Measuring the Pulse Rate of Lumbriculus Variegatus

What Makes a Worm’s Heart Race? Part 1 Student Lab Guidelines & Worksheet Name: Date: Hour: Purpose: To explore the impact of treatments on the pulse rate of the worm Lumbriculus variegatus while refreshing and refining your understanding of experimental design with a focus on recognizing and minimizing experimental bias. Objectives: Upon completion of this activity, you should be able to:  Count pulse rate in blackworms (Lumbriculus variegatus).  Demonstrate the ability to design and perform an experiment using the strong inference model and multiple hypotheses with attention to the minimization of experimental bias.  Demonstrate an understanding of graphing and the use of simple statistical data analysis to evaluate the impact of an experimental treatment.  Explain the relationship between dependent and independent variables (in this particular case – the pulse rate of the blackworms and the treatment with a stimulant/depressant/toxin). Technique Practice and Gathering of Baseline Data (Day 1): 1. Read and complete Use of Animals in the Classroom (Addendum A at the back of this packet). Have your instructor initial your form after you read and sign it. 2. For every 2 students get: o Petri dish o 2-3 blackworms in spring water (from the class container) and place these in your Petri dish o ½ piece of plastic capillary tube o Thin stem pipette o Compound microscope or dissecting/stereoscope o Stopwatch 3. Draw one worm into your thin stem pipette. Squirt the worm gently into the capillary tube. o Place the worm in the tube on the stage of your compound microscope. o Focus on low power (red objective) if using compound microscope, high if using stereoscope o Inspect your worm by moving (including rolling) the capillary tube – find the head and tail and the dorsal (back) and ventral (front or belly) sides. 4. Answer the following questions as you explore your worm (record your answers here): o What color is your blood? ______What color is the blackworm’s blood? ______What’s the purpose of the circulating blood? ______o What physical situations can cause a change in your pulse rate/heart rate? (name at least two) ______o What chemicals can affect human pulse rate? (include at least one that is commonly found in drinks and at least one common medicine) Common in drinks: ______Common in medicine: ______Other: ______5. Once you’re familiar with your worm’s structure, find the pulsation of blood in the dorsal blood vessel. Practice counting the number of pulses per minute (count for a full minute; do NOT measure for shorter segments of time). You should try to be consistent as to what location on the worm you are counting (is it in the middle, near the head, near the tail,. . .) When you’re comfortable with the process, count and record 5 measurements in the following table:

1 | P a g e Pulses per Minute in the Dorsal Vessel of Lumbriculus variegatus Pulse/Min Count #1 Count #2 Count #3 Count #4 Count #5 Mean Value Median Value

NEXT, you will design an experiment using worms from two of the three containers of worms that will be available. One of the containers will be labeled Plain Water, one Water with Depressant, and one Water with Stimulant. You will design and perform an experiment comparing the pulse rate of worms from two of the containers. You need to have three hypotheses for your experiment (specific predictions of results, one for each possible outcome of the experiment) – will the pulse rates be the same or different and if different, higher or lower) and your variables identified. Include a statement of what positive results (ones that support that particular hypothesis) would mean. To help you get started see the Sample Hypothesis below. Note: This sample is for if you tested worms from all three containers, you will only be test worms from two containers. Sample Hypothesis (comparing worms from 3 containers, you’ll only be using worms from 2 containers): I predict the worms in the plain water will have the same pulse rate as the worms from the other two containers meaning that the worms are not impacted by the differences in the water. YOU MUST GET your instructor’s approval and initials on your hypotheses and variables BEFORE you begin to experiment or you lose points! Which two containers of worms will you be using? ______and ______Hypothesis 1: ______Hypothesis 2: ______Hypothesis 3: ______Independent variable (the experimental condition): ______Dependent variable (what you are measuring): ______Control Setup (what are you comparing your experimental results to? OR Which setup is lacking the experimental treatment?): ______

