Biology Lessons Part 2: Population Biology


 Lesson 2.4: How Do Organisms Vary?

Alternative Ideas

 Issue Naive Idea* Scientific Idea
Dominance & Frequency Dominant alleles are generally the most frequently occurring alleles in a population. Dominance refers to expression of an allele within an individual organism. Prevalence in the population is determined by fitness and natural selection.
Nature/Nurture If a trait is genetically controlled it can't be influenced by the environment. Every genetic trait is influenced by the environment, often to large degree.
Political Correctness The social and psychological sciences must ignore genetics because it is overwhelming. Greater progress is possible when all relevant information is integrated.
Dominance & "Goodness" Dominant alleles are the most desirable ones. Some dominant alleles are deleterious or neutral.

Alternative ideas are known by many names including alternative conceptions, misconceptions, and naive ideas. They have been extensively studied during the past 15 years. These alternative ideas are shared by a significant fraction of the population of students, often 20-60% of students in a class; they are surprisingly resistant to being taught away (especially with traditional, didactic teaching); and while some alternative ideas are culturally bound, most appear in similar frequencies in classrooms around the world.

This does not imply that all prior knowledge is faulty. Students have a great deal of valuable prior knowledge or anchoring conceptions. A good teacher will draw out some of the students' prior experiences and link them to events in the classroom. Scientific understanding is strengthened when it is integrated with everyday knowledge.