Parthenogenesis means the growth and development of an embryo or seed without fertilization by a male. Parthenogenesis occurs naturally in some plants, invertebrates (e.g. water fleas) and some vertebrates (e.g., lizards, snakes, and some fish), where it can be used for reproduction in the absence of males.
Animals that can reproduce through parthenogenesis are more likely to settle in isolated habitats like oceanic islands, as only a single (female) member of the species has to reach the habitat.
This video segment presents information on Komodo dragons.