Thermoregulation Day ______Learning Objective(s): AZ DOE---Grades 6-8, Life Sciences, Energy Meets Biology Describe how various organisms thermoregulate (Behavioral, Morphological and Physiological Thermoregulation) CORE IDEA—“How organisms obtain and utilize thermal resources” -How organisms behave to obtain solar radiation -The importance of body temperature in ectotherms: Temperature and jumping performance in American Bullfrogs (Rana catesbeiana) The body temperature of ectotherms (organisms that need to obtain heat from an outside source – solar radiation) greatly impacts an individual’s locomotor functions, and therefore body temperature will often impact a given ectotherm’s performance (i.e. jumping ability). Materials: Heat Lamps with heat bulbs (2) American Bullfrogs (Rana catesbeiana) (6, 2 at each temperature) Treated water (2 gallons of de-chlorinated water for lab – obtain from animal care) Cooler (to transport frogs) Measuring Tape (to measure distance of jumps) Lab tape (to mark jumps) Plastic containers/tubs with lids (to put frogs in for temperature treatments) Hot plate (to heat warm group) Ice (to cool cold group) Thermometers (3) (to keep track of temperature treatments – make sure fogs are not cooked) Tarp (to put frogs on when measuring jumping distances) During -Setup: mentors need to set up the three temperature stations – warm, room snack temperature and cold -Warm station: place 2 frogs in plastic or glass tub with about an inch of water on hot plate (must test heating rate of water WITHOUT frogs before conducting lesson so as to know where to set the dial of the heating plate – don’t want to cook frogs – desired temperature is 31°C) -Cold station: place 2 frogs in a plastic or glass tub with about an inch of water. Add ice to water so the frogs cool slowly – desired temperature is 10°C) -Room temperature station: place two frogs in a plastic or glass tub with about an inch of water. *Allow frogs to sit at desired temperature for at least 10 minutes – longer is better *Note it is important to start the frogs at room temperature and gradually increase or decrease their body temperature so as they do not go into shock 10 minutes Engage -Ask for two student volunteers to come to front of room and sit in chairs facing the class. -Tell students to only look forward (at class) and tell the class not to tell them what is going on behind them. Inform the volunteers that they can move if at any point they feel “uncomfortable”, but they cannot speak. -It may also be helpful to blindfold the volunteers so they cannot see what the mentors are doing, or the reactions of the class. -As soon as the volunteers sit on the chair and are facing forward, the mentors will each aim a heat lamp towards the back of their heads, but only one of the lamps will be on. -Eventually, the student with the hot lamp should move (or at least wiggle in the seat). -We will ask the class what they had observed, and why that one of the volunteers eventually moved out of their seat. The student that moved should say that the “heat” made them uncomfortable. And we will explain that by moving out of the “uncomfortable” environment was a form of thermoregulation. This will then start a discussion of what thermoregulation is and the different mechanisms by which organisms thermoregulate and why they do it at all. -Be brief, but a general understanding is needed for the students to do the activity.

45 minutes Explore -Split students into equal groups (of 4 if possible since there are four roles per group) -Each group will measure frog jumping performance (based on temperature) -A minimum of six frogs will be tested (2 from each temperature treatment) -If time allows, test more frogs. 10-15 Explain Minutes -The data will be compiled and transferred to Excel where the mentors are to make bar graphs for the three temperature groups. This will allow for visual analysis of the data by the students (make one chart of averages). -Mentors should ask the students to interpret the data; this will lead into a class discussion on the importance of body temperature and organismal performance. 5-10 Expand Minutes -Relate to real life: talk about humans as endotherms and how they still have to thermoregulate just as animals do – through physiology (metabolism and sweat) and behavior (heaters, air conditioners and clothing). -Ask students when and why they thermoregulate. -Do they “warm-up” before sporting events? Why? -Explain the importance of thermoregulation in relation to survival. Discuss some costs and benefits. What decisions do organisms have to make (exposure to predators, competition for thermal resources) 5-10 Evaluate Minutes -Give students an organism, a list of behaviors and a description of it’s environment (predators, forest vs. desert, ectotherm or endotherm). Then have students draw or write about how the organism should thermoregulate

