For anyone who has hesitated to teach evolution, closes down at the idea of drift, or uses the term "% homology," Jim Smith and I wrote this review to help clear up common confusions and make evo life a bit easier.
The Perspective, published this month in ASM's education journal, discusses why evolution is so critical -- but still underused and misunderstood -- in the biomolecular sciences. We share our vision for how to teach and think evolutionarily, and we review a slew of published studies and resources for doing so.
I'm pretty excited about this "Side Project" especially Table 1, which I see as a handy guide to speaking the Language of Evolution, equally useful for research as for teaching.
We hear more about antimicrobial resistant infections every year. Where are these pathogens coming from? In a new article published in Evolution, Medicine, and Public Health, I explain the role of horizontal gene transfer in the evolution of antibiotic resistance. Check it out it at: Burmeister, A. 2015 Horizontal Gene Transfer. EMPH doi: 10.1093/emph/eov018.
Should all biology classes include evolution? Lately I have been thinking about "evolution across the curriculum," the initiative promoting evolution as a core concept of biology that should exist in class of every subdiscipline -- from ecology to microbiology to physiology and biochemistry (Wei, Beardsley, & Labov, 2012). Working on a project to move evolutionary thinking into a microbial genetics course here at MSU, I am learning that transplanting concepts from one field into another is not so simple. In this post, I discuss how language can impede learning when terms have multiple definitions and non-scientific meaning for students.
Mead and Scott (Mead & Scott, 2010a) discuss how evolutionary biology language use differs between students and scientists, specifically discussing the ambiguous meanings of terms “design” and “purpose.” Language ambiguity is problematic when words have more than one meaning (Rector, Nehm, & Pearl, 2012). For example, the word “purpose” in a biological sense often refers to a structure’s function, but non-experts may associate “purpose” with non-scientific existential meaning. Without explicitly discussing the meaning of “purpose” in a given context, use of the word could inadvertently lead to student confusion about the content. Mead and Scott suggest one way to avoid confusion is for teacher's to use alternative words that don't have teleological connotations. For example, a teacher might substitute in "function" where "purpose" was previously used. Mead and Scott give an example:
How can I stay clear of potential teleological thinking in microbiology? One way is to focus on structure-function reasoning, similar to the aardvark example above. Rather than asking a vague “why” question, I could ask "What structures and functions are involved with the E. coli colony color turning blue?" I could then explicitly contrast methodological practices with natural phenomena by following with, "In this experimental setup, the E. coli are blue. Are they blue in nature? Would this trait be adaptive in nature?" Finally, I could explicitly disambiguate the "design" we do as human researchers from the adaptive emergence of functions produced by evolution by natural selection.
The classroom is not the only place facing confusion due to language ambiguity. I commonly find this problem in non-evolutionary biology writing and discourse, such as in microbiology seminars and biomedical literature. Here's an example from the CDC (Antibiotic Resistance Questions & Answers, 2013)
What do you think? Where is there room to incorporate evolutionary thinking across the curricula? How do different biology disciplines have unique challenges when it comes to making those changes?
Antibiotic Resistance Questions & Answers. (2013). Antibiotic Resistance Questions & Answers. Center for Disease Control. Retrieved June 1, 2014, from http://www.cdc.gov/getsmart/antibiotic-use/antibiotic-resistance-faqs.html#why-bacteria-resist
Mead, L. S., & Scott, E. C. (2010a). Problem Concepts in Evolution Part I: Purpose and Design. Evolution: Education and Outreach, 3(1), 78–81. doi:10.1007/s12052-010-0210-8
Mead, L. S., & Scott, E. C. (2010b). Problem Concepts in Evolution Part II: Cause and Chance. Evolution: Education and Outreach, 3(2), 261–264. doi:10.1007/s12052-010-0231-3
Rector, M. A., Nehm, R. H., & Pearl, D. (2012). Learning the Language of Evolution: Lexical Ambiguity and Word Meaning in Student Explanations. Research in Science Education, 43(3), 1107–1133. doi:10.1007/s11165-012-9296-z
Wei, C. A., Beardsley, P. M., & Labov, J. B. (2012). Evolution Education across the Life Sciences: Making Biology Education Make Sense. Cell Biology Education, 11(1), 10–16. doi:10.1187/cbe.11-12-0111
It doesn’t. It’s E. coli.
Today we began Day 1 of the Microbial Genetics Lab for Undergrads here at Michigan State – we’re lucky this year with small class sizes of 32 and 28 students, with three instructors per section! Students arrive, usually without the pre-lab completed, hear a short technical lecture on the day’s tasks, and then set out to do the tasks. I find the entire thing to be a crazy fun bustle of confusion as we teachers tumble about the room correcting flaws in sterile technique, quizzing students about their conceptual understanding of the experiments, encouraging the especially curious. (Will there be any Martin Arrowsmiths this semester?) This is my second semester of teaching, so I'm still learning how to organize a classroom.
Today we spent an hour covering all the things micro students “should” know already: how to flame sterilize an inoculating loop until red hot, how to ethanol and flame a`hockey stick, how to put out an ethanol fire… (On this last point, we demonstrated and then had each student repeat this process: 1. Purposely lighting our ethanol containers on fire, and then 2. Calmly placing the container lid over the blaze, which extinguishes the fire.) The students seemed to get a kick out of this. No, lab safety doesn’t have to be boring. <<That said, you should read safety instructions like this and have someone experienced demo the technique before you before trying it out yourself.>>
Next I asked the students what they would be observing in the next lab period. Most said, “Whether or not the strains grow.” This answer, I think, is a residual response from the intro micro lab, where the students spend the semester streaking unknown isolates on various media, using growth to help identify species and strains – it’s typical flowchart work that doesn’t require much thinking. So, I next got to explain that we’ll be observing gene expression using color indicators and that we’ll be thinking a lot about genes and operons this semester, and welcome to microbial genetics. Today we used x-gal to indicate expression of the gene coding for B-galactosidase, which results in blue colonies.
Sometimes I ask my students questions like, “Why does E. coli want to produce blue pigments?” That gets them to think and provides a teaching moment that a) E. coli doesn’t really want or not want to do anything; it's E. coli, and b) In the natural environment B-galactosidase metabolizes the sugar lactose, not x-gal, which is a convenient substrate we use in the lab to produce blue colonies.
If everything makes more sense from an evolutionary perspective, we might ask, “Why did E. coli evolve to produce blue pigments?” It didn’t. The E. coli lac operon evolved as an efficient way to regulate expression of lactose metabolism. (Not everything is an adaptation, after all.)
Side Projects, The Blog!
A blog for all things non-dissertation.