Macroevolution

Rucete ✏ Biology In a Nutshell

1. What Is Macroevolution?

Macroevolution refers to large-scale evolutionary changes that occur over long periods of time.
It includes the origin of new species, major evolutionary trends, and extinction events.

2. Phyletic Gradualism

• Evolution occurs as a gradual accumulation of small changes over long time periods.
• Suggests transitional forms should exist in the fossil record.
• Species slowly transform into new species without clear boundaries.

3. Punctuated Equilibrium

• Proposes that species experience long periods of stability (equilibrium) with short bursts of rapid change.
• Rapid changes may result from sudden environmental shifts or mutations.
• Explains gaps in the fossil record better than gradualism in some cases.