2 | P a g e Constant(s) (name at least one condition that it is important to hold constant in this experiment): ______Instructor’s initials (REQUIRED BEFORE you proceed) Student Designed Experiment (Day 2 and 3): When you arrive in class you may begin immediately IF you already have your hypotheses and variables approved and initialed by your instructor. BUT, before you begin to experiment CREATE a data table and REVIEW your rubric (Addendum B at the back of this packet) so you know what you’ll need! You need to verify your results by having multiple trials. More trials are almost always better although you need to be practical about your time and materials available. You also should consider what type of analysis you will do. Are you just going to analyze the mean and/or median values? (This is weak unless you include additional analysis like analysis of the standard deviation. Consider taking enough data to do a box plot (aka box and whiskers graph). Box plots, when practical, are outstanding tools for quickly comparing sets of data. However, they require a minimum of 15 trials per condition to be valid.) Once you’ve completed your experiment, each student will need to complete and place in their lab notebook a summary lab report with unique conclusion sections (although you are working together and will have the same data, write your conclusions in your own words). Finally, create a poster of your lab to share with the class (be sure to read your rubric first). Include: 1. Hypothesis (list only the one which was supported by your data) 2. Variables 3. Graph (don’t forget titles, labels, etc.) 4. Conclusions 5. Hour and names of lab partners Present your poster to the class (Day 4). Your classmates will rate your presentation based on the rubric. Your grade for this portion of the activity will be a weighted average of this score and the instructor’s score on your written lab.

3 | P a g e What Makes a Worm’s Heart Race? Internet Treasure Hunt (Day 4 homework) Name: Date: Hour:

This web info search will help you find information about blind and double-blind experiments. You will be looking at pre-selected websites to answer each question. It is important to not only find the information at the site, but also to consider who wrote the site, what their purpose is in writing it, and how credible (accurate) you think the information is.

Question #1: What is meant by a “blind” experiment? What is meant by a “double-blind” experiment? How are they similar? How are they different? What is a placebo and how is it used? Site 1 Site 2 Website Title: What is a clinical trial? Double-Blind, Placebo-Controlled Trial URL: http://www.antigenics.com/trials/about/ http://chronicfatigue.about.com/od/fmsglossary/g/ doubleblind.htm Who created this web site (organization, etc.)? Why did they  To provide factual information  To provide factual information create it? (check  To influence the reader’s opinion  To influence the reader’s opinion all that apply)  To sell a product or service  To sell a product or service  I’m not sure  I’m not sure How credible  Very accurate  Very accurate (accurate) do  Somewhat accurate  Somewhat accurate you think the  Not very accurate  Not very accurate info is?  I’m not sure  I’m not sure

What did you learn about Question #1 (see above)?

4 | P a g e What Makes a Worm’s Heart Race? Internet Treasure Hunt (Day 4 homework) Name: Date: Hour:

This web info search will help you find information about blackworms and testing their physical responses to chemicals. You will be looking at pre-selected websites to answer each question. It is important to not only find the information at the site, but also to consider who wrote the site, what their purpose is in writing it, and how credible (accurate) you think the information is.

Question #2: What is a “biological smoke detector”? What was the role of canaries in coal mining? What chemicals can be tested for their impact on the pulse rates of blackworms? What procedures can be used for these experiments? How can the experiment be designed so it does not harm/kill the worms? Site 1 Site 2 Website Title: Biological Smoke Detectors Effects of Drugs on Pulsation Rate of Lumbriculus variegatus (Blackworms) URL: http://www.eeob.iastate.edu/faculty/Dre http://www.ableweb.org/volumes/vol- wesC/htdocs/Toxweb3.PDF 27/07_Bohrer.pdf Who created this web site (organization, etc.)? Why did they  To provide factual information  To provide factual information create it? (check  To influence the reader’s opinion  To influence the reader’s opinion all that apply)  To sell a product or service  To sell a product or service  I’m not sure  I’m not sure How credible  Very accurate  Very accurate (accurate) do  Somewhat accurate  Somewhat accurate you think the  Not very accurate  Not very accurate info is?  I’m not sure  I’m not sure

What did you learn about Question #2 (see above)?

5 | P a g e What Makes a Worm’s Heart Race? Part 2 Student Lab Guidelines & Worksheet Name: Date: Hour:

Designing and Performing an inquiry lab based on Internet research (Day 5 and 6): From your Internet research you now have information on chemicals which can impact pulse/heart rates of animals. You are now charged with designing a double-blind experiment to test the impact of one of those substances on blackworms. First, in either a blind or double-blind study, what does it mean to be “blind”? ______Who is blind in a double-blind study? ______AND ______Who is blind in a study that is just blind? ______Will the participants/experimental organisms in this experiment be aware/cognizant of their treatments? ____ How do you know? ______Why are we choosing to do a double-blind study? ______Now, what chemical are you going to test? ______How and/or what are you going to test with that chemical? Be specific in your response: ______Think back to the three hypotheses you tested on your first blackworm experiment, what two OR three hypotheses will this new experiment be testing? Make sure you have a hypothesis for each possible outcome of the experiment and include a statement of what positive results for that hypothesis would mean. YOU MUST have your instructor approve and initial these (and your procedures and variables) BEFORE you begin to experiment or you lose points!

