“Change and decay in all around I see”, hymned Henry Francis Lyte in Abide With Me. Nobody is more conscious of that than a taphonomist. I found the word over Christmas in a dystopian SF book, Zero Point by Neal Asher, in which a future dictator used computer technology to simultaneously kill off eight billion human beings and then had to work out what to do with the bodies.
Asher defined the word as a specialist who studies the decomposition of dead organisms. That’s pretty much correct, though there’s more to it and the timescales can vary hugely. A sub-discipline, forensic taphonomy, takes a relatively short-term view, looking into ways in which human remains decay through natural processes as a way to guide police investigations — you may have heard of macabre studies in which corpses are left out in the open so their decomposition can be studied. The main focus of taphonomy, however, is on processes that take much longer — ones by which dead organisms transform into fossils.
Taphonomy was coined in 1940 by a Russian palaeontologist (and SF author), Ivan Efremov. He took it from the classical Greek taphos, a grave, plus the -nomy ending for a specified area of knowledge that originated in nomos, law. German scientists had been working in the field since the 1920s but the specialism gained much greater prominence in the 1970s.