Key concepts
Organisms carry two alleles for each modeled gene, one inherited from each parent. During gamete formation, the pair separates, so each gamete receives one allele. Fertilization restores a pair.
P is used here for a purple-flower allele and p for a white-flower allele. PP and Pp are purple because P is dominant; pp is white.
Questions and applications
Why can two purple-flower plants produce white-flower offspring? Why does a probability of 25% not guarantee one white flower in every four offspring?
Inheritance predictions support plant breeding, animal breeding, and genetic counseling, though many real traits involve several genes and environmental effects.
Common misconceptions
Dominant does not mean common, better, or stronger. A 3:1 ratio is a long-run expectation, not a fixed order. Offspring do not blend alleles; they inherit discrete copies.