共查询到20条相似文献，搜索用时 203 毫秒
1.
雌雄两性黄颡鱼头部形态特征的增长 总被引：4，自引：0，他引：4
测定了黄颡鱼的体长、头长、吻长、眼径、眼间距、眼后头长、头高等形态指标。雌性个体的体长显著小于雄性个体，雌雄两性个体头长、吻长、眼间距、眼后头长随体长的增长呈同速增长．无显著差异。雌性个体在眼径、头高随体长的增长速度显著大于雄性个体。 相似文献
2.
蔡垚 《南京晓庄学院学报》2010,26(3):64-66
报道了江西婺源地区蓝尾石龙子（Eumeces elegans）头、体大小的两性异形.蓝尾石龙子成体体长存在显著的两性差异（雄性大于雌性）,雄性个体有较大的头部（头长和头宽）,雄性头部增长速率明显大于雌性,表明成年雄体分配较多的能量用于头部和身体的生长;而成年雌体则相对延缓头部的生长,以维持躯干生长,增大腹腔容纳量,可提高其繁殖输出. 相似文献
3.
用PIT-tag标签标记了69(33♀♀,36♂♂),测量了6月龄(亚成体)和成体棘胸蛙的7个形态特征指标(体长、头长、头宽、腹长、前肢长、后肢长和体重),用于分析棘胸蛙两性形态特征在个体发育过程的变化。结果表明:亚成体棘胸蛙两性在头宽和前肢长上差异显著,头宽和前肢长雄性均大于雌性,而其它形态特征差异不显著。成体棘胸蛙除头长这一形态指标没有差异外,其它6个形态特征差异显著,其中腹长雌性大于雄性,而其他五个指标雄性均大于雌性。我们的结果表明,棘胸蛙在个体发育过程中雌性有较大的腹长与生育力选择的作用有关,而雄性具有较大的体长、头宽和前肢长与性选择有关。 相似文献
4.
笔者对浙江省临海市郊区农田的黑线姬鼠内脏器官的生长进行了研究。结果表明,根据内脏器官相对重量、绝对重量与胴体重和体长之间的相关性,可将内脏器官的生长方式分成四类。 相似文献
5.
6.
7.
8.
瓯江鲫鱼头部形态特征的两性异形 总被引：1，自引：0，他引：1
测定了鲫鱼成体的体长、头长、头宽、头高、吻长、眼后头长、眼径和眼间距.Kruskal-Wallis ANOVA显示雌性个体的体长显著大于雄性个体.头部形态特征变量分别与体长的回归关系显著,回归剩余值的单因素ANOVA显示,特定体长的雌性个体的头长、头宽和眼间距显著大于雄性个体,雌性个体的眼径显著小于雄性个体,其他的头部形态特征变量包括头高、吻长和眼后头长无显著的两性差异.对头部7个形态特征变量作主成分分析(Eigenvalue≥1)发现,前3个主成分共解释67.1 %的变异.头长和吻长在第一主成分有较高的正负载系数(解释26.7%变异),头宽和眼间距在第二主成分有较高的正负载系数(解释23.1 %变异),眼径在第三主成分有较高的正负载系数(解释17.3 %变异).两性成体第一主成分的分值差异不显著;第二主成分的分值雌性显著大于雄性;第三主成分的分值雌性显著小于雄性. 相似文献
9.
10.
北极霸主
北极熊是世界上第一大的陆地食肉动物,雄性身长约2．4～2．6米,体重400～800千克;雌性身长约1．9—2．1米,体重200～300千克。虽然周身覆盖着厚厚的毛看起来是白色的,实际上是一根根中空而透明的毛,但北极熊的皮肤却是黑色的。这可以从它们的鼻子、爪垫、嘴唇以及眼睛四周的肤色上看出来。中间空的毛和黑色的皮肤有助于吸收热量和保暖。 相似文献
11.
Terry F. Pettijohn 《Learning & behavior》1977,5(4):370-372
Forty sexually mature Mongolian gerbils served as subjects in a study designed to examine responsiveness to samples of urine. In a two-choice comparison situation in the home cage, each isolated gerbil was tested for amount of time spent with each urine sample during a 3-min period. Male gerbils spent significantly more time with estrus female urine than nonestrus female gerbil urine, and with nonestrus female gerbil urine than with either male gerbil urine or water. Female gerbils did not respond differentially to any of the stimuli. Neither sex discriminated between gerbil and hamster urine of either sex. Results suggest that female gerbil urine communicates sexual identity and, especially, sexual readiness to the male gerbil. 相似文献
12.
苦参不同器官中的生物碱含量分析 总被引：2，自引：0，他引：2
[目的]探讨苦参不同器官中的生物碱含量,为该资源植物的合理应用提供依据.[方法]用薄层色谱法(TLC)分析测定了辽宁产苦参不同器官中苦参碱及氧化苦参碱含量.[结果]各类器官,除叶片外,氧化苦参碱含量均显著超过苦参碱含量;苦参碱含量以种子中的为最高,占干重的0.065%,其次为茎(0.034%)、根(0.016%)、叶(0.013%);氧化苦参碱含量以根最高,占干重的3.847%,其次为种子(1.982%)、茎(0.140%),叶中未检测到;粗老根(直径大于1 cm)与细嫩根(直径在0.5~1.0 cm)中的两种生物碱含量差别不大.[结论]达到一定生长年限后,生物碱积累不再有明显增加而趋于饱和;大部分器官中,氧化苦参碱含量高于苦参碱含量;种子及茎更适合作为苦参碱的提取器官. 相似文献
13.
