Final answer:
Polyploid species inherit two complete sets of chromosomes from different progenitor species, commonly found in plants and rare in animals due to problems with meiosis and sterility. Polyploidy in animals is extraordinary and can result in asexual reproduction mechanisms like haplodiploidy.
Step-by-step explanation:
Polyploid species have inherited two complete sets of chromosomes from different progenitor species. This biological phenomenon is common in the plant kingdom, where polyploid plants are known to be larger and more robust than their euploid counterparts.
In contrast, polyploid animals are extremely rare, as polyploidy can lead to sterility because meiosis cannot proceed normally with an odd number of chromosomes sets, making most polyploid animals unable to reproduce sexually. An example of animal polyploidy is haplodiploidy, where an unfertilized egg divides mitotically to produce offspring, a method that some rare polyploid animals may use.
Most organisms, including humans, are diploid, meaning they have two sets of chromosomes with one set inherited from each parent. The phenomenon of polyploidy arises due to errors in meiosis or from the fertilization involving gametes with abnormal chromosome numbers, leading to offspring with more than the typical two sets of chromosomes.