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1.
Human evolution began in East Africa four million years ago, with a transition from an arboreal state to a more terrestrial
one. This evolution seems to be correlated with a large environmental change in East Africa around 2.5 m.y. due to a major
climatic change leading to drier and cooler conditions.
Cenogram analysis (a graphical representation of community structure) can be used to reconstruct the vegetation cover at a
regional scale, and to infer the changing climatic conditions. Using cenogram sequences of different sites along the Rift
Valley, we were able to determine the regional ecological context in which mammals and hominids have evolved in East Africa
during the last 3 million years.
Between 3.5 and 2 m.y., during a general climatic change, successive faunas of South Tanzania reflect the progressive opening
of their environment. In contrast around Lake Turkana a mosaic of isolated dry and wet habitats were present throughout this
period. At this time, the Rift seems to have been spatially structured in several basins isolated from one other, and isolated
faunas experienced separate speciation events (particularly with the appearance ofHomo genus).
After 2 m.y., the disappearance of the isolating barriers on one hand, and a regional increase in aridity, on the other hand,
led to more homogenous faunas arising throughout the region. Replacements of mammal species occurred (especiallyHomo erectus replacingHomo habilis) and several others mammal species, including australopithecines, disappeared during this same period. 相似文献
2.
中国北方黄土地层中的哺乳动物群及在磁性地层中的位置 总被引:4,自引:0,他引:4
本文研究了中国黄土地层中有确切层位的哺乳动物化石记录,并进行了生物地层学与磁性地层学对比,将黄土地层中的动物化石归纳成如下哺乳动物群:早更新世(2.50─0.73Ma):午城动物群(2.50─1.20Ma)、公王岭动物群(1.20─1.10Ma)和阳郭动物群(1.10─0.90Ma)、中更新世(0.73─0.13Ma):陈家窝子动物群(0.73─0.40Ma);晚更新世(0.13─0.01Ma):柔远─靖远动物群(0.13─0.01Ma);全新世(0.01Ma─Rec):半坡动物群。结果表明:早更新世许多森林习性的化石动物虽然反映出气候较第三纪的寒冷,但比后期温暖湿润。中更新世出现了较多的草原、干旱草原习性的动物,气候更为寒冷干旱,森林逐渐减少或消失,草原或干旱草原得到发展;晚更新世出现的沙鼠、跳鼠等动物,表明气候更加寒冷、干旱,部分地区甚至沙化。 相似文献
3.
John T. Huber 《ZooKeys》2013,(345):47-72
The monotypic genus Mymarilla Westwood is known only from St. Helena, a remote island in the South Atlantic Ocean. The peculiar species M. wollastoni Westwood (Mymaridae) is redescribed and illustrated from non-type material. Mymarilla is compared with Cremnomymar Ogloblinspp. from the Juan Fernández Islands in the South Pacific Ocean. Stephanodes Enock is shown to be the most likely sister genus to Mymarilla. Nesopolynema Ogloblin, syn. n., Oncomymar Ogloblin, syn. n., Scolopsopteron Ogloblin, syn. n., are placed in synonymy under Cremnomymar and their species transferred as Cremnomymar caudatum (Ogloblin 1952), comb. n., C. dipteron (Ogloblin 1957), comb. n., and C. kuscheli (Ogloblin 1952), comb. n. Wing shape and wing reductions in Mymaridae are discussed in relation to biogeography, particularly with respect island faunas and to four genera, Cremnomymar, Mymarilla, Parapolynema Fidalgo, and Richteria Girault, some or all of whose species have more or less convex fore wings. 相似文献
4.
Armand Salvador Mijares Florent Détroit Rainer Grün Maxime Aubert Nida Cuevas Eusebio Dizon 《Journal of human evolution》2010,59(1):123-132
Documentation of early human migrations through Island Southeast Asia and Wallacea en route to Australia has always been problematic due to a lack of well-dated human skeletal remains. The best known modern humans are from Niah Cave in Borneo (40-42 ka), and from Tabon Cave on the island of Palawan, southwest Philippines (47 ± 11 ka). The discovery of Homo floresiensis on the island of Flores in eastern Indonesia has also highlighted the possibilities of identifying new hominin species on islands in the region. Here, we report the discovery of a human third metatarsal from Callao Cave in northern Luzon. Direct dating of the specimen using U-series ablation has provided a minimum age estimate of 66.7 ± 1 ka, making it the oldest known human fossil in the Philippines. Its morphological features, as well as size and shape characteristics, indicate that the Callao metatarsal definitely belongs to the genus Homo. Morphometric analysis of the Callao metatarsal indicates that it has a gracile structure, close to that observed in other small-bodied Homo sapiens. Interestingly, the Callao metatarsal also falls within the morphological and size ranges of Homo habilis and H. floresiensis. Identifying whether the metatarsal represents the earliest record of H. sapiens so far recorded anywhere east of Wallace’s Line requires further archaeological research, but its presence on the isolated island of Luzon over 65,000 years ago further demonstrates the abilities of humans to make open ocean crossings in the Late Pleistocene. 相似文献
5.
