Final answer:
Polyploidy is a condition in which an organism has an extra set of chromosomes and can lead to reproductive isolation. There are two types of polyploidy - autopolyploidy, which occurs within a single species, and allopolyploidy, which occurs between individuals of two different species.
Step-by-step explanation:
Polyploidy is a condition in which a cell or organism has an extra set, or sets, of chromosomes. There are two main types of polyploidy that can lead to reproductive isolation - autopolyploidy and allopolyploidy.
Autopolyploidy occurs within a single species when there is an error in meiosis, causing all the chromosomes to move into one cell instead of separating. This results in an individual with multiple complete sets of chromosomes from its own species.
Allopolyploidy occurs when individuals of two different species reproduce to form a viable offspring. The offspring, called an allopolyploid, has gametes from two different species. Allopolyploidy can result in immediate reproductive isolation between the new species and the parent species.