Macro-evolutionary changes typically occur over:

Macro-evolutionary changes refer to significant evolutionary transformations that lead to the emergence of new species or major changes in existing ones. These changes typically unfold over long time frames, often spanning thousands to millions of years. This extended duration allows for the accumulation of genetic variations and adaptations due to natural selection, genetic drift, and other evolutionary processes.

The evolutionary processes underpinning macro-evolution, such as speciation events and extensive diversification, require ample time for environmental pressures to shape species in fundamental ways. For example, the divergence of lineages that leads to the formation of entirely new taxonomic groups—such as the evolution of mammals from reptilian ancestors—demonstrates the lengthy timescales involved in macro-evolution.

Shorter time scales, such as decades, centuries, or even just a few years, are generally more associated with micro-evolutionary changes. Micro-evolution focuses on smaller-scale changes within a species—like shifts in allele frequencies—rather than large-scale transformations that result in the creation of new species or major evolutionary lineages. Hence, recognizing that macro-evolutionary change operates over a much broader temporal scale is key in understanding this aspect of evolutionary biology.