Reading Comprehension

PT145 · S1 · P4 · Q24 Genetic Typos

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The French biologist Jean-Baptiste de Lamarck (1744–1829) outlined a theory of evolutionary change in 1809, 50 years before Darwin’s On the Origin of Species.

Topic

The revival of Lamarckian evolutionary theory through new research on heredity in the immune system.

Framework

Old / New; Present Debate

Main Point

Edward J. Steele and his team are challenging the widely dismissed Lamarckian theory of evolution by proposing that a mechanism in the immune system could allow acquired traits to be inherited, although most biologists remain skeptical due to lack of direct evidence. ( — End of P1 gives the core new idea, while P4 presents ongoing skepticism and the debate.)

P1: Introduction to Lamarck and Steele's Revival

Lamarck, a French biologist, suggested in 1809 that organisms could inherit traits acquired during their lifetimes. While this idea has been mostly laughed off by modern biologists, Edward J. Steele is now trying to bring Lamarckism back, claiming he’s found supporting evidence in how our immune system works.

P2: The Immune System’s Mutating Genes

This paragraph lays out the mystery of how the immune system adapts so quickly to new threats—partly by certain cells mutating their genes at an unusually high rate, creating "typos" as the DNA is copied to RNA. This enables the immune system to experiment with defenses on the fly.

P3: Steele’s Lamarckian Hypothesis and Its Mechanism

Here we get the details of Steele’s theory: he proposes that altered RNA is turned back into DNA (a process called "reverse transcription"), and suggests that viruses could carry this altered DNA into reproductive cells—potentially passing acquired traits to offspring.

24.

What is the primary function of the last paragraph in the structure of the passage as a whole?

to present various objections that
Too Narrow
Only the final two sentences raise objections. The preponderance of this paragraph is about presenting Steele's evidence for their claims.
17% picked this
to dismiss the neo-Lamarckian theory
Too Strong: dismiss the theory
Our author never really takes a stand. She seems inquisitive and somewhat skeptical. She definitely doesn't dismiss the theory out of hand. The last paragraph is also contradicting this answer, which says Steele's theory is not supported by evidence, because it presents Steele's evidence.
11% picked this
to explain how the neo-Lamarckian
Out of Scope: new findings
This paragraph is just asking Steele for what evidence he's got for his theory. The author isn't trying to revise Steele's theory, and I have no idea what "new findings" this answer choice is referring to.
2% picked this
to suggest several possible directions
Out of Scope
Out of Scope: directions for new research Nowhere in this last paragraph does our author suggest anything. She asks a question, makes a concession as to the limits of a possible answer, provides Steele's answers, and ends with other scientists' pushback. I guess this answer choice is trying to get people to over-value the fact that other biologists said "there may be other explanations for this pattern", and it's pretending that this line was the author suggesting that a possible new research direction would be pursuing these other explanations. But this was just a quote from biologists. The author made no suggestions.
4% picked this
Correct
to indicate the nature of
Why this is right
We were looking for something like "assess the evidence Steele has for his theory". To indicate the nature of the evidence is a vague phrase that can cover "what kind of evidence does he have and how compelling is it". In the 2nd sentence of this paragraph, the author indicates the type of evidence will be circumstantial. In the 3rd and 4th sentences she indicates that Steele cite a distinct pattern of mutations in the genes that carry instructions for immune system responses, as their evidence. In the last two sentences, we learn that this evidence is not seen as very compelling by other biologists, since they think it could be interpreted different ways.
Skill tested: Paragraph Purpose · how this choice captures the passage's function is the move to repeat next time.
66% picked this

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