Homeostasis and Crypsis: an Inquiry Into in Color Change In

Homeostasis and Crypsis: An Inquiry into in Color Change in Canyon Tree Frogs Oliver Hyman and Jackie Christoffel

This lesson takes an inquiry based approach to increase student understanding of physiological tradeoffs using Canyon tree frogs (Hyla arenicolor) as a model organism. Using easy-to-assemble enclosures, students will be able to test the importance of cryptic coloration and homeostasis in this intriguing species of color changing frog. By allowing students to empirically test the validity of important scientific concepts, this lesson not only helps to internalize their understanding of homeostasis and camouflage, but also enhances their mastery of the scientific method.

Key words: Adaptation, Homeostasis, Crypsis, Thermoregulation, Endothermy, Ectothermy, Amphibian, Frog, Experimentation, Manipulation, Independent and Dependent Variables,

Grade level: 8-12 * this lesson was designed to meet 8th grade science standards.

Duration: 6–12 class periods (dependent on time available and student ability)

SCIENCE STANDARDS: Strand I: Inquiry Process Concept 1: Observations, Questions, and Hypotheses PO 1&3: Students will formulate questions and hypotheses from their observations Concept 2: Scientific testing/Controlled Investigations PO 1: Students will learn proper handling/safety with live organisms. PO 2-5: Students will design and conduct controlled experiments to test their hypotheses. Concept 3: Analysis and Conclusions PO 1-8: Students will assess the results of their experiment using basic graphs, interpret their results in relation to their initial hypothesis/predictions, evaluate their validity and suggest future studies Concept 4: Communication/Assessment PO 1-5: Group work will develop communication Write up/ppt. presentation of experiment and results Strand II: Nature of Scientific knowledge Concept 2: Nature of scientific knowledge PO 1: Students will apply the scientific method to test scientific concepts. PO 4: Explain why claims may be questionable if based on small sample sizes, biased studies, or no control. Strand IV: Life Science Concept IV: Diversity, adaptation, and behavior PO 1: Demonstrates how an organism’s behavior allows it to survive PO 2: Describes one specific mechanism for how an organism can maintain a stable internal environment while living in a constantly changing external environment. PO 3: Determine characteristics of organisms that could change over several generations. Can be tied into this through a simple “dot” exercise. PO 6: Describe factors that allow for the survival of living organisms. - protective coloration, thermoregulation

LESSON OVERVIEW: This lesson is meant to enhance students’ understanding of homeostasis and protective coloration through both formal lecture and scientific inquiry. Students will be introduced to important concepts including Homeostasis, Ectothermy, Endothermy, Poikilothermy, Homeothermy, and Crypsis. Following a brief introduction, students will be asked to test the validity of these concepts by designing experiments using Canyon tree frogs and easily manipulated microhabitats. Student designed experiments will not only solidify their understanding of these concepts, but also improve student ability to implement the scientific method. Throughout the course of the lesson, student learning will be assessed through the use of informal review, in class worksheets, quizzes, tests, and a final lab write up.

MAIN OBJECTIVES

Science Content: 1) An organism’s habitat is the supportive environment in which it lives. 2) Anthropomorphism is attributing human thoughts and feelings to nonhuman organisms. 3) Frogs are amphibians and therefore ectotherms that have to behaviorally control their body temperatures. Metachrosis (or color changing) is one way to do this. 4) Homeostasis (maintaining a stable internal environment) is important for an organism to optimally perform basic functions such as digestion, running, hunting, attracting mates, etc. 5) Ectothermy is getting heat from an outside source. Endothermy is generating heat internally/metabolically. 6) Poikilothermy is having a variable body temperature. Homeothermy is having a stable body temperature. 7) Ectothermy is advantageous because it requires less energy than Endothermy. Endothermy is advantageous because it allows organisms to always perform optimally.

Conducting Investigations: 1) Conduct structured investigations to determine the importance and validity of metachrosis and behavior in maintaining a stable internal temperature. a) making observations b) forming questions and hypotheses c) experimental design constants, independent, and dependent variables d) Recording, organizing, and interpreting data 2) Demonstrate respect for living organisms while conducting investigations

Building explanations: 1) Describe and quantify habitat color preferences at different temperatures. 2) Construct graphs/tables to show trends in the data and interpret the graphs. 3) Interpret results with respect to hypotheses regarding thermoregulation and homeostasis. 4) Evaluate validity of results. 5) Communicate results using oral presentation and written lab report.

