共查询到20条相似文献，搜索用时 406 毫秒
1.
[目的]探讨建立掌骨和跖骨的残缺标本推断掌骨和跖骨整体指标的回归方程。[方法]选用成年太行山猕猴35例（掌骨13例,跖骨22例）,按测量最大长度的方法进行测量,将所得数据用SPSS13.0软件进行相关和回归分析。[结果]建立了掌骨和跖骨整体指标的一元线性回归方程10个,对方程检验有统计学意义。[结论]所得的回归方程可用于利用掌骨和跖骨的残损标本对其整体主要指标的推断,为掌骨和跖骨的复原提供了依据,为进一步对灵长类掌骨和跖骨的研究提供方便,为灵长类的基础研究积累资料。 相似文献
2.
CHURCHER CS 《Science (New York, N.Y.)》1959,130(3375):564-565
New fossil material has been obtained from La Brea, Peru. Included in this material are remains of a large wolflike canid which could not be referred to any living or fossil South American canine genus. Comparison with fossil canids from Rancho La Brea, Calif., shows that it closely resembles Canis (Aenocyon) dirus Leidy. 相似文献
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The cell walls of sieve elements in the primary phloem of the Carboniferous fern Tubicaulis contain structural features that morphologically resemble cellulose microfibrils in extant plants. This may be the oldest example of distinct fibrillar structures in the fossil record. The possible identity and significance of these features are discussed and their structure is compared with that of cell walls in other fossil and extant plants. 相似文献
5.
林麝前肢骨骼解剖 总被引：2，自引：0，他引：2
袁朝富 《四川农业大学学报》1995,13(3):374-376
运用大体解剖学方法对三头林麝前肢骨骼进行了研究，并与牛、羊和鹿类的前肢骨骼进行了比较。林麝前肢骨骼的主要特征是：肩胛骨短而宽、肩胛冈特别长，肩峰呈锐角，其末端与肩臼位于同一平面；肱骨近端外侧结节的前部特别发达；前臂骨明显向前弯，只有一个前臂骨间隙，尺骨体呈薄板状；第3和第4掌骨发达，第2和第5掌骨保留远侧部；第3和第4指发达，冠骨和蹄骨较长；第2和第5指较小，每指各有3个指节骨和2个近籽骨。 相似文献
6.
广东地质发展简史及植物区系溯源 总被引：2，自引：0，他引：2
广东植物区系的发展由来已久，现代的广东植物是晚白垩世或早第三世的孑遗物，地层中存在磊量的古植物化石。如本内苏铁，银杏，苏铁等极为丰富，种子特别是大羽羊齿尤为突出，而且在白垩纪晚期至第三纪的广东地层中，存在着丰富的现代植物的化石或化石孢粉组合，如朴树，桦木、鹅耳枥及松、冷杉、雪松等，还有其它阔叶树和针叶树，所有这些都与广东复杂的地质发展史密切相关，它预示着广东植物区系可能起源于亚带山地，而且广东无颖 相似文献
7.
