In the context of the history of life on Earth, gradualism is a pattern of evolution in which:

• A. new species arise primarily through the inheritance of acquired characteristics during an organism’s lifetime
• B. evolution occurs only in response to sudden global catastrophes that cause mass extinctions
• C. species evolve through the accumulation of many small changes over long periods of time
• D. species remain unchanged for long intervals, with most change occurring rapidly during brief speciation events

Answer: (C)

Verified step by step guidance

1. Understand the concept of gradualism in evolutionary biology, which proposes that species evolve through the accumulation of many small genetic changes over long periods of time.
2. Recognize that gradualism contrasts with other evolutionary patterns such as punctuated equilibrium, where species remain unchanged for long periods and then undergo rapid changes during brief speciation events.
3. Eliminate options that describe mechanisms inconsistent with gradualism, such as inheritance of acquired characteristics (Lamarckism) or evolution only after sudden global catastrophes (catastrophism).
4. Focus on the definition that emphasizes slow, continuous, and incremental changes leading to the formation of new species over geological time scales.
5. Conclude that the correct description of gradualism is that species evolve through the accumulation of many small changes over long periods of time.