Materials: ~10 habitat boxes: Cardboard boxes constructed with velcro attachment sites for 8 ceramic tiles. (click here for instructions). ~160 ceramic tiles Standard ~4 in.X 4 in. tiles. 80 black and 80 white on the back. You can buy these in bulk from Home Depot for $0.15/tile. ~160 velcro fasteners to stick to the back of the tiles ~10-20 Canyon tree frogs* (Hyla arenicolor) – click here for notes on husbandry. ~2 heat lamps. ~1 rubber snake ~Saran wrap ~Rubber bands ~1 aquarium with tight, metal lid (10-20 gallon) ~10-20 clear plastic cups (use these to house frogs individually during experiment) ~10 “colorimeters” ~10 rubbermaid shoe boxes or any clearish container of comparable size. ~Rocks

*if Canyon tree frogs are not available, other tree frogs (family Hylidae) or anoles purchased from local pet stores will also work.

Worksheets: Initial assessment worksheet Observations worksheet Notes for day 2 (Print the “student notes for powerpoint” in note taking format for students) Project design worksheet Analysis worksheet Lab report grading rubric Final Assessment Test

Powerpoint Lectures: Introduction to Homeostasis, Camouflage, and Amphibians and Making Observations

Review questions: For a list of important review questions click here Procedures:

PREPARATION: Previous Week Construct habitat to hold frogs. Collect frogs from field, or contact local expert to help (I recommend getting in contact with local the local fish and game non-game division, or email me: [email protected]) Construct habitat boxes. Gather other materials including lamps, heat lamp bulbs, observation containers, and colorimeters. Review lecture material. Reserve computers for “graphing day” – Day 5 Day 1 Print initial assessment worksheet and observation worksheet Set up stations with frogs in observation containers Day 2 Print notes for powerpoint Day 3 Project design worksheet Day 4 Print analysis worksheet Day 5 Print lab report rubric Day 6 Print final assessment test

EXECUTION:

This lesson builds upon itself, so it will be very important to remind students throughout the week to keep all of the worksheets, quizzes, notes, etc. together and well organized in an easily accessible notebook/folder/binder.

PART 1: MEET THE TREE FROG

Synopsis: students observe tree frogs to familiarize themselves with their external structures and how they move and behave. They record what they know about frogs and list what they would like to find out about them.

Objectives: Students should demonstrate respect for living organisms while learning how to make and record basic observations.

Preparation: 1) Set out individual frogs in 6-12 separate observations chambers. 2) Print out assessment and observation sheets.

Step-by-Step: Day 1: 1) Initial assessment quiz (15 min). Hand out the initial assessment sheet. This will give you an idea of weaknesses and misconceptions in the students’ background knowledge, and will help you to assess points that will need to be stressed and those that can be glazed over in following lectures. Give them 20 minutes tops. If they don’t finish no big deal. Once they are all handed in proceed to step 2.

2) Explain rules of handling frogs/respect for living organisms (5 mins): a) Be extremely gentle. Do not squeeze or throw. b) Do not rub eyes, nose, or mouth after handling c) Must remain very quiet and avoid bumping tables and crowding over enclosures during observation d) DO NOT freak out if frog gets away. Just stay calm, recapture the frog and continue with the experiment. e) DO NOT tap on glass or try to rile the frogs up.

3) Observations (40 min): Set up a couple different “stations”. Warm room. Cold room. Light colored room. Dark colored room. Rocky room. Feeding room. Dark room. Predator room. Multiple frogs room. Hand out observation worksheets. Have students rotate to each station for 5 minutes and record observations. Encourage students to write down all their observations, no matter how trivial. Remind them to remain quiet and not disturb the frogs’ natural behavior. During this time teachers should be working the classroom, asking questions, encouraging ideas, etc. BE SURE STUDENTS KEEP THEIR OBSERVATION SHEETS. This concludes the first day.

PART 2: FROG BIOLOGY, HOMEOSTASIS, AND ANTHROPOMORPHISM.

Synopsis: Class discusses observations from previous class period, and addresses the issue of anthropomorphism. After discussion students are introduced to the concepts of homeostasis and related terms.

