小学校における胚発生の観察方法に関する実践的研究:―固定胚の活用方法の提案―  [in Japanese] Practical research on the observation of embryogenesis of medaka in elementary school science classes:—A suggestion for the utility of fixed embryos—  [in Japanese]

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Abstract

<p>小学校理科教科書第5学年「動物の誕生」では,ヒメダカ(<i>Oryzias latipes</i>)を観察材料として胚発生を観察し,その観察結果を記録してまとめる活動が扱われている.メダカの卵の中が変化して体が作られていく過程を理解するためには,卵の中の様子を一時点で捉えるのではなく,発生過程を継続的に捉えることが重要である.しかし,発生の観察において,無作為に採取した生きた胚の断続的な観察だけでは児童がメダカの発生段階を正しく認識できていないことが問題点として挙げられる.そこで本研究では,児童が生きた胚の発生段階を認識しやすくする補助が必要であると考え,ヒメダカの初期胚を発生段階を追って詳細に観察するとともに,いつでも目的の発生段階の観察が可能な固定胚を作製した.固定胚の適性を評価するため,大学生を対象として,生きた胚と固定胚において観察できる構造に差はないかを調べると,血管,血球,心臓など動きのあるものは生きている胚の方が識別できたが,他の構造や器官については大きな違いはなかった.そして小学生を対象として固定胚を一連の発生段階を示す標本として用いた発生観察の授業実践を行い,その有用性を検討した.その結果,生きた胚を観察して発生段階を考える上で,観察の補助として固定胚を用いた授業では教科書を用いた授業と比べて,メダカの卵の産卵後日数と発生過程のどちらにおいても,正しく認識できた児童の割合が高かった.よって,生きた胚の観察にいつでも各発生段階を観察できる固定胚を併用することは,教科書を用いて観察を行うより生きた胚の発生段階を認識できることが示唆された.</p>

<p>In elementary school science textbooks, the study unit "animal birth" has an activity to observe the embryogenesis of medaka (<i>Oryzias latipes</i>) while in the egg. It is important to understand this process not in isolation, but continuously. Elementary school children cannot recognize embryonic development correctly while they intermittently observe living embryos selected randomly from adult medaka or attached on waterweeds growing in an aquarium. Some supplementary teaching materials are required in observing living embryos to understand the morphogenetic process continuously. In this study, we observed the development of medaka and prepared fixed specimens of embryos, allowing their developmental stage to be observed at any time. First, we investigated whether college-level students could observe the organs and structures of fixed embryos the same as for living embryos in order to evaluate the applicability of the fixed embryos before trying to use the embryo specimens with elementary school children. The structures of the living embryos such as the blood, blood vessels, and heart, for which movements can be easily observed were better recognized compared with the fixed embryos, but there was no significant difference between the recognition of other organs and structures of living and fixed embryos. We also implemented the observation of medaka embryos in elementary school science classes with fixed embryo specimens which can show the sequence of embryonic development and we considered their utility. As a result, in the class using the fixed embryos as supplementary teaching materials along with living embryos, more children were able to recognize correctly either the days after oviposition or the process in which the body was developing, compared with the class using only textbooks. Therefore, we suggest that the use of fixed embryo specimens, along with living embryos, helps children to comprehend better the embryogenesis of medaka than the use of only textbooks does.</p>

Journal

  • Japanese Journal of Biological Education

    Japanese Journal of Biological Education 59(1), 2-9, 2017

    The Society of Biological Science Education of Japan

Codes

  • NII Article ID (NAID)
    130007500659
  • NII NACSIS-CAT ID (NCID)
    AN0012957X
  • Text Lang
    JPN
  • ISSN
    0287-119X
  • NDL Article ID
    028737095
  • NDL Call No.
    Z18-53
  • Data Source
    NDL  J-STAGE 
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