Bone tools were used during this period as well but are rarely preserved in the archaeological record.The Stone Age is further subdivided by the types of stone tools in use.
He is presently employed in the Space & Atmospheric Sciences Group at the Los Alamos National Laboratory.Starting in the grasslands of the rift, Homo erectus, the predecessor of modern humans, found an ecological niche as a tool-maker and developed a dependence on it, becoming a "tool equipped savanna dweller." Archaeological discoveries in Kenya in 2015, identifying possibly the oldest known evidence of hominin use of tools to date, have indicated that Kenyanthropus platyops ( a 3.2 to 3.5-million-year-old Pliocene hominin fossil discovered in Lake Turkana, Kenya in 1999 ) may have been the earliest tool-users known.Prior to the discovery of these "Lomekwian" tools, the oldest known stone tools had been found at several sites at Gona, Ethiopia, on the sediments of the paleo-Awash River, which serve to date them.The study was originally published in September 2014, and a writer broke down some of the stats and brought the news in an easier-to-read format.Randal Olson is the one who analyzed the stats from Emory, making a graph that shows couples with a 5-year gap in age are 18 percent more likely to divorce, and those with a 30-year gap in age are a whopping 172 percent more likely to divorce.