Self-study
P1
The French biologist Jean-Baptiste de Lamarck (1744–1829) outlined a theory of evolutionary change in 1809, 50 years before Darwin's . ██ ███ ██████ ██ ████████ █████████ █████ ████ ███ ████ █████████ ██████ ██ ████████ ██ █████ ███████████ ███ ████ ████ ██ ██ █████ █████████ ███ ███ ███████████████ ████ ████ █████████ ███
Lamarck's Theory of Evolution ·
Environmental adaptations could be inherited
Critique ·
Consensus view among scientists is that Lamarck is wrong
Steele ·
Claims to have evidence for Lamarckism
Steele claims to have found evidence for Lamarckian hereditary mechanism in the immune system. Not sure what this means but presumably the rest of the passage will flesh this out.
P2
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Phenomenon ·
Complexity of the immune system
How does our immune system work? If knowledge of how to defend against attacks are coded in the genes, how does it defend against a new disease, something it's never encountered before?
Partial Explanation ·
Some immune system cells mutate a lot
The immune system doesn't know. But "typo" mutations (when an error occurs when transcribing DNA into RNA) happen a lot which allows immune system to test different defenses.
P3
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Steele's Hypothesis ·
Supporting Lamarckism
Steele hypothesizes that the "typo" mutations that end up working gets coded back into the immune cell's DNA. Steele further hypothesizes that a virus then carries the altered immune cell DNA into the DNA of the reproductive cells. That's the mechanism by which an environmentally induced adaptation (in the immune cell) gets inherited.
P4
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Evidence ·
for Steele's Hypothesis?
Steele ·
Yes, circumstantial evidence
Steele claims that there's circumstantial evidence. Something about a pattern of mutations. Not sure what this means.
Other Biologists ·
No, there are simpler explanations for the "pattern of mutations"
Passage Style
Critique or debate
Phenomenon-hypothesis (RC)
25.
The passage most strongly suggests ████ ███ ██████ █████ █████ ████ █████ ███ ██ ███ █████████ ███████████
Question Type
Author’s perspective
Implied
We can’t predict the correct answer just from the question stem, so let’s use process of elimination.
a
Contrary to the ███████ ██ ████ ██████ ███████████ ███████ ████████ ███████████████ ████████ ███ ██ ██████ ██ ████ ███ ██████████ ██ ███ █████
Not supported, because the author never endorses Steele’s hypothesis. We don’t know that the author thinks Steele’s proposed mechanism for passing along acquired characteristics actually occurs.
b
Steele and his ██████████ ████ ███ ████████ ████████ ███ ███████ ██ ███████ █████████████ ██ ██████ ██████
Supported, because the author notes that reverse transcription has been observed
c
The patterns of █████████ ████████████ ██ ██████████ █████ ██ █████ ████ █████ ████████████ ███ ██████ ██████ █████████ ████████ ████ ███ ███ ██ █████ █████ ███ ████ ███████ ██ █ ██████
Not supported, because the author never endorses Steele’s hypothesis. We don’t know that the author thinks Steele’s proposed mechanism for passing along acquired characteristics actually occurs.
d
The passing on ██ ████████ ███████████████ ████ ███ ██████████ ██ ███ █████ ██ ██ ██████ ██ ████ ██ ████████ ████████ ██ ███ ██████ ███████
Although Steele’s hypothesis happens to involve the immune system, the author doesn’t suggest that the passage of acquired characteristics is limited to the immune system.
e
Unless a hypothesis ███ ██ █████████ ██ ██████ ████████████ ██ ██████ ██ ████████ ██ ███████████ ██████ ████ ██ ████████
Although the author does call Steele’s theory speculative, this doesn’t imply that she believes any hypothesis that can’t be confirmed by direct observation is speculative. We can’t say that she thinks, for example, Darwin’s theory of evolution is speculative. In addition, the author doesn’t believe Steele’s theory isn’t “science.” Something can be science and still speculative. The author never draws a division between speculation and science.