(1977) UNDERSTANDING THE LIFE CYCLES OF ANIMALS: A PEDAGOGIC PROPOSAL FOR BIOLOGY STUDENTS

摘要

Zoology is an integral subject of the four-year Biology Degree in Spanish Universities that is usuallytaken during the first or second academic year. Given the key role of zoology as a descriptivefoundation for other disciplines, and the tight schedules to develop contents, emphasis is given to afunctional and evolutionary account of adult body plans and diversity patterns. This sensible approach,however, hampers an in-deep treatment of the extraordinary diversity of animals' life cycles, whichrequires a great deal of integration to foster significant learning in students;;otherwise, students couldend up just memorizing a number of life cycles and names of larvae. In this paper, we propose ansingle-session activity (2 h) devoted to understand major ecological and evolutionary principles behindanimals' life cycles, with a special focus on the differences between direct and indirect (i.e., withlarvae) cycles. The activity is devised for small-groups (up to 16 students) and is scheduled afterlectures dealing with at least several invertebrate phyla (e.g., Porifera, Cnidaria, Platyhelminthes,Annelida and Mollusca).The structure of the activity is as follows:1 Before the face-to-face session, the students are requested to condense basic data on the lifecycles and names of larvae (if any) of the phyla dealt with in lectures;;2 in the face-to-face session, students, working in groups, are asked to find patterns in theoccurrence of larvae (e.g., when adults are sessile);;3 a discussion follows, in which students agree about the regularities they have found;;4 students are then asked to create a conceptual map that explains the adaptive advantages ofhaving / lacking larval stages;;5 students share their conceptual maps and, after a discussion, a merged map is agreed upon.The activity is evaluated through:1 quality of the individual report on larval types;;2 active participation during the discussion, and3 a problem in the theory exam. In the latter, students are asked to predict whether, and why,the life cycle of an animal from a phylum they have not dealt with in theory lectures shouldcontain larval stages.In our experience, the activity has clear pedagogic virtues. First, students must review their factualknowledge about life cycles and larval types. Second, students must search functional principles tointegrate information, and this strongly facilitates meaningful learning. In fact, students could readilyapply these principles to new contexts (e.g., to understand the life cycles of plants). Third, studentswork on concepts that will serve as a basis for upper-level subjects (e.g., ecology). Finally, the activityis cost-effective because it is little time-consuming.