A speciation in which new species evolve from a single ancestral species while inhabiting the same geographic region.
Sympatric speciation is more common in plants. For instance, parent plants produce offspring that are polyploid. Hence, the offspring live in the same environment as their parents but are reproductively isolated.
Another example is the rare sympatric speciation in animals, which is the divergence of resident and transient Orca in the northeast Pacific. These two groups of Orca occur in the same habitat but are avoiding each other and they do not interbreed. They have different diets, vocal behaviour, and social structures.
Word origin: roots sym- (meaning same, alike, similar, or fellow) and -patry (meaning homeland or fatherland).
Compare: allopatric speciation, peripatric speciation, peripatric speciation.
See also: speciation, genetic isolation.