25: Cichlid fish in African lakes: sympatric or allopatric speciation?
Lake Victoria was dry some 12,400 years ago, yet 500 cichlid fish species evolved since then.
Allopatric speciation: altering lake levels results in smaller lakes forming, isolating populations.
Sympatric speciation: sexual selection drives speciation
Postscript: Human pollution is breaking down reproductive isolation by increasing the cloudiness of the lake's waters