Question
Topic – 7.9 Phylogeny
(a) – Topic – 7.9 Phylogeny
(b) – Topic – 7.9 Phylogeny
(c) – Topic – 7.9 Phylogeny
(d) – Topic – 7.10 Speciation
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.
(a) Describe how a scientist would use a comparison of the DNA sequences of different organisms to suggest the most likely evolutionary relationship among the organisms.
(b) Based on Figure 1, explain why Bovidae is likely to be more closely related to Moschidae than it is to Giraffidae.
(c) 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).
(d) Based on Figure 1A, explain why a characteristic found only in the Cervidae and Bovidae families is more likely evidence of convergent evolution than it is of common ancestry.
▶️Answer/Explanation
5(a) Describe how a scientist would use a comparison of the DNA sequences of different organisms to suggest the most likely evolutionary relationship among the organisms.
• The (DNA) sequences of organisms that are more closely related are more similar (than those of organisms that are less closely related).
5(b) Based on Figure 1, explain why Bovidae is likely to be more closely related to Moschidae than it is to Giraffidae.
Accept one of the following:
• (The molecular data/Figure 1B support(s) this relationship, and) molecular data are more reliable (than are morphological data).
• (The molecular data/Figure 1B support(s) this relationship.) Morphological similarities may not reliably indicate evolutionary relatedness.
4(c) 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).
Sample Response:
• Response must show an X placed on the line leading to Bovidae and an X placed on the line leading to Antilocapridae.
4(d) Based on Figure 1A, explain why a characteristic found only in the Cervidae and Bovidae families is more likely evidence of convergent evolution than it is of common ancestry.
Accept one of the following:
• There are other families that have the same common ancestor as the Bovidae and Cervidae families but do not have the characteristic.
• It is more likely that the characteristic arose independently in Cervidae and Bovidae than it arose in their common ancestor and was lost in Giraffidae, Moschidae, and Antilocapridae.