Development of a Program for Secondary School Science to Encourage Student Understanding of the Responses of Organisms to Light

这个项目的目的是为中学水平的生物和环境之间的关系研究开发一个程序。该程序是从以下角度开发的：在一定的环境因素下，生物体会产生什么样的反应。光被选为这个项目的环境因素。在开发的程序中，光被教导为光合生物的能量来源，并作为许多生物开始和停止某些反应的信号。该节目包括以下主题：海藻的颜色和它们的栖息地之间的关系。学生们了解到，一些海藻有特殊的光收集色素用于光合作用，这与它们的垂直分布有关。本主题包括实验室练习，如光合色素的提取和分离，以及海藻对不同波长光的光合反应的检查。与光有关的光周期和植物形态发生。学生学习到花蕾的诱导、开花和叶片的剧烈运动是由光（光的数量和质量）调节的。检查(1)威斯康星快速植物的花芽诱导，(2)牵牛花的开花，(3)草叶的开合运动是为本主题开发的实验室练习。昆虫对光刺激的反应。实验中选择果蝇是为了检验它们对不同波长的光的光致反应，通过这种反应，学生们可以比较昆虫和人类的视觉感觉。一些开发的练习已在中学科学课上实施。实现是成功的。为进一步的研究提供了一些改进程序的建议。

The purpose of this project was to develop a program for studying the relationships between organisms and their environment for the secondary school level. The program was developed from the following point of view : what kinds of responses are evoked in organisms by a certain environmental factor. Laght was chosen as the environmental factor for this project. In the program developed, light is taught as an energy source for photosynthetic organisms and as a signal to start and to stop certain reactions for many organisms.The program contains the following topics :The relationship between the color of seaweeds and their habitats. Students learn that some seaweeds have special light-harvesting pigments for their photosynthesis, and this is related to their vertical distribution. This topic includes laboratory exercises such as the extraction and separation of photosynthetic pigments and the examination of the photosynthetic responses of seaweeds to different wavelengths of light.Photoperiodism and plant morphogenesis in relation to light. Students learn that flower bud induction, flowering and the nastic movement of leaves are regulated by light (both quantity and quality of light). Examination of (l) flower bud induction in the Wisconsin Fast Plants, (2) the flowering in morning glories, and (3) the opening-closing movements of oxalis leaflets are the laboratory exercises developed for this topic.The responses to light stimuli in insects. The fruit fly was chosen for this laboratory exercise to examine the phototactic responses to different wavelengths of light through which students can compare the visual sense between insects and human beings.Some of the developed exercises have been implemented in secondary school science classes. The implementations were successful. Some hints to improve the program have been obtained for further studies.