Final answer:
The difference between expected and experimental phenotypic ratios in a dihybrid cross is due to various factors including sample size, environmental influence, genetic linkage, or random chance. The expected 9:3:3:1 ratio from a Punnett square might not match the observed ratio precisely.
Step-by-step explanation:
The student is asking about the difference between expected and experimental phenotypic ratios in a dihybrid cross. A dihybrid cross typically results in a phenotypic ratio of 9:3:3:1 based on Mendelian genetics. This assumes independent assortment of two non-interacting genes with dominant and recessive alleles. The expected results can be construed using a Punnett square or by applying the product rule to the expected chances of individual traits.
The experimental values given are purple smooth = 75, white smooth = 28, purple wrinkled = 24, and white wrinkled = 8. To account for the difference between expected and actual results, we must recognize that the actual proportions of genotypes can vary due to sample size, environmental factors, or other genetic variables such as linkage between genes or genetic drift. The observed ratios are close to the expected 9:3:3:1 ratio but exhibit some variance, which could be due to random chance or experimental error.