Final answer:
A karyotype with an extra set of chromosomes indicates polyploidy, a condition with more than two sets of chromosomes, differing from aneuploidy, which involves an inconsistent number of chromosomes like in trisomy or monosomy.
Step-by-step explanation:
A karyotype with an extra set of chromosomes indicates polyploidy. Polyploidy is a condition in which an organism has more than two sets of chromosomes, which is more than the standard diploid number that is typical for that species. This condition can lead to reproductive isolation, as it often results in errors during meiosis, making it difficult for polyploid individuals to produce viable offspring through sexual reproduction. Aneuploidy, on the other hand, is the condition of having an incorrect number of chromosomes, such as a missing chromosome (monosomy) or an extra chromosome (trisomy), which can manifest in various disorders, like Down Syndrome.