common oak 中文意思是什麼
common oak
解釋
有梗花櫟-
Abstract : biological invasions are a continuous feature of a non - equilibrium world, ever more so as a result of accidental and deliberate introductions by mankind. while many of these introductions are apparently harmless, others have significant consequences for organisms native to the invaded range, and entire communities may be affected. here we provide a survey of common models of range expansion, and outline the consequences these models have for patterns in genetic diversity and population structure. we describe how patterns of genetic diversity at a range of markers can be used to infer invasion routes, and to reveal the roles of selection and drift in shaping population genetic patterns that accompany range expansion. we summarise a growing range of population genetic techniques that allow large changes in population size ( bottlenecks and population expansions ) to be inferred over a range of timescales. finally, we illustrate some of the approaches described using data for a suite of invasions by oak gallwasps ( hymenoptera, cynipidae, cynipini ) in europe. we show that over timescales ranging from 500 10000 years, allele frequency data for polymorphic allozymes reveal ( a ) a consistent loss of genetic diversity along invasion routes, confirming the role of glacial refugia as centres of genetic diversity over these timescales, and ( b ) that populations in the invaded range are more subdivided genetically than those in the native range of each species. this spatial variation in population structure may be the result of variation in the patchiness of resources exploited by gallwasps, particularly host oak plants
文摘:生物入侵是不均衡世界的一個永恆話題，尤其是當人類有意或無意地引入物種后.很多引入顯然是無害的，但另外一些則有著嚴重的後果，會給入侵地的生物以至於整個生物群落造成影響.本文總結了分佈區擴張的常見模式，概述了它們對遺傳多樣性和種群結構式樣所造成的影響.描述了如何根據以一批遺傳標記所得到的遺傳多樣性式樣來推斷入侵途徑，來揭示伴隨擴張選擇和漂變在形成種群遺傳樣式中的作用.本文對日益增多的群體遺傳學方法進行了總結，這些技術可以用來在不同的時間尺度上推斷種群規模所發生的巨大變化（瓶頸效應及種群擴張） .最後，我們以歐洲櫟癭蜂（膜翅目，癭蜂科，癭蜂族）一系列入侵的數據為例對一些方法進行了說明.從500 10000年的時間尺度上，多態的等位酶位點上等位基因頻率的數據表明: 1 ）遺傳多樣性沿入侵路線呈不斷下降的趨勢，支持了冰河期避難所作為遺傳多樣性中心的作用; 2 ）入侵地區的種群與該物種原產地的種群相比，遺傳上的分化更為強烈.這種種群結構在空間上的變異可能是被櫟癭蜂開發的資源尤其是櫟樹寄主在斑塊上出現變異的反映 -
I see in this simply such a coincidence of events as is common in every phenomenon of life, and i see that however long and minutely i might examine the watch hand, the valve, and the wheel of the steam - engine and the oak - bud, i shall not discover the cause of the bells ringing, of the steam - engine moving, and of the spring wind
我只看到日常生命現象中一些條件的偶合，我清楚，無論我多麼仔細地觀察時鐘的指針，機車的閥門和車輪及橡樹芽，我依然不會明白祈禱鐘聲，機車運動和倒春寒的原因。要明白其究竟，我必須完全改變觀察點，去研究蒸汽教堂大鐘及風力的運動規律。
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