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SNAKE FIELD TRIP EXPERIENCE THE USE OF OBSERVATIONAL STUDIES IN SCIENCE OBJECTIVES In this experience, you will endeavor to achieve the following objectives: 1. 2. 3. 4. 5. 6. Explore the potential of observational studies in sciences Develop two observational studies in ecology, behavior and morphology Become familiar with dispersion patterns of organisms Witness antipredator behaviors of several snake species Correlate antipredator behaviors with morphological adaptations Handle data collection and data handling to answer biological questions BACKGROUND: Observational studies are a powerful tool to start collecting evidence in science. Today, we will explore the potential of observational studies in examining the ecology and behavior of several snake species on Beaver Island. Before any field trips involving data collection, students should be familiar with the natural history of the organisms being observed. In our case, we will watch a video and go over a couple of PowerPoint slides explaining the main biological concept covered in this field experience. These concepts are briefly described below as a future reference. BIOLOGICAL CONCEPTS: Patterns of dispersion: a key concept in ecology (the study of populations’ in their environments) is the distribution of organisms in their environment. Organisms can be dispersed randomly, just as many plant species that grow where their seeds were dropped, nearly regular, typically due to some negative interactions with neighbors such as in many crab species on a beach, or clumped, typically due to some positive interactions with neighbors. Understanding the dispersion of organisms is critical to developing management plans for any species. Antipredator behaviors often involve particular morphological traits such as body surface shape and coloration. Sometimes they involve physiological traits such as the production of venoms or noxious smells. These morphological or physiological traits are tightly linked with behavioral adaptations; for instance, blending into the background may require staying motionlessness and the effective use of noxious smells may involve decisions of when to release them. Success at evading predators can thus be dependent on these correlations between behaviors and morphological or physiological traits. ORGANISMS OF INTEREST: We will be going to Miller’s marsh, a property of CMU located in the south west part of Beaver Island. The marsh provides an ideal habitat for snakes and is the home to 7 different snake species, none venomous, out of the 8 species present on the island. Dr. Gillingham, a retired professor of Biology from CMU, described the snakes as following: Of the eight species of snakes found in the Beaver Island archipelago, the largest by weight is the Northern water snake while the largest by length is the Eastern milk snake. The smallest are the red-bellied snake and its close relative, the northern brown snake. The smooth green snake is totally insectivorous and an egg-layer with one of the shortest incubation periods of any North American snakes: nine days. The Eastern ringneck snake is very aptly named with a well-defined ring around its neck, and feeds on salamanders. The Eastern garter snake is the most abundant snake in the archipelago, and feeds on a wide variety of food, from earthworms to small mammals. The Northern ribbon snake, very similar in appearance to the garter snake, is much more slender, with a longer tail. It feeds primarily on amphibians. Below are pictures of all 7 species you are likely to see. Garter snake Garter snake Ribbon snake Ringneck snake Ribbon snake Red-bellied snake milk snake Brown snake Smooth green snake DEVELOPING THE RATIONALE FOR THE STUDIES: Today, we will be collecting data on two different aspects of snake biology: their ecological dispersion, and whether their escape behavior is linked to their morphology, as theory would predict. Before heading for the field, brainstorm in groups of 3-4 what you would predict would happen. What type of dispersion pattern should we find? Would it be similar for all species? Why or why not? Similarly, what are ways that snakes may escape their predators once detected? Would certain body patterns help or deter these escape behaviors? How would you predict snakes to avoid their predators based on their body patterns? What resources can we use to make a guess? How can students locate these resources? For each of the 7 snakes you might see at the marsh, we will gather predictions as a group regarding which ecological dispersal patterns we expect each snake species to have, and which escape behavior snakes are most likely to adopt based on their body coloration. We will test these predictions in the field. FIELD ACTIVITY: Miller’s marsh contains a large number of wooden boards under which snakes like to rest. Today, we’ll divide into pairs and turn over as many boards as we locate. Each time a board is flipped, we will keep track of: - The species found under the board, and their abundance. Be sure to record the number of boards in which no snakes were found, and mark an X on boards that have been looked under using chalk. - How they escape the perceived threat of predation Snakes may try to escape as soon as the board is lifted. If so, make note of the ways the snakes move away. If the snake is staying motionless, record this and try to catch it. Again, as the snake tries to escape this new predation threat, record its behavior. FOLLOW UP QUESTIONS Once back in the lab, we will compile data across the whole group by species, and see whether the predictions you made before the field observations were correct. Follow up questions are useful at this stage to draw from the field experience and enrich the learning environment. As a group, we will develop different types of follow-up questions that are likely to further develop students’ scientific inquiry, including questions that require quantitative evaluations of the data collected.