The Biology II Course was developed through the Ohio Department of Higher Education OER Innovation Grant. The course is part of the Ohio Transfer Assurance Guides and is also named OSC004. This work was completed and the course was posted in October 2019. For more information about credit transfer between Ohio colleges and universities, please visit: www.ohiohighered.org/transfer.Team LeadCathy Sistilli                                         Eastern Gateway Community CollegeContent ContributorsLisa Aschemeier                                 Northwest State Community CollegeShaun Blevins                                     Rhodes State CollegeRachel Detraz                                     Edison State Community College                                     Sara Finch                                          Sinclair Community CollegeWendy Gagliano                                 Clark State Community College AJ Snow                                             University of Akron Wayne CollegeLibrarianAmanda Rinehart                               Ohio State UniversityReview TeamJessica Hall                                        Ohio Dominican UniversitySanhita Gupta                                    Kent State UniversityErica Mersfelder                                 Sinclair Community College

In more advanced animals, the senses are constantly at work, making the animal aware of stimuli—such as light, or sound, or the presence of a chemical substance in the external environment—and monitoring information about the organism’s internal environment. All bilaterally symmetric animals have a sensory system, and the development of any species’ sensory system has been driven by natural selection; thus, sensory systems differ among species according to the demands of their environments. The shark, unlike most fish predators, is electrosensitive—that is, sensitive to electrical fields produced by other animals in its environment. While it is helpful to this underwater predator, electrosensitivity is a sense not found in most land animals.  In this chapter we will be exploring the different sensory systems found in animals.