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Pre AP Biology -EVO 3.2 Rates of Speciation- MCQ Exam Style Questions -New Syllabus 2025-2026

Pre AP Biology -EVO 3.2 Rates of Speciation- MCQ Exam Style Questions – New Syllabus 2025-2026

Pre AP Biology -EVO 3.2 Rates of Speciation- MCQ Exam Style Questions – Pre AP Biology – per latest Pre AP Biology Syllabus.

Pre AP Biology – MCQ Exam Style Questions- All Topics

Question

Which of the following best summarizes the theory of punctuated equilibrium?
A. After periods of directional selection, the allelic frequencies in a population will reach equilibrium and then undergo disruptive selection.
B. Most species evolve gradually, with discrete changes appearing in the fossil record at short, regular intervals.
C. To ensure survival of the fittest, natural selection eliminates those species that disrupt the balance of nature.
D. Most taxa experience relatively short periods during which they undergo rapid change, followed by relatively long periods during which they undergo relatively little change.
▶️ Answer/Explanation
Detailed solution

The correct option is D.
Punctuated equilibrium suggests that evolution occurs in rapid bursts of speciation.
These bursts are separated by long periods of stasis where little to no morphological change occurs.
This theory contrasts with phyletic gradualism, which proposes slow, steady accumulation of changes.
The “punctuation” refers to the sudden appearance of new species in the fossil record.
The “equilibrium” refers to the long durations of stability (stasis) for most taxa.
This model helps explain why “missing links” or intermediate forms are often absent in fossil layers.

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