共查询到20条相似文献，搜索用时 31 毫秒
1.
宋珍炎 《淮南职业技术学院学报》2002,2(2):50-51,54
距今543Ma前的寒武纪，地球上发生无脊椎动物大爆发，按照生物进化论的观点，在其更早的地层中，应能见到其相应的祖先或其活动痕迹，中国淮南新元古代地层中发现的掘迹化石是迄今为止世界上最早的掘迹化石，其时限为距今700Ma，阐述了该掘进迹化石的特征，并对其地质意义进行了讨论。 相似文献
2.
P V Sukumaran 《Resonance》2001,6(11):4-17
The prebiotic organic synthesis occurred in a reducing or mildly oxidising atmosphere. There was no dearth of energy sources
to drive this reaction. The speculation that life originated in ocean floor vent habitats is supported by the recent discovery
of fossil microbes in a mid-Archaean vent ecosystem. Evidence from nucleic acid sequencing that the last common ancestor of
all extant life is a hyperthermophile also lends credence to this hypothesis. The first living molecule that held heritable
genetic information was probably ribonucleicacid. The course of events that nature would have followed to reach the RNA-world
is fairly clear, but simulating this course in the laboratory to reach RNA remains a formidable problem and has little relevance
to an early Earth setting. A prolonged period of abiotic chemical evolution undoubtedly preceded the emergence of the first
living molecule.
P V Sukumaran took his M Tech degree in applied geology from the University of Saugar and has been with the Geological Survey
of India since 1974. His interests include petrology, geochemistry, palaeoceanography and organic evolution. He is presently
posted as Director in the Department at Nagpur 相似文献
3.
Ramesh Maheshwari 《Resonance》2006,11(4):33-44
The roots of most land plants establish intimate associations with soil fungi. This association of plant roots with fungi
is termed mycorrhiza. It is a marriage between two highly dissimilar organisms based on mutual exchange of nutrients: while
the plants provide photosynthetically made carbon compounds to the fungi, the fungi in turn provide to the plants nitrogen
and phosphorus scavenged from the breakdown of organic polymers in natural substrates. This mutually beneficial partnership
makes possible the green cover on Earth and of all life, ultimately, dependent on plants. 相似文献
4.
Sujan Sengupta 《Resonance》2016,21(7):641-652
Is there life anywhere else in the vast cosmos? Are there planets similar to the Earth? For centuries, these questions baffled curious minds. Either a positive or negative answer, if found one day, would carry a deep philosophical significance for our very existence in the universe. Although the search for extra-terrestrial intelligence was initiated decades ago, a systematic scientific and global quest towards achieving a convincing answer began in 1995 with the discovery of the first confirmed planet orbiting around the solar-type star 51 Pegasi. Since then, astronomers have discovered many exoplanets using two main techniques, radial velocity and transit measurements. In the first part of this article, we shall describe the different astronomical methods through which the extrasolar planets of various kinds are discovered. In the second part of the article we shall discuss the various kinds of exoplanets, in particular about the habitable planets discovered till date and the present status of our search for a habitable planet similar to the Earth. 相似文献
5.
Shari L. Britner 《科学教学研究杂志》2008,45(8):955-970
The aims of this study were to examine self‐efficacy and other motivation variables among high school science students (n = 502); to determine the degree to which each of the four hypothesized sources of self‐efficacy makes an independent contribution to students' science self‐efficacy beliefs; to examine possible differences between life, physical, and Earth science classes; and to investigate patterns of gender differences that may vary among the fields of science. In Earth science classes, girls earned higher grades and reported stronger science self‐efficacy. In life science classes, girls earned higher grades but did not report stronger self‐efficacy, and did report higher science anxiety. In physical science, there were no gender differences in grades or self‐efficacy, but girls again reported higher levels of science anxiety. For boys across science fields, science self‐efficacy significantly predicted course grades and mastery experiences was the only significant predictor of self‐efficacy. For girls, self‐efficacy was also the strongest predictor of science grade across fields. Mastery experiences significantly predicted self‐efficacy in Earth science for girls, but social persuasions, vicarious experiences, and physiological states were better predictors of science self‐efficacy in life and physical science classes. Results support (Bandura, A., 1997) hypothesized sources of self‐efficacy, previous research findings on self‐efficacy in the domain of science, and validate the suggestion made by Lau and Roeser (2002) to disaggregate data by science field. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 45: 955–970, 2008 相似文献
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7.
数字地球是现代信息科学与地球科学的高度综合和升华，是地球科学的最新发展成果和未来发展趋势。数字地球技术系统复杂多样，是多种信息技术的综全应用。数字地球将深刻的改变人类未来的生活方式和生产方式。 相似文献
8.
