共查询到20条相似文献,搜索用时 31 毫秒
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Moore CG 《Science (New York, N.Y.)》1987,236(4804):1006-1007
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Adams DB 《Science (New York, N.Y.)》1979,205(4411):1155-1158
Two North American fossil species of large felids, hitherto regarded as Late Cenozoic pumas (mountain lion), are in fact closely related to the living cheetah, Acinonyx, of Africa and Eurasia. A new subgenus (Miracinonyx) is proposed for the American species. Cheetahs and pumas may have had a common ancestor in the Miocene of North America. 相似文献
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Scheiber HN 《Science (New York, N.Y.)》1986,232(4753):1016-1018
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Blackburn RT 《Science (New York, N.Y.)》1986,234(4772):92-93
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Census data confirm that in the 1970's population grew more rapidly outside than inside metropolitan territory, reversing a historic pattern. The new data reveal that the dispersion of population growth beyond metropolitan areas was not so much a movement to small towns as a movement to the open countryside. The trends appear strong enough to suggest a new shift toward rural life-styles. 相似文献
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Morin NR 《Science (New York, N.Y.)》1987,235(4790):800b-801b
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Novacek MJ 《Science (New York, N.Y.)》1986,231(4741):1021-1022
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Fries JF 《Science (New York, N.Y.)》1984,224(4650):710-711
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Griffin JB 《Science (New York, N.Y.)》1967,156(3772):175-191
The initial occupation of Eastern North America was by small bands of people who gained their livelihood by hunting and gathering. As time passed, the occupants of different regions be came increasingly familiar with the available natural resources. The de velopment or introduction of new tools and devices enabled the people to ex ploit their environments more effective ly, until, by Late Archaic times, popu lation size had increased, in terms both of density within a given area and num ber of people in individual social units. The initial agricultural productivity aided the culmination of the long cul tural traditions in the remarkable pro ductions and practices of the Hope wellian complexes of Middle Woodland times. The major Hopewellian centers reflect the marked change in societal organization and patterns. The costumes of the dead and the manner of their burial clearly reflect individual status differentiations, while artistic creativity is probably to be equated with incipient specialization of labor. Many of the Mississippian societies reached an even more advanced plateau of cultural de velopment, with fortified towns, an or ganized priesthood, dominant hereditary chiefs, political and military alliances, and a well-developed class system. The details of the cultural develop ment in Eastern North America are unique, but the general trend may be regarded as a common one in human society, and the patterns of behavior, as analogous to those developed by other peoples in other areas of the Old World and the New. 相似文献
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Wise G 《Science (New York, N.Y.)》1989,244(4906):830-831
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