Lessons of the Galapagos

Abstract

Hiking slowly over the rocky terrain, I tune into the whistling and honking sounds around me, being careful not to step on the radiating blue feet that are literally in my path. A colony of blue-footed boobies intent on the business of courtship dances and displays surrounds me. Just when I think it can't get any better, a male, red-flanked marine iguana gently steps over my boot as he makes his way toward the water's edge to feed on algae. This was my experience on my first visit to the Galapagos Islands. I was awestruck by the uniqueness of these enchanted isles and the natural lessons they present. A biology teacher and naturalist at heart, I have an affinity for wild places and for birding, photographing plants and animals, and learning about species and their natural history. In my classroom, nature serves as a tool to connect students to relevant biological concepts and processes through anecdotes, discussion, multimedia, and studying alluring species. Many endemic species of the Galapagos are captivating and useful for a biology teacher planning an extended lesson on evolution. To promote teaching science through inquiry, I wanted to use my experience in the Galapagos to design a lesson that allows students to immerse themselves in the essential science and engineering practices identified in the Next Generation Science Standards (NGSS Lead States 2013; see box, p. 46), as they ask questions; analyze and interpret data; engage in argument from evidence; and obtain, evaluate, and communicate information. Students may have preconceived ideas and sometimes misconceptions about evolution from their previous experiences, so a lesson plan must reflect the contemporary constructionist view of learning wherein students redefine, reorganize, expand, and change their initial concepts and views through classroom activities and experiences while interacting with other students and their environment. To satisfy these concerns, I followed the 5E instructional model (Trowbridge, Bybee, and Powell 2000). This model describes a sequence of phases--engagement, exploration, explanation, elaboration, and evaluation--that align with both inquiry processes and constructivism. Engaging islands During the engagement phase, the challenge is to gain students' attention, spark their inquisitiveness, and have them pose initial questions. Showing an enticing video clip, passing around photographs, projecting a slide show of an attractive species such as the Galapagos hawk (Buteo galapagoensis), or describing a spectacle such as that of the male great frigatebird (Fregata minor ridgwayi) in his courtship ritual work for me as a way to accomplish this task. I then have students pose their own questions about the features, location, wildlife, and scientific significance of the islands to assess their prior knowledge. This discussion generates some useful Galapagos facts, and presenting a brief history and description of Darwin's Islands further serves to establish a base of knowledge. Once students have been engaged, they can be given--or research for themselves--some geographical information about the island. These oceanic islands form an archipelago that consists of 13 relatively large islands, each with an area greater than 10 km2, six smaller islands, and more than 40 named islets. Formed from undersea volcanoes three million to five million years ago, the islands today straddle the equator some 960 km from the coast of Ecuador on the South American mainland (Jackson 2001). Because these islands sit in the middle of nowhere, so to speak, the question arises as to how plants and animals colonized and inhabited them, especially in view of the geologic fact that these volcanic islands were barren when they first appeared above the sea's surface. At this point, student exchanges and discussion focus attention on dispersal mechanisms and island colonization. By the end of this introduction, the class acquires insights into possible dispersal mechanisms to the Galapagos from potential mainland areas: for example, by sea for penguins and marine mammals; through floating vegetation rafts for insects and reptiles; by air for seabirds; and by wind for plants, lichens, and fungi. …