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

该项目的目的是为中学制定一个研究生物体与其环境之间关系的方案。该程序是从以下角度开发的：什么样的反应是由一定的环境因素引起的生物体。Laght被选为该项目的环境因素。在开发的程序中，光被教导作为光合生物的能量来源，并作为启动和停止许多生物的某些反应的信号。该程序包含以下主题：海藻的颜色和它们的栖息地之间的关系。学生将了解到一些海藻具有特殊的捕光色素用于光合作用，这与它们的垂直分布有关。本课题包括实验室练习，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研究。光周期和植物形态发生与光的关系。学生将学习到花芽诱导、开花和叶子的弹性运动受光（光的数量和质量）的调节。（1）威斯康星州快速植物的花芽诱导，（2）牵牛花的开花，（3）酢浆草叶片的开合运动是为这一课题开发的实验室练习。昆虫对光刺激的反应。是次实验以果蝇为对象，研究它们对不同波长光线的趋光反应，让学生比较昆虫与人类的视觉感受。部分实验已在中学科学课上进行。实施是成功的。为进一步的研究提供了一些改进的思路。

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.