Tail's Inheritance: Challenging Secondary School Student's Ideas About the Inheritance of Acquired Traits‪.‬

Numerous studies have been conducted in the last two decades on students' conceptions regarding natural selection and adaptation. These studies repeatedly indicate that students of all ages--from middle school to college students--have difficulties understanding the notion of natural selection (summaries can be found in AAAS, 1993). Students', ideas are typically intuitive and consistent with their everyday life experiences. In everyday life, individuals adapt deliberately to changes in their environment by changing their form or behavior. Consequently, students explain a gradual change in populations in terms of deliberate change of individuals rather than inadvertent change in the proportion of individuals carrying advantageous traits in a population. Similarly, students may sometimes see that traits such as smoking or bodybuilding "run" in some families and intuit incorrectly that these acquired traits are inherited. Students' ideas are presented in Table 1. The purpose of this article is to outline a lesson plan that is designed to challenge one commonly held naive idea, namely, the inheritance of acquired traits. While scientists believe that the experiences an organism has during its lifetime can affect its offspring mainly if the genes in its own sex cells are changed by the experiences, it was repeatedly found that many middle school students believe that experiences and traits acquired during an individual's lifetime can be passed on to its offspring (for example, Brumby, 1984; Clough & Wood-Robinson, 1985). This naive idea may in turn hinder the understanding of the theory of natural selection, leading to beliefs concerning the inheritance of environmentally induced characteristics over several generations.