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Question

Difficulty: MediumImplicit and Inferred Relationships

Passage:

In 1862, Charles Darwin received a shipment of the Madagascar orchid Angraecum sesquipedale, a flower distinguished by an astonishingly long, foot-long green nectar spur. In his treatise on orchids, Darwin noted that the nectar was pooled at the very bottom of this deep tube, out of reach for any insect known to science at the time. He hypothesized that there must exist a species of moth with a proboscis of equivalent length, capable of reaching the nectar to facilitate pollination. Critics ridiculed the idea, arguing that such an absurdly specialized creature could not exist and that the orchid’s spur was merely a decorative anomaly. Undeterred, Darwin maintained that the flower’s structure made no evolutionary sense without a corresponding pollinator. It was not until 1903, two decades after Darwin's death, that entomologists in Madagascar discovered the sphinx moth Xanthopan morganii praedicta, possessing a twelve-inch proboscis. This finding vindicated Darwin’s evolutionary prediction, demonstrating that the anatomical link between the orchid and the moth was a product of coevolutionary pressures, where each species had gradually driven the adaptation of the other over millennia.

Based on the passage, the relationship between Darwin’s evolutionary hypothesis and the perspective of his critics is best described by which of the following statements?

  1. Darwin viewed the physical traits of organisms as functionally interdependent, whereas his critics believed that some anatomical features could exist independently of ecological utility.Answer
  2. B
    Darwin anticipated that the sphinx moth would eventually evolve a longer proboscis to match the orchid, whereas his critics believed the moth's anatomy had already reached its evolutionary limit.
  3. C
    Darwin’s critics rejected his prediction because they believed entomologists had already documented all insect species in Madagascar, whereas Darwin knew the island's fauna was largely unexplored.
  4. D
    The discovery of the sphinx moth in 1903 proved that the orchid had evolved its long spur after the moth developed its long proboscis, whereas Darwin argued the orchid evolved first.

Answer

Darwin viewed the physical traits of organisms as functionally interdependent, whereas his critics believed that some anatomical features could exist independently of ecological utility.
The correct answer is supported by the passage's contrast between Darwin's view and that of his critics. Darwin argued that the orchid's foot-long spur 'made no evolutionary sense' without a pollinator, indicating his belief that physical traits are functionally linked to other species. In contrast, the critics dismissed the spur as a 'decorative anomaly,' implying they believed that traits could exist without ecological utility or functional relationships.

Step-by-Step Solution

1
Identify Darwin's stance on the orchid's spur.
Darwin believed the flower's spur could not exist without a matching pollinator to access the nectar, implying a functional connection.
To understand the core of Darwin's hypothesis regarding the orchid's anatomy.
2
Identify the critics' stance on the orchid's spur.
The critics argued that the spur was a 'decorative anomaly' and that the predicted moth could not exist.
To determine how the critics conceptualized the relationship between physical traits and ecological function.
3
Compare the two perspectives to find the implicit relationship.
Darwin assumed physical traits are interdependent and serve functional purposes, while critics allowed for non-functional anomalies.
To select the option that accurately describes this conceptual contrast.

Key Concept

Analyzing implicit relationships and contrasting viewpoints in a passage
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Topics

Implicit and Inferred Relationships

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