The research of the spider fauna of Slovenia dates back to the very beginning of binomial nomenclature, and has gone through more and less prolific phases with authors concentrating on taxonomy, faunistics, ecology and zoogeographic reviews. Although the body of published works is remarkable for a small nation, the faunistic data has remained too scattered for a thorough understanding of regional biotic diversity, for comparative and ecological research, and for informed conservation purposes. A national checklist is long overdue. Here, a critical review of all published records in any language is provided. The species list currently comprises 738 species, is published online at http://www.bioportal.si/katalog/araneae.php under the title Araneae Sloveniae, and will be updated in due course. This tool will fill the void in cataloguing regional spider faunas and will facilitate further araneological research in central and southern Europe. 相似文献
6.
R.D.E. MacPhee 《Journal of Biogeography》2005,32(4):551-564
Aim Through analysis of fossil records, the aim of this paper is to show that fossil representatives of at least three land‐mammal clades (pitheciine atelid primates, heteropsomyine echimyid rodents, and megalonychid phyllophagan xenarthrans) that once lived in the Greater Antilles are as old as, if not older than, ‘first’ occurrences of these same groups on the South American mainland. Location Greater Antilles, South America, Antarctic Peninsula. Methods Analysis of Cenozoic land‐mammal fossil records for the three areas. Results Comparison reveals an interesting similarity to the Tertiary vertebrate palaeontological record for the Antarctic Peninsula (Seymour Island), in the sense that the latter also includes early (Eocene) representatives of some typical ‘South American’ groups (e.g. meridiungulates, sloths, certain marsupial groups). Conclusions Given how limited the Antillean and Antarctic records are in quantity and quality, it seems unlikely that these ‘first’ appearances have much bearing on real origins (basal divergences). Rather, it suggests that the fossil basis for interpreting the origin and earliest diversification of ‘South American’ clades during the latest Cretaceous/early Cenozoic is probably even scantier than generally realized. In particular, the Antillean record strengthens arguments that some crown‐group continental lineages are considerably older than fossil evidence currently allows – a point increasingly (if unevenly) supported by molecular studies of many of the same clades. 相似文献
7.
We give a list of Cirripedia from Madeira Island and nearby deep water, based on specimens in the collection of the Museu Municipal do Funchal (História Natural) (MMF), records mentioned in the literature, and recent collections. Tesseropora atlantica Newman and Ross, 1976 is recorded from Madeira for the first time. The Megabalanus of Madeira is M. azoricus. There are 20 genera containing 27 species, of which 22 occur in depths less than 200 m. Of these shallow water species, eight are wide-ranging oceanic forms that attach to other organisms or to floating objects, leaving just 13 truly benthic shallow water barnacles. This low diversity is probably a consequence of the distance from the continental coasts and the small area of the available habitat. No endemic species have been found. 相似文献
8.
David H. Eccles 《Biological journal of the Linnean Society. Linnean Society of London》1986,29(2):115-122
Both Lake Malawi and Lake Victoria have many species of offshore demersal cichlids, most of which are stenotopic. In Lake Tanganyika there are fewer, more eurytopic, demersal species. These differences may be the effect of the physical regimes of the lakes. In Lake Victoria there is no permanent anoxic layer. In both the other lakes, water below 250 m depth is permanently anoxic and the seasonal cycle is dominated by upwelling. In Lake Malawi this is mainly derived from intermediate water containing free oxygen. In Lake Tanganyika upwelling involves hypolimnetic water, which may rise to within 80 m of the surface, causing great short-term changes in oxygen concentration over the depth range 50–250 m. This has inhibited the development of deep water species restricted to narrow depth ranges. 相似文献
9.
《Geobios》2016,49(6):423-431
Recent works on feeding habits of ungulates, isotopic composition of equid tooth enamel, and phytoliths from late Miocene localities of northern Greece suggested the presence of savannah and excluded dense forests. Furthermore, Mediterranean-like climates were advocated for the late Miocene of Greece. Here, I compare palaeoenvironments inferred for two mammal localities from Chalkidiki and the Axios Valley (Nikiti, upper Vallesian and lower Turolian; Dytiko, upper Turolian) with evidence from contemporaneous plant assemblages from adjacent areas in Greece and Bulgaria. I use vegetation units inferred from pollen and spore, fruit and seed, and leaf assemblages and compare them with the vegetation inferred from mammal and phytolith data. Open vegetation as inferred from mammal and phytolith data is also part of the range of vegetation units discovered from the pollen and spore, seed and fruit, and leaf record (here called the palaeobotanical record). Poaceae are consistently present in late Vallesian to late Turolian pollen records of northern Greece. Further, a number of vegetation units are indicative of forest vegetation ranging from lowland to upland forests dominated by woody angiosperms and mixed coniferous-angiosperm forests. The presence of such forests is not in conflict with the results from mammal and phytolith studies, but it broadens the view on landscapes present in the late Miocene of northern Greece. In addition to a generalized vegetation type commonly inferred by mammal studies, the palaeobotanical record demonstrates the presence of various complementary vegetation types. A comprehensive view on late Miocene landscapes in northern Greece shows that there is no conflict in inferring open herb dominated landscapes and light to dense forests and provides new opportunities for the ecological interpretation of late Miocene ungulates. 相似文献
10.