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Difficulty: MediumAligning Data and Predictions with Viewpoints

Two scientists discuss the possible causes of the Permian-Triassic extinction event, which occurred approximately 252 million years ago.

Scientist 1
The extinction was caused by the eruption of the Siberian Traps, a massive volcanic province. These eruptions released large quantities of carbon dioxide (CO2CO_2) and sulfur dioxide (SO2SO_2) into the atmosphere over a period of approximately 100,000 to 200,000 years. The accumulation of these gases led to severe global warming, acid rain, and ocean acidification. This hypothesis predicts that geological evidence will show a gradual decline in biodiversity coinciding with volcanic emissions, with no evidence of high-pressure impact shock waves.

Scientist 2
The extinction was caused by the impact of a large asteroid or comet. The collision instantly ejected massive amounts of dust, pulverized rock, and sulfur into the stratosphere, blocking sunlight and causing rapid global cooling and a shutdown of photosynthesis within days. This event deposited a distinct, thin layer of impact debris containing shocked quartz (grains with microscopic deformation structures from high pressure) and high levels of iridium globally. The extinction of species was sudden and occurred immediately following the impact.

A researcher analyzed rock layers from the Permian-Triassic boundary and found a 150,000-year-long fossil record showing a progressive decline in marine organisms, accompanied by a steady increase in soil acidity indicators. No shocked quartz or iridium anomalies were detected in any of the layers. This finding is most consistent with the viewpoint of which scientist?

  1. Scientist 1, because the findings indicate a gradual extinction timeline and environmental acidification without indicators of a high-pressure impact.Answer
  2. B
    Scientist 1, because Scientist 1 predicts that volcanic eruptions would produce high-pressure shock waves that leave shocked quartz in the rock layers.
  3. C
    Scientist 2, because the prolonged 150,000-year extinction timeline and rising acidity are key components of the impact hypothesis.
  4. D
    Scientist 2, because the absence of shocked quartz and iridium anomalies confirms that the impact was from a comet rather than an asteroid.

Answer

Scientist 1, because the findings indicate a gradual extinction timeline and environmental acidification without indicators of a high-pressure impact.
The correct answer is the option stating that the finding is consistent with Scientist 1 because of the gradual extinction timeline and acidification without impact indicators. The data records a 150,000-year gradual decline and rising acidity, which directly matches Scientist 1's prediction of volcanic greenhouse gas and sulfur emissions over a 100,000 to 200,000-year timeline. Furthermore, the absence of shocked quartz and iridium anomalies supports Scientist 1's expectation of no high-pressure impact shock wave markers.

Step-by-Step Solution

1
Summarize the key characteristics of the new finding.
The finding exhibits a gradual marine decline over 150,000 years, increased acidity, and lacks shocked quartz or iridium.
This establishes the parameters that must be compared against the predictions of both scientists.
2
Compare the finding parameters to the predictions of Scientist 1.
Scientist 1 predicts emissions over 100,000 to 200,000 years (matching the 150,000-year timeframe), acid rain (matching the acidity), and a gradual decline in biodiversity without impact shock indicators (matching the lack of shocked quartz).
To evaluate alignment with the first hypothesis.
3
Compare the finding parameters to the predictions of Scientist 2.
Scientist 2 predicts a sudden extinction, rapid global cooling, and the clear presence of shocked quartz and iridium. The data directly contradicts these predictions.
To evaluate alignment with the second hypothesis and confirm the correct option.

Key Concept

Aligning data timelines and physical markers with predictions made by conflicting scientific viewpoints.
Estimated Time:1m 30s
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Topics

Aligning Data and Predictions with Viewpoints

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