共查询到19条相似文献，搜索用时 206 毫秒
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崇武潮间带贝类调查 总被引：1，自引：1，他引：0
谢进金 《泉州师范学院学报》1999,(6)
崇武潮间带贝类,经记录整理、鉴定共得标本178 种,隶属于3 纲、60科和106 属.其中,双神经纲4种,瓣鳃纲65 种,腹足纲109 种. 并对所得标本进行分析和讨论. 相似文献
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福建泉州湾河口湿地潮间带贝类调查 总被引：3，自引：0，他引：3
谢进金 《泉州师范学院学报》2002,20(6):66-70
对泉州湾河口湿地自然保护区潮间带的贝类，进行初步的调查和分析，共得标本151种，经整理，鉴定，隶属于3纲，48科和92属，其中，双神经纲3种，瓣鳃纲68种，腹足纲80种，根据它们对湿度的适应性质可分为4个类群，暖温带种占3．3％，亚热带种占57．6％，广温广布种占35．8％，热带种占3．3％。 相似文献
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鱼类的食性同取食器官的形态结构、摄食方式密切相关。 一、鲢、鳙的食性 鲢、鳙是典型的滤食性鱼类。滤食器官主要靠鳃耙。在生活时,每个鳃弧的内外两列鳃耙不断张开和合拢。张开时和水一起进入口腔中的 相似文献
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鱼虱Caligus seriolae形态结构的电镜观察 总被引：1，自引：0，他引：1
通过时寄生于石斑鱼鳃部的鱼虱的扫描电镜观察，作者对鱼虱的感觉器官、摄食器官和部分游泳足的结构进行描述．并对口器结构与摄食方式的关系、微细结构在分类中的作用、以及体表及部分附肢的附生毛的形态特点进行讨论． 相似文献
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大亚湾潮间带软体动物分布和区系分类研究 总被引：2，自引：0，他引：2
潮间带底栖软体动物由于其活动能力较低,在研究环境与生物的关系方面往往起着稳定的指示剂作用.笔者自1987年至1999年对大亚湾潮间带的软体动物进行了采集调查,共鉴定软体动物有241种,分属3纲60科.其中多板纲3科3种,瓣鳃纲24科117种,腹足纲33科121种.分析表明,其区系特点是以南海亚热带一热带种和东海、南海亚热带种为主要成分. 相似文献
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《中学生(作文版)》2007,(1)
贝类共分五大纲,即腹足纲、双壳纲、掘足纲、多板纲和头足纲。每一纲再分为若干不同的族群。腹足纲类是最常见的,大部分的腹足纲贝类都有口盖,口盖可以御敌并防止水分散失。口盖大多是角质, 相似文献
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Rats lived continuously in an operant chamber in which they were able to press a bar to obtain food on a chained FR50:CRF schedule that allowed them control of both the size and frequency of individual meals. Independent groups of animals were scheduled to receive 12, 24, 48, or 96 electric shocks per day, which were given randomly in time and independent of the subjects’ behavior. Rats could avoid shock by remaining in a safe area of the chamber, but they were always at risk while barpressing. The introduction of shock resulted in a number of changes in feeding patterns. In rats exposed to a possible 12 shocks/day, meal size increased whereas meal frequency changed very little. At 24 shocks/day, meal frequency decreased whereas meal size increased such that net intake remained stable relative to a preshock baseline period. As shock density was increased to 48 or 96 shocks/day, total intake was suppressed. At 96 shocks/day, both meal frequency and meal size decreased dramatically. Shock-related changes were also observed in rates of operant responding and in the amount of time the animals engaged in feeding-related behavior. All of the animals were able to achieve a greater than 50% reduction in the total number of shocks received relative to equivalent random samples of their position in the apparatus taken during baseline. These results support the position that the nature of defensive changes in feeding behavior that are seen when an aversive stimulus is introduced: into a simulated foraging situation varies as a function of risk. 相似文献
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研制了一套药芯焊丝生产线电磁振动送粉机构及其单片机控制系统．通过对电磁振动送粉机构参数的测试，找到了送粉速度ＶＬ和电流Ｉ之间的数学表达式，使控制系统不仅可以根据带宽、药粉密度、轧丝速度和填充率自动计算出送粉量，而且可以根据轧丝速度调节送粉速度，使填充率保持稳定 相似文献
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In three experiments, the time horizon over which the rat evaluates alternative feeding sources was investigated. The time horizon was measured by the suppression of intake of one incentive (a 0.15% saccharin solution) when a preferred alternative incentive (a 32% sucrose solution) was available but delayed. In Experiment 1, we found a direct function between the amount of saccharin intake and the delay time before access to 32% sucrose. Compared with intake for a saccharin-only control, saccharin intake was suppressed before 4-min and 16-min sucrose delays, but not before a 32-min delay. Because previous work (Flaherty & Checke, 1982) had reported suppression before a delay of nearly 32 min, in the subsequent experiments we examined factors that might account for this difference. In Experiment 2, we found that saccharin intake was suppressed before a 32-min delay interval when saccharin and sucrose solutions were presented in a bright-novel test environment but not when the same solutions were presented in the home cage. In Experiment 3, we found that the time between testing and subsequent postsession feeding could also affect the suppression of saccharin intake. Saccharin intake was suppressed when access to 32% sucrose was delayed by 32 min and the test situation was followed by immediate postsession feeding, but not when postsession feeding was delayed by 90 min. These results thus extend estimates of the rat’s time horizon to at least 32 min, but indicate that the effective time horizon can vary, depending on the test situation. 相似文献
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Edward P. Sarafino 《Learning & behavior》1978,6(2):235-243
