AA DDaayy oonn tthhee RRiivveerr A film by Tom Fitz Classroom Discussion Guide High School Version (9-12) Content created for Schoolyard Films, Inc. by Cypress Curriculum Services, LLC Film Overview "Partly cloudy skies and clear water"—it's a perfect day on Central Florida's Rainbow River. Join Florida naturalists Tim Walsh and Steve DeCresie as they set out on a misty morning to explore the underwater world of the Rainbow River. These energetic and passionate naturalists share their understanding of the river—in the river—offering an intimate view of aquatic wildlife in their element. "You get a different view of wildlife underwater" says Tim, and this is aptly demonstrated as he mingles underwater with a surprisingly graceful snapping turtle. Winner of the 2010 International Wildlife Film Festival Best Internet and Best Children's Program, A Day on the River offers a springboard for classroom discussion on many environmental and science topics such as wildlife ecology, resource conservation, and the nature of science. The film's leading roles are played by some of nature's more distinctive animals—turtles. These fascinating reptiles are one of the great success stories of animal evolution. For over 200 million years, turtles have humbly and unhurriedly made their way with very little change to their body structure—a strong case that "taking your shelter with you" is an excellent survival strategy. But turtles are now on the decline worldwide, and despite the great interest in understanding these animals, they still hold many secrets about their biology and behavioral ecology. With stunning imagery and an engaging narrative, A Day on the River offers an intimate look at a delicate river ecosystem and the turtles that make it their home, in an informative yet charming short film. Teachers can use this guide to supplement a study of the Florida Sunshine State Standards in Science, specifically on content standard topics such as scientific investigation, structure and function of living things, the processes and diversity of life, interactions between living organisms and their environments, and the impact of scientific knowledge and technology on communities, cultures and societies. Key Terminology Be sure that students are comfortable with these terms either before the film, or as part of discussion after the film. If the students are doing writing prompts, provide these terms as a "word bank" to help guide their writing. abiotic, adaptation, biodiversity, biotic, carnivore, competition, consumer, dependent variable, ecosystem, environment, food chain, food web, habitat, herbivore, impact, independent variable, inherited, instinctual, life cycle, limiting factor, model, omnivore, organism, population, predator, prey, producer, sample, society, species National Standards Correlations Discussion Guide Element Unifying Science as Science in Personal Life Science History and Concepts and Inquiry and Social Nature of Processes Perspectives Science Discussion Question #1 • • Discussion Question #2 • • • • Discussion Question #3 • • • Discussion Question #4 • • Discussion Question #5 • • Activity 1: Turtles of Florida and Where They Thrive: A Literature Review and • • • • • Field Visit Project Activity 2: Mark and Recapture: Simulating Turtle Population Monitoring • • • • • Sunshine State Standards Correlations Discussion Guide Element Sunshine State Standards Discussion Question #1 SC.912.L.15.4 SC.912.L.15.6 SC.912.L.15.7 Discussion Question #2 SC.912.L.17.2 Discussion Question #3 SC.912.L.17.7 Discussion Question #4 SC.912.L.17.8 SC.912.L.17.16 SC.912.L.17.18 Discussion Question #5 SC.912.N.4.1 SC.912.N.4.2 Activity 1: Turtles of Florida and Where SC.912.L.17.20 They Thrive: A Literature Review and Field Visit Project Activity 2: Mark and Recapture: SC.912.L.17.1 Simulating Turtle Population Monitoring SC.912.L.17.13 SC.912.N.4.1 SC.912.N.3.5 SC.912.N.4.1 Discussion Questions/Writing Prompts Use the following questions as a springboard to stimulate classroom discussion or use them as writing prompts. Either way, the goal is to foster discussion on the level of synthesis and analysis. Below each question, you will find possible areas of discussion to guide the teacher. 