Objectives: Frogs are amphibians and therefore ectotherms that have to behaviorally control their body temperatures. Metachrosis (or color changing) is one way to do this. Homeostasis (maintaining a stable internal environment) is important for an organism to optimally perform basic functions such as digestion, running, hunting, attracting mates, etc. Ectothermy is getting heat from an outside source. Endothermy is generating heat internally/metabolically. Poikilothermy is having a variable body temperature. Homeothermy is having a stable body temperature. Ectothermy is advantageous because it requires less energy than Endothermy. Endothermy is advantageous because it allows organisms to always perform optimally.

Preparation: 1) Review powerpoint presentation for Day 2. 2) Print powerpoint presentation in note taking format to give to students.

Step-by-Step Day 2: 1) Discussion of observations (30 mins). First, pass out the note taking sheets for your lecture. Next have students volunteer their observations and write them up on the board. See if students have any biological explanations for their observations. This is the opportunity to address the issue of anthropomorphic observations. Invariably, students will come out with observations like, “the frog likes heat” or “the frog hates the snake”. These statements are incorrect because they imply that the students are able to observe a frog’s feelings. This is beyond the abilities of our senses. All we can do is observe if the frog prefers one thing over another. The students are projecting their own feelings upon the frogs, when there is no way for us to really know how a frog feels or if it even has feelings. This is what is known as anthropomorphism, or giving human emotions to things that we can only observe. We cannot know an animal’s feelings or emotions. All we can know are their preferences. It is important to make these distinctions because once we begin to project our own feelings on the animals we are studying, we begin to introduce bias into our studies.

Write a few examples of these kind of statements and have students correct them. Example: “the frog likes the dark”  “the frog moves less when it is dark” We have no way to know if the frog likes or hates the dark, all we know is that it moves around more in the light than in the dark.

So what is a preference? And how do we show whether an animal has preferences or not? A preference is shown when an animal is given two or more options (be they different habitats, foods, mates, etc) and consistently chooses one over the others. For example if you took everyone in the room and gave them the choice between dog food or a piece of fruit, almost all would choose the fruit. That is a preference. Next you introduce them to a fair test of preference. First, make this statement, “For example, I could give _Student X_ a choice between coke and pepsi.” Then ask student x which she prefers. Then you say, “therefore 8th grade students like coke more than pepsi” Immediately students will begin to disagree that they like pepsi better. Ah ha! So how do we make this a fair test? Now present them with a more rigorous example and have them pick out the problems with it. Ex. Ted’s Experiment: Ted is examining frog habitat preferences. He puts a frog on top of a piece of sand paper and the frog immediately jumps off. It then lands on a piece of yellow tape. Ted writes, “Frogs like yellow tape the best.” Do you agree with his conclusions? What is wrong with them?

2) What is a Frog? What is Homeostasis? Lecture (45 min) This should be a brief review of the animal kingdom and the Class Amphibia. Show them the different kinds of amphibians (Caecilians, Salamanders, and Frogs). Tell them what all amphibians have in common: Ectothermic, Permeable skin, no shells on eggs, often associated with aquatic breeding and terrestrial habitats. Suggestions for directing class: 1) Open up with question: what is a frog? Is it an animal? Is it an amphibian? What is an amphibian? 2) Allow students a few minutes to discuss what they think in groups before going into lecture. PART 3: EXPERIMENTAL DESIGN: WHY DO FROGS CHANGE COLOR? CRYPSIS OR METACHROSIS?

Synopsis: Class develops different hypotheses for the questions “why do frogs change color” Students then design and conduct an experiment to test the competing hypotheses of crypsis and metachrosis.

Objectives: Frogs may change color for either crypsis (camouflage) or metachrosis (to thermoregulate). Using habitat boxes students can make the background light/dark and hot/cold to design a box and experiment that will determine which of these competing hypotheses is correct. Students will learn to distinguish between hypotheses (crypsis and metachrosis) and predictions (the frog will get lighter or darker). Students will learn to identify independent/manipulated variables (tile color and temperature) and dependent variables (frog color). Students will learn experimental design and the importance of objective quantification (using colorimeters to measure color). Students will use graphs to interpret their data and determine whether it supports or rejects their competing hypotheses. Finally, they will learn to write a formal lab report of their experiment and results.

Day 3: Experimental Design

Preparation: Print copies of experimental design worksheet and colorimeters for each student. Also, have boxes and tiles ready to be distributed to each student group. Be sure to review and fully understand the experimental design worksheet.

