Allopatric vs Sympatric speciation
The process of origin of new species is called speciation. The formation of new species from existing species can occur in two ways; sympatrically or allopatrically.
Allopatric speciation (‘Allo’: different, ‘patris’: country)
- Speciation occurs when the population becomes separated by geographical barriers like mountains, rivers etc.
- Thus the chance of interbreeding between these populations is greatly reduced.
- Each population acquires mutations by natural selection to adapt to the new environment. After a long time, reproductive isolation sets in separating two populations into two species.
- Geographical isolation leads to reproductive isolation and speciation.
- This is the most common form of speciation.
Sympatric speciation (‘Sym’: same or together, ‘patris’: country)
- It is the formation of two or more species from a single ancestral species all occupying the same geographical area.
- In sympatric speciation, the populations are not geographically separated.
- Sympatric speciation often occurs through polyploidy. A diploid individual cannot interbreed with tetraploid individual leading to reproductive isolation.
- This type of speciation is rare and occurs often in plants as self fertilization and polyploidy is common in plants compared to animals.