Microevolution and Macroevolution

Microevolution describes how populations change from generation to generation and how new species originate.

Macroevolution describes the patterns in groups of organism over long periods of time. Phylogeny, the relationship between species and groups of species, is involved. There are two distinct theories of macroevolution:

• Phyletic gradualism argues that evolution occurs through the accumulation of small changes in organisms.
  
  
• Punctuated equilibrium argues that evolution occurs in bursts. Long periods of little speciation are punctuated with short periods of rapid evolution.