Answer:
Instantaneous speciation
Step-by-step explanation:
Instantaneous speciation is sympatric speciation and occurs through spontaneous mutation or polyploidy. It does not need geographical isolation. Single spontaneous mutation led to instantaneous speciation in apple maggots.
Similarly, autopolyploidy is shown to cause the evolution of new species in a single generation in evening primrose. It included duplication of chromosomes in some of the progeny organisms during reproduction.