Summary:
- Macroevolution is evolution over geologic time above the level of the species.
- The process by which a new species evolves is called speciation.
- Some members of a species must become reproductively isolated from the rest.
- This means they can no longer interbreed with other members of the Species.
- Usually they become geographically isolated first.
- If they remain separated long enough, they may evolve genetic differences.
- If the differences prevent them from interbreeding with the original species, they have evolved.