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101.
This study presents age‐based life‐history information for the red lip parrotfish Scarus rubroviolaceus based on a 5 year sampling programme from the commercial fishery of American Samoa. Females reached sexual maturity at 31·9 cm fork length (LF) and 2·6 years and sex change occurred at 42·3 cm LF, although not all females change sex through their ontogeny. The maximum observed age was 14 years and c. 65% of the fishery harvest was above the median LF at sex change. 相似文献
102.
Jess A. Peirson Ricarda Riina Mark H. Mayfield Carolyn J. Ferguson Lowell E. Urbatsch Paul E. Berry 《Botanical journal of the Linnean Society. Linnean Society of London》2014,175(2):191-228
The 480 species of leafy spurges, Euphorbia subgenus Esula, represent the main temperate radiation in the large genus Euphorbia. This group is distributed primarily in temperate Eurasia, but with smaller, disjunct centres of diversity in the mountains of the Old World tropics, in temperate southern Africa and in the New World. The majority of New World diversity (32 species) occurs in a single section, section Tithymalus. We analysed sequences of the nrITS and plastid ndhF, trnH‐psbA, trnS‐trnG and trnD‐trnT regions to reconstruct the phylogeny of section Tithymalus and to examine the origins and diversification of the species native to the New World. Our results indicate that the New World species of section Tithymalus form a clade that is sister to the widespread, weedy E. peplus. The New World species fall into two primary groups: a ‘northern annual clade’ from eastern North America and a diverse clade of both annual and perennial species that is divided into three subgroups. Within the second group, there is a small ‘southern annual clade’ from Texas and northern Mexico, a perennial ‘Brachycera clade’ from the western United States and northern Mexico, and a perennial ‘Esuliformis clade’ from montane areas of Mexico, Guatemala, Honduras and the Caribbean island of Hispaniola. Ancestral state reconstructions indicate that the annual habit probably evolved in the ancestor of E. peplus and the New World clade, with a subsequent reversal to the perennial habit. In conjunction with this phylogenetic framework, the New World species of section Tithymalus are comprehensively reviewed. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175 , 191–228. 相似文献
103.
A. Boskovic 《Dialectical Anthropology》2005,29(2):221-239
The paper describes the predicament of Brazilian anthropology through a personal experience of teaching and living in Brasilia.
Just like Brasilia, Brazil is many ways considered as “a work in progress” – and Brazilian anthropology as a lively and thriving
area, although frequently overlooked by non-Brazilian scholars. The situation in which Brazilian anthropologists find themselves
is put in the context of their own history, as well as the particular social conditions of the country – with special reference
to Brazil as invention, taking as an example celebration of “500 years of Brazil.” 相似文献
104.
Cáassia?M.?L.?UgayaEmail author Arnaldo?C.?S.?Walter 《The International Journal of Life Cycle Assessment》2004,9(6):365-370
Data acquisition to perform LCA is time and capital consuming. There is already international data about environmental aspects
in several processes. This study aims to verify the possibility of adapting international data to Brazilian conditions. Therefore,
a Life Cycle Inventory was conducted to compare the use of national and international data for steel used in automobiles.
This was done in three steps: objective and scope definition, inventory analysis and interpretation. LCI is a simplification
of Life Cycle Assessment (LCA) as impact assessment is not taken into account. Even so, LCI takes into account all life cycle
stages of a product, that is, from its extraction through its deposition. In this study, three phases of the life cycle were
considered: steel manufacturing, automobile use and disposal. In the case studied, the amount of steel evaluated was 263 kg,
which would be possible to be replaced by other materials in a 1,300 kg automobile. Resources and energy consumption, atmospheric
emissions and solid residues production were taken into account within the analysis done. Results show that automobile use
and materials manufacturing are responsible for the bulk of energy and resources consumption. Solid residues occur mainly
in the discard phase, due to the low level of recycling. Several differences were also achieved between national and international
data, which implies the need of environmental databases development. 相似文献
105.
Marko Rohlfs 《Evolutionary ecology》2006,20(3):271-289
Competitive interactions between organisms from distantly related phylogenetical branches have been suggested as being one
of the most pervasive forms of interspecific competition. However, so-called inter-kingdom competition has rarely been the
focus of ecological and evolutionary studies. Thus, a relatively novel hypothesis has been proposed on the basis that saprophagous
insects might intensively compete with filamentous fungi for ephemeral resources (e.g. decaying plant tissue). Consideration
that life history traits (e.g. developmental time) are adaptive in determining developmental success in the presence of con-
or hetero-specifics competitors implies that these traits have been progressively established by natural selection. Because
a similar scenario may apply to antagonistic interactions between saprophagous insects and filamentous fungi, one can expect
the existence of heritable variation in developmental success when insect larvae are forced to grow in the presence of noxious
mould. Therefore, this study aimed at discovering whether a local population of Drosophila melanogaster indeed harbours genetic variation in developmental success in the presence of the mould Aspergillus niger. By using the isofemale line technique, single larvae forced to feed on fungal infected or uninfected substrate were analysed
for variation in survival probability to the adult stage, developmental time and body size of emerged adults. I found genetic
variation in survival probability in fungal infected substrates but not in uninfected larval food sources. Mean developmental
time and body size varied significantly among isofemale lines in both types of larval environment. Survival was negatively
correlated with developmental time on fungal infected substrate, but variation in developmental time on fungal-free substrates
was not correlated with survival on fungal infected food patches. Within-trait correlation between fungal infected and uninfected
substrates was surprisingly weak, and developmental time was not correlated with body size. The results of this study demonstrate
(a) the existence of genetic variation for larval developmental success in the presence of A. niger in a Drosophila population, and (b) heritability of important insect life history traits differed as a function of the larval environment
(fungal infected or uninfected feeding substrate). I discuss models that might explain heritability differences and the evolutionary
consequences of these results. 相似文献
106.
