Final answer:
Bernard Davis demonstrated the occurrence of conjugation in bacteria by disrupting the process at different times and analyzing the recipient cells for specific gene function.
Step-by-step explanation:
Bernard Davis demonstrated that conjugation occurs in bacteria through a series of experiments. One of these experiments involved mechanically disrupting the conjugation process at different times after the formation of a conjugation tube.
The recipient cells from each disrupted conjugation were then analyzed for specific gene function. The results showed that genes were transferred from the donor to the recipient cells in a specific order, indicating the occurrence of conjugation.