Twenty-four male rats were reared under three feeding conditions. These conditions manipulated the number and variety of exploratory behaviors required to obtain diets of powdered food and water in feeding boxes. One group performed minimal exploratory responses to obtain their diets. Another group shuttled between two feeding stations, thereby executing several exploratory components, primarily locomotor. The third group performed a considerable number and variety of exploratory components in search of their diets, located unsystematically throughout the feeding box. Adult testing occurred without food and water in an apparatus resembling the feeding boxes. The results showed that exploratory behavior was affected by feeding conditions, enhanced with increased dietary deprivation, and reduced across both trials and within-trial intervals. These results indicate that the particular exploratory behavior measured must be selected by reference to the subjects’ prior experience. 相似文献
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Feeding practices are important determinants of growth and development of children. Using infant and young child feeding indicators and complementary feeding guidelines, 7 practices in 28 countries are described, showing substantial variation across countries. Only 25% of 0- to 5-month-olds were exclusively breastfed, and only half of 6- to 8-month-olds received complementary foods the previous day. Median duration of breastfeeding and increase of fluid intake during diarrhea were low among countries with a high Human Development Index (HDI). Living in high-HDI countries may not translate to positive feeding practices. Across countries, there is a need for promotion, protection, and support of optimal breastfeeding and complementary feeding practices as well as better adherence to recommendations for feeding during illness. 相似文献
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In four experiments, the once daily availability of saccharin (.15%) preceded the availability of sucrose (32% or 2%). Experiment 1 showed that the intake of saccharin was reduced when it preceded 32% sucrose but not when it preceded 2% sucrose, as compared with saccharin-alone conditions. Experiment 2 showed that less saccharin was consumed when the saccharin preceded sucrose by 5 min than when there was a 30-min intersolution interval. Experiment 3 replicated this finding and showed that the presentation of the two solutions through the same or different access holes in the apparatus was not relevant to the result. Experiment 4 showed that there was an inverse relationship between saccharin intake and the length of the intersolution interval in the range of 1 to 30 min. These data were interpreted to indicate that the animals learn the predictive relationship between the saccharin and sucrose solutions and that the intake of the saccharin is reduced by an anticipatory contrast mechanism—a mechanism that may have restricted temporal parameters. 相似文献
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Lei SJ 《Journal of Zhejiang University. Science. B》2006,7(7):580-585
The effects of ration level and feeding frequency on digestibility in juvenile soft-shelled turtle, Pelodiscus sinensis, were investigated. Four ration levels 1.5%, 2.5%, 4.0% and satiation （6.0% BW/d） were used. Apparent digestibility （AD） of dry matter （DMAD）, protein （PAD） and protein real digestibility （PRD） were significantly affected by ration level, but not by feeding frequency when the ration level was similar. However, the feeding frequency affected the AD, DMAD, PAD and PRD significantly when the turtles were fed to satiation. The relationship between fecal protein content （Y） and protein intake （At） can be expressed as a quadric equation： Y=-0.1742＋0.1476X-0.0003X^2 （r^2=0.876, n=27, F=93.92, P〈0.01）. 相似文献
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The purpose of this experiment was to compare the problem-solving performance of rats allowed to explore either one or two tables of Maier’s three-table-problem apparatus on successive days. The feeding experience and test trial were administered on the day after all tables and runways had been explored in this piecemeal fashion. No rat that explored only one table and runway per day was able to solve the problem, whereas 60% of the rats that explored two tables and their interconnecting runways did solve the problem. All rats that explored the entire apparatus on each exploratory day were able to solve the problem. These data support the notion that animals can conceptually link objects experienced successively into cognitive representations which specify the constant relationships existing between those objects. The existence of such an absolute spatial mechanism makes it unnecessary for an organism to depend upon relative spatial mechanisms such as routes or cues. 相似文献
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Henry Marcucella 《Learning & behavior》1989,17(1):101-112
The present paper suggests that the difficulty in inducing animals to orally self-administer quantities of ethanol sufficient to produce dependence is related to the schedule of ethanol access. If the variables that control the various patterns of ethanol consumption can be identified, then the patterns of ethanol consumption leading to excessive intake and the development of dependence will be able to be identified and generated experimentally. Evidence is presented which shows that the amount of ethanol consumed per bout, the daily frequency of ethanol bouts, as well as the total amount of ethanol consumed, is a function of the frequency of ethanol access periods, feeding condition, ethanol concentration, and the temporal proximity of ethanol access periods. 相似文献