牙齿大小与颅骨大小的相关研究——上颌牙齿大小与颅围长等的相关研究

对上颌牙齿大小和颅骨大小进行了相关研究。全部上颌牙齿大小与上齿槽弓长和弓宽相关显著或非常显著,与颅围长(右I~2无显著相关,左I1、左I2、右I2、左M1、右M1和右PM1与中部面宽)相关显著或非常显著。在此基础上求出了17个以牙齿大小推算颅骨大小的回归方程。     

GENOME SIZE

采用Feulgen-显微分光光度计方法,以鸡红细胞为标准DNA（3.22pg/2C）测定了长江白鲟、达氏鲟、中华鲟、史氏鲟和北美匙吻鲟的体细胞基因组大小（DNA含量）。结果表明,上述五种鲟鱼DNA含量分别为4.11、8.26、9.07、6.07和3.96pg。长江白鲟和北美匙吻鲟均属于四倍体鱼类,分布在长江水系的中华鲟和达氏鲟两种鲟属鱼类为八倍体类型。史氏鲟初步判断为八倍体,据分析可能存在四倍体的类型。根据所得到的结果并结合已发表的DNA含量和染色体资料,分析了鲟形目鱼类在细胞遗传上的进化特点。鲟形目鱼类全为多倍体起源的鱼类,在鲟形目的两科（白鲟科和鲟科）六个属中,除鲟属外,其他五个属均为四倍体,而鲟属已发现有四倍体、八倍体、十二倍体和十六倍体。说明在细胞水平的染色体加倍与鲟形目鱼类各科、属分化没有直接联系,只在鲟形目形成的早期和鲟形目形成后的鲟属种间分化中扮演着重要角色。鲟属鱼类的染色体剧烈分化可能是造成现今鲟属种类数最多（占整个鲟形目鱼类的65%以上）的重要原因。     

激光粒度仪测定浮游植物粒径的可行性研究

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噬菌体颗粒大小与其遗传控制的噬菌斑大小的关系

测定培养温度、琼脂浓度、感染系数、培养基丰度和时间等因子对形成噬菌斑大小的影响程度,从而排除了影响噬菌斑大小的非遗传本底。分析电镜下噬菌体颗粒大小和平板上噬菌斑大小两者之间的关系,发现在同一容量较恒定的细胞内,不向噬菌体其生物合成总量趋于相等,该原理解释了决定噬菌斑大小的主要遗传控制方式。计算并推导出在一定程度上可反映噬菌体颗粒大小的经验公式。     

GENOME SIZE IS NOT CORRELATED WITH EFFECTIVE POPULATION SIZE IN THE ORYZA SPECIES

Genome sizes vary widely across the tree of life and the evolutionary mechanism underlined remains largely unknown. Lynch and Conery (2003) proposed that evolution of genome complexity was driven mainly by nonadaptive stochastic forces and presented the observation that genome size was negatively correlated with effective population size (N_e) as a strong support for their hypothesis. Here, we analyzed the relation between N_e and genome size for 10 diploid Oryza species that showed about fourfold genome size variation. Using sequences of more than 20 nuclear genes, we estimated N_e for each species after correction for the effects of demography and heterogeneity of mutation rates among loci and species. Pairwise comparisons and correlation analyses did not detect a negative relationship between N_e and genome size despite about 6.5‐fold interspecies N_e variation. By calculating phylogenetically independent contrasts (PICs) for N_e, we repeated correlation analysis and did not find any correlation between N_e and genome size. These observations suggest that the genome size variation in the Oryza species cannot be explained simply by the effect of effective population size.     

CLUTCH SIZE AND EGG SIZE IN FREE-LIVING AND PARASITIC COPEPODS: A COMPARATIVE ANALYSIS

The evolution of reproductive strategies and the trade-off between number and size of eggs were investigated in a comparative analysis of free-living and parasitic copepods. Data from 1038 copepod species were used to obtain family averages for 105 families; the phylogenetic relationships among these families include 94 branching events or 94 independent contrasts on which the analysis was based. Transition from a free-living existence to parasitism on invertebrates resulted in small increases in body size. Transition from parasitism on invertebrates to parasitism on fish was associated with greater increases in body size. After controlling for body size, a switch to fish hosts resulted in an increase in the number of eggs produced and a reduction in egg size. Among all contrasts, there was a negative relationship between changes in relative clutch size and changes in relative egg size, suggesting the existence of a trade-off between egg size and numbers. However, opposite changes in these measures of clutch size and egg size were not quite more frequent than expected by chance, therefore indicating that investments into egg numbers are not necessarily made at the expense of egg size, and vice versa. Latitude affected copepod body size, clutch size, and egg size, whereas the effects of freshwater colonization or size of the fish host were not significant. Comparative analyses at either the genus or species levels within given taxa of copepods parasitic on fish provided limited support for a trade-off between clutch size and egg size, but were hampered by the small number of independent phylogenetic contrasts available. From the family-level comparative analysis, it appears that the evolutionary transition from a free life to parasitism on invertebrates, and the transition from parasitism on invertebrates to parasitism on fish, have led to changes in life-history traits in response to the different selective pressures associated with the different modes of life.     

