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81.
Summary. Allopatric populations of the leaf beetle Chrysomela lapponica are known to feed upon either willow (Salicaceae) or birch (Betulaceae). This study aimed to elucidate the differentiation
process of these allopatric populations. We investigated whether these allopatric populations specialized on different host
plants are still able to produce fertile offspring when interbreeding. Individuals from a population in Finland (willow specialists)
and one in the Czech Republic (birch specialists) were crossed in laboratory. Hybrid formation succeeded only between females
from the Czech, birch specialized population and males from the Finnish, willow specialized population, while no eggs were
produced by females of the willow specialists having mated males of the birch specialists. Behavioral, morphological, physiological,
and chemical features of the F1 hybrids were studied. The chemical composition of larval defensive secretion and feeding preferences of the resulting F1 hybrids mainly showed similarities with the paternal phenotype, while the area of black coloring on the offspring’s elytra
was intermediate between those of the parental elytra. F1 hybrids did not accept the host plant (birch) of their mothers for feeding and only survived on willow. Thus, since mothers
only lay eggs on birch, we found evidence for a postzygotic isolation mechanism between the individuals of the two investigated
populations: when having been mated with willow specialized Finnish males, the birch specialized Czech mothers place the hybrid
eggs on a plant species (birch), on which the hatching larvae cannot survive. 相似文献
82.
Terry V.Callaghan Lars Olof Bjrn Yuri Chernov Terry Chapin Torben R.Christensen Brian Huntley Roll A.Ims Margareta Johansson Dyanna Jolly Sven Jonasson Nadya Matveyeva Nicolai Panikov Walter Oechel Gus Shaver 《Ambio-人类环境杂志》2004,33(7):369-373
引言
人们普遍认为,全球气候变暖在北极将进一步放大,由于平流层臭氧修复的可能延误,紫外线B(UV-B)辐射可能继续增加,北极环境及其居民可能特别易受这类环境变化的影响.上述共识促进了对气候变化影响的国际评估工作.北极气候影响评估(ACIA)是一项为时4年的研究,结果出版了一篇重要的科研报告[1]并产生了其他的成果.在本文以及本期Ambio专刊下面的文章中,我们提供了报告中针对北极陆地生态系统(从树线群落交错带到极地荒漠)的部分研究成果. 相似文献
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Locher-Krause Karla E. Lautenbach Sven Volk Martin 《Regional Environmental Change》2017,17(8):2477-2493
Regional Environmental Change - The understanding of how ecosystem services are distributed across the landscape and their change over time provides key information to manage multi-functional... 相似文献
90.
It is generally accepted as a useful and workable hypothesis that when an ecosystem receives an inflow of exergy (energy that can do work) it will utilize this flow of exergy to move as far away from thermodynamic equilibrium as possible after the exergy (energy) for maintenance has been covered. If more combinations of system components including organisms are offered, the combination of components and processes that will bring the system most away from thermodynamic equilibrium will win.The amino acid sequences of the proteins e.g. enzymes determine and control the life processes of the organisms and may be viewed as information sensu lato. The free energy of oxidation of the amino acids and the peptide bonds of the cell enzymes expresses therefore the exergy content, eco-exergy or work capacity that the information contributes to “moving further away from thermodynamic equilibrium”. In this paper eco-exergy is calculated and plotted versus the β-values (a measure of the information contained in the genome) for different organisms. The eco-exergy density was previously (see
[J?rgensen et al., 1995] and [J?rgensen et al., 2005]) proposed to be calculated as the summation of the product of the β-values representing the information of the genome multiplied by the concentrations of the respective ecosystem components. This analysis shows a strong correlation between the β-values and free energy released when oxidizing the enzymes. The β-values can therefore be assumed to represent the free energy that the organisms have invested in genetic information. 相似文献