Copy of FA 23 Lab 1 Finch Evolution Worksheet

BIO 1131 L AB E XERCISE 1 W ORKSHEET : F INCH N ATURAL S ELECTION D ATA A NALYSIS N AME : Part A: Analyzing Graphical Data 1. In Figure 1 (on page 2 of your Lab Manual) there are two histograms shown. What is the variable that is measured in these histograms? The beak depth of birds that did not survive the drought and the beak depth of those who did survive the drought. 2. What was the mean and range of the data for birds in the left histogram? The mean was 9.11 mm and the range was 3.75. 3. What was the mean and range of the data for birds in the right histogram? The mean was 9.67 mm and the range was 3.25. 4. What can you conclude by comparing the two histograms? I can conclude that the medium ground finches with longer beak depth were able to withstand and survive the drought conditions because they were able to consume larger food. And I can also say that if you had a beak size larger than the mean beak size you were more likely to survive the drought. 5. Propose a biologically-based research hypothesis to explain the differences in the distributions of the variable measured on the birds that survived vs. those that did not survive the drought of 1977. Finches with longer beak depth are more likely to survive the drought of 1977 opposed to finches that have shorter beak depth. 1

BIO 1131 L AB E XERCISE 1 W ORKSHEET : F INCH N ATURAL S ELECTION D ATA A NALYSIS N AME : Part B: Descriptive Statistics 6. Fill out this data table based on the data you recorded on page 3 of the lab manual. You may copy and paste your table if preferred. Descriptive Statistics Nonsurvivors Survivors Body Mass (g) Wing Length (mm) Tarsus Length (mm) Beak Depth (mm) Body Mass (g) Wing Length (mm) Tarsus Length (mm) Beak Depth (mm) Mean () 15.7126 67.7886 19.0388 9.111 16.99 42 69.2966 19.3472 9.6738 Variance (s 2 ) 1.842 5.181 0.701 0.775 3.087 5.448 0.735 0.709 Standard Deviation = 1.3571 2.2762 0.8370 0.880 1.757 2.334 0.857 0.8422 Standard Error of the Mean (SEM) 0.919 0.321 0.1183 0.1244 0.248 0.3300 .121 .119 95% Confidence Interval 0.383 0.643 0.236 0.248 0.496 0.660 0.242 0.238 2

BIO 1131 L AB E XERCISE 1 W ORKSHEET : F INCH N ATURAL S ELECTION D ATA A NALYSIS N AME : d. Beak depth (mm): p = .0015 Reject Null: {Yes or No} PART E: Examining the Importance of Sample Size 9. Enter the values here from page 6 (Table 3) in a table form here:. Mean Standard deviation 5-finch sample 15-finch sample 50-finch sample 5-finch sample 15-finch sample 50-finch sample Non-survivors 8.784 9.616 9.111 9.784 9.564 9.673 Survivors 1.15 0.983 0.880 1.060 0.848 0.8422 10. Which results (from 5, 15, or 50 birds) do you think are closest to the means and standard deviations of the entire population of medium ground finches on the island? Explain your answer. I think the 50 inch sample is the closest to the means and standard deviations of the entire population of the medium ground finches on the island. I feel like the bigger the sample the more accurate it would be to the medium ground finches on the island. 11. The film that you watched before the lab that is posted on Canvas claims that beak depth is the trait that made the greatest difference in survival for the birds during the drought. Do the data you examined support this claim? Explain your answer based on your analyses and figures. Why might beak depth play a more important role in survival during the drought than either wing length or body mass? Yes, the data examined in the histogram does support the claim. In the video, there's this graph that pops up where you can see the offspring's beak length from the medium ground finches who survived. From this you can see that there were more offspring with longer beaks than shorter ones. The offspring were given longer beaks due to the environment at the time. If you examine the non-survivors histogram you can see that if the bird beak size was larger than the mean beak size less birds died. When examining the survivors beak size you can see that the beak sizes that were larger than the mean beak size had more survivors. 4