Article Eric E. Goff† Katie M. Reindl‡ Christina Johnson§ Phillip McClean§ Erika G. Offerdahl‡,|| Noah L. Schroeder¶ Alan R. White†* From the †Department of Biological Sciences, University of South Carolina, Columbia, South Carolina 29208, ‡Department of Biological Sciences, North Dakota State University, Fargo, North Dakota 58102, §Department of Plant Sciences, North Dakota State University, Fargo, North Dakota 58102, ¶Department of Leadership Studies in Education and Organizations, Wright State University, Dayton, Ohio 45435, ||Biol Sciences, NDSU and School of Molecular Biosciences, Washington State University, Pullman, WA 99164 Abstract The use of external representations (ERs) to introduce con- cepts in undergraduate biology has become increasingly common. Two of the most prevalent are static images and dynamic animations. While previous studies comparing static images and dynamic animations have resulted in somewhat conflicting findings in regards to learning out- comes, the benefits of each have been shown individually. Using ERs developed by the Virtual Cell Animation project, we aim to further investigate student learning using differ- ent ERs as part of an introductory biology lecture. We focus our study on the topic of photosynthesis as reports have noted that students struggle with a number of basic photosynthesis concepts. Students (n 5 167) in ten sections of introductory biology laboratory were introduced to pho- tosynthesis concepts by instructional lectures differing only in the format of the embedded ERs. Normalized gain scores were calculated, showing that students who learned with dynamic animations outperformed students who learned from static images on the posttest. The results of this study provide possible instructional guidelines for those delivering photosynthesis instruction in the introduc- tory biology classroom. V C 2016 by The International Union of Biochemistry and Molecular Biology, 45(3):226–234, 2017. Keywords: Animation; photosynthesis; introductory biology; external representations Introduction External representations (ERs; such as drawings, images, and animations) have been established as a crucial aspect of classroom instruction [1, 2]. This is profoundly evident in undergraduate biology education. Scientific mechanisms are ripe with complex step-wise processes that require the association of many individual concepts to fully understand. One example of this is the production of ATP during cellu- lar respiration. While some students may grasp surface lev- el concepts of energy production, a deeper understanding of respiration requires the integration of many additional components such as the transport of electrons and the for- mation of concentration gradients. Learning the complexi- ties of this process could be a truly monumental task if a student is provided with only a text. However, ERs provide students with an effective medium to help formulate more accurate mental models. Volume 45, Number 3, May/June 2017, Pages 226–234 *To whom correspondence should be addressed. Tel.: (803) 777-1813. Fax: (803) 777-4532. E-mail: arwhite@mailbox.sc.edu. Received 11 July 2016; Revised 23 September 2016; Accepted 26 October 2016 w s Additional Supporting Information may be found in the online version of this article. *Funding for the Virtual Cell Animation Collection has been provided by National Science Foundation (NSF)/CCLI, NSF/TUES, (NSF awards: 0086142, 0618766, and 0918955) and United States Department of Education/FIPSE. DOI 10.1002/bmb.21032 Published online 28 December 2016 in Wiley Online Library (wileyonlinelibrary.com) Variation in External Representations as Part of the Classroom Lecture: An Investigation of Virtual Cell Animations in Introductory Photosynthesis Instruction* w s 226 Biochemistry and Molecular Biology Education