Dawn L. Sanders 《International Journal of Science Education》2013,35(10):1209-1228
Plants are essential to life on Earth and yet are often deemed invisible by the human populace. Botanic gardens are an under‐researched educational context and, as such, have occupied a peripheral arena in biology education discussions. This article seeks to readdress this absence and present the case for a more sustained use of informal learning environments, such as botanic gardens and homes, to make public the private life of plants and their role in sustaining life on Earth. By drawing on empirical data from a doctoral thesis and reviewing relevant research literature, the author argues for a renewed focus on botanical education within science education in both formal and informal contexts. 相似文献
9.
谢素霞 《沙洋师范高等专科学校学报》2006,7(3):50-51,70
阿兰是赛珍珠的代表作《大地》中旧中国农村妇女的文学形象，她忠厚老实，勤劳朴素，任劳任怨，深受男权社会的迫害。文中分析阿兰对王龙的奉献及其所受到的屈辱，进而揭示旧中国女性难以摆脱男权重压下的悲惨命运。 相似文献
10.
Sindhu Radhakrishna 《Resonance》2006,11(7):51-60
Looking at ourselves today, it is a little difficult to conceive of our origins as “small, fuzzy critters” that ate insects
and lived in trees. And yet, as modern biology suggests, humankind is only part (and a very small part!) of an evolutionary
continuum that stretches back to the origins of the primate order, some 80 million years ago. This article attempts to trace
the origin and evolution of the primate order from its beginnings as a small and obscure species in a corner of the planet
to the rise and spread of humankind, the most formidable species on Earth today. The first part of this article briefly reviews
the evolutionary history of primates and significant phenomena that affected the course of this evolution, while the second
part of the article focuses on the important stages in human evolution. 相似文献
11.
Karin Ehrlén 《European Journal of Psychology of Education - EJPE》2009,24(3):281-292
To acknowledge both conceptual and situational factors, children’s understanding of the Earth was considered from three angles: 1, the perspective as the physical point or direction from which something is seen or depicted; 2. conceptual frameworks; 3. the relevance of explanations in a situation. Fourteen children were interviewed individually in front of a poster of a satellite photo of the Earth. The interviews were semi-structured and focused on what the children understood was depicted in the poster and if they had seen the Earth. The effect of choice of perspective was demonstrated by children who only talked about how the Earth could be seen from space. The need to relate different conceptual frameworks became apparent with children, who meant that the Earth was situated in the direction of the sky. Different understandings of the relevance of an explanation were detected when the interviewer talked from the perspective in the room, but children talked about the perspective in the present poster. The results indicate that not only both conceptual frameworks and understanding of perspectives play a part when students encounter questions related to the concept of Earth, but also the students’ judgments of the relevance of different explanations in a situation. 相似文献
13.
Ricardo Trumper 《International Journal of Science Education》2013,35(11):1111-1123
Junior high school students' astronomy conceptions were analysed by means of a written questionnaire presented to them during the beginning of the first semester. The main findings were as follows: almost half of the students indicated that the cause of the day-night cycle is the Earth spinning on its axis; most students chose as their best account for changes in the Moon's phases the Moon moving around the Earth. Despite that, most students thought that the Moon must be in its Full phase for there to be a total solar eclipse; most students underestimated the distances in the Universe and overestimated the Earth's diameter. A great proportion of students indicated that the reason for the different seasons is the tilt of the Earth's axis relative to the plane of its orbit as it revolves around the Sun. But almost the same number of students chose the varying distance between Sun and Earth or between the Earth, Moon and Sun, as a reason for the seasons. Only a third of the students answered correctly that in Israel's latitude, north of the Tropic of Cancer, the Sun is never directly overhead at noon; most students chose the correct estimate of a month for the Moon revolving around the Earth and a year for the Moon going around the Sun; about a third of the students chose the correct answer that when it is noon in Haifa, it would be about sunset in Beijing (90° east of Haifa). Few students indicated that the fact that we always see the same side of the Moon from the Earth implies that the Moon rotates on its axis once a month. 相似文献
14.
Thousands of years ago,the Jews were forced to leave their homeland and began to live an exiled life and gradually melted into other neighboring peoples.However,they were not welcomed by others.For thousands of years,Jews’ "Bible" has become a source of literary and artistic creation,but the image of Jews were excluded from the literary and artistic creation,even if there were some occasions,they were but described as autistic Misers or loan shark.Shakespeare is one of the most outstanding writers;he described many people from all walks of life in his works,the Jews,also included.Based on the corpus of Shakespeare’s works,we can see that most adjectives used by Shakespeare to modify the word "Jew"are derogative words.Therefore,we can prove that anti-Semitism does exist in Shakespeare’s works. 相似文献
15.
