演绎与推理作为生物学科核心素养中科学思维的重要组成部分，在高中生物学尤其是 《遗传与进化》模块具有普遍应用。PBL（Problem-based learning）是指“以问题为基础” 的教学方法，基于建构主义理论，将学生置于复杂、创新的问题情境中，引导学生围绕问 题进行自主、探究式学习。查阅和梳理文献发现 PBL 教学模式与演绎推理在理论基础、教 学手段、学习程序等方面都有一定的契合性，因此本研究聚焦于在《遗传与进化》模块运 用 PBL 教学模式，探索能否通过问题式教学提高学生的演绎推理能力。

本文首先通过文献研究法分别梳理了 PBL 教学和演绎推理的理论研究，概述了 PBL 的理论基础、涵义、研究现状和基本教学模式，阐述了演绎推理的内涵、培养策略及评价 方式。接着，以两者理论的相融性为依据，分析了 PBL 教学模式培养学生演绎推理能力的 可行性。在此基础上，选取人教版高中生物学《遗传与进化》模块中“遗传因子的发现”、 “基因在染色体上”、“伴性遗传”、“DNA 的复制”和“基因表达与性状的关系”这五 个具有代表性的案例，设计出培养学生演绎推理能力的 PBL 教学方案。最后，选取吴忠中 学高二年级两个理科普通班进行一学期的教学实验，一个班实施 PBL 教学，另一个班实施 常规教学。在教学实验结束后，通过《第二科学推理试题》问卷和期末生物学业成绩定量 检测两班学生的演绎推理能力和学科知识水平的变化，结合学生访谈结果评价实践效果。

教学实践结果的统计分析表明：教学实践前，两个班级的科学推理能力和学业成绩均 无显著差异；实践后，实验班的演绎推理能力和生物学业成绩都出现明显的提升，显著优 于对照班级。访谈发现尽管存在查阅资料花费较多时间和刚开始小组成员配合不够默契等 困难，实验班同学还是普遍认可 PBL 教学，演绎推理意识较强，尊重问题和实验证据。由 此推论：相比于传统教学，PBL 教学能更有效地培养学生的演绎推理能力并促进学科知识 的掌握。合理利用 PBL 教学有助于提升学习兴趣，培养学生尊重问题和实验的科学态度。

结合对研究结果的分析，对今后教学提出了三点建议：增大样本数量，延长实验周期； 邀请同组教师进行课堂观察，用科学量表对学生和授课教师的表现进行评分；加强问题式 教学理论学习，提高设计 PBL 教学方案的能力。

Deduction and reasoning is an important part of scientific thinking in the core quality of biology, It is widely used in high school biology, especially in the module of Genetics and Evolution. PBL (Problem based learning) refers to the "problem based" teaching method, which is based on the constructivism theory. It places students in complex and innovative problem situations, and guides students to carry out autonomous and exploratory learning around problems. Through consulting and sorting out the literature, the author found that PBL teaching model and deductive reasoning have certain consistency in theoretical basis, teaching methods, learning procedures, etc. Therefore, this research focuses on the application of PBL teaching mode in the module of "Genetics and Evolution" to explore whether students' deductive reasoning ability can be improved through problem-based teaching.

This paper first combs the theoretical research of PBL teaching and deductive reasoning through literature research, summarizes the theoretical basis, meaning, research status and basic teaching mode of PBL, and expounds the connotation, cultivation strategies and evaluation methods of deductive reasoning. Then, based on the integration of the two theories, the feasibility of PBL teaching mode to cultivate students' deductive reasoning ability is analyzed. On this basis, the author selects five representative cases in the module of "Inheritance and Evolution" of senior high school biology published by People's Education Press: "Discovery of Genetic Factors", "Genes on Chromosomes", "Sex linked Inheritance", "Replication of DNA" and "Relationship between Gene Expression and Traits", and designs a PBL teaching program to cultivate students' deductive reasoning ability. Finally, the author selected two ordinary science classes in senior two of Wuzhong Middle School for a semester of teaching experiment. One class implements PBL teaching, and the other class implements conventional teaching. After the teaching experiment, the change of deductive reasoning ability and subject knowledge level of the two classes of students was quantitatively detected through the questionnaire of the Second Scientific Reasoning Test and the final biological academic performance, and the practical effect was evaluated based on the student interview results.

The statistical analysis of the results of teaching practice shows that: Before teaching practice, there is no significant difference between the two classes in scientific reasoning ability and academic performance; After practice, the deductive reasoning ability and biological academic performance of the experimental class were significantly improved, significantly betterthan the control class. Through the interview, it was found that despite the difficulties such as spending more time to consult the data and the lack of tacit cooperation among the group members at the beginning, the students in the experimental class generally recognized PBL teaching, had a strong sense of deductive reasoning, and respected the problems and experimental evidence. It is concluded that PBL teaching can more effectively cultivate students' deductive reasoning ability and promote the mastery of subject knowledge than traditional teaching. Rational use of PBL teaching is helpful to enhance learning interest and cultivate students' scientific attitude of respecting problems and experiments.

Based on the analysis of the research results, three suggestions are put forward for future teaching: Increasing the number of samples and prolonging the experimental period; Invite the same group of teachers to observe in class, and use the scientific scale to grade the performance of students and teachers;Strengthen the theoretical learning of problem-based teaching and improve the ability to design PBL teaching plans.