Question

Difficulty: Very hardOverall Text Structure Analysis

Until recently, evolutionary biologists held that the diversification of angiosperms (flowering plants) during the Cretaceous period was a slow, gradual process facilitated primarily by insect co-evolution. However, paleobotanist Dr. Marcus Thorne has disrupted this narrative. By analyzing fossilized pollen distributions in high-latitude sediments, Thorne demonstrates that angiosperms experienced a rapid, catastrophic radiation that coincided with a sudden shift in global temperatures. He argues that this climate anomaly, rather than animal mutualism, was the primary catalyst for their ecological dominance. Consequently, Thorne proposes a revised model wherein abiotic factors play a more decisive role in early plant diversification than previously acknowledged.

Which choice best describes the overall structure of the text?

  1. A
    It compares two competing theories about plant diversification, details a series of experiments that prove one theory correct, and argues that both models should be integrated into a new framework.
  2. B
    It asserts that abiotic factors are the sole drivers of plant evolution, refutes the role of insect co-evolution entirely, and advocates for a complete halt to research on animal mutualism.
  3. It summarizes a widely accepted scientific theory, introduces a researcher who disputes that theory, describes the empirical evidence used in the researcher's analysis, and outlines the broader implications of the researcher's alternative explanation.Answer
  4. D
    It presents a recent hypothesis about Cretaceous climate changes, introduces a researcher who validates this hypothesis using agricultural data, and concludes by calling for more precise temperature measurements.

Answer

The correct option is the one that states the text summarizes a widely accepted scientific theory, introduces a researcher who disputes that theory, describes the empirical evidence used in the researcher's analysis, and outlines the broader implications of the researcher's alternative explanation.
The correct answer accurately outlines the structure of the passage. The text first summarizes a prevailing scientific consensus (that angiosperm diversification was slow and insect-mediated), then introduces Dr. Marcus Thorne as a researcher challenging this view. It describes Thorne's analysis of fossilized pollen distributions as the empirical evidence supporting his claim, and concludes by presenting Thorne's revised model and its broader implications for evolutionary biology.

Step-by-Step Solution

1
Analyze the first sentence of the passage to identify the initial rhetorical move.
The text begins by outlining a long-standing consensus among evolutionary biologists regarding the gradual, insect-mediated diversification of angiosperms.
This establishes the context or baseline theory that the passage will engage with.
2
Analyze the second sentence to identify the transition.
The word 'However' introduces Dr. Marcus Thorne, who challenges or disrupts this established consensus.
This marks the introduction of a counter-argument or new perspective.
3
Analyze the third sentence to determine how the challenge is supported.
The text explains that Thorne analyzed fossilized pollen distributions in high-latitude sediments to demonstrate a rapid radiation coinciding with temperature shifts.
This presents the empirical evidence or data that supports the researcher's challenge.
4
Analyze the final two sentences to identify the conclusion.
The passage states that Thorne argues a climate anomaly was the primary driver and proposes a revised model emphasizing abiotic factors.
This outlines the alternative theory and its broader implications for plant evolutionary models.

Key Concept

Overall Text Structure Analysis
Rate this question