Continental drift orogeny at the boundaries of convection cells. By 1967, barely two decades after discovery of the mid-oceanic rifts, and a decade after discovery of the striping, plate tectonics had become axiomatic to modern geophysics. In addition, Marie Tharp, in collaboration with Bruce Heezen, (who initially ridiculed Marie's observations that her maps confirmed continental drift theory), provided essential corroboration, using her skills in cartography and seismographic data, to confirm the theory. Evidence for the movement of continents on tectonic plates is now extensive. Similar plant and animal fossils are found around the shores of different continents, suggesting that they were once
Antigenic drift has been an important topic of study for over a decade. Antigenic drift has been responsible for heavier-than-normal flu seasons in the past, like the outbreak of influenza H3N2 variant A/Fujian/411/2002 in the 2003–2004 flu season. All influenza viruses experience some form of antigenic drift, but it is most pronounced in the influenza A virus. Antigenic drift should not be confused with antigenic shift, which refers to reassortment of the virus' gene segments. As well, it is different from random genetic drift, which is an important mechanism in population genetics. Antigenic drift Antigenic drift is a mechanism for variation in