Step-by-Step: 1) 15 minutes: begin with quiz/review game to review the concepts we learned yesterday. 2) Remainder of class:

Experimental Design The goal is to come up with one experimental design that the entire class can do as a group and combine all their data at the end. Hand out experimental design worksheet, habitat boxes with tiles, and colorimeters for students to mess with. Tell students they will be able to chose black or white tiles and make them hot or cold as they see fit. Each group will work individually to develop an experiment to test the question: “Why do frogs change color?” First make sure each student is able to come up with the following hypotheses for why frogs change color: Crypsis and Metachrosis (see worksheet for details). Once students understand these two hypotheses, allow them time to come up with their own experimental designs to test these hypotheses. The worksheet will lead them step-by-step through this thought process. Once the each group has completed the worksheet, have groups trade worksheets and evaluate each other’s experiments. After students have had time to look at someone else’s experiments then have them volunteer an experimental design that they like best. Discussion: Now it is your job to direct a group discussion of this experimental design. Using the Chalk board, have a student draw how the tiles will be set up and what their steps will be. Your job is to criticize different aspects of the design that you feel are weak. The first part is coming up with a design that has clear predictions. This will be the hardest part for the students. They need to design experiments that have clear predictions for one hypothesis and not another. For example, a student comes up with the following design: You have a half black and half white box, you put a frog in for 10 minutes and observe which color it picks. So now you must ask students the following question: “What does our hypothesis predict will happen?” Frogs could pick the black tiles to blend in or to heat up, or maybe they’ll pick the white tiles to cool off and blend in we can’t say for sure. This experiment is bad for two reasons. 1) it doesn’t have a clear prediction that supports one hypothesis and not another 2) it doesn’t really address the initial question of why do frogs change color? This experiment actually address the question, Which color of tile do frogs prefer? Which is fine, but is not our initial question. The best design is as follows: Have a box with all white all cold tiles. (or an all black all hot box). Then measure the frog color before and after you put it in this box for about 10 mins. Now we have clear and opposing predictions for each hypothesis: Crypsis predicts the frog will turn lighter to blend in with the white tiles while Metachrosis predicts the frogs will turn darker to absorb more heat while on the cold tiles. Allow students to figure this out on their own. They can do it. I’ve seen it done. Once they come up with the right box design then you need to really nail down the procedure: What parts of the frog are they going to measure. How do we ensure that everyone measures the same way? When do you want to measure the frog? How long does the frog need to be in the box? How many frogs should we use? How many trials should each group do? Where do we keep the frog when it’s not in the box? How long should we keep it out of the box? How are we going to record the data? What should our data table look like? Once they’ve got all this stuff figured out then you can do the experiment.

Day 4: Conducting the Experiment

Preparation: Print experimental analysis worksheet. Have frogs in individual containers with some water to ease distribution to groups. Have tiles prepared (heated or chilled accordingly).

Daily Plan: 1) 15 minutes: Review of concepts from Day 2. 2) Remainder of class: Conduct experiment and begin Analysis worksheet Review the experimental procedures that were decided upon during last class and write them on the board/ppt, so all can see the step-by-step process. Also, review rules for handling animals carefully and respectfully. Have the boxes on the desks and have tiles (cold/hot) ready to go at the start of class. Also, I recommend putting frogs into individual plastic cups with a bit of water in the bottom. You can cover these cups using Saran wrap and rubberbands. Then you can use these cups to hold frogs in-between trials. Have students work in original groups, and delegate responsibilities so that everyone has a job. Have students develop table to record data and be sure that each group holds onto their data until next class. During down time students should be working on the analysis worksheet. They will only be able to answer up to question 5.

Day 5: Data Analysis

Preparation: review experimental analysis worksheet and print lab report rubric be sure you understand the answers. Obviously, these answers will change according to the results and experimental design your class came up with. The answers on this sheet are just an example of what could happen.

Daily Plan: 1) First 15 minutes: Review of concepts. 2) 30 minutes: Combine data, analyze, and finish analysis worksheet

The goal for today is to combine results from the entire class, construct a bar graph to help interpret these results, and finally to use these results to complete the question on the experimental analysis worksheet.

