Question

question 24 of 25
humans and gibbons have two different amino acids in their hemoglobin sequence. what does this say about the evolution of these two species?
a. gibbons evolved from humans.
b. they have a recent common ancestor.
c. they are not closely related
d. they are the same species.

Explanation:

• Option A: Gibbons did not evolve from humans. Evolution is a branching process, not a linear one where one modern species evolves from another modern species.
• Option B: Similarities in protein (hemoglobin) sequences, like having only two different amino acids out of many in the sequence, suggest a relatively recent divergence from a common ancestor. When two species have a recent common ancestor, their proteins (which are coded by genes) will be more similar. Small differences in the amino - acid sequence of hemoglobin can accumulate over time since the divergence from the common ancestor.
• Option C: The fact that there are only two different amino acids in their hemoglobin sequence indicates a close relationship rather than not being closely related. If they were not closely related, there would be many more differences in such a conserved protein (a protein that has a similar structure and function across species).
• Option D: They are not the same species. Gibbons and humans have many other differences (e.g., in morphology, behavior, and other genetic and protein - level differences beyond just the two amino - acid differences in hemoglobin).

Answer:

B. They have a recent common ancestor.