ZHANG Bu xin ZHANG Zhi lin ZHU Wen qing JIANG Xue yin XU Shao hong School of Material Science Engineering Shanghai University Shanghai China 《上海大学学报(英文版)》2001,5(2):151-155
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｓｉｎｃｅａｎｏｒｇａｎｉｃｌｉｇｈｔ ｅｍｉｔｔｉｎｇｄｉｏｄｅ (ＯＬＥＤ)ｗｉｔｈｈｉｇｈｅｆｆｉｃｉｅｎｃｙｗａｓｒｅｐｏｒｔｅｄｂｙＴａｎｇａｎｄＶａｎＳｌｙｋｅ[1]ｉｎ 1987,ｆｌａｔｐａｎｅｌｄｉｓｐｌａｙｓｂａｓｅｄｏｎＯＬＥＤｓｈａｖｅｂｅｅｎｄｅｖｅｌｏｐｅｄ .Ｉｎｒｅｃｅｎｔ ｙｅａｒｓ ,ｓｅｖｅｒａｌｌａｂｏｒａｔｏｒｉｅｓａｒｏｕｎｄｔｈｅｗｏｒｌｄａｒｅｅｎｇａｇｅｄｉｎｄｅｖｅｌｏｐｉｎｇｔｈｅｍａｔｅ ｒｉａｌｓ ,ｄｅｖｉｃｅｓａｎｄｐｒｏｃｅ… 相似文献
16.
This article studies the conceptions of the interior of the Earth held by Portuguese elementary school children and senior citizens. Several studies were conducted regarding conceptions related to Earth sciences, such as rocks, minerals, earthquakes geological time, and Earth structure. Most of these studies involved students enrolled in compulsory education, some involved higher education students, several involved teachers, and only a few involved adults. The majority of the results showed that many misconceptions are held by people of all ages. Similar results were found in this study, as both children and senior citizens revealed several misconceptions. The research resorted to a questionnaire based on a drawing task so as to find out the way that children and senior citizens imagine the structure and composition of the interior of our planet. A comparison between children’s and senior citizens’ drawings was made, as well as a comparison between those drawings and the historical models of the internal structure of the Earth. We found that only a small number of children and even a smaller number of senior citizens recognize that the interior of the Earth is organized in concentric layers. They assume that soil and water are a common part of the internal composition of our planet. Similarities between the drawings and the historical models were identified, particularly similarities related to Gautier’s model, which accepts the possibility of the existence of life in the interior of the planet as it happens on its surface. 相似文献
17.
Despite the protracted history of life on earth spanning well over 3.8 Ga, fossil record of the Precambrian (> 543 Ma) largely
documents only microscopic life. The mostly simple Precambrian life forms were followed by a sudden explosive radiation of
multicellular animals at the turn of the Cambrian period (543–490 Ma) between 530 and 520 Ma ago, when almost two-thirds of
the animal phyla make their dramatic appearance in the fossil record. This unusual and amazing burst of macroevolutionary
change is called the Cambrian explosion 相似文献
18.
Annette Gough 《Environmental Education Research》1999,5(4):383-394
In this article I respond to the special issue of Environmental Education Research (EER) by problematising significant life experiences research from the perspective of research and commentaries on intergenerational differences, environment‐related research with youth, and the silences in significant life experiences (SLE) research on gender, race and class. I argue that the youth of today are very different from older generations, so the achievement of the goals of environmental education through the extension of significant life experiences for older generations to the youth of today is a questionable activity. If our goal is the achievement of environmentally literate youth through environmental education, and, if we are going to use significant life experience research at all, then we need to be investigating the experiences which have been significant to youth at the end of the 20th century, not the experiences of those who were youths decades ago. 相似文献
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20.
Haimanot Habte Lemji Hartmut Eckstädt 《Journal of Zhejiang University. Science. B》2013,14(10):924-933
Evaluating the performance of a biotrickling filter for the treatment of wastewaters produced by a company manufacturing beer was the aim of this study. A pilot scale trickling filter filled with gravel was used as the experimental biofilter. Pilot scale plant experiments were made to evaluate the performance of the trickling filter aerobic and anaerobic biofilm systems for removal of chemical oxygen demand (COD) and nutrients from synthetic brewery wastewater. Performance evaluation data of the trickling filter were generated under different experimental conditions. The trickling filter had an average efficiency of (86.81±6.95)% as the hydraulic loading rate increased from 4.0 to 6.4 m3/(m2·d). Various COD concentrations were used to adjust organic loading rates from 1.5 to 4.5 kg COD/(m3·d). An average COD removal efficiency of (85.10±6.40)% was achieved in all wastewater concentrations at a hydraulic loading of 6.4 m3/(m2·d). The results lead to a design organic load of 1.5 kg COD/(m3·d) to reach an effluent COD in the range of 50–120 mg/L. As can be concluded from the results of this study, organic substances in brewery wastewater can be handled in a cost-effective and environmentally friendly manner using the gravel-filled trickling filter. 相似文献