Wednesday, April 20, 2011
AAAS Flunks Evolution!
As I noted yesterday, the AAAS document, Vision and Change in Undergraduate Biology Education, defines five core concepts for biological literacy [Core Concepts: Evolution]. Evolution is the first core concept and this is a very good thing. Congratulations to the committee for a wise choice.
However, the way that the core concept is described was troubling. It suggested to me that the members of the committee may not understand evolution as well as they think they do. This worry is reinforced by the AAAS Project 2061 Science Assessment Website where a series of questions and responses about evolution indicates that AAAS flunks the test.
There's no mention of the standard definition of evolution as a change in the heritable characteristics of a population over time [What Is Evolution?]. This is important because a fundamental part of the core concept is the understanding that any mechanism of change counts as evolution—not just natural selection. Another fundamental part of evolution is understanding that it is populations that evolve and not individuals. The population genetics definition of evolution was developed in the 1930s and became a key part of the Modern Synthesis in the 1940s. The definition is almost 70 years old. Why don't the authors of the report know this?
There's no mention of random genetic drift. The assessment questions are all about natural selection. In fact, the key topic concept is called "Evolution and Natural Selection." How are students supposed to understand phylogenetic trees based on sequences if they don't understand the basic stochastic process that generates these trees? How are they supposed to understand genetic variation if they've never heard of neutral mutations and how they can be fixed by random genetic drift?
There's nothing about mutation. Don't students need to understand mutation in order to understand variation? Of course they do.
There's nothing about speciation. Understanding how new species arise is an important part of evolution.
The problem with the Vision and Change document is that it identifies five core concepts but it doesn't tell us what they are beyond giving them names. If you want to reform undergraduate teaching you have to not only identify what the core concepts are but also make sure they are accurate. If you don't understand the core concepts to begin with then you aren't going to teach them properly to your students. I don't think most professors understand evolution well enough to be able to teach it effectively as a core concept. (This also applies to the other core concepts as I will explain over the next few days.)
What we really need is a committee that examines how to teach PROFESSORS the core concepts of biology. Unfortunately, ignorance of the core concept of evolution is widespread and seems to include many of the professors who created the Vision and Change document.