• 제목/요약/키워드: Evolutionary evidence

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Development of an Effective Strategy to Teach Evolution

  • Ha, Min-Su;Cha, Hee-Young
    • 한국과학교육학회지
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    • 제31권3호
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    • pp.440-454
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    • 2011
  • This study proposes a new instructional strategy and corresponding materials designed from various alternative frameworks to help students understand evolution as a biologically acceptable theory. Biology teachers have normally taught the evolutionary mechanism by means of comparing Lamarckism with natural selection. In this study, a new instructional strategy in which the Lamarckian explanation is first excluded because Lamarckism is known to be subsumed in a learner's cognitive structure as a strong preconception of evolution is suggested for teaching evolution. After mutation theory is introduced, Darwinism including natural selection is explained separately during the next class hour. Corresponding instructional materials that aid student understanding of the evolutionary mechanism were developed using recently published articles on human genetic traits as scientific evolutionary evidence instead of the traditional evolutionary subject matter, giraffe neck. Evolutionary evidence from human genetic traits allows students to exclude anthropocentric thoughts effectively and raise concern for the phenomenon of evolution positively. The administered instructional strategy and materials in this research improved student conception, concern, and belief of evolution and it is believed that they helped students understand the evolutionary mechanism effectively.

현생 기저 피자식물에 대한 끝나지 않는 논쟁 (Endless debates on the extant basal-most angiosperm)

  • 김상태
    • 식물분류학회지
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    • 제40권1호
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    • pp.1-15
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    • 2010
  • 한 분류군의 진화의 역사를 파악하기 위해서는 분류군 내에서 가장 먼저 분지한 군(기저군)을 알아내는 것이 중요하다. 피자식물의 계통과 진화를 이해하고자 많은 식물학자들은 형태적 연구와 화석적 증거에 의해 현존하는 피자식물들 중 가장 먼저 분지하여 다른 모든 피자식물들과 자매군을 형성하는 분류군을 파악하려고 노력해 왔다. 최근 분자계통학의 기술적 발달과 자료의 축적으로 현생 기저 피자식물군에 대한 객관적 증거들이 제시되고 있다. 여전히 논쟁의 여지는 있지만, 대부분의 식물계통학자들은 1) 다수의 유전자들의 계통분석적 접근, 2) 복제된 두 유전자군의 계통수 네트웍 형성법, 3) 유전자의 구조적 접근 등의 분자적 증거에 의해 현생 기저 피자식물이 뉴칼레도니아에 자생하는 1과 1속 1종 식물인 Amborella trichopoda Baill.임에 동의하고 있다. 그러나 또 다른 가능성으로 Nymphaeaceae (수련과)와 A. trichopoda가 하나의 분계조를 형성하고 형성된 분계조가 다른 모든 피자식물의 자매군임을 지지하는 증거들도 일부 제시되어 현생 기저 피자식물에 대한 논쟁은 계속되고 있다. 현대 분자생물학적인 신기술의 발달은 대량의 분자적 자료를 제공하고 있어 이들 논쟁 해결의 실마리를 제공해 주고 있고, 진화적 모델식물로서의 Amborella 전체 유전체의 염기서열 결정과 이에 대한 파생연구는 Darwin이 지독하게 풀리지 않는 미스터리라 표현한 피자식물의 기원과 분화에 대한 해답을 제시해 줄 수 있을 것으로 기대된다.

