冰期天文理论的演变

冰期天文理论是运用地球轨道偏心率、地轴倾角和地转轴进动的3种参数的变化幅度与周期来解释上新世——第四纪期间冰期——间冰期交替变化的一种理论．该理论1842年由Adhemar提出， 经过Croll发展到Milankovitch最终完成，经历了整100年的时间。上世纪60年代开始，深海、黄土、冰芯等大量的地质记录都揭示出３种周期变化，从而证实冰期天文理论的正确性，同时也对冰期天文理论带来了一些概念上的修正．但是，Berger计算的天文曲线至少从6 Ma以来展示同一规律的变化，然而地质记录却显示清晰的分段响应模式:41 kyr的地轴倾角周期在5.3～1.4 Ma期间一直是记录曲线的主要特征；北半球冰川作用只是在2.7 Ma BP才开始大规模出现；0.8 Ma开始100 Ka周期转变为主要周期，称之为中更新世转型（MPT）．还有:11阶段和全新世是2个偏心率很低的时期，但记录中却是冰期——间冰期振幅最大的时期，即大的间冰期为何出现于低偏心时期；由间冰期进入冰期比由冰期进入间冰期时来的快，意味大冰盖建造需要很长的时间，而消融则比较迅速．这些都是冰期天文理论本身不能解释的问题，正在由地球响应系统的研究来探索答案．

The Evolution of Astronomical Theory of Ice Age

We studied the genetic differentiation of Goniurosaurus indet. from northwestern Guangdong Province, China, and its phylogenetic relationships with other Chinese species, using partial sequences of the mitochondrial 12S rRNA and 16S rRNA genes of 10 species in total and Gekko gecko as the outgroup. A total sequence of 862 nucleotides of 12S rRNA (385 bp) and 16S rRNA (477 bp) genes were analyzed; 388 variable sites and 123 parsimoniously informative sites were detected in combination of the two genes. Analyses of Bayesian inference (BI), maximum likelihood (ML), maximum parsimony (MP), and neighbor-joining (NJ) all showed similar results: a close phylogenetic relationship between Goniurosaurus indet. and G. yingdeensis (genetic distance = 0.044-0.046), comparable to that between accepted known species G. araneus and G. luii (genetic distance = 0.051). Combined with morphological differences, our results support the notion that there is significant genetic differentiation between Goniurosaurus indet. and G. yingdeensis even though the two forms are separated only by a river; thus, Goniurosaurus indet. may be a new species. The phylogenetic analyses also indicated the uniqueness of G. hainanensis with the greatest genetic distance from others, suggesting that the character state of four body bands including nuchal loop is plesiomorphic as compared to that of five body bands. Our study lends support to the known phylogeny of Eublepharidae and provides complementary data for the conservation of Goniurosaurus. We hypothesized for the first time that rivers act as isolatiing barrier for population differentiation and speciation among continental Goniurosaurus species.