A Simple Twist of Evolution

“This online eLesson is designed to teach students about the role fatty acids play in a plant's life, and where herbicides block the pathway,” says Dyer.

How some plants resist these herbicides is described in the lesson, written to target the educational needs of upper-level undergraduate students and graduate students. A set of quiz questions focusing on these objectives is a part of the lesson.

In plants, fatty acids are so important that they have two parallel biosynthetic pathways that are similar to those found in animals and bacteria. Plants also process fatty acids into waxes and other protective compounds. Obviously, a chemical that blocks this pathway (such as an herbicide) should be lethal to all plants. However, a tiny alteration in the DNA sequence of the first enzyme in the pathway makes some grasses completely susceptible to these herbicides, while other grasses and broadleaf plants are not harmed.

According to Dyer, “This very small evolutionary change allows farmers to kill grassy weeds without affecting their crops.”

Development of the lesson was supported in part by the Montana Agricultural Experiment Station, Montana State University, and the Western Society of Weed Science.

The full article is available for no charge for 30 days following the date of this summary. View the abstract at http://www.jnrlse.org/pdf/2008/E07-0014.pdf. After 30 days it will be available at the Journal of Natural Resources and Life Sciences Education website, www.jnrlse.org. Go to http://www.jnrlse.org/issues/ (Click on the Year, “View Article List,” and scroll down to article abstract).

Today's educators are looking to the Journal of Natural Resources and Life Sciences Education, http://www.jnrlse.org for the latest teaching techniques in the life sciences, natural resources, and agriculture. The journal is continuously updated online during the year and one hard copy is published in December by the American Society of Agronomy.

The American Society of Agronomy (ASA) www.agronomy.org, is a scientific society helping its 8,000+ members advance the disciplines and practices of agronomy by supporting professional growth and science policy initiatives, and by providing quality, research-based publications and a variety of member services.