| Staphylococcus aureus is an aerobic or facultatively anaerobic gram positive spherical microorganism. |
| Mycoplasma species are mostly facultatively anaerobic, colonial microorganisms that lack cell walls. |
| Organisms belonging to the genus Aeromonas are facultatively anaerobic, Gram-negative rods possessing polar flagella. |
| Streptocarpella flowers are occasionally produced by the cotyledon, suggesting that the evolution of the unifoliate condition evolved from ancestral plants that could develop facultatively. |
| Some facultatively hypothermic species alleviate this cost by group roosting on the nest, but this adaptation has not led to the evolution of joint laying. |
| However, some tetraploid lines are facultatively apomictic and an individual plant may set seed both apomictically and sexually. |
