Advanced Placement (AP) Biology Practice Exam

What does a pedigree diagram illustrate?

1. The relationship between different species

2. Occurrence of genetic traits across several generations of a family

3. Variations in a population's physical traits

4. Environment-induced changes in individuals

The correct answer is: Occurrence of genetic traits across several generations of a family

A pedigree diagram is a visual representation that illustrates the inheritance of genetic traits across multiple generations within a family. It typically shows the relationships between family members, indicating how traits are passed down from one generation to the next. Each individual is represented by shapes (usually circles for females and squares for males), and lines connecting them demonstrate their familial relationships, with specific indications denoting the presence or absence of certain traits. By observing a pedigree, geneticists can track dominant or recessive traits, identify carriers of genetic disorders, and assess the likelihood of inheriting those traits in future generations. This makes pedigree diagrams particularly useful in understanding genetic conditions, lineage, and evolving traits within a given family over time.