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AP Biology 7.9.A: Evidence for Phylogenetic Relationships

Practise AP Biology 7.9.A questions by using outgroups, shared derived characters, cladograms and molecular data to infer evolutionary relationships.

Syllabus
Effective Fall 2025
Course
AP Biology

Exam points

  • distinguish phylogenetic trees from cladograms and identify how fossils or molecular clocks provide time information
  • use outgroups and shared derived characters to construct or interpret evolutionary relationships
  • compare morphological, DNA and protein evidence and evaluate which data better resolve a phylogeny

7.9.A—Describe the types of evidence that can be used to infer an evolutionary relationship question 1

[Maximum number: 1]

Ruminants are hoofed animals, including cattle and sheep, that have a unique four-chambered stomach specialized to digest tough, fiber-filled grasses. Researchers studying ruminants are investigating the morphological and molecular characteristics of different ruminant families in order to determine the evolutionary relationships among the families. Cladograms of several ruminant families were constructed based on morphological data (Figure 1A) and molecular data (Figure 1B). Table 1 shows a sample of the morphological characteristics present in each family used to construct the cladogram in Figure 1A.

Figure 1. Cladogram of six ruminant families based on (A) morphological data and (B) molecular data

Figure 1. Cladogram of six ruminant families based on (A) morphological data and (B) molecular data

TABLE 1. MORPHOLOGICAL CHARACTERISTICS FOUND IN EACH RUMINANT FAMILY

TABLE 1. MORPHOLOGICAL CHARACTERISTICS FOUND IN EACH RUMINANT FAMILY

Using the template in the space provided for your response, represent the point(s) at which characteristic 1, listed in Table 1, evolved by marking "X" on the line(s) of the cladogram in the correct location(s).

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