Blue profile in different evolutionary stages of massive star forming regions

  • Jin, Mihwa;Lee, Jeong-Eun;Kim, Kee-Tae
    • 천문학회보
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    • 제40권1호
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    • pp.68.1-68.1
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    • 2015
  • Gravitational collapse is a dynamical process associated with star formation. One observational evidence of such infall motion is so called "blue asymmetry" profile, which is the optically thick line profile with the intensity peak skewed blueward relative to the intensity peak of optically thin lines. We analyzed both HCN J=1-0 and HNC J=1-0 line profiles to study the inflow motion in different evolutionary stages of massive star formation; Infrared dark clouds (IRDCs), High-mass protostellar object (HMPOs), and Ultra-compact HII regions (UCHIIs). The infall asymmetry in the HCN spectra seems to be more prevalent than the HNC spectra throughout all the three evolutionary phases. The prevalence of the blue profile in the HCN spectra is found in every evolutionary stage, with IRDCs showing the largest blue excess. In the case of the HNC spectra, only IRDCs show the blue excess statistically significant. These results suggest that HCN may be a better infall tracer in massive star forming region. In addition, even though the characteristics of the blue profile largely depend on the suitable combination of optical depth and critical density, our analyses also indicate that IRDCs may have the most active infall process compared to other evolutionary phases.

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OBSERVATIONAL EVIDENCE OF MULTIPLE STELLAR POPULATIONS IN STAR CLUSTERS

  • Piotto, Giampaolo
    • 천문학논총
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    • 제25권3호
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    • pp.91-99
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    • 2010
  • An increasing number of observations have confirmed the presence of multiple stellar populations in Galactic globular clusters. Multiple populations evidence come from the complex chemical pattern of stars hosted in GCs and from the split or broadening of different evolutionary sequences in the color-magnitude diagrams. Multiple stellar populations have been identified in Galactic and Magellanic Cloud clusters, as well as in external galaxies. In this paper I will summarize the observational facts.

A New Extensive Census of Warped Disk Galaxies in Nearby Universe

  • 지웅배;윤석진
    • 천문학회보
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    • 제43권2호
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    • pp.32.1-32.1
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    • 2018
  • The galactic warp is almost ubiquitous among disk galaxies and suspected to be an imprint of recent interactions with other galaxies. The detailed evolutionary course, however, is still uncertain due to the lack of observational evidence. To address this issue, we construct a new extensive catalog of 412 conspicuously warped disks at z = 0.01 ~ 0.05, based on SDSS DR7. We classify the warp morphology through a visual inspection from the Zooniverse Project and our new automated scheme for the warp measurement. We find an interesting color difference between S-and U-shaped warps. The U-type warp galaxies exhibits considerable color offset towards blue compared to both the S-type warps and the control sample of un-warped galaxies. The effect is even more pronounced for galaxies (a) with the greater warp amplitude and (b) with lower luminosity. This is the first piece of observational evidence that the S- and U-shaped warps are on different evolutionary phases in terms of not only dynamics but stellar populations as well. We discuss the implications in the context of the warp evolution theory.

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고등학교 생물 교과서에서의 진화내용분석 (Analysis of Evolutionary Content in High School Biology Textbook)

  • 김학현;장남기
    • 한국과학교육학회지
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    • 제23권5호
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    • pp.470-483
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    • 2003
  • 1차에서 6차에 이르기까지 13종의 교과서의 진화내용을 분석하였다. 9가지 성분으로 구분된 교과서의 내용분석은 80가지 진화내용 항목에 대해 이루어졌다. 분석결과 교과서에서 진화내용의 총량은 증가하였으나 총 진화내용 중 본논문내용이 차지하는 비중은 1차에서 6차 교육과정에 따라 개발된 교과서로 가며 점차 감소하였고 진화내용의 비중은 생물교육과정과 교과서 저자의 시각에 의해서도 영향을 받았다. 대체로 분석된 교과서에서 다루어진 진화주제는 다양성면에서 부족하였다. 어떤 주제 항목은- '집단선택', '유전자 선택', '화석 기록에서의 공백', '공진화', 단속 평형설', '혼합진화', '인류진화에 있어서의 노동의 위치', 인종의 차이', ''개체발생의 계통발생을 반복한다'에 대한 비판', '진화에 영향을 미치는 인간의 활동'-다루어지지 않았고 또 어떤 항목은-'중립설', '지질시대에서 발견되는 주요사건에 관한 설(멸종에 관한 내용 제외)', '동소적 종분화', '연속변이적 종분화 및 지역효과 종분화', '배수성과 진화', '점진주의', '연장류의 기원과 진화'-거의 언급되지 않았다. 가장 강조된 주제 항목은 '일반적인 계통학', '세포전 단계의 형성', '기타' 순으로 많이 강조되었다. 자연선택설은 진화의 중요 주제임에도 불구하고 여러진화설중의 하나로 다루어졌다. 또한 유전적 평형을 붕괴시키는 요인으로서 유전적 부동이나 이주 등도 소홀히 다루어지고 있었고 종분화의 속도와 관련된 주제도 거의 언급되지 않았다. 반면 신뢰성이 의심되는 발생반복설이 진화 증거의 하나로 교과서에서 제시되었다. 이 결과에 근거해 교과서 저자들이 진화와 진화설을 설명할 때 자연 선택설에 초점을 맞추어 보다 의미 있는 주제를 소개할 것을 제안한다.

