Scoring should be done by teacher observation during the exercise.

3 points - Successfully sets up the petri dish with the arrangement of wet/dry paper towels, and construction paper screen.

2 points - For having two factors correct.

1 point - For having one factor correct.

0 points - Incorrect setup; no factors correct.

 

3 points - Predictions relate to both variables.
A prediction might be: (a) The sow bugs will seek the moist/dark side of the Petri dish, (b) The sow bugs will be all over the setup, (c) The sow bugs will move toward the dry/light side of the petri dish, etc. Answers should be written using complete sentences.

2 points - For having a prediction, for only one factor in complete sentences.
A prediction might be: (a) The sow bugs will seek the dark side of the petri dish.
*** Deduct 1 point if complete sentences are not used. ***

0 points - Incorrect response, even if in complete sentences, or no response provided.

 

3 points - As long as students provide a sound rationale for both factors based on biological principles. They may have answers such as: (a) They will prefer the dark because it is cooler or because they can hide from predators or they normally feed at night. (b) They will scatter all over because they are disoriented due to being handled or they are attempting to find their home area. (c) They seek moisture because they require the dampness for respiration or to keep from drying out, etc. Predictions should be written using complete sentences.

2 points - Identifies only one factor in explanation
*** deduct 1 point if complete sentences are not used***

0 points - Incorrect response even if in complete sentence, or no response provided.

Part B

2 points - For completing chart properly with both sets of time and numbers.

1 point - One part of the data is missing.

0 points - If there is more than one part missing.

Part B

3 points - "Yes, most or all of the sow bugs were on the moist/dark side or dry/light side." They may say "Yes, 7 of the 10 sow bugs were on the moist/dark side," or "No, 6 bugs were on the moist/dark side and 4 were on the illuminated/dry side." The students should use the numbers of sow bugs located in the various parts of the setup. As long as they have an appropriate response based on what they discovered and recorded on their chart and answers are written in complete sentences.

2 points - In the case of partial answres, for correctly deciding "yes or no" based on their numbers for preference.
or
For properly using the numbers of bugs in various locations as evidence but with a weak explanation.

*** Deduct 1 point if complete sentences are not used. ***

0 points - Incorrect response even if in complete sentence, or no reponse provided.

3 points - "No. Movement to the moist/dark side could be evidence that the sow bugs prefer darkness and have nothing to do with the moisture." Students should indicate that there are two variables involved, not just one. Answers should be written in complete sentences.

2 points - Identifies only one of the above variables.
*** Deduct 1 point if complete sentences are not used. ***

0 points - Incorrect response even if in complete sentence, or no response provided.

3 points - "No. Movement to the dry/light side might indicate preference for a dry environment. It might not be related to the amount of light available." Again, students should indicate that there are two variables involved, not just one. Answers should be written in complete sentences.

2 points - Identifies only one of the above variables.
*** Deduct 1 point if complete sentences are not used. ***

0 points - Incorrect response even if in complete sentence, or no response provided.

1 point - Student responds, "No."

2 points - Student explains that two (2) variables were used at the same time. Answers should be written in complete sentences.

1 point - Student gives a correct explanation for answer, but not in complete sentences.

0 points - Incorrect answer even if written in complete sentences.

2 points - Student suggests a procedure to eliminate the problem of two (2) variables, such as, "The construction paper screen could be left off the petri dish. That way the sow bugs would be selecting between a moist and a dry environment." Or, "The towels on the bottom of the petri dish could all be dry or all moist, with the construction paper shading on one side and the other side illuminated."

Answers should be written in complete sentences.
*** Deduct 1 point if complete sentences are not used. ***

0 points - If student response that the design is fine as it is, even if it is written in complete sentences.

2 points - The sow bugs prefer a moist environment because they respire with gills. They must have moisture to keep their gills so that the diffusion of gases can occur.
or
The sow bugs prefer a dark environment because it keeps them from being easily spotted by predators. It also keeps them cooler and prevents them from drying out.
or
The sow bugs prefer dry environments so that they are not drowned. They must have the proper moisture level. Answers should be written in complete sentences.

Answers should be written in complete sentences.
*** Deduct 1 point if complete sentences are not used. ***

NOTE: There are other possible correct answers. Use your discretion in deciding if the choice is reasonable based on the findings and that the survival factors are based on sound, biological reasoning.

2 points - There is no preference since neither the moist and dark or the dry and light are a detriment to the animal's survival, and neither condition is needed for their survival.
or
In order to maintain a proper homeostatic balance, the sow bugs must move back and forth between the two environments.

Answers should be written in complete sentences.
*** Deduct 1 point if complete sentences are not used. ***

0 points - If either choice (a) or (b) is selected and is not based on a reasonable interpretation of the lab results even if it is written in complete sentences.

0 points - Incorrect response, even if written in complete sentences, or no response provided.

"Sow Bug Habitats" - Scoring Form

Student ID ____________

Male / Female (circle one)

Circle the student's score for each question. Add the points for each question and write the total score at the bottom of the scoring form.

Total Score _______________

Total possible score - 24 points