According to the punctuated equilibria model, which of the following best describes the pattern of evolutionary change in species?

• A. Species evolve at a constant rate regardless of environmental conditions.
• B. Species remain relatively unchanged for long periods, interrupted by brief periods of rapid change.
• C. Species change only in response to catastrophic environmental events.
• D. Species evolve gradually and continuously over long periods of time.

Answer: (B)

Verified step by step guidance

1. Understand the concept of punctuated equilibria: This model of evolution suggests that species experience long periods of stasis (little or no evolutionary change) interrupted by brief, rapid periods of significant change, often due to environmental shifts or other factors.
2. Compare the punctuated equilibria model to other evolutionary models: Gradualism, for example, proposes that species evolve slowly and continuously over time, which contrasts with the punctuated equilibria model.
3. Analyze the options provided in the question: Identify which option aligns with the definition of punctuated equilibria. Look for keywords such as 'relatively unchanged for long periods' and 'brief periods of rapid change.'
4. Eliminate incorrect options: For example, the option stating 'Species evolve at a constant rate regardless of environmental conditions' does not align with punctuated equilibria, as this model emphasizes periods of stasis and rapid change.
5. Select the correct answer: Based on the definition and analysis, the correct answer is the option describing species remaining relatively unchanged for long periods, interrupted by brief periods of rapid change.