Hypothesis 1: ______Hypothesis 2: ______Hypothesis 3: ______Independent variable:______Dependent variable :______Control Setup:______Constant(s) (name at least one):______6 | P a g e Procedures (be sure to mention the unique steps for YOUR experiment AND number of trials per condition): ______

______Instructor’s initials (REQUIRED BEFORE you proceed) You may begin immediately IF you have your hypotheses, variables, and procedure approved and initialed by your instructor. Before you begin to experiment CREATE a data table and REVIEW your rubric (Addendum B) so you know what you’ll need! Don’t forget you need to verify your results by having multiple trials. As with the first blackworm experiment (and any experiment) you also should consider what type of analysis you will do. Are you just going to analyze the mean and/or median values, do a box and whiskers or . . .? As before, each student will need to complete a full summary report with individual conclusion sections (although you are working together and will have the same data, write your conclusions in your own words). Finally, create a poster of your lab to share with the class (be sure to read your rubric first). Include: 6. Hypothesis (list only the one which was supported by your data) 7. Variables 8. Graph (don’t forget titles, labels, etc.) 9. Conclusions 10. Hour and names of lab partners Present your poster to the class (Day 7). Your classmates will rate your presentation based on the rubric. Your grade for this portion of the activity will be a weighted average of this score and the instructor’s score on your written lab.

7 | P a g e Addendum A: Name: ______Hour: _____

Instructor initials: _____

8 | P a g e Addendum B: Summary Lab Write-up Rubric Partners names: Hour: Points ____/1 Neat, easy-to-read, uses ruler for lines, elements of lab are in order listed here ____/1 3 hypotheses initialed by Instructor - these must be specific predictions of your results – will the pulse rates be the same or different and if different, higher or lower. ____/1 Initialed hypotheses are scientific and each includes a statement of what positive results (ones that support that hypothesis) would mean. ____/2 Variables properly identified (independent, dependent, constants, and control); adequate number of trials used (min 3, optimal 15+) ____/2 Data Table (raw data recorded DURING the experiment) with descriptive title, clearly identified variables and labeled units ____/2 Table of summary or calculated values (such as mean and standard deviation OR box & whisker values) ____/3 Appropriate graph which clearly reflects patterns in data with descriptive title, clearly identified axes, labeled units, evenly scaled, and legend if needed. Graph is box plot or includes summary data such as means and/or medians ____/3 3-part Conclusion - MUST address: (1) “support” or non-support of hypothesis, what support of this hypothesis means about the worms AND discussion of supporting data patterns (with mention of specific numbers); (2) problems with experimental procedure WITH suggested solutions; and (3) future related experiment to expand knowledge gained in this experiment and/or answer questions raised by this experiment. _____/15 Total Score

Lab Poster Presentation Rubric Presenter names: Hour: Evaluator name: Points ____/2 Neat, easy-to-read from back of the room, uses ruler for lines, items are in order listed here ____/2 Hypothesis includes specific prediction of results, is scientific, includes a statement of what positive results (ones that support that hypothesis) would mean. ____/2 Variables properly identified (independent, dependent, constants, and control); adequate number of trials used (min 3, optimal 15+) ____/3 Appropriate graph which clearly reflects patterns in data with descriptive title, clearly identified axes, labeled units, evenly scaled, and legend if needed. Graph is box plot or includes summary data such as means and/or medians ____/3 3-part Conclusion - MUST address: (1) “support” or non-support of hypothesis, what support of this hypothesis means about the worms AND discussion of supporting data patterns (with mention of specific numbers); (2) problems with experimental procedure WITH suggested solutions; and (3) future related experiment to expand knowledge gained in this experiment and/or answer questions raised by this experiment ____/3 Presentation is easy to hear and understand and clearly involves all group members. _____/15 Total Score

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