Purpose: To apply the principles of natural selection to the effect of predation and background on the color patterns of male guppies over a period of 15 generations.
Natural Selection Virtual Lab Schedule
Note: Complete the online Natural Selection Virtual Lab and this lab report in the following order:
- From within the classroom, click on the link to the online Natural Selection Virtual Lab and follow the lab instructions. Stop when the STOP sign appears in the virtual lab.
- Complete Step 1 in the Results section of this lab report.
- Complete the Hypothesis section of this lab report.
- Return to the virtual lab and finish conducting the virtual experiment.
- Record your observations from the virtual experiment by completing Step 2 in the Results section.
- Complete the Analysis and Conclusion sections of this lab report.
- Submit the finished lab report to your Instructor, following the submission instructions in your online classroom.
Hypothesis
Note: Complete Step 1 in the Results section first. The observations you make there are ultimately part of the results and contribute to your hypothesis. Then, write your hypothesis (see instructions below).
In the table below, explain what you expect to observe in the color patterns of the male guppies in each of the ponds based on what you know about natural selection.
| Pond 1 Prediction | |
| Pond 2 Prediction | |
| Pond 3 Prediction | |
| Pond 4 Prediction |
Note: After completing Step 1 in the Results section and writing your hypothesis, above, return to the Natural Selection Virtual Lab and select the NEXT button to complete the virtual experiment.
Materials and Methods
Before running this experiment you will create four different experimental ponds. The ponds will vary according to the kind of gravel (large, coarse gravel or small, fine gravel) and according to whether a guppy predator is present. In order to set up the experimental ponds you need to “drag and “drop” the correct sand size and the predators into the appropriate pond. You will then view a representative of a typical male guppy from a common pool and place a breeding population of these guppies in each of the experimental ponds. After approximately 15 guppy generations pass, the simulator will allow you to view a representative male guppy from each pond. You will observe and then record the male guppy color pattern representative of each pond in the results table and note any variations from the common ancestor.
Results
Step 1:
- Record your observations of the guppy color pattern before the start of the experiment in the table above.
Describe a typical male guppy at the beginning of the experiment here:
- Complete the Gravel Type and Predator columns in the table below.
Note: After completing Step 1, complete the Hypothesis section.
Step 2: After you select the TIME button in the interactive virtual experiment, record your observations of the changes in the color patterns of the guppies in the Observations Over Time column.
| Gravel Type (coarse / fine) | Predator (yes / no) | Observations Over Time. Note the color pattern of typical male guppies in each pool and how they differ from that of their common ancestor. | |
| Pond 1 | |||
| Pond 2 | |||
| Pond 3 | |||
| Pond 4 |
Analysis
Write a 3+ paragraph analysis of your results that includes the following:
- A summary of the observations of the changes in the guppy populations in each pond.
- A statement that explains whether you observed the results you expected, as well as why you did or did not observe the expected results.
- Explicitly describe the role of natural selection and the selection pressures present in this experiment.
- A statement explaining how, if at all, you think coloration in the male guppy populations in Ponds 1 and 2 would change over time if the predators were permanently removed (Note: Explain your hypothesis in terms of selection pressures.)
- A summary of the overall knowledge you gained from this lab
Conclusion
Write a conclusion of one or more paragraphs that includes the following:
- A brief recap of the main points in your analysis.
- Propose a question about this lab topic that you would like to research in the future.
