Moreover, when I enterd 'Camera' and 'Camera not detected' in the search pane, nothing came up. I checked in System Settings but there is no icon for Camera. I am quite diligent about applying software updates when prompted to by Ubuntu.
The last time I used the camera was either April 26 or May 31, 2018. This was surprising, as I have used the camera about once every two months for the four-and-a-half years I have owned this machine.
The browser reported 'Camera not detected'. Today I went to participate in a Google Hangout using Chrome browser.