近年来，随着当前新课改的提出和不断推进，大概念教学，发展核心素养，学习进阶等已经成为研究热点。在新课标中提出的“内容聚焦大概念”这一理念背景下，针对大概念构建学习进阶在理论层面上更有利于精准把握大概念教学，发展学生核心素养。而学生发展核心素养，最终还是要落实到课堂教学中。一线的课堂教学，无论是教师为主导还是学生为主体，都离不开教学设计。但是在进行教学设计过程中，教师很难通过单课时教学达到教学目标。单元教学设计理论的提出很好的解决了这一问题。因此，本研究将学习进阶和单元教学设计相联系，突破了传统研究中只针对学习进阶或单元教学设计的研究，在构建学习进阶的基础上进行单元教学设计。学习进阶为单元教学设计提供理论指导，单元教学设计作为学习进阶的具体体现。

本研究选择了“遗传的分子基础”这部分内容作为单元教学设计的主题。以课标和教材作为参考，围绕“亲代传递给子代的遗传信息主要编码在DNA分子上”这一大概念，归纳出学习进阶的四个维度。分别是基因和DNA的关系、DNA的结构和复制、基因指导蛋白质的合成、基因表达与性状的关系。学习进阶的构建从这四个维度出发，将每一个进阶维度划分出了四个进阶水平。接下来，运用测量工具对学生进行测量评估，验证学习进阶的合理性，对所构建的学习进阶进行检验和修正。在进行单元教学设计时，依据进阶起点和进阶终点可以帮助教师合理设置教学目标。分析教学重难点时，以学习进阶为基础，可以精准把控方向。单元教学目标的制定分别从学习进阶的四个维度出发，并基于“生命观念、科学思维、科学探究、社会责任”生物学核心素养，在每一维度中制定相应教学目标。

本研究构建了“遗传的分子基础”单元学习进阶，基于学习进阶完成了单元教学设计方案。研究发现，基于学习进阶的单元教学设计在一线教学中有较强的实用性和实践性。因此，研究最后提出了“DNA是主要的遗传物质”这一节两个课时的具体教学案例，为一线教学提供参考和借鉴。

In recent years, with the proposal and continuous advancement of the current new curriculum reform, the teaching of big concepts, the development of core literacy, and learning progression have become a research hotspot. Under the background of the concept of "content focusing on big concepts" proposed in the new curriculum standard, the construction of learning progression for big concepts is more conducive to accurately grasp the teaching of big concepts and develop students' core literacy. However, the development of students' core literacy ultimately needs to be implemented in classroom teaching. The front-line classroom teaching, whether it is teacher led or student led, cannot be separated from teaching design. However, in the process of teaching design, it is difficult for teachers to achieve teaching objectives through single class hour teaching. The theory of unit teaching design solves this problem well. Therefore, this study links learning progression with unit teaching design, breaking through the traditional research that only focuses on learning progression or unit teaching design. This study carries out unit teaching design on the basis of building learning progression. Learning progression provides theoretical guidance for unit teaching design, which is the concrete embodiment of learning progression.

"The molecular basis of genetics" is selected as the theme of unit teaching design in this study. Based on curriculum standards and textbooks, four dimensions of learning progression are summarized around the core concept that "genetic information transmitted from parents to children is mainly encoded in DNA molecules". The four dimensions are the relationship between genes and DNA, the structure and replication of DNA, the synthesis of proteins directed by genes, and the relationship between gene expression and traits. The construction of learning progression starts from these four dimensions, and divides each progression dimension into four advanced levels. Next, measurement tools are used to evaluate students, verify the rationality of learning progression, and revise the constructed learning progression. In unit teaching design, according to the starting point and ending point of the progression, it can help teachers set teaching objectives reasonably. When analyzing key and difficult points in teaching, it is possible to accurately control the direction based on learning progression. The formulation of unit teaching objectives starts from the four dimensions of learning progression respectively, and is based on the core biological literacy of "life concept, scientific thinking, scientific inquiry and social responsibility".

This study constructed the unit learning progression of "molecular basis of Heredity" and completed the unit teaching design based on the learning progression. It is found that unit teaching design based on learning progression has strong practicality and practicality in front-line teaching. Therefore, the study finally proposed a specific teaching case of "DNA is the main genetic material" for two class hours, which provides reference for front-line teaching.