David Strayer 《Hydrobiologia》1988,160(2):189-191
The ostracod Cypria turneri has one generation per year in Mirror Lake, New Hampshire. Juveniles hatch in January through May and reach maturity by August. The life history of this ostracod suggests that the turnover rate of the population is low. 相似文献
107.
108.
Francisco Amorim Orly Razgour Vanessa A. Mata Susana Lopes Raquel Godinho Carlos Ibáñez Javier Juste Stephen J. Rossiter Pedro Beja Hugo Rebelo 《Journal of Zoological Systematics and Evolutionary Research》2020,58(1):499-518
The Mediterranean Basin is a global biodiversity hotspot, hosting a number of native species belonging to families that are found almost exclusively in tropical climates. Yet, whether or not these taxa were able to survive in the Mediterranean region during the Quaternary climatic oscillations remains unknown. Focusing on the European free-tailed bat (Tadarida teniotis), we aimed to (a) identify potential ancient populations and glacial refugia; (b) determine the post-glacial colonization routes across the Mediterranean; and (c) evaluate current population structure and demography. Mitochondrial and nuclear markers were used to understand T. teniotis evolutionary and demographic history. We show that T. teniotis is likely restricted to the Western Palearctic, with mitochondrial phylogeny suggesting a split between an Anatolian/Middle East clade and a European clade. Nuclear data pointed to three genetic populations, one of which is an isolated and highly differentiated group in the Canary Islands, another distributed across Iberia, Morocco, and France, and a third stretching from Italy to the east, with admixture following a pattern of isolation by distance. Evolutionary and demographic reconstruction supports a pre-Last Glacial Maximum (LGM) colonization of Italy and the Anatolian/Middle East, while the remaining populations were colonized from Italy after the Younger Dryas. We also found support for demographic expansion following the Iberian colonization. The results show that during the LGM T. teniotis persisted in Mediterranean refugia and has subsequently expanded to its current circum-Mediterranean range. Our findings raise questions regarding the physiological and ecological traits that enabled species with tropical affinities to survive in colder climates. 相似文献
109.
3种地中海橡树在叶脉和气孔性状上的个体发育性变化及其与叶片经济性状的关系
我们比较了3个地中海栎属(Quercus)树种幼苗和成龄树的叶脉和气孔性状。之前的研究表明,幼苗的气体交换率往往比成龄树的要高。我们的研究目标是确认叶脉和气孔的性状在整个植物个体发育过程中是否会随着气体交换率的变化而同步改变。我们提出了以下两个备选假设:幼苗比成龄树有着更高的叶脉和气孔密度(假设1);幼苗在维管组织上的投资更少,从而降低了建设成本(假设2)。本研究是在西班牙中西部进行的,我们对每个树种不同生长阶段的植株随机采集了10个样本。我们测量了气孔和叶脉的平均性状(单位叶面积里的气孔大小和数量、叶脉密度、叶脉体积、叶脉到表皮的距离),比叶质量和叶片厚度。研究结果表明,细脉密度和单位面积叶脉体积随着树龄的增加而增加,这似乎与气体交换率方面的个体发育趋势不一致。这种差异支持了我们的假设2,说明植株在幼苗阶段减少对维管组织的投资以最大限度地提高生长速度是其当务之急。幼苗叶片中较大的叶脉间距可以由叶脉到表皮的较短距离所补偿。因此,薄叶片可能是幼苗的一个必要性状,它可以让水分沿较短路径输送到蒸发点,而无需对高成本的维管组织进行大量投资。 相似文献
110.
松科冷杉属植物的化石历史和现代分布 总被引:2,自引:0,他引:2
冷杉是北半球阴暗针叶林的优势种和建群种,现全世界共有52种1亚种12变种,在北半球形成南欧、北美和东亚三个分布中心,这三个地区也是冷杉属化石最丰富的地区。在垂直分布上,冷杉集中分布于1000~2000m(15种)和2500~4000m(13种)两个海拔地段。在中国,冷杉植物呈南北间断分布,集中分布在横断山地区。冷杉属的特有现象和孑遗分布现象都十分突出,有7个种呈孑遗分布。根据冷杉属的地史分布和现代分布的研究并结合最新的系统演化资料,本文推测冷杉属于白垩世中期起源于北半球的中高纬度地区,始新世以后,随着全球气候的变冷,逐步向南迁移,由于喜马拉雅山脉、阿尔卑斯山、落基山脉抬升及东亚季风气候的出现以及第四纪冰期的影响而形成了现代间断的分布格局。冷杉与银杉、金钱松等其它松科植物的形成模式十分相似。 相似文献