以概念演化樹探討跨年級學生對演化概念之發展

Abstract

本研究以問卷方式調查跨年級學生的演化概念，研究對象為國小六年級、國中一年級、高中一年級、高中二年級和大學一年級，每個年級施測人數約在110~140人，有效問卷共747份。 演化概念共分成四個主概念依序為「個別變異」、「遺傳決定」、「不同的存活率」和「累積世代的改變」，再細分成六個次概念依序為「變異的來源」、「族群裡的變異」、「可遺傳的變異」、「特定性狀比例改變」、「性狀的存活」和「適應」。 整合選擇與開放題之演化概念組合，以四個主概念做為分析單位，透過系統分類學的分析軟體PAUP* 4.0找出可能的概念演化樹，藉由本研究的數據資料進一步找出最適合的概念演化樹，用以解釋跨年級演化概念之發展和主概念之出現時間順序。 本研究結果發現如下，可分成五點說明：

1.尚未學習演化前的小六學生較容易使用外在、後天、短暫、特質類別來解釋演化概念，雖然經過教學的學生仍有此現象，但比例較為學習前低。 2.跨年級學生於選擇題和開放題的表現趨勢相近達高度相關，唯一差別在於開放題表現低於選擇題，整合兩種題型結果做為整體演化概念組合。 3.使用系統分類學繪製跨年級學生演化概念發展支序圖，科學模式的發展，在小六前已具備主概念三「不同的存活率」，小六發展出主概念一「個別變異」，國一階段依序發展出主概念二「遺傳決定」和主概念四「累積世代的改變」。 4.當主概念一「個別變異」尚未建立時，會影響主概念二「遺傳決定」的學習，嚴重甚至會導致主概念三「性狀的存活」轉變為混合類型，連同主概念四亦會出現混和或錯誤類型。 5.尚未經歷演化教學的小六學生出現的心智模式較少，經過國一教學後出現的心智模式類型則較多，因為結合初始和科學模式而產生較多的心智模式，直到高二階段以後心智模式類型才漸漸集中。

整體而言，學生都很容易使用外表能看到的特徵或特質來解釋演化過程，較缺乏深度思考其演化之內部機制。教學上可參考學生的概念發展歷程適時給予正確的引導，增加例子說明或是實際體驗演化活動，以協助學生在演化概念之發展可以更朝向科學模式邁進。This is a cross-age study of students’ conceptions about evolutionary. This study investigated students at 6th grade, 8th grade, 9th grade, 10th grade, 11th grade (science major), and freshmen majored in Life Science. All questionnaires toward evolution theory are 747 copies. There are about 110~140 students in each grade. Evolutionary concept divides into four major conceptions: individual variation, genetic determination, differential survival rates, and accumulation of changes over many generations. Major conceptions also divide into six small parts of sub-conceptions: the origin of species, variation within a population, variation inheritable, changes of the specific characters, and adaptation. The result combines multiple choice questions with essay questions. Four conceptions are used for the analysis unit of Evolutionary concept. The study utilizes the software PAUP* 4.0 of phylogenetic systematics finding the fittest conceptual evolution tree of evolution concept. The fittest cladogram represents the developmental process of evolutionary concept and the order of four major conceptions. The results are as follows: First, most 6th students who don’t have the specified lesson of evolution often use external, acquired, transient, speculative types to explain the process of evolution. Even the students after learning the lesson, the result is still the same, but rate lower than before. Second, the scores between multiple choice and essay questions have high correlation. The only difference is the score of essay questions lower than multiple choice ones. Therefore, integrating the two scores serves as the combination of the whole evolutionary concept. Third, the fittest cladogram represents the development of the scientific model. Younger than 6th grade had the third major conceptions “differential survival rates”, and then the phase of 6TH grade has the first major conceptions “individual variation”. Finally , the phase of 7th grade has the second ones “genetic determination” and the forth ones “accumulation of changes over many generations.” Forth, when students don’t establish the he first major conceptions “individual variation”, it will affect the learning of the second ones “genetic determination”, seriously also result in changing to mixed type of third ones “differential survival rates”, and then make the mistake or mixed types of the forth ones “accumulation of changes over many generations.” Finally, the number of mental models at 6th grade is less than 7th grade after teaching and learning.It is because mental models combine initial ones into scientific ones because of learning. To sum up, most students prefer the characters or speciality they can see to explain the process of evolution, and they ignore the inner mechanism of evolution. The development of concept can provide the teaching guide, giving the help at the right moment, and adding the examples or activities. It will make the development of evolutionary concept across to scientific model.