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The German paleontologist H. G. Bronn is best remembered for his 1860 translation and critique of Darwin’s Origin of Species, and for supposedly twisting Darwinian evolution into conformity with German idealistic morphology. This analysis of Bronn’s writings shows, however, that far from being mired in an outmoded idealism that confined organic change to predetermined developmental pathways, Bronn had worked throughout the 1840s and 1850s on a new, historical approach to life. He had been moving from the study of plant and animal forms in the abstract towards placing them into geological and biogeographical context, analyzing patterns of progress and adaptation, explaining species diversity and individual variation, and applying biological insights to practical problems such as artificial breeding. Even though Bronn never fully accepted the idea of species transformation, he saw Darwin’s theory as a bold new move toward his own goal of establishing a comprehensive, historical science of life, and he presented it as such in his translation and commentary. Thus Darwin’s ideas gained a quick and generally favorable hearing in Germany not because of their easy assimilability into an older tradition, but because of their appeal to the innovative Bronn.  相似文献   

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M. T. Ali 《Hydrobiologia》1984,110(1):305-314
Developing lake conditions in Lake Nubia were found to offer good commercial fisheries potential. This prospect initiated fishery research since 1967.In this study, 26 fish species belonging to 10 families were recorded. Compared with previous studies the total number has decreased and some of the species that were commercially important during the early years of the lake formation, are now negligible in occurrence (Distichodus, Citharinus, Bagrus). The species widely distributed in the lake are Labeo niloticus, Lates niloticus, Sarotherodon niloticus, Hydrocynus forskallii, Alestes baremose and Eutropius niloticus. Their highest production occurs during two periods: February to May and July to September. The dominant fish species feed on different items in a balanced equilibrium with the ecological and biological conditions.  相似文献   

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Morphometric analysis of compact femoral tissue was applied to a prehistoric population from Sudanese Nubia. Microradiographs of thin sections from below the lesser trochanter were examined. A total of 74 adults (40 females, 34 males) from the X-Group population (A.D. 350–550) were used to determine the underlying processes of bone remodeling in skeletal growth and maintenance. The relationship of bone turnover to the age of onset, patterning and frequency of cortical bone loss (osteoporosis) as a function of age and sex was examined. The cortical thickness, cortical area and formation/resorption frequencies were determined. Males exhibit a 4.9% net loss in cortical area, while females show a 10.7% loss. A substantial amount of female loss occurs in the third decade, with a slight gain in the fourth and a steady loss up to the sixth decade. These trends were further explored and refined histologically. The periosteal and endosteal frequencies for males show a variable but definite decrease in mineralization (i.e., increased numbers of osteons in the forming stage) and a slight increase in resorption. Third decade females show a marked difference with high frequencies of resorption spaces and forming osteons. It is suggested that in this population, stress related to childbearing and childrearing may be effecting the frequencies of formation foci and resorption spaces.  相似文献   

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