SAT #9 Reading (Question 52)

Question

Niklas counters Martone's proposal about the evolutionary history of red and green algae by suggesting that the [...]?

Answer 1

52.R.9 (medium)

Answer Choice C is the correct answer because Lines 76-81 describe Nicklas’s view that red and green algae evolved from two separate endosymbiotic events, and so evolved the ability to photosynthesize separately. Answer Choice A is incorrect, because Niklas doesn’t believe that “major molecular pathways present in red and green algae must have been in place long before their evolutionary lines separated,” but argues the opposite — that they evolved from separate endosymbiotic events. Answer Choice B is incorrect because, although it may be true that “evidence uncovered in Martone’s research does not directly address the issue of when the last common ancestor of red and green algae existed,” it doesn’t seem that Niklas would counter Martone for this since there isn’t the expectation that Martone’s work would address this issue. Answer Choice D is incorrect because Niklas doesn’t mention any difference between the processes of lignin production for C. cheilosporoides and for its ancestral species.

How to solve this? The Question asks, “Niklas counters Martone’s proposal about the evolutionary history of red and green algae by suggesting that the [...]?” To solve this, we should go back to the Passage to look for Niklas’s view on the evolutionary history of red and green algae. Before this, however, we should also try to get a grasp on Martone’s proposal about that evolutionary history, because Niklas’s view is framed as a counter to it. In Paragraph 10, we’re told that Martone believes that “molecular pathways producing lignin emerged long before land plants evolved from green algae, back to some ancestor shared with red algae more than a billion years ago,” and that red and green algae descended from a single endosymbiotic event. In the next paragraph, we’re told that Niklas thinks that “red and green algae evolved from separate endosymbiotic events.” In other words, Martone believes that red and green algae have a shared ancestor from which they received their ability for lignin production, while Niklas believes they evolved separately and thus developed their ability for lignin production separately. So, we should expect our answer choice to highlight this specific difference.

Answer Choice A says that “major molecular pathways present in red and green algae must have been in place long before their evolutionary lines separated,” which matches Martone’s view, but not Niklas’s contrasting view, so we should eliminate this option. Answer Choice B says that “evidence uncovered in Martone’s research does not directly address the issue of when the last common ancestor of red and green algae existed,” which may be true but not a relevant counterargument for Niklas to make. Answer Choice C says that “evolutionary lines leading to the two kinds of algae might have diverged before they acquired the ability to photosynthesize.” This answer choice does match our Text, since Niklas believes that red and green algae evolved from separate endosymbiotic events. This answer choice focuses on photosynthesis ,however, and not molecular pathways relevant to the production of lignin, so we should double check to make sure Niklas’s view can extend to photosynthesis as well. In Lines 67-73, Martone describes his view that not only did red and green algae descend from a single endosymbiotic event, but also that this event was simultaneous with the ability for photosynthesis. It makes sense, then, to say that Niklas’s contrasting view about the evolutionary history of red and green algae also diverges in its view of the acquisition of photosynthesis. So, we can keep our answer. Answer Choice D says that the “process by which C. cheilosporoides produces lignin might be different from the process by which ancestral species of algae produced it.” Because neither our Text nor our Passage describe a difference between the present and ancestral processes of lignin production, we should eliminate this option. That leaves only Answer Choice C, which we should choose as our answer.