Reading ComprehensionDifficulty: Easy

PT110 S1 P3 Q16 Explanation

Lamarck’s Theory

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Passage

In the eighteenth century the French naturalist Jean Baptiste de Lamarck believed that an animal’s use or disuse of an organ affected that organ’s development in the animal’s offspring. Lamarck claimed that the giraffe’s long neck, for example, resulted from its ancestors stretching to reach distant leaves. But because biologists could find characteristics never occurs. Yet new research has uncovered numerous examples of the phenomenon.

In bacteria, for instance, enzymes synthesize and break down rigid cell walls as necessary to accommodate the bacteria’s growth. But if an experimenter completely removes the cell wall from a bacterium, the process of wall synthesis and breakdown is disrupted, and the bacterium continues to grow—and multiply indefinitely—without walls. This inherited absence interactions among genes, without any attendant changes in the genes themselves.

A fundamentally different kind of environmentally induced heritable characteristic occurs when specific genes are added to or eliminated from an organism. For example, a certain virus introduces a gene into fruit flies that causes the flies to be vulnerable to carbon dioxide poisoning, and fruit flies infected with the virus will pass an ability that normally would have taken eons to develop through random mutation and natural selection.

The new evidence suggests that genes can be divided into two groups. Most are inherited “vertically,” from ancestors. Some however, seem to have been acquired “horizontally,” from viruses, plasmids, bacteria, or other environmental agents. The evidence even appears to show that genes can be transmitted horizontally between organisms that are considered to has long eluded biologists, and that may eventually prove Lamarck’s hypothesis to be correct.

What this question is testing

Strengthen

Your task

Find the choice that makes the argument's conclusion more likely to be true.

Common trap

Answers that are consistent with the argument but add no real support, or that strengthen a claim the argument doesn't make.

Winning move

Locate the gap between evidence and conclusion, then pick the choice that closes it.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
16.

Which one of the following, if true, offers the most support for

Answer choices

  1. Darwin's Theory2% picked this

    Deer have antlers because antlers make deer more likely to survive

    This doesn't have anything to do with Lamarck's notion that using an organ makes you offspring have a different version of that organ. This is talking about the Darwinian sense of evolution: natural selection. Deers evolved antlers, because mutations that led to bigger antlers provided deers with a survival / reproduction advantage, and thus the gene for bigger antlers slowly got more an more represented throughout the gene pool.

  2. Correct85% picked this

    Anteaters developed long snouts because the anteater stretches its snout in order to reach ants

    Why this is right

    We were looking for something like, "if you use an organ, your offspring will have an 'enhanced' version of that organ. If you don't use an organ, your offspring will have a 'degraded' version of that organ." This is saying that anteaters used their snout by stretching it (like the giraffe example) to reach underground ants, and as a result their offspring then developed even longer snouts.

    Skill tested: Strengthen · how this choice captures the passage's function is the move to repeat next time.

  3. No Relationship7% picked this

    Potatoes produced from synthetic genes tend to be more resistant to disease than are potatoes

    This is talking about "synthetic vs. natural", which has nothing to do with Lamarck's hypothesis. He cares about "use vs. disuse of an organ".

  4. No Relationship3% picked this

    Lions raised in captivity tend to have a weaker sense of direction than do lions

    This is talking about "raised in captivity vs. raised in the wild", which has nothing to do with Lamarck's hypothesis. He cares about "use vs. disuse of an organ". Now, it's reasonable for us to think that a lion raised in captivity would not use their sense of direction as much as a lion that lives in the wild. So if we were told that "the offspring of lions who lived in captivity end up having a worse sense of direction than do the offspring of lions who lived in the wild", that would strengthen. That would make it seem like lions who don't use their sense of direction (because they live in a tiny zoo habitat) pass on that degraded organ to their kids. But this answer isn't talking about offspring. If a lion is raised in captivity, then of course it will have different traits than lions raised in the wild (f.e. the lion raised in captivity is probably much more comfortable around humans).

  5. No Relationship4% picked this

    Pups born to wild dogs tend to be more aggressive than are pups born to

    This doesn't have anything to do with "how they use an organ gets passed on to their kids". The different behavior in pups of hunting dogs isn't resulting from how their parents used or disused an organ. It's resulting from the fact that humans are selectively breeding dogs with temperaments better suited to the discipline of hunting.

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