沱江内江段福寿螺中重金属调查 总被引：1，自引：0，他引：1
用石墨炉原子吸收光谱法检测沱江内江段下游福寿螺肌肉与内脏Cd,Pb和Cu的含量．结果表明：沱江内江段福寿螺体内Cd,Pb和Cu的含量远高于国家规定标准,内脏高于肌肉;Cd的含量大于0．2ug／g,超过国家规定标准1．2倍以上．Cu的含量大于200μg／g,超过国家规定标准3倍以上．福寿螺对Cu的富集高于Cd,Pb,沱江Cu,Cd污染是比较严重的． 相似文献
14.
Susan L. Golbeck 《科学教学研究杂志》1986,23(4):365-376
Sex-related differences on Piagetian horizontality (water level) and verticality (plumb line) tasks were examined in 64 college students. It was hypothesized that females' difficulties on these Euclidean spatial problems are due not to differences in underlying spatial competence, but rather to differences in knowledge of task specific information about the physical properties of water levels and plumb lines. This was tested by presenting subjects with the standard water level and plumb line problems and also modified problems not requiring knowledge of physical principles (i.e., drawing “straight up and down” or “straight across” lines inside tipped rectangles). While males were expected to outperform females on the standard tasks, no sex differences were expected on the modified tasks. Results of an ANOVA on scores for horizontality and verticality each showed main effects for sex and task version but failed to reveal the hypothesized interaction. However, performance on the Euclidean spatial tasks was also considered in terms of overall success versus failure. While males were more successful than females in the standard format, males and females were equally successful in the modified, nonphysical, format. Hence, college aged males and females generally do not differ in spatial competence although they may be differentially influenced by task content. Findings are discussed in terms of their implications for theory and practice. It is emphasized that science educators must be especially aware of such task influences for females so that performance deficits are not mistaken for competence deficits. 相似文献
15.
对幼果期富士苹果树体各器官及其皮层、木质部的生物量、含水量、钙含量及累计进行了调查分析。结果表明：单株生物量地上部分〉地下部分。植株含水量总趋势为幼嫩器官高于成龄器官;单株钙累积地上部〉根系,钙素主要贮藏器官是骨干枝和直径1.0～5.0㎝的根;皮层钙累积地上部〉根系,骨干枝最高,1年枝最小;木质部钙累积地上部〉根系,多年枝最高,1年枝最小;新生器官的钙含量在各器官中最高。 相似文献
16.
Students' Understandings of Human Organs and Organ Systems 总被引：1，自引：0，他引：1
How do people develop their understanding of what is inside them? This study looks at students' understandings of their internal structure. A cross-sectional approach was used involving a total of 158 students in England from six different age groups (ranging from four year old students to first year undergraduates). Students were given a blank piece of A4-sized paper and asked to draw what they thought was inside themselves. Repeated inspections of the completed drawings allowed us to construct a seven point scale of these representations. Our analysis shows the extent to which student understanding increases with age and the degree to which students know more about some organs and organ systems than others. While gender differences in the drawings were generally not large there were some intriguing differences in the ways males and females drew reproductive organs.
相似文献17.
Dennis A. Vanderweele 《Learning & behavior》1974,2(4):309-312
Mongolian gerbils (Meriones unguiculatus) were examined for components of thirst in the laboratory. The gerbil, reputed to be a desert-adapted rodent, was tested for its response to quinine adulterations of water, hypertonic solutions (1 M sodium chloride, NaCl), and hyperoncotic solutions (40% W/V polyethylene glycol in isotonic saline, PG). Both NaCl and PG were administered intraperitoneally. Gerbils accepted quinine when it was the only solution available and food was ad lib, but preferred distilled water to quinine if both were available. Both PG and NaCl produced increased water intakes in gerbils within the first 2 h, postinjection. PG, however, produced the most reliable and largest increase in water consumption, illustrating that extracellular dehydration is probably a more significant thirst stimulus in gerbils. 相似文献
18.
红树植物无瓣海桑北移种植的生长适应研究 总被引：1，自引：0，他引：1
分析了北移种植在福建省霞浦、连江、泉港、集美、漳浦5个样地无瓣海桑（Sonneratiaapetala）的存活率、株高、根长、冠幅、生物量及生物量分配,结果表明：无瓣海桑人工引种北界在26°47′N～26°16′N之间,且存活率随着纬度的增高而降低;各样地无瓣海桑营养器官的含水量为：叶〉根〉茎,其含水量均值分别为86．4％、71．0％、63．0％,植株有机质在根茎叶器官分配为茎〉根〉叶;根部的长度和重量随着纬度的升高而下降;株高、冠幅随着纬度的升高有所变化,但没有显著性差异． 相似文献
19.
20.
Cats were observed in four moderately frightening novel situations. One of 12 response measures indicated that females are more fearful than males, 1 indicated that males are more fearful than females, and the remaining 10 measures revealed no significant difference between males and females. The results thus yield no evidence of any large and consistent difference in fear between female and male cats. Gonadal hormones do not determine any single pattern of sex difference in fearfulness in different species of mammals. Species-specific patterns of social organization may predict sex differences in fear in studied species more accurately than endocrine factors. 相似文献