1. a) To what chordate class do turtles belong? Describe the features of turtles that are distinguishing characteristics for most members of this class. What are some characteristics of turtles (Order Testudines)? Turtles belong to the diverse chordate class Class Reptilia, which also includes the crocodilians, birds, tuataras, snakes, and lizards. The evolutionary relationship of turtles to other reptiles is not well understood, but molecular studies suggest that they are closely related to the crocodilians. Like many members of Reptilia, turtles have amniotic eggs and most have skin with scales, plates, or similar structures formed from the protein keratin. For example, turtles have scutes--bony plates formed from the turtle's skin. Birds have feathers which are thought to be derived from scale-like structures of earlier ancestors. Obviously, the carapace and plastron are unique to the Testudines. Also, turtles do not have teeth and most turtles can withdraw their head and neck inside their shell. b) One of the biologists in the film describes the unique morphological features of turtles. From what bone does the carapace develop? Compare and contrast the position of the "ribs" in turtles, other reptiles, and humans. The carapace develops from ribs. The result is that the "ribs" encapsulate the scapula, which is inconsistent with the body plans of every other vertebrate. If class time allows, find picture examples of each body plan to do a simple verbal compare and contrast. c) As you heard in the film, turtles have existed for approximately 200 million years and have changed very little over that time. From an evolutionary perspective, what does this suggest about the basic body plan of the turtle? Review concept of animal adaptations—changes in behavior, physiology, and body structure, which allow animals to survive in their environment. Prompt students to consider the differences between divergent body plans among four- limbed vertebrates and how these differences relate to survival strategies. Examples: i) Canines: long legs, sharp teeth, agile bodies—body plan is adapted to chasing and killing prey ii) Birds: bipedal, winged, feathers, light-weight skeleton—body plan is adapted to flight; allows birds to rapidly flee from predators or, as predators, to chase prey. iii) Turtles: short limbs, protective shell around body, retractable or folding neck—body plan relies on physical protection from predators; rather than overcoming prey or outrunning predators, turtles adopt a "hide and wait" defensive approach. Ask students if the turtle body plan seems to be "inferior" or "poorly adapted" compared to the other body plans discussed. Point out that the persistence of the turtle body plan over 200 million years suggests that the protective shell and associated behavior are successful adaptations for the turtle. d) Can you think of other animals with armor that serves as protection from predators? Are any of these species closely related to turtles? Examples include: i. Armadillo (means "little armored one" in Spanish) ii. Pill millipede and pill bug iii. Snail iv. Mollusk Define convergent evolution as the attainment of similar traits in unrelated species. Explain that similar solutions to biological challenges may evolve independently among unrelated lineages. In this case, the solution of physical protection through armor evolved separately in reptiles, insects, mammals, and mollusks. e) Can you think of adaptations among the world's turtles species that help them survive in their particular environment? Webbed feet: Like other aquatic four-limbed animals, freshwater turtles have skin between their digits to help move them through water. Paddle-like limbs: Sea turtles need more than webbed feet to swim in strong ocean currents. Their forelimbs are modified into flippers for fast swimming. Worm-shaped appendage: The alligator snapping turtle has a worm-like appendage on its tongue that it wiggles to attract prey. Strong front legs and claws: Burrowing turtles such as the gopher tortoise have very strong forelimbs and claws that help them dig into soil. 2. One of the conservationists in the film explains that the primary water source for the Rainbow River is the direct flow of water from the Floridan Aquifer. How do you think water quality in the Rainbow River compares to rivers that originate primarily from surface waters (i.e. runoff from land)? In what ways might these differences affect the distribution and types of aquatic organisms in each type of river? Formulate a testable hypothesis to explain why one of these water quality differences occurs. Ask students to consider differences and similarities in the following areas: water clarity, temperature variation, pH, nutrient levels. Prompt students to consider how identified differences translate to differences in plant and/or wildlife composition. 3. Many factors contribute to the unique characteristics of an ecosystem. These may be abiotic (non-living) or biotic (living). Can you identify abiotic and biotic characteristics of spring-fed freshwater ecosystems like Rainbow River? How do these factors influence the characteristics of this type of ecosystem? Ask students to consider abiotic factors first. Possible responses may include: current velocity, temperature, substrate chemistry (e.g.,