth rate and death rate was obtained at 27°C when fed on T. putrescentiae was (0.256 individuals/♀/day) followed by (0.233 individuals/♀/day) when fed on A. siro at 32°C, whereas the lowest (0.090 individuals/♀/day) was recorded when fed on C. berlesei at 22°C. The finite rate of increase (λ) ranged from 1.09 offspring/individual/day at 22°C when fed on C. berlesei to 1.29 offspring/individual/day at 27°C when fed on T. putrescentiae. Gross reproduction rate (GRR) recorded the highest value (117.4 eggs/ female/generation) when fed on A. siro at 32°C, the lowest value (43.82 eggs/ female/generation) when fed on C. berlesei at 22°C Table 6.