Frog Jumping Performance Procedure: -Student Roles: 1) Measurer (measures leaping distance of the frog with measuring tape) 2) Recorder (records data – distance of jumps) 3) Marker (places a piece of tape where frog lands after each jump) 4) Frog Wrangler (handles the frog and encourages it to jump) -Procedure: -Start by having students form some hypotheses after they’ve been told about thermoregulation and temperature (from heat lamp exercise). -Measure frog jumping performance: -After frogs have been exposed to their temperature treatment for at least 10 minutes, randomly select a frog from one of the three treatment groups for the first trial. -Place the frog on one end of the tarp (facing the direction of the opposite end). -The frog wrangler will move the frog into starting position and then release it. If the frog does not jump on its own, the student will gently poke the back of the frog or slap the ground behind it to encourage it to jump. -After each successive jump, the student “marker” will place a piece of tape where the frog lands so as to make reference points to later measure. -Each frog will be allowed to jump three times and both the individual and total distances will be measured using a measuring tape by the student “measurer”. -The data will be recorded the student’s lab notebook by the student “recorder”, and then all data is to be transferred to an Excel spreadsheet and graphed by the mentors. -Each group will get at least one frog assigned to them. -Only one frog will be tested at a time, so the students not currently testing their frog will sit in a circle around the tarp to help prevent the frog from jumping off the tarp. -After each trial the frog will be placed back into its treatment group and multiple trials can be run if time allows. -After trials are complete, frogs will be placed together in a container with fresh room temperature pre-treated water (the water the mentors brought with them from the animal care facility) *Note: All students and mentors must wash their hands with soap before and after the experiment. *Note: All students and mentors involved in handling the frogs must wear clean latex gloves (unless there is an allergy problem)

DATA TABLE: Temperature Treatment Jump 1 Jump 2 Jump 3 Total (cm) (cm) (cm) (cm) Hot 1 Hot 2 Room 1 Room 2 Cold 1 Cold 2

Background information (for mentors): Heat (energy) is essential for life as it is required for virtually all biotic processes. However, as with most things in life, there is a limit as to the amount that is useful before it turns harmful. Therefore, organisms need to regulate its heat exchange with the surrounding environment by a process known as thermoregulation. However, thermoregulation is not simply the idea that an organism’s body temperature differs from that of its surrounds. Rather, a thermoregulator maintains a particular mean or variance of body temperature using neural mechanisms to sense and respond to its environment (Bicego et al. 2007), either physiologically, behaviorally or morphologically (Angilletta 2009).

Examples: -A physiological mechanism would be autonomic control of blood flow within the body. For example, when a person is exposed to a cold environment the body will attempt to protect the vital organs from the cold by restricting blood flow to the extremities. By doing this, less heat is lost from the core and vital functions within the body are able to continue. -A behavioral mechanism could simply be movement in and out of microclimates. Desert lizards are a great example for this. Since they are ectotherms, they cannot produce sufficient internal body heat required for many functions (e.g. digestion) and must actively thermoregulate by shuttling in and out of patches of their environment in order to both gain and lose heat by means of radiation in order to attain an optimal body temperature. -A morphological mechanism would be a dog shedding its winter coat. In the fall most dogs grow a “winter jacket” in order to prepare for the cold of the ensuing winter (serves as an insulator – preserves body heat during the cold winter). Then, in the spring when the environment starts to warm up, they shed the coat in an effort to keep cool (release more heat through thinner coat) in the summer.

But obviously all organisms are not the same and therefore utilize different types and even combinations of the thermoregulation mechanisms. Endotherms, or “warm-blooded” organisms, are able to produce internal by heat by means of internal metabolic processes (e.g. catabolism). Ectotherms, or “cold-blooded” organisms, are essentially organisms that are not able to use their metabolism to maintain body temperature. And since our module focuses on ectotherms (lizards or invertebrates), I will mainly focus the discussion on ectothermic thermoregulation.

All of these strategies incur both benefits and costs in the form of energy, mortality (e.g. predation risk), missed opportunities (e.g. could be foraging or searching for a mate) and hydric losses. Therefore, there is typically what is known as an optimal temperature for specific performances (e.g. sprint speed). Many researchers find this “optimum” by housing organisms at different temperatures and then measuring the performance of a trait. And this essentially what we will be doing with the kids – measuring the optimal temperature for sprint speed.