Have students get out their data tables from last class. Then draw the following table up on the board (but obviously it should be blank and big enough for each group to fill in the data for all of their trials: Trial Leg Spots Back Total Lighter? Darker? 1 2 3 5 10 1 3 4 6 13 X 2 3 3 4 10 2 3 4 4 11 X 3 Etc.

Then have one member or each group come up to the board and fill in all the data from all their trials. The idea here is to combine data from all the experiments and see how many total times the frog got lighter or darker or stayed the same.

Once all the data is up your job is to show students what is going on by explaining what all these numbers mean. a) Count the total number of trials conducted (this will probably be like 30 or so) b) Count the number of trials in which the frog got light/darker/stayed the same and white these total on the white board.

These totals may look something like this:

Same = 4 Darker = 24 Ligher =2 Once students understand what these numbers mean you should have them individually design bar graphs to represent the data. Be sure that they :

a) label axes b) give an informative title c) allow you to determine the meaning of each bar

Below is an Example of what their graphs should look like:

Color change in Canyon Treefrogs: Crypsis vs. Metachrosis

30 s

l 25 i a r

t 20

f o 15 r e

b 10 m

u 5 n 0 Darker Lighter Same color change

Students should individually complete this graph and the experimental analysis worksheet. You can choose to collect the worksheet or go over it as a group. However, you like, but is important that they understand their results and which hypotheses they support or reject.

4) Once this sheet has been completed to you satisfaction, students should begin writing their lab reports following the guidelines of the lab rubric.

5) Remind students about closed note quiz on Monday.

Day 6: Final Test

Preparation: Print final assessment worksheet

Daily Plan: 1) 45 minutes – 1 hour: Test: Administer final assessment worksheet. This will cover all major concepts from last week as well as assess whether students have met the objectives of this lesson. 2) Remainder of class: allow students to work on lab report.

*Note to teachers: Because this lab introduces students to the idea of cryptic coloration and predator avoidance, it sets the stage for a perfect transition into the jellybean lab or dot lab. This lab helps to demonstrate the process of natural selection and meets a number of state standards. I highly recommend using the jellybean experiment as a follow up lesson to this one. Canyon Tree Frog Lesson Initial Assessment Questions:

Please answer the following questions to the best of you ability.

1) Why do all humans have a body temperature of 98.6 degrees?

2) Why do chameleons change color?

3) Why are warm blooded animals called warm blooded and why are cold blooded animals called cold blooded?

4) Can you name a warm blooded animal? How about cold blooded?

5) Which is better in terms of survival, being warm blooded or cold blooded? Why?

6)What is homeostasis?

7) What is an amphibian? What makes an animal an amphibian?

8) How would you define what a frog is? What would you like to know about frogs? Frog Observation Sheet

Name______

YOUR JOB IS TO WRITE DOWN ANYTHING THAT YOU THINK IS INTERESTING ABOUT THE FROGS YOU OBSERVE. Station: Observations: What color is the frog? Does it blend in well with its background? Does it change color?

Station:

Observations: What color is the frog? Does it blend in well with its background? Does it change color? Other observations?

Station:

Observations: What color is the frog? Does it blend in well with its background? Does it change color? Other observations? Table Game Review Questions

1) Name one attribute that makes an animal an amphibian

2) Give me an example of an amphibian.

3) What do you call an animal that get its heat from an outside source?

4) Having variable body temperature.

5) Having a constant body temperature.

6) Producing your own body heat internally.

7) Maintaining a constant body temperature.

8) Maintaining a constant internal environment

9) Give me one reason homeostasis is important.

10) Changing colors to aid in thermoregulation

11) Example of an endothermic animal

12) Example of an ectothermic animal

13) Example of a cold blooded animal

14) Example of a warm blooded animal

15) Name one advantage of being endothermic

16) Name one advantage of being ectothermic

17) Giving human traits and emotions to animals

18) Why is anthropomophisizing bad?

19) Having camouflage to avoid predators.

20) What does permeable mean?

21) Name one method ectotherms use to thermoregulate.

22) Errors in an experiment due to beliefs of the experimenter.

23) What’s wrong with this statement, “Bird love pine trees”

24) When an animal consistently chooses one thing over another. Frog Lesson Experimental Worksheet:

Names of Group Members: ______

Answer the following questions completely:

1) Come up with 3 hypotheses that may be answers to the following research question:

Why did the frogs change color?

(Example: The frogs change color to communicate with each other.)