Weyl PK 《Science (New York, N.Y.)》1978,202(4367):475-481
The interpretation of micropaleontological data based on the fossil remains of planktonic organisms requires an appropriate reference frame. The environmental changes that the plankton experience are a combination of geographic and seasonal factors, correlated by the average drift trajectories. Appropriate methods have been developed to study two drifts in the North Atlantic, one form the west-central Sargasso Sea to the Norwegian Sea and another around the subtropical Sargasso Gyre. The data on planktonic foraminifera from core tops can be used to relate the relative species distribution to the characteristics of the present sea surface. At any one location, the fossil assembly results from a superposition of plankton that have had varied time-temperature histories. To interpret the climatic and geologic history from downcore data will require an iterative technique. One assumes a surface climatology, determines the fossil record this would produce, and then compares this inference with available core data. The climatological assumptions are then modified until a satisfactory agreement is reached. 相似文献
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Some molecular clock estimates of divergence times of taxonomic groups undergoing evolutionary radiation are much older than the groups' first observed fossil record. Mathematical models of branching evolution are used to estimate the maximal rate of fossil preservation consistent with a postulated missing history, given the sum of species durations implied by early origins under a range of species origination and extinction rates. The plausibility of postulated divergence times depends on origination, extinction, and preservation rates estimated from the fossil record. For eutherian mammals, this approach suggests that it is unlikely that many modern orders arose much earlier than their oldest fossil records. 相似文献
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以生态足迹模型为基础,通过分析森林和草原生态系统在碳循环过程中的碳蓄积能力(NEP),计算了广东省1990—2007年化石能源消费的生态足迹,并对广东省化石能源生态足迹的产值和生态压力进行了分析,提出了相应的对策。结果表明,广东在20世纪90年代至2007年的经济快速发展过程中,化石能源占地面积总量由6398.21×103hm2增长到18340.74×103hm2;能源消费对生态环境的压力呈不断增加趋势,由1990年的0.57上升至2007年的1.64。以煤炭为主的能源消费结构正逐步改善,能源利用效率和经济价值不断提高。煤炭生态足迹由1990年的66%下降至2007年的45%,化石能源产值2.43万元/hm2增长至16.95万元/hm2。 相似文献
10.
Boersma PD 《Science (New York, N.Y.)》1986,231(4736):373-376
The ingestion by seabirds of fossil fuel hydrocarbons and other pollutants has been of great interest. This paper reports that storm-petrels ingest petroleum at sea and that residues can be detected in their stomach oil. The incidence of gut samples containing fossil fuel hydrocarbons (dirty samples) increased significantly after oil spills, and significantly more birds regurgitated dirty samples after large nearby spills than small distant ones. This appears to be one of the first reported instances where individuals of a natural population of marine birds have been shown to ingest sublethal doses of oil from sources of low-level, long-term pollution or from oil spills. Because of certain natural traits, Procellariiformes could serve as monitors of pollutants in the marine environment. 相似文献
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以风化石为主要原料,蔗渣、药渣为辅料,组合成4个基质配方,以常规草炭基质为对照进行育苗对比试验,研究不同风化石含量配以一定量的有机质辅料对烟苗出苗率、成苗率以及不同阶段烟苗素质的影响.结果表明,40％～70％风化石加一定蔗渣、药渣所育烟苗均能达到壮苗标准.其中40％风化石含量的基质处理出苗率和成苗率比对照分别提高4.02个百分点和1.48个百分点;50％风化石含量的基质处理茎叶及根系干物质累积75 d时分别比对照增加0.13和0.05g.其他几个基质配方所育烟苗的千物质累积、地上部分-地下部分协调性及成苗素质等指标都与对照接近,甚至优于对照;育苗成本较对照降低47.8％～56.2％,说明以风化石为主要原料来代替草炭作烤烟漂浮育苗基质完全可行. 相似文献
12.
A 95-million-year-old fossil snake from the Middle East documents the most extreme hindlimb development of any known member of that group, as it preserves the tibia, fibula, tarsals, metatarsals, and phalanges. It is more complete than Pachyrhachis, a second fossil snake with hindlimbs that was recently portrayed to be basal to all other snakes. Phylogenetic analysis of the relationships of the new taxon, as well as reanalysis of Pachyrhachis, shows both to be related to macrostomatans, a group that includes relatively advanced snakes such as pythons, boas, and colubroids to the exclusion of more primitive snakes such as blindsnakes and pipesnakes. 相似文献
13.
Thomasson JR 《Science (New York, N.Y.)》1978,199(4332):975-977
Morphological study of fossil grass anthoecia of Berriochloa and Nassella collected from Miocene-Pliocene strata in Kansas has revealed well-preserved epidermal structure. This seems to be the first micromorphological information known from fossil grass floral bracts. The epidermal pattern on the lemma in the fossils and their living counterparts are evidence in support of the view that the North American species of Stipa of the section Hesperostipa Elias and species of Piptochaetium have a common ancestry in Berriochloa, and that species of both taxa have been distinct from species of the Nassella, Oryzopsis, and other Stipa since at least the Miocene or Pliocene. 相似文献
14.
