Internet communications are based on the IP protocol suite, and network engineers will no doubt be familiar with the OSI 7 layer model. Fundamentally, this model has the communications medium (wires, wifi, fibre optic) at the lowest layers, and the applications (web, mail etc) up at layer 7, and all the internet gubbins in the middle. The clever thing is that each layer only needs to know about what is immediately above and below. So, for example when browsing this website, the web browser doesn’t need to know how you’re actually connected - wire, wireless, fibre, or hundreds of other obsolete and current technologies.
While the lower layer technologies are typically based on copper, radio or optical communications these days, a number of other technologies have been demonstrated, including using carrier pigeons as the underlying communication. In practice this has never been commercially implented, due to the high latency.
https://tools.ietf.org/html/rfc1149 “A Standard for the transmission of IP Datagrams on Avian Carriers”, published 01/04/1990