Final answer:
Autopolyploidy and allopolyploidy are two types of polyploidy that differ in the source of the extra chromosomes. Autopolyploidy involves multiple sets of chromosomes from the same species, while allopolyploidy involves chromosomes from two different species.
Step-by-step explanation:
In polyploidy, a condition where a cell or organism has an extra set of chromosomes, there are two main types: autopolyploidy and allopolyploidy. The main difference between them is the source of the extra chromosomes. Autopolyploidy occurs when an individual has multiple sets of chromosomes from its own species, resulting from an error in meiosis. Allopolyploidy, on the other hand, occurs when individuals from two different species reproduce, leading to a viable offspring with chromosomes from both species.