Everyday example of evolution
A graduate student of evolutionary biology at UC Berkeley corrected columnist Pam Peirce today in her weekly gardening column in the San Francisco Chronicle. Peirce had originally described an insect pest as “developing” a resistance to pesticides, but the correct term is “evolve.” The difference: both describe change, but development is change over an organism’s lifetime while evolution is change over generations, in this case in response to environmental pressure. (A more complete explanation of how evolution is change and how this terminology can be used can be found here.)
The correction tidily dispenses with a common blurring of concepts. Evolution of pesticide resistance is an everyday example of natural selection, one obviously well established in the popular imagination. It’s satisfying to see the practical importance of understanding the process, even if it comes as a correction.
May 17th, 2007 at 9:34 am
One favourite experiment is evolution of antibiotic resistance in E. coli on petri plates. Can Analise comment on what are the general feelings of the students in Introductory Biology when observing that resistance does not evolve spontaneously because bacteria is “smart” and it “wants” to become resistant, but rather resistant mutants boringly pre-exist in the population?
May 17th, 2007 at 10:44 am
Oh, good question. The undergraduates in our department perform a Luria and Delbruck type experiment in their intro bio class. It’s my favorite lab experiment because it so elegantly tests between two hypotheses: Darwin’s theory of natural selection and Lamarck’s theory of acquired characteristics. It’s extraordinary that such profound concepts can be probed by such a simple experiment! That’s why I love it so much. Few of the undergrads appreciate this, though, and it’s a surprise every time. I think it’s because the concepts are deceptively “deep.” Despite my dorky enthusiasm for this experiment, an embarrassing fraction of them consistently fail the “which hypothesis does this outcome support?” question. I’ve never had a student deny the plausibility of antibiotic resistance evolving through natural selection based on principle–now THAT would be interesting–but an awful lot of them prefer Lamarck’s theory based on sheer lack of studying.
May 17th, 2007 at 6:33 pm
Checking out various blog formats with a new WordPress install for a customer of mine, I ran across your request for comments. But as a former chemistry & biology teacher (from undergrads to jr. high – whew!) and environmental engineer, I cannot help but comment on this posting. Awesome.
Its great to hear/see that there are individuals who are adding clarity to what it means to evolve.
Yes! I recall a conference I attended on evolution in the mid-80s that became a heckling point for those seeking to make evolution into something it is not — i.e. those who blur the questions science asks with those religion asks. But, I’ll save the commentary on that for those better equipped to respond (and I don’t want to derail a great post), but Carl Sagan had some wonderful insights as was recently pointed out by Rudy Baum in a recent editorial (Editor of Amer. Chem. Society’s Chem & Engineering News). Suffice it to say, its heartening to see young scientists like yourself making the connections between environmental changes. Kudos.
(And by the way, nice blog!)
May 17th, 2007 at 6:38 pm
Oops.
That should have read “between environmental changes and natural selection/evolutionary change.”