Teaching Evolution

Abstract

Evolutionary Evidence is an original, intelligently designed, amusing and informative part of SimBio's instructional series, Virtual Labs. The CD-ROM comes with a student workbook with easy-to-follow, step-by-step instructions. Evolutionary Evidence is divided into five exercises: Organizing Organisms, Designing Lizards, Evolving Lizards, Predicting Patterns, and Testing Darwin's Theory, each with its own screen selected from a pop-up menu. Evolutionary Evidence uses a “laboratory notebook” grid as a background, a sort of gameboard. There is also a set of tools (select—arrow, delete—trash, copy—camera, pencil, and spade) for the student to click on and employ, and a control panel that “advances” and “stops” time, simulating evolution.The first exercise screen, Organizing Organisms, instructs the student in the basic strategy of the CD, which involves three steps: (1) identifying traits, (2) grouping organisms with shared traits, and (3) inferring ancestral relationships between the organisms. Organizing Organisms displays pictures of seven organisms of varying degrees of complexity, from amoeba to bird. By double-clicking on a picture, the student views a pop-up window with a list of traits (eukaryotic cells, amniote egg, jaws, etc.) belonging to that organism. The student then infers relationships among the organisms by comparing their shared or absent traits and uses the pencil tool to show these relationships by making connecting arrows or surrounding the pictures with rings (lines can vary in pattern, length, and color). The copy—paste feature, “camera,” allows the student to “photograph” her lab notebook page with pictures and ancestry diagrams and insert it into a word document for later viewing.In the next two exercises, Designing Lizards and Evolving Lizards, the student is invited to “design” lizards, choosing from an eight-trait palette, adding traits in sets of two and three to a base-model lizard that is shown on five different islands. If the student selects “dewlap,” the lizard immediately changes its appearance — eye candy in service of an important idea. The student continues to modify the other plain lizards on the four remaining islands, making sure that each lizard differs from the previous one by at least one trait. Then the passage of time is simulated, causing the different lizards to multiply like crazy on each of the islands. As in the first exercise, the student is asked to look for patterns, grouping lizards with similar traits.The fossil record makes its appearance in the form of a pit, in which lie the remains of 720 years of lizard evolution on seven islands. In the exercise Predicting Patterns, the student is presented with a nested series of lizard traits whose order of evolution is predictable and the spade tool for unearthing the buried traits. The student predicts the level in the pit (corresponding to both the time and the island) in which the trait first appeared. If the student's predictions are correct, the spade reveals the trait. This is a connect-the-dots lesson in which the inference of ancestral relationships among the lizards leads to the understanding that the traits shared by the fewest lizards must have evolved the most recently, and the converse. A chart of the predicted order of appearance of the eight traits is used to make a correlation graph when the actual order is obtained from the “excavation” results. This was a useful exercise for the classroom, especially if there were varied predictions in the class.The last exercise, Testing Darwin's Theory, is an encore performance by the initial seven organisms, which are brought back so that the student can apply methods from the lizard exercise to all organisms. The fossil record is again used to verify the student's predictions, although now the pit extends back a more satisfying 1000 million years. In this last exercise, the “descent with modification” schema is transferred from squamate reptiles to all organisms.References are included for the student to pursue independently or for assignment by the teacher. According to the notes that accompanied the CD-ROM, it was tested extensively on college nonscience majors and introductory biology classes, but it would also be appropriate for 10th-grade biology majors who have already been taught evolution and the terminology. School districts should purchase this CD to further their student' understanding of evolution in an enjoyable, entertaining, and interesting way.