Examine the pelvic score data. Does the pelvic phenotype differ between Bear Paw Lake and Frog Lake fish?

Examine the pelvic score data. Does the pelvic phenotype differ between Bear Paw Lake and Frog Lake fish?

• A. No, the pelvic phenotype is the same in both lakes.
• B. Bear Paw Lake fish have pelvic spines, Frog Lake fish lack spines.
• C. Some Bear Paw Lake fish have pelvic spines but Frog Lake fish lack any pelvic spines.
• D. Bear Paw Lake fish lack spines, and Frog Lake fish have spines.

Answer: (D)

Variation in a trait between populations shows how divergent they are and what might have shaped that difference. Here, the trait is the presence or absence of pelvic spines in sticklebacks. If Bear Paw Lake fish lack pelvic spines while Frog Lake fish have them, that indicates a clear difference in the pelvic phenotype between the two lakes. The data support a pattern where Bear Paw Lake fish are spine-free and Frog Lake fish have spines, a consistent lake-specific difference across samples. This suggests population-level divergence in this trait, potentially due to different ecological pressures or historical genetic differences between the lakes. The other options would require reports of no difference, the opposite pattern, or variation within a lake, which isn’t what the data show.

Variation in a trait between populations shows how divergent they are and what might have shaped that difference. Here, the trait is the presence or absence of pelvic spines in sticklebacks. If Bear Paw Lake fish lack pelvic spines while Frog Lake fish have them, that indicates a clear difference in the pelvic phenotype between the two lakes. The data support a pattern where Bear Paw Lake fish are spine-free and Frog Lake fish have spines, a consistent lake-specific difference across samples. This suggests population-level divergence in this trait, potentially due to different ecological pressures or historical genetic differences between the lakes. The other options would require reports of no difference, the opposite pattern, or variation within a lake, which isn’t what the data show.