Bates reported that there was no Vulcan named Spock serving with the Starfleet in any capacity. He then displayed and narrated the family history of Sarek, noting his accomplishments as a diplomat, his separation from and the subsequent deaths of his wife Amanda and their son Spock. (TAS: "Yesteryear")
As evidenced by the first draft script of "Yesteryear", Bates was originally not in the episode; his involvement in the outing was instead initially written for EnsignChekov, though Bates was created to replace his part in the story. Whereas the pre-established character of Chekov wasn't described in the first draft script, Bates was described as "a young officer, but efficient" in the final draft. He was also, like Chekov had been, written into the script as having the rank of ensign, though this detail did not make the transition to the screen. Nonetheless, the novelization of "Yesteryear" (in Star Trek Log 1) additionally gives Bates' rank as ensign.