The answers we’re looking for are: 1)Crypsis: changing color to hide from predators/camo 2)Metachrosis: changing color to thermoregulate (they get dark to heat up and light to cool off)

2) Do any of these hypotheses relate to any of the concepts we learned in class (such as homeostatis or crypsis)? Please explain how it relates to these ideas.

Yes, metachrosis relates to thermoregulation and homeostasis. Since the frog is an ectotherm it gets its body heat from the sun. Therefore, changing color from light to dark makes a difference in how quickly it heats up. This is an exmple of thermoregulation and thermoregulation is a type of homeostasis.

3)Design an experiment using the materials we have in class to see if frogs change color for the purpose of crypsis or metachrosis (or both/neither).

a) What is the question you want to answer? Why does the frog change color?

b) What is your hypothesis? (ie your answer to this question) To blend in (crypsis) or to heat up (metachrosis) or both

c) Draw how your frog habitat will be set up.

Basically students decide whether they want these blocks to be black/white and hot/cold.

d) Give step by step instructions for how your experiment will be conducted. Be sure to include the number of times the experiment must be repeated. This should be something like: 1)measure frog color, 2) put frog in box, 3) give 10 minutes for frog to adjust 4) Measure frog color again 5) take frog out for 10 mins. 6) Repeat.

It is important that students remember1) to measure the frog color before and after. 2) to come up with a standardized way to measure frog color (ie what parts (back?belly?legs?spots?) do you measure, how do you measure them?(just eye it or use colorimeter?), when do you measure them (before and after,etc).

c) What variables will you be measuring, and how will you record them?

We will record the color of the frog’s back, legs, and spots before and after being in the box using a colorimeter

d) Draw a table for recording your data.

Trial Time Leg Back Spots Total 1 10:00 3 4 6 13 1 10:10 4 5 6 15 2 10:20

d) Tell me what your independent, dependent, and constant variables are.

Independent – Tile temperature and color

Dependent – Frog color

Constants –Time in container, type of tiles, size of box, colorimeter, species of frog, etc. e) If your hypothesis from 3b is correct, what do you predict will happen in your experiment? This should be an “if…then” statement. Ex. If frogs change color for crypsis, then they should turn black in an all black container. Canyon Treefrog Final Assessment Test: Homeostasis

Match each of the following terms to its definition. Some letters may be used more than once ( X points each):

1) Homeostasis__e___ a. Giving human traits and emotions to nonhuman organisms 2) Endotherm__f___ b. Changing color to blend in with your environment, like camouflage. 3) Ectotherm__j___ c. An animal that has a variable body temperature 4) Poikilotherm___c__ d. Errors in an experiment due to the notions or beliefs of an experimenter 5) Homeotherm__g___ e. Maintaining a stable internal environment through physiological or behavioral 6) Thermoregulation__h___ responses f. An animal that produces its own heat 7) Metachrosis___i__ internally g. An animal that maintains a constant body 8) Crypsis __b___ temperature h. maintaining a stable body temperature 9) Anthropomorphism_a____ through behavioral or physiological responses 10) Cold-blooded___j___ i. Changing colors to aid in absorption of heat/thermoregulation 11) Bias___d__ j. An animal that receives its heat from external sources

12) Circle which animal(s) is/are Endothermic a) Mouse b) Lizard c) Lion d) Fish e) Eagle

13) Circle which animal(s) is/are Ectothermic a) Cat b) Human c) Penguin d) Crocodile e) Caecilian

14) Circle the animal(s) that is/are Poikilothermic a) Bear b) Beetle c) Fish d) Squirrel e) Whale 15) Circle the animal(s) that is/are Homeothermic a) Horse b) Gila Monster c) Fly e) Rat f) Rabbit

16) Why is Homeostasis important for an animal to survive. Give two good reasons? Animals must maintain a stable internal environment in order to conduct basic physiological/chemical processes such as running, digesting, hunting, reproducing, etc.

17) Is it possible for an animal to be Ectothermic and Homeothermic? Be sure to explain your answer. Yes! If are in a place, say the tropics, where it stays warm all the time you can be and ectotherm and still keep your body at the same temperature.

