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Unit 1: The Nature of Biology

A Snail Attraction Inquiry

Walking through the process of the scientific method

INTRODUCTION: Today you will apply scientific methods to answer a question of interest about the life of a snail. One way to remember the methods involved in the scientific process is through the pneumonic: "I Have Einstein's Rules Clear." "I" is the inquiry step, which involves making observations, doing background research, asking questions, deciding variables and pinpointing a specific problem. "H" is the hypothesis step, which involves making a testable prediction or outcome to the problem in your experiment. "E" is the experimental step, which involves coming up with a testable and repeatable procedure. "R" is the results step which involves designing tables and graphs to best show your results. Finally, "C" is the conclusion step, which involves your reflection and analysis of the entire process of solving the problem.

A little background on snails…

 

Snails are invertebrates (no backbone/ endoskeleton). More specifically, they are part of the phylum Mollusca, which happens to be the same category in which you find slugs, oysters and squid. Snails are grouped into this category because they have a similar body plan: a head and foot region, a radula (tongue lined with "teeth"), and a membranous sac, mantle, that sometimes secretes a shell. Snails are vegetarians eating many kinds of plant material. Cornmeal, oatmeal and fresh green leaves are all foods that a snail might prefer in an artificial setting, such as a classroom. They also like to eat foods high in calcium (chalk, egg shells, etc.) to maintain a healthy shell. Adult snails can be recognized by a small lip at the open end of their shell to signify the end of growth. Snails are also hermaphrodites, meaning one individual contains both male and female sex organs. Thus, any two snails can mate. Each fertilizes the eggs of the other. The translucent pea sized eggs are usually laid in a small hole in the soil carved out by the snail.

PART I: INQUIRY

STEP 1: MAKING OBSERVATIONS: Take about 15 minutes to get acquainted with the snail. Use the guidelines below to provide you with some direction in your observations and to spark your curiosity about a possible question you would like to test on the snail.

a) Getting acquainted with a snail's anatomy and physiology

-Examine the external anatomy of the snail; pay close attention to specific structures and how they might be designed for the environment they live in. Try to find the foot, tentacles, eyes, pneumostome (breathing hole), radula, etc.

-Make note of the colors, shapes and textures you see. Don't be afraid to touch the snail.

-Make two drawings below of your snail from the side and underside. You may look at the underside by putting it on some transparent surface. Your drawings should be large, detailed and labeled. You may use the resources provided to identify specific parts. Use the table on the following page to sketch in your diagrams. In the right hand column, jot down a few key observations about your snail's appearance.

b) Getting acquainted with a snail's movement

-Observe the snail move across the table, glass /other comparable surface and your hand.

-Determine the preferred direction of the snail's movement. Does it appear to be random or directed?

-Place your snail on a ruler and record how far the snail moves in a minute if possible.

-Record your observations in the left hand column of the table on the following page.

c) Getting acquainted with a snail's eating habits

-Feed the snail lettuce, cornmeal or cornstarch. Listen for the scratching sound when it begins to eat. The scratching is due to the radula, "teeth-covered" tongue. These "tooth marks" should be visible in some of the substances you feed to the snail.

Compare the marks left in the two substances.

-Continue to record your observations in the table.

d) Getting acquainted with what a snail's attracted to and repelled from

-test a handful of substances that you think the snail might be attracted (available substances: sand, sawdust, flour, chalk dust, sticky tape, white glue, milk, etc. You may not use substances that might be harmful to the snail ( salt, sugar, detergent, boiling water, etc.)

-try testing different factors that might affect its movement (light vs. darkness, cold vs. warm temperatures, etc.)

-record factors in your observations on the following page

INQUIRY: MAKING OBSERVATIONS

Drawing

Written Description of Observations

Lateral (Side) View

 

 

 

 

 

 

Appearance:

 

 

 

Movement:

 

 

Eating habits:

 

 

Attraction/Repellant:

 

Ventral (Underside) View

 

 

 

 

 

Additional observations

a) What factors are influencing the movement of the snail? Write down at least 3.

1) _____________________________ 2) ______________________________ 3)_______________________________

2nd step: Come up with a testable question using the following 5-question strategy.

QUESTION 1: What materials are available to do this experiment?

-Examples of available substances

- sand, sawdust, flour, chalk dust, sticky tape, white glue, milk, etc

-paper, petri dishes, fish bowls, lamps, water, ice, etc.

-rulers, stopwatches, etc.

-No substances that will harm the snail will be allowed. ( salt, sugar, detergent, boiling water, etc.)

QUESTION 2: How do snails move? Write down 2 observations.

1)______________________________________________________________________

2)______________________________________________________________________

QUESTION 3: How can I change the set of materials to affect the movement/behavior of the snails?

List at least 3 factors.

1)______________________________________________________________________

2)______________________________________________________________________

3)______________________________________________________________________

QUESTION 4: How does _____________________ affect the movement/behavior of the snails?

QUESTION 5: How can you measure the response of the snails to the ____________ (change)?

List at least 2.

1)______________________________________________________________________

2)______________________________________________________________________

3rd step: Identify variables.

 Independent variable ( changing variable): _____________________

Dependent variable (responding measurable variable): ______________________

Constants: (You must have at least 5. These are the conditions that must be kept the same.

1)________________________

2)________________________

3) ________________________

4) ________________________

5) ________________________

Part II: Hypothesis

4th step: Make a hypothesis. (This should be a "if.. then.. because.." statement The " If we change.." part should contain the independent variable. The "then we predict.." part should contain the dependent variable and a relevant predication. The

"because…" part contains a well thought out explanation of why you made the prediction (previous observations or prior knowledge).

HYPOTHESIS: _______________________________________________________________________________

_____________________________________________________________________________________________

Part III. Experiment

5th step: Procedure: Write a detailed experimental procedure.

*Your procedure must be at least 10 steps.

*Make sure to keep your constant variables in mind when writing your procedure.

*Decide if you need a control group and an experimental group.

* Decide how many trials you must do to get accurate results.

*Be specific to detail. Write it to the "idiot standard"

*The teacher must check your variables, hypothesis and procedure before you are allowed to gather the materials and do the experiment.

6th step: Carry out your own procedure.

7th step: Record observations and measurements on a separate sheet of paper.

8th step: Organize results into tables and graphs on a separate sheet of paper.

9th step: Analyze your results.

10th step: Write a conclusion on a separate sheet of paper.

Part IV. Results

1) DATA TABLE: Organize your results in an easy to follow data table. Make sure you have 1) specific title that reflects both variables, b) descriptive labels for the rows and columns with units of measurement if applicable. Use the space below.

 

 

 

 

2) GRAPH: Show your results appropriately either through a line or bar graph. Make sure to include a) descriptive title that reflects the variables of the x and y axis, b) descriptive label of the x-axis (independent variable) and c) descriptive label of the y-axis (dependent variable) including units if applicable.

 
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

 

PART V. Conclusion

Write a one-paragraph conclusion summing up your overall findings from this lab on a separate sheet of paper. Your conclusion should include: 1) purpose restated, 2) brief overview of procedure, 3) hypothesis discussion (major findings: include numbers if you can), 4) analysis of your results (reasons behind your numbers) 5) overall conclusion (did you find the answer to your question? What questions are still left unanswered?) and 6) recommendations (areas of improvement and future ideas).

 

Questions or Comments can be sent by e-mail to Moore Biology.