Emlet RB 《Science (New York, N.Y.)》1985,230(4728):937-940
The type of larval development in echinoids (Phylum Echinodermata) was found to determine crystal patterns in adult apical skeletal plates. This relation between larvae and adults will allow fossil species to be examined to determine the effects of developmental mode on evolutionary patterns, such as species longevity and speciation rate. Independent tests of hypotheses of such patterns now shown among fossil mollusks with and without feeding larvae can thus be performed. 相似文献
15.
Rodhe H 《Science (New York, N.Y.)》1990,248(4960):1217-1219
The current concern about an anthropogenic impact on global climate has made it of interest to compare the potential effect of various human activities. A case in point is the comparison between the emission of greenhouse gases from the use of natural gas and that from other fossil fuels. This comparison requires an evaluation of the effect of methane emissions relative to that of carbon dioxide emissions. A rough analysis based on the use of currently accepted values shows that natural gas is preferable to other fossil fuels in consideration of the greenhouse effect as long as its leakage can be limited to 3 to 6 percent. 相似文献
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随着对化石能源的不断开采,对矿物燃料的过度依赖,使得化石能源已经濒临枯竭,寻找一种新能源来代替化石能源是21世纪的科研主题。目前,对于能源植物的开发和利用备受人们的关注,它与石油资源不同,是可再生资源,且燃烧产物没有污染。本文通过对能源植物的开发和利用进行简单的介绍和粗浅的分析,进而发表一些浅见。 相似文献
17.
Chandrasekharam A 《Science (New York, N.Y.)》1972,177(4046):354-356
Spongy mesophyll tissue has been discovered preserved in fossil leaf compressions. The fossils occur in an outcrop at Genesee, Alberta, Canada. The fossiliferous beds belong to the Edmonton formation of Upper Cretaceous-lower Tertiary age. The mesophyll characteristic, when taken in conjunction with other characteristics, was found useful in the identification of some fossil leaves. Numerous detailed observations as well as comparisons of both living and fossil leaves show that the remains represent neither the epidermal nor the palisade tissue. 相似文献
18.
A general problem in biology is how to incorporate information about evolutionary history and adaptation into taxonomy. The problem is exemplified in attempts to define our own genus, Homo. Here conventional criteria for allocating fossil species to Homo are reviewed and are found to be either inappropriate or inoperable. We present a revised definition, based on verifiable criteria, for Homo and conclude that two species, Homo habilis and Homo rudolfensis, do not belong in the genus. The earliest taxon to satisfy the criteria is Homo ergaster, or early African Homo erectus, which currently appears in the fossil record at about 1.9 million years ago. 相似文献
19.
Silicified woods, the remains of mid-Tertiary tropical forests, are abundant in the vicinity of Ocú, Panama. Initial identifications reveal plant taxa not previously recorded as fossil woods. The plants identified can be found today in moist forests of tropical America, but not in the savanna-like vegetation now growing at the fossil site. 相似文献
20.
Jablonski D Roy K Valentine JW Price RM Anderson PS 《Science (New York, N.Y.)》2003,300(5622):1133-1135
Up to 50% of the increase in marine animal biodiversity through the Cenozoic at the genus level has been attributed to a sampling bias termed "the Pull of the Recent," the extension of stratigraphic ranges of fossil taxa by the relatively complete sampling of the Recent biota. However, 906 of 958 living genera and subgenera of bivalve mollusks having a fossil record occur in the Pliocene or Pleistocene. The Pull of the Recent thus accounts for only 5% of the Cenozoic increase in bivalve diversity, a major component of the marine record, suggesting that the diversity increase is likely to be a genuine biological pattern. 相似文献