SIZE AND SEX IN CYPRAEIDAE

Samples of Cypraea (Notocypraea) angustata Gmelin 1791 and ofCypraea errones L. 1758 have been measured, and the sex of theindividuals determined. The males of C. angustatawere foundto be significantly shorter than the females. Differences betweenother dimensions in this species, and between all dimensionsmeasured in C. errones, were of little significance It has recently been shown (Griffiths, 1961) that the malesof Umbilia hesitata Iredale were greater in length than thefemales. Other evidence in this paper, and some subsequent measurementsmade by Schilder and Schilder (1961) have suggested that theconverse might be true for some other species of CYPRAEIDAE Sample groups of shells of C. errones and C.(N) angustata havenow been measured. The shells were then cut open, and thesexof the animal determined by the presence or absence of a penis.The results are givenin Tables I and II (Received 10 March 1961;     

THE EVOLUTION OF CLUTCH SIZE. I. AN EQUATION FOR PREDICTING CLUTCH SIZE

We derive an equation for calculating the clutch sizes of birds and other long-lived animals from Murray's (1979) theory on the evolution of clutch size. For the Prairie Warbler (Dendroica discolor) in Indiana, this equation predicts an average clutch size of 3.49, less than half an egg smaller than the recorded average clutch size of 3.89. We attribute the discrepancy to sampling error and suggest that the equation satisfactorily identifies the important factors affecting the evolution of clutch size. The success of the equation in predicting clutch size of the Prairie Warbler provides additional support for Murray's theory on the evolution of clutch size.     

BODY SIZE AND HAREM SIZE IN MALE RED-WINGED BLACKBIRDS: MANIPULATING SELECTION WITH SEX-SPECIFIC FEEDERS

We experimentally manipulated the strength of selection in the field on red-winged blackbirds (Agelaius phoeniceus) to test hypotheses about contrasting selective forces that favor either large or small males in sexually size dimorphic birds. Selander (1972) argued that sexual selection favors larger males, while survival selection eventually stabilizes male size because larger males do not survive as well as smaller males during harsh winters. Searcy (1979a) proposed instead that sexual selection may be self limiting: male size might be stabilized not by overwinter mortality, but by breeding-season sexual selection that favors smaller males. Under conditions of energetic stress, smaller males should be able to display more and thus achieve higher reproductive success. Using feeders that provisioned males or females but not both, we produced conditions that mimicked the extremes of natural conditions. We found experimental support for the hypothesis that when food is abundant, sexual selection favors larger males. But even under conditions of severe energetic stress, smaller males did not gain larger harems, as the self-limiting hypothesis predicted. Larger males were more energetically stressed than smaller males, but in ways that affected their future reproductive output rather than their current reproductive performance. Stressed males that returned had smaller wings and tails than those that did not return; among returning stressed males, relative harem sizes were inversely related to wing and tail length. Thus, male body size may be stabilized not by survival costs during the non-breeding season, nor by energetic costs during the breeding season, but by costs of future reproduction that larger males pay for their increased breeding-season effort.     

胶州湾12种饵料鱼类耳石大小与体长的关系

根据2008年11月至2009年8月在胶州湾海域进行的逐月定点底拖网调查, 选择12种常见的饵料鱼类作为研究对象, 运用最小二乘法分析了每种饵料鱼类的体长与耳石形态大小(包括耳石的长度、宽度、长半径和短半径)的关系, 并建立回归方程, 旨在为深入研究高营养级鱼类的摄食生态和食物网营养动力学提供基础资料。研究表明, 12种饵料鱼类的体长与体重均呈显著的幂函数关系(P0.05), 回归系数b值在2.871-3.371, 平均值为3.1590.110 (95% CL), b值最小的鱼种是六丝钝尾虾虎鱼Amblychaeturichthys hexanema, 最大的是细条天竺鲷Apogon lineatus。经检验, Liza haematocheilus和箭鱼衔Callionymus sagitta的b值与3无显著差异(P0.05), 属等速生长; 李氏鱼衔Callionymus richardsonii和六丝钝尾虾虎鱼的b值显著小于3 (P0.05), 属负异速生长; 其余8种鱼类的b值均大于3 (P0.05), 为正异速生长。方差分析表明, 12种鱼类的体长与耳石各个形态参数的回归关系均极显著(P0.01)。在所有48个回归方程中, 有37个方程的决定系数R2值大于0.8, 拟合效果较好; 有9个回归方程的R2值在0.7-0.8; 其余2个回归方程的R2值小于0.7, 拟合效果略差。其中, 各方程拟合效果最好的是六丝钝尾虾虎鱼, 其R2值均接近于1。通过比较同种鱼类各个回归方程的R2值可知, 在这12种饵料鱼类中, 多数鱼种体长与耳石长度和宽度的拟合效果要略好于体长与耳石半径的拟合效果, 因此在实际应用中, 可以通过测量耳石的长度和宽度来推算饵料鱼类的体长等形态参数。另一方面, 由于多数鱼类的耳石比较脆, 尤其是耳石的两端更容易破损, 因此与耳石长度相比, 耳石宽度与体长的回归方程更加适合于实际应用。       

浙江舟山五种卵生游蛇科动物个体大小、窝卵数和卵大小之间的关系

阐明五种游蛇科动物雌体大小、窝卵数和卵大小之间的关系和雌性繁殖特征的种间差异。５种蛇均产单窝卵,产卵高峰期为６月下旬至７月,窝卵数与雌体大小（ＳＶＬ）呈显著的正相关,相对窝卵重与雌体ＳＶＬ无关,卵理与窝卵数无关。灰鼠蛇卵重与雌体ＳＶＬ呈正相关,赤链蛇、王锦蛇、黑眉锦蛇和乌梢蛇的卵重与雌体ＳＶＬ无关,黑眉锦蛇卵长径与窝卵娄呈负相关,其余４种蛇卵长径与窝卵数无关。５种蛇卵长径与短径无关。黑眉锦蛇卵短径