It is the basic requirement and central goal of compulsory education, and also the premise and foundation of environmental education for students. In biology teaching, we should pay full attention to the knowledge of ecological environment scattered in various chapters and the chapter of "Biology and Environment", analyze basic concepts from two aspects of connotation and extension, and guide and train students to say concepts, compare concepts, remember concepts and use concepts; Use schematic diagrams and typical examples to guide students to understand the relationship between biological form, structure and function, the relationship between living habits and environment, and the relationship between organisms, so that students can gradually establish a scientific view of adaptation between organisms and the environment; Through memorizing, understanding, comprehensive application and practical operation, we can cultivate students' interest in environmental issues, train students' observation ability, memory ability and imaginative thinking ability, cultivate students' scientific spirit of being objective and realistic, lofty and rational, and advocate experiments, and finally achieve the goal of "laying the foundation for textbooks" The slightly extended biology textbook is very rich in content, but due to the limitation of class hours and space, the description of the ecological environment is often very simple, and it is difficult to achieve the expected goal if you "read the book" in teaching; On the contrary, if narrative is slightly extended in teaching, better results will be achieved.
For example, when teaching the meaning of photosynthesis, we can extend it like this: the general broad-leaved forest 1 hectare can absorb 1 1,000 kilograms of carbon dioxide and release 750 kilograms of oxygen every day during the growing season. If adults need to consume 0.75 kg of oxygen and emit 0.9 kg of carbon dioxide every day, then every urban resident has 100 m2 of trees.
For another example, frog predation can be extended to: According to estimates, there are/kloc-0 zebra and 65438+266 edible insects every day. If you eat 50 insects a day on average, there will be 1000 zebras per mu of rice field, and more than 50,000 pests such as Chilo suppressalis and Chilo suppressalis can be eliminated every day. Extension is the "expansion" or "explanation" of textbook narration. Proper application can make the knowledge of ecological environment more concrete, intuitive, vivid and interesting, and students like it, but we can't "gild the lily" or "put the cart before the horse" in application. When properly introduced into teaching, some abstract or complex environmental problems are difficult to be accepted by junior high school students, and some important environmental knowledge points are hidden and easily ignored, which becomes a "blind spot" in teaching. Introducing some environmental protection knowledge properly after class can help students understand the difficulties, pay attention to "blind spots", and also stimulate students' interest in learning, broaden their horizons and enrich their knowledge. For example, in the teaching of "reasonable irrigation", in order to save water and educate students, it can be introduced that agricultural irrigation needs a lot of water. According to the investigation in North China, it takes about 2.5×104 kg ~ 3.5×104 kg per mu to grow vegetables and 4× 104 kg ~ 5 to grow wheat. Irrigation should be "drip irrigation" or "sprinkler irrigation" instead of "flood irrigation" to avoid waste.
Another example can be introduced when teaching "Respiratory Hygiene": an adult breathes fresh air about 20,000 times a day through his nose, and the amount of air inhaled reaches 15 m3 ~ 20 m3, which is about 10 times the weight of food and drinking water needed every day. If the inhaled air is unclean or contains toxic components, it will do great harm to human health. When it comes to population, it can be introduced that food on the earth can only feed 8 billion people at best. Based on the analysis of land resources, population growth, means of subsistence growth and employment, scientists in China believe that the moderate total population of China is 6.5 billion to 700 million. According to this goal, China's existing population has exceeded 500 million, so we must strictly control the natural population growth and implement family planning.
Appropriate introduction is the enrichment and supplement of environmental knowledge in teaching materials, and it is necessary to prevent far-fetched or excessive introduction and increase students' learning burden. The teaching materials of special lectures have certain stability and lag, but environmental problems occur all over the world every day. In order to arouse students' attention to environmental hot issues, special lectures can be given to students in time. For example, a special lecture will be held in conjunction with the Environmental Remembrance Day. On Arbor Day (March 12), Water Day (March 22), Earth Day (April 22), Environment Day (June 5), Population Day (June1kloc-0/day), Desertification Day (June1day) You can also give lectures in combination with the content of the textbook. For example, after "exploring the mysteries of biology", we can talk about "four major problems facing the world today". After talking about "preventing food poisoning", we can talk about "food pollution"; Special lectures can also be given in combination with sudden major ecological events. For example, in July and August of 1998, a once-in-a-century flood occurred in China, which can give students a special lesson on "Ecological balance cannot be destroyed" in time.
According to the active practice of teaching content, organize students to investigate the environmental conditions of towns or residential areas, observe the changes of river reach caused by sewage discharge from small smelters, wineries and other enterprises and sewage injection into rivers, observe the pollution of domestic garbage to water quality and surrounding air and the terrible breeding of mosquitoes and flies, organize students to clean up "white pollution", investigate the use of chemical fertilizers and pesticides, and guide students to read popular science books such as Silent Spring and Environmental Protection after class, and combine learning with application. Practical activities have exercised students' abilities of observation, hands-on and brain-thinking, which further clarified the universality and seriousness of environmental pollution, thus inspiring their sense of responsibility and mission, and laying a solid foundation for the cultivation of good environmental quality.