Phlox, a Denobulan, was on Earth as part of the Interspecies Medical Exchange when called to serve aboard the Enterprise. As part of the Exchange, he corresponded regularly with his human counterpart on Denobula Triaxa, Dr. Lucas.

During shore leave on Deep Space station K-7, Chekov, along with Lieutenant Uhura, brought one tribble back to the Enterprise, which reproduced so fast that the ship became overrun with them in three days.

Hoshi served as the interpreter between the Enterprise crew and new alien species, even after the universal translator was on-line. She suffered anxiety about her place on board originally, but exposure to frequent danger helped her realize her value to the ship.

McCoy's assigned quarters were "3F 127" on Deck 9, section 2.

Tasha was born in 2337 on the failed colony world of Turkana IV. Her sister, Ishara, was born five years later. Both of their parents were killed shortly following Ishara's birth, after which they were looked after for a few months by "some people" who later abandoned them, leaving Tasha to care for herself and her sister.

Chekhov was an only child. However, he once believed, while under the influence of the Beta XII-A entity (TOS: "Day of the Dove"), that he had a brother named Piotr who was killed by the Klingons.

In the TNG episode "Disaster," O'Brien's wife Keiko starts to feel the onset of childbirth unexpectedly, forcing Worf to help her deliver Molly despite having only basic medical training.

Dr. Mark Piper was both the ship's Chief Medical Officer and Life Sciences department head.

To extend the life of the symbiont and avert a war, William T. Riker volunteered to become a temporary host.

The species map on the Kelpien homeworld did not have food chains, but instead was a binary of predator or prey, with Kelpiens being the latter. They were hunted, bred, and farmed like livestock.