首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到17条相似文献,搜索用时 15 毫秒
1.
S. George Pemberton 《Ichnos》2013,20(4):264-270
In the early nineteenth century, the discovery of trace fossils fired the imagination of the discoverers and inspired them to compose unique poems. John Joly of Ireland wrote a poem about the invertebrate trace fossil Oldhamia that had been discovered in rocks around Bray Head. In the United States, the Reverend Edward Hitchcock discovered what he felt were giant bird tracks that later turned out to be reptile tracks. The traces inspired Hitchcock, who published a poem “The Sandstone Bird” in The Knickerbocker magazine under the pseudonym Poetaster. The poem is about a sorceress bringing the great sandstone bird back to life and probably represents the first ichnological poem.  相似文献   

2.
S. George Pemberton 《Ichnos》2013,20(4):246-263
William Buckland not only was an eccentric scientist liked by virtually all his peers, but in the early 1800s he was also one of the foremost authorities on geology. Buckland's vivid sense of humor and the fact that he enjoyed working on rather strange subjects, such as coprolites, rain drop impressions, cave paleontology, and fossil footsteps, provoked a great deal of light-hearted jesting from both his friends and his students. A collection of humorous poems and caricatures were produced to pay homage to the “Geologic Wizard.” Among these fugitive poets and artists were Buckland's good friends Phillip Duncan, Philip Shuttleworth, Henry De la Beche, Richard Whately, William Conybeare, and Thomas Sopwith. Buckland was still the subject of humorous verse well into the 1950s by the contemporary South African poet William Plomer.  相似文献   

3.
Historically labor has been central to humaninteractions with the environment, yetenvironmentalists pay it scant attention. Indeed, they have been critical of those whoforeground labor in their politics, socialistsin particular. However, environmentalists havefound the nineteenth-century socialist WilliamMorris appealing despite the fact that he wroteextensively on labor. This paper considers theplace of labor in the relationship betweenhumanity and the natural world in the work ofMorris and two of his contemporaries, theeminent scientist Thomas Henry Huxley, and theFabian socialist Herbert George Wells. Isuggest that Morris's conception of labor hasmuch to recommend it to environmentalists whoare also interested in issues of socialjustice.  相似文献   

4.
5.
6.
7.
8.
9.
Human tracks discovered in 1874 at a site named El Cauce or Acahualinca near the shores of Lake Managua, Nicaragua, are the most famous and abundant human tracks in the Americas. They represent a landmark ichnological discovery during the late 19th century that generated much debate regarding their age and origins. Reported dates for the tracks range from 2,120 to 6,500 B.P. The site, which is now situated within the limits of Nicaragua's capital city of Managua, forms the basis of the Acahualinca Tracks Museum (Huellas de Acahualinca) and has been in place since 1953. However, it is still little known and has not been systematically studied, despite being an important window into Meso-American prehistory. Two exposures of a surface of volcanic ash reveal hundreds of human tracks comprising a minimum of 12 clearly defined trackways, and a trampled zone or path representing at least three more individuals, all heading in the same northwesterly direction. Tracks of deer, opossum and at least one bird are also present. Bison tracks collected from another nearby site (El Recreo) that is no longer accessible are on display at the museum. The Acahualinca tracks are noteworthy for the exceptional quality of preservation. We herein present the first maps of the two exposures, which combine to tell a story of human and animal activity along the shores of ancient Lake Managua several thousand years ago.  相似文献   

10.
11.
12.
13.
14.
Abstract The Florida Museum of Natural History's McGuire Center for Lepidoptera and Biodiversity, on the University of Florida campus in Gainesville, Florida, has become one of the world's largest institutions for research on butterflies and moths, and an important research facility for insect science. The facility was constructed by combining the staff and merging the Lepidoptera holdings from the Allyn Museum of Entomology, the Florida State Collection of Arthropods and other University of Florida collections, and now includes over ten million specimens from all over the world, rivaling some of the largest Lepidoptera research collections globally. The facility includes a team of domestic and international researchers studying many areas of lepidopterology, including behavior, biodiversity, biogeography, ecology, genomics, physiology, systematics and taxonomy. In this paper, we introduce the McGuire Center, its staff, and the many research activities for researchers across entomological disciplines.  相似文献   

15.
William Bateson (1861–1926) has long occupied a controversial role in the history of biology at the turn of the twentieth century. For the most part, Bateson has been situated as the British translator of Mendel or as the outspoken antagonist of W.␣F. R. Weldon and Karl Pearson’s biometrics program. Less has been made of Bateson’s transition from embryologist to advocate for discontinuous variation, and the precise role of British and American influences in that transition, in the years leading up to the publication of his massive Materials for the Study of Variation (1894). In this paper, I first attempt to trace Bateson’s development in his early career before turning to search for the development of the moniker “anti-Darwinist” that has been attached to Bateson in well-known histories of the neo-Darwinian Synthesis.  相似文献   

16.
Two forces are in general, hypothesized to have influenced the origin of the organization of the genetic code: the physicochemical properties of amino acids and their biosynthetic relationships. In view of this, we have considered a model incorporating these two forces. In particular, we have studied the optimization level of the physicochemical properties of amino acids in the set of amino acid permutation codes that respects the biosynthetic relationships between amino acids. Where the properties of amino acids are represented by polarity and molecular volume we obtain indetermination percentages in the organization of the genetic code of approximately 40%. This indicates that the contingent factor played a significant role in structuring the genetic code. Furthermore, this result is in agreement with the genetic code coevolution hypothesis, which attributes a merely ancillary role to the properties of amino acids while it suggests that it was their biosynthetic relationships that organized the code. Furthermore, this result does not favor the stereochemical models proposed to explain the origin of the genetic code. On the other hand, where the properties of amino acids are represented by polarity alone, we obtain an indetermination percentage of at least 21.5%. This might suggest that the polarity distances played an important role and would therefore provide evidence in favor of the physicochemical hypothesis of genetic code origin. Although, overall, the analysis might have given stronger support to the latter hypothesis, this did not actually occur. The results are therefore discussed in the context of the different theories proposed to explain the origin of the genetic code. Received: 10 September 1996 / Accepted: 3 March 1997  相似文献   

17.
The pairs of nitrogen fixation genes nifDK and nifEN encode for the α and β subunits of nitrogenase and for the two subunits of the NifNE protein complex, involved in the biosynthesis of the FeMo cofactor, respectively. Comparative analysis of the amino acid sequences of the four NifD, NifK, NifE, and NifN in several archaeal and bacterial diazotrophs showed extensive sequence similarity between them, suggesting that their encoding genes constitute a novel paralogous gene family. We propose a two-step model to reconstruct the possible evolutionary history of the four genes. Accordingly, an ancestor gene gave rise, by an in-tandem paralogous duplication event followed by divergence, to an ancestral bicistronic operon; the latter, in turn, underwent a paralogous operon duplication event followed by evolutionary divergence leading to the ancestors of the present-day nifDK and nifEN operons. Both these paralogous duplication events very likely predated the appearance of the last universal common ancestor. The possible role of the ancestral gene and operon in nitrogen fixation is also discussed. Received: 21 June 1999 / Accepted: 1 March 2000  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号