18) Name one advantage and one disadvantage of being Ectothermic: Advantage: Consume less energy, need less food, bring more biomass into the system Disadvantage: Not always at optimal temp, limits habitats, less predictable, limits activity

19) Which do you think is better, being endothermic or ectothermic? Defend your answer using two specific examples of why one is better/worse/just as good as the other. Students can answer this either way as long as they defend their arguments. Example of full credit answer: Endothermy is better than Ectothermy. Although endotherms use a lot more energy to maintain a constant body temperature, they still have the huge advantage of always being at an optimal temperature to mate or evade predators, or digest food.

20) Which graph represents a poikilotherm, A or B? Explain your answer? Chart A Chart B

35 35 30 30 25 25 20 15 20 10 15 10 Body Temp (Celcius) Body Temp (Celcius) 1:00 3:00PM 5:00PM 7:00PM 9:00PM PM 5:00 7:00AM 9:00AM AM 1:00 PM3:00 PM5:00 PM7:00 PM9:00 PM 11:00 AM 11:00 PM 5:00 AM7:00 AM9:00 11:00AM AM 11:00 PM

21) Name 3 attributes that make an animal an amphibian?

1)Permeable Skin 2)Two life Stages (aquatic and terrestrial) 3)No shell on eggs 4)Backbone

22) Circle the animals below that are amphibians. Tell me why the ones that you did not circle are not amphibians.

Penguin, Alligator, Salamander, Earthworm, Tadpole, Snake

Penguins Alligator and Snakes do not have 2 life stages, they do not have permeable skin, and they do not lay eggs with no shells.

23) What is Anthropomorphism? Give one example.

Giving human traits or emotions to nonhuman organisms. For example, saying, “Cats hate lettuce.” would be anthropomorphizing.

24) Why is it bad to anthropomorphize?

Because it introduces subjectivity, bias, and opinions of the experimenter, and science/experiments should be unbiased.

25) What is a preference? This is when given a choice between two or more things an animal consistently chooses one option over the others.

26) Bill is examining Dog food preferences. He puts a dog on in a room with wet food in one corner and dry food in the other. The dog immediately goes for the wet food. Ted writes, “Dogs love wet food the best.” Do you agree with his conclusions? Explain your answer thoroughly. Do a good job, because it’s worth a lot of points.

I disagree for a few reasons. 1) He is anthropomorphizing. He should say dogs like or prefer wet food, not love. 2) He is overstating his case. He has only done one trial with one dog and one set of options. It could be a weird dog that isn’t representative of most dogs, It could be a bad brand of dry food. The dog may choose differently on a different day, so to say categorically that dogs prefer wet food the BEST is wrong. We need more rigorous experiments to be sure. Experimental Analysis Worksheet:

1) What was the initial question our experiment set out to answer? Why do frogs change color?

2) What were our hypotheses? Crypsis and Metachrosis

3) What are the scientific concept(s) that our experiment tested? Homeostasis, thermoregulation, ectothermy, crypsis. Etc.

4) What were the independent and dependent variables in our experiment? Independent – tile color and temperature; Dependent – frog color

5) How did we predict our dependent variable would change in response to our independent variable if each of our hypotheses were correct? If crypsis is correct then frogs in a cold white box should turn white to blend in. If metachrosis is correct then frogs in a cold white box should turn dark to heat up.

6) What were the results of our experiment? ie how many frogs did we test in total? How many trials did we do for each frog? In total how many times did a frog change color as we predicted it would? Use tables or graphs in your answers. We sampled 10 frogs ten times each for a total of 100 trials. In 90 out of 100 trials the frogs turned lighter.

7) What was the major outcome of our experiment? Canyon tree frogs change color for crypsis.

8) Did this outcome support or reject each of our hypotheses? Explain. It supported crypsis and rejected metachrosis. 90 out of 100 times the frogs turned lighter as crypsis predicted they should. Only 10 out of 100 times did they turn darker as metachrosis would predict. Therefore our results support crypsis as the reason frogs change color

Habitat Boxes

Velcro Attachment 4.75”

4.75”

9”

Cut box from cardboard, fold up side walls and secure with duct tape. Once box is Constructed you can cover with saran wrap secured by a strong rubber band.

