Final answer:
Polyploidy can lead to instant speciation. In autopolyploidy, a plant species produces gametes with double the expected number of chromosomes, resulting in offspring with four sets of chromosomes. These tetraploids can only reproduce with individuals of the same kind, leading to reproductive isolation and sympatric speciation.
Step-by-step explanation:
Polyploidy, a condition in which a cell or organism has an extra set or sets of chromosomes, can lead to instant speciation. In autopolyploidy, a plant species may produce gametes with twice as many chromosomes as they should have. These new gametes can either self-pollinate or reproduce with other autopolyploid plants, resulting in offspring with four sets of chromosomes, called tetraploids. These tetraploids can only reproduce with individuals of the same kind, leading to reproductive isolation and sympatric speciation.