We’re doing it again: we’re offering our workshop, Changes in Nature, to interested teachers this summer, 11-15 July. It was fun and we learned a lot last year, so it’s going to be even better this year. This is a workshop that focuses on helping teachers develop strategies to teach “controversial” topics, evolution and climate change, so there’s a bit of us lecturing at them, and a lot of discussion and listening to teachers, so we all win.
I’ve been keeping my eyes open for papers on teaching evolution for this purpose, and one that caught my attention is a recent article by Price and Perez, Beyond the Adaptationist Legacy: Updating Our Teaching to Include a Diversity of Evolutionary Mechanisms. This has been a hobby horse of mine for a while, that so many people turn to selection and only selection to explain biological phenomena, and it impoverishes the field. So I was happy, sort of, to see an attempt to describe the errors a lack of diversity of explanations leads students to. I’m not happy to see these errors — and I see them in my students, too — but identifying the problem is a first step to correcting it.
Here, for instance, is a table of recognized misconceptions. You don’t have any of these, of course…right?
|CI||Misconceptions about Natural Selection That Appear When Students Discuss Other Evolutionary Processes|
|Genetic drift||Genetic drift is natural selection/acclimation to the environment that results from a need to survive.|
|Genetic drift is not evolution because it does not lead to directional change that increases fitness.|
|Natural selection is always the most powerful mechanism of evolution, and it is the primary agent of evolutionary change.|
|Dominance||Dominant alleles always increase in frequency in a population.|
|Dominance is related to the selective advantage of an allele or allelic pair.|
|Heterozygotes always have a selective advantage over other genotypes.|
|Evo-devo||Natural selection is always the preferred explanation, even when students are prompted to invoke more appropriate evo-devo mechanisms.|
|Characteristics that are not used by the organism are lost because they are not used, not because of the loss of maintenance selection.|
|Evolution proceeds through the inheritance of acquired characteristics (not including potentially legitimate examples such as the genetic assimilation of induced phenotypes, the assimilation of learned behaviors, or inheritance of epigenetic modifications).|
|Evolutionary stasis occurs only when stabilizing or positive selection does not occur.|
|Lack of understanding of population-level processes. For example, attributing evolutionary adaptation, the population-level process, to an individual.|
This paper also leads to some very useful concept inventories that will be helpful, and that I’ll need to steal from next time I teach introductory biology (I may also be taking over teaching our evolution course in a few years, and I’ll definitely use them then). You might be wondering how you assess understanding of concepts in evo-devo, so here’s a sample question:
That one is easy — you can even rule out a couple of the choices directly from the stated premises of the question. But the appeal of selection is a powerful force, and students still get it wrong.
Price & Perez have an important message for improving the teaching of evolution.
Students more thoroughly exposed to a diversity of evolutionary processes can use these additional contexts to understand evolution. This strategy may be particularly appropriate for students who are having the hardest time understanding a diversity of evolutionary processes (low- and mid-level performers). We propose that refocusing our teaching to more equally include a diversity of evolutionary processes could result in a better understanding of natural selection and a better understanding of all evolutionary processes.
Dang. Now you don’t have to sign up for our workshop, since you’ve already got one of my major messages. But there’ll be more! And you get to spend a week in delightful Morris, Minnesota, at a time when it’s not snowing!
The workshop is sponsored by the Howard Hughes Medical Institute (HHMI). The grant we received from them a few years ago has been driving some wonderful programs here at Morris.