Differences and Similarities Between Sympatric and Allopatric Speciation
- Two main pathways to speciation are:
- Allopatric Speciation: Populations are geographically separated.
- Sympatric Speciation: Populations remain in the same area but are reproductively isolated by non-physical barriers.
Allopatric Speciation: Speciation in "Different Homelands"
Definition
Allopatric speciation
Allopatric speciation occurs when populations are physically separated by a geographical barrier, such as a river, mountain range, or ocean.
Key Features
- Geographical isolation: A physical barrier prevents gene flow.
- Independent evolution: Each population experiences different selection pressures, genetic drift, and mutations, leading to divergence.
- Time: Speciation occurs gradually over many generations.
Why It’s Common
- Physical barriers are widespread in nature, making allopatric speciation the most common form of speciation.
When studying allopatric speciation, look for evidence of a physical barrier and differences in environmental conditions that drive evolutionary changes.
Sympatric Speciation: "Same Homeland"
Definition
Sympatric speciation
Sympatric speciation occurs when populations in the same geographical area become reproductively isolated.
Mechanisms of Isolation in Sympatric Speciation
- Behavioral Isolation: Differences in courtship or mating preferences prevent interbreeding.
