Question

In the lab, you will change the number of birds with each beak phenotype for the second and third generations. What row of the data table will be the basis for computing new numbers?


✔ Percentage of food eaten by the flock
Why is the percentage of food eaten a good number to use? Explain.

Answer 1

The row labeled "Percentage of food eaten by the flock."

Why this is a good number to use
- It gives a standardized measure of how well each beak phenotype acquires resources (a proxy for fitness).
- Because it is a percentage, it normalizes for differences in total food or starting numbers, so different phenotypes are directly comparable.
- You can easily convert the percentage into expected numbers for the next generation by multiplying the percent (as a fraction) by the total number of birds you want in the next generation (e.g., 50% × 20 birds = 10 birds).
- In short, percent food eaten reflects relative success at getting food, which is what drives survival and reproduction and therefore changes in phenotype frequencies.

(Keep in mind this assumes that food-acquisition translates into survival and reproduction — i.e., that percent eaten is a valid proxy for reproductive success.)