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11.
Evolutionary biology of the Devonian Brachiopoda of New York State: no correlation with rate of change of sea-level? 总被引:1,自引:0,他引:1
GEORGE R. McGHEE 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1992,25(2):165-172
McGhee, G. R., Jr. 1992 04 15: Evolutionary biology of the Devonian Brachiopoda of New York State: no correlation with rate of change of sea-level?Lethaia, Vol. 25, pp. 165–172. Oslo. ISSN 0024–1164. Previous study has revealed the surprising lack of a relationship between relative sea-level position and the evolutionary biology of the Brachiopoda during the Devonian. To further explore this seeming anomaly, the potential relationship between the rate of change of sea-level and the evolutionary biology of these sessile benthic organisms is analyzed here. Successive linear modeling reveals a lack of correlation between the rate of change of sea-level and either extinction rate, origination rate, or diversity of the Devonian brachiopods. *Sea-level, rate of sea-level change, extinction, origination, diversity, Brachiopoda. 相似文献
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SYNOPSIS. Cladistic analysis of mayflies suggests that dispersalwas very asymmetrical after the new land connection betweenNorth and South America. Twenty-one genera apparently movedfrom South to North and Central America, but there is good evidencefor only one North American genus moving into the south. Testablepredictions are possible once the boreal (Laurasian) or austral(Gondwanian) designations are made. For example, Paracloeodes,a genus of austral origin, was predicted to be found in SouthAmerica, and in North America in warm rivers north and eastof its known distribution. These predictions have been confirmed.Other characteristics of tropical mayflies, such as length oflarval period and emergence and mating patterns, may be usedto predict habitats and characteristics of present North Americangenera. Merger events and consequent dispersal of organismshave profound influences on distributional patterns, and fromsuch information, biologically useful generalities can be made. 相似文献
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A remark on the shape of the logistic distribution 总被引:3,自引:0,他引:3
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PAMELA B. SHARP GEORGE W. KEITT HAROLD H. CLUM Jr. ULRICH NÄF 《Physiologia plantarum》1975,34(2):101-105
Pure samples of the antheridiogen of Anemia phyllitidis (AAn) were tested for their ability to affect the growth of dwarf corn (d5) and lettuce seedlings, and to influence α-amylase production by barley half-seeds. Stimulation of dwarf corn growth and barley amylase production was, on a molar basis, from 1/2 to 1/250 that given by GA3. In lettuce, AAn had a synergistic effect with low levels of GA3; alone, AAn was inhibitory or ineffective. Therefore, in addition to having a close chemical resemblance to gibberellin, AAn induces similar, but not identical physiological responses in flowering plants as well as ferns. 相似文献
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THE interaction between the cell surface and the substratum is very important in determining several characteristics of cells growing in tissue culture. Transformed cells are less adherent to the substratum than untransformed cells1 and this reduced interaction with the substratum may be responsible for abnormal properties such as the loss of contact or density dependent inhibition of growth2 and the ability to form colonies in agar and to grow in suspension culture. 相似文献
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RITA COLÓN-URBAN PAUL J. CHEUNG GEORGE D. RUGGIERI ROSS F. NIGRELLI 《Invertebrate reproduction & development.》2013,57(4):245-252
Thirty-two pedunculate barnacles, O. a. geryonophila, were maintained in culture for a period of 2 yr in the laboratory. These barnacles were obtained from the pleopods and mouth parts of the giant marine isopod, Bathynomus giganteus, which had been collected, at a depth of 200 fathoms, in the Gulf of Mexico. The carina, scutum, mandible and maxilla of adult barnacles were typical of deep water species. However, the tergum and labrum were intermediate between those of shallow and deep water species. Adults 3.1–4.1 mm in length were cultured in sea water (15–19°C), and fed on benthic copepods such as Tisbe furcata and Laophonte sp. Three broods of nauplii from 8 barnacles were obtained in 2 yr. Larvae were reared on plankton collected from Coney Island waters in which nauplii reached Stage IV in 10–14 days at 16°C. Isochrysis galbana and Thalassiosira pseudonana individually or in combination maintained nauplii to Stage IV, but with very high mortality. The lack of spines on the carapace edge of the nauplii distinguishes this deep water species from the shallow water form, O. mulleri. 相似文献