在高中生物教学中有很多涉及计算事物存在方式的多样性问题,如 DNA、RNA 分子的多样性,1个密码子的碱基数是如何推算出来的,进行有性生殖的生物后代为什么会出现较多的变异类型,遗传病的出现几率等。利用乘法原理进行分析和计算,可以使学生更容易理解这些有趣的生物现象。1 乘法原理乘法原理是“概率论”的基本原理之一。其内容是:若 A事件有 n_1种方式,B 事件有 n_2种方式,且 A 事件的方式对 B事件的方式无影响,则 A、B 事件的发生方式共有 n_1×n_2种不同类型。数学教师常以抛硬币的例子帮助学生理解,甲抛一次硬 In high school biology teaching, there are many issues concerning the calculation of the existence of things, such as the diversity of DNA and RNA molecules, how the number of bases of a codon is derived, and why the biological generation of sexual reproduction appears. More variant types, the occurrence of genetic diseases and so on. The use of multiplication principles for analysis and calculations can make it easier for students to understand these interesting biological phenomena. 1 Multiplication principle The multiplication principle is one of the basic principles of “probability theory”. The content is: If there are n_1 ways of A events, n events of B events, and the way of A events has no effect on the way of B events, there are n_1×n_2 different types of A and B events. Math teachers often use coins to help students understand and throw a hard one