Tectonics and Evolutionary History of the Cretaceous Intra-arc Yongdong Basin, Korea

  • Lee, Dong-Woo
    • 한국지구과학회지
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    • 제30권5호
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    • pp.565-580
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    • 2009
  • The Yongdong basin developed during Early Cretaceous in the central part of the Korean Peninsula and bounded on the northwest and southeast by northeast trending mega-scale strike-slip Yongdong Fault. An 8 km thick succession of exclusively terrigeneous sediments can be grouped into two mega-sequences. In concert with the migration of depocenter, the upper sequence overlaps the lower and occupies northern part of the basin during basin evolution. Alluvial and lacustrine environments were predominantly formed from early to late stage of the basin formation. Several lines of evidence support that the basin was formed within intra-arc tectonic environments and destroyed by polyphase tectonic force. Schematic evolutionary diagram of the basin is proposed.

Revisited Meaning of Gated Community as a Tieboutian Voter: Evidence from Seoul of Private Governance and Local Public Goods

  • 우윤석
    • 토지주택연구
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    • 제11권1호
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    • pp.39-48
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    • 2020
  • Main research question of this study is about whether gated community (GC) as private urban governance gets along with local public goods by locating near to them. We examine this question through testing the Tiebout hypothesis from case study of Seoul, capital city of South Korea, in which GCs are so common to test the assumption empirically. For this, we examine the meaning of GC in 3 Es viewpoints; conceptualize the framework of Tieboutian co-evolution of GC and local public goods by hedonic price modeling. As a result, possibilities are found that GCs are to be seen from different point of view, viz. co-evolutionary mechanism between private and public governance; GCs effectively capture and represent the demand of residents for local public goods through voting by their collective locational choice. It allows us different kind of approach to investigate APTs as a co-evolutionary form of private and public urban order rather than seeing them only as a tool of speculative investment, particularly in rapidly urbanizing countries like Korea.

Evolutionary Models for Helium Giant Stars as Type Ibn Supernova Progenitors.

  • Kim, Jihoon;Yoon, Sung-Chul
    • 천문학회보
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    • 제43권2호
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    • pp.40.1-40.1
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    • 2018
  • Among Type I supernovae, which show no evidence for hydrogen lines in spectra, Type Ib/c supernovae lack of strong Si absorption lines and are involved with massive progenitors. While strong helium absorption lines are present in Type Ib supernovae, narrow helium emission lines also can appear in some Type Ib that are often called Type Ibn supernovae (SNe Ibn). We consider helium giant stars as a promising progenitor candidate for SN Ibn and suggest the evolutionary scenario through binary systems using MESA code. In our models the range of primary mass is 11 - 20 solar mass, mass ratio is 0.5 - 0.9, and initial period is 1.5 / 1.7 / 2.0 / 2.5 / 3.0 day. In particular, we find that the evolution of the secondary star can overtake the primary through mass transfer from the secondary to the primary, which is so-called 'reverse case B' mass transfer. In such systems the secondary star may undergo a supernova explosion earlier than the primary star. In this case, the primary star evolves towards a single helium giant to become a SN Ibn progenitor. These cases are more frequent in relatively low initial primary mass.

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