Basic Amphibian Care: You should keep the frogs in an aquarium as described below. Once you have this aquarium set up all you need to do is feed each frog about two crickets per a week and change the water once a week. Very easy.

timer timer Treefrog Aquarium

Regular lamp Heat lamp

Rocks

Canyon tree frogs are a basking species of frog. They normally like to take a dip in the water early in the morning then heat up throughout the day. To create the ideal habitat For this you tilt the aquarium so there is a deep pool of water on one side and not the other. Then stack up rocks as shown to provide basking sights and shelter. Put a metal Mesh lid on the top that is tight, otherwise they will crawl out. On top of the lid you put two Lamps, each of which should be connected to a timer. The regular lamp should turn on in The morning (7am) and off at night (7pm). The heat lamp should be set to turn on for about One hour four different times throughout the day (say 8am, 11am, 2pm, and 5pm). Water Should be changed weekly and it is recommended to use aged tap water as opposed to Water straight from the tap that still has a lot of chemicals in it. Laboratory Report: Canyon Treefrogs and Color Change

Below is a list of the sections and requirements for your lab reports. These will be done individually. Please fill in each section and be sure to follow the directions carefully. This assignment is worth 40 points. Six of the 40 points will come from formatting, so please follow the formatting directions below: Format (6 points) - Methods and Results written in past tense and paragraph form (2) - Standard formatting: double-spaced, 12 point font, 1” margin (1) - Spelling and grammatical errors minimal (2) - Information is presented in appropriate sections (i.e. no results in introduction, no interpretation in results) (1)

Title (2 points) The title should be a short description of your main question or findings. It should not be uninformative, (for example, “Frogs are cool” or “Homeostasis” are not a good titles) (2)

Abstract (4 points) This is a very short summary of your entire experiment: This sections should introduce the behavior of interest, present our question and hypotheses, briefly describe methods, state the main result, indicate your conclusion, and relate conclusion to other studies and/or broader ideas (3) - short (<300 words) (1)

Introduction (6 points) This is your chance to give your reader some background information, so that they know what your study was about and why it might be important. For full credit, you should make sure that your introduction: - Introduces background about the animal behavior we studied(for example: metachrosis, crypsis, thermoregulation, homeostasis, etc.) (1) - Provides relevant background information about the study organism (1). - Describes the importance of the behavior of interest, including its role in the survival and/or reproduction of the organism and other relevant information (1) - Research Question clearly stated (1) - Hypothesis(es) are clearly stated (1) - Predictions (if….then statements) are clearly stated for each hypothesis. (1)

Methods (6 points) This section should explain how the experiment was run. It should not be a list. You should clearly describe how the experiment was conducted, how you set up your box, and how you recorded the data. Feel free to include figures or diagrams to aid in your explanations (for example, a drawing of the boxes would be helpful). Along with explaining how the experiment was done, be sure that your methods section: - Clearly identifies independent variables and dependent variables, including units. (2) - Clearly describes experimental design, including how independent variables were manipulated and other variables controlled, and the number of frogs tested and how many times each frog was tested (2) - Clearly describes method of measurement/observation/quantification of dependent variable(s) (2)

Results (6 points) This section should explain your results, but it should not go into to detail about why you got these results. Save this for the Discussion. Your results section must have at least one table or figure. More than one table or figure is welcome. Be sure that your results section: - Includes total sample sizes. (Example: “Twenty frogs were tested 4 times each for a total of 80 trials”) - Describes relationship between independent and dependent variable (2) - Numerical results reported (example: Seventy five times out of a 80 trials, the frog got darker).(1) - Figure(s) and/or table(s) clearly show the main result(s); Does not include table of all the raw data (2) - Figures and tables include units and captions that describe information presented, and are referred to in the text (each student must generate their own graphs)(1).

Discussion (8 points) This is your chance to explain why you got the results you got and tie these results into your initial hypotheses and predictions. You should also mention potential sources of error, but error analysis should not be the bulk of your discussion. Be sure that your discussion: - Explicitly compares results to predicted results of each hypothesis (1) - States conclusion in context of original question and hypotheses (1) - Conclusion is a logical and correct interpretation of results (2) - Discussion of error is specific and describes potential effects on results. error analysis should not be the bulk of the discussion(0.5) - Relates findings to other studies of behavior of interest (1.5) - Identifies future directions for research prompted by results of this study including clearly stated new research questions and hypotheses (2)

Literature Cited (2 points) - At least one book/paper/website is properly cited in text: (Author, year) (1). - All citations in text are found in literature cited section and vice versa (0.5) - Citations are complete: Author(s), Year. Title, Journal(Volume):Pages (0.5)

Total 40 points Colorimeters: Print in black and white and cutout

6 5 4 3 2 1