Types of archaeological dating methods
It is difficult to say how the wide variety of early hominins were interrelated.Moreover, although these ancient forms were clearly members of the same larger group, discerning exactly how any of them may have been connected to later species is problematic because of incomplete fossil evidence or different interpretations of the same evidence.
Use of this concept, together with a reanalysis of the fossil record, moved the estimated time of the evolutionary split between apes and human ancestors forward to as recently as about 5 mya.
Some paleoanthropologists extend the span of this species far back into time to include many anatomically distinctive fossils that others prefer to allocate to several different extinct species.
In contrast, a majority of paleoanthropologists, wishing to bring the study of hominins into line with that of other mammals, prefer to assign to molecular clocks to calculate how long species had been separated from a common ancestor.
Found near Kenya’s Lake Turkana in a layer of rock dating to approximately 3.3 mya, during the middle of the Pliocene Epoch (5.3 million to 2.6 million years ago), the first tools—primitive hammers, anvils, and cutting tools—predate the emergence of .
Cranial remains dating to slightly less than 2 mya have been discovered at Koobi Fora, Kenya.
No consensus has developed on exactly where this find fits into the human family tree (or, more appropriately, “family bush”), but, even if it is a hominin, it is highly unlikely to be a direct ancestor of , then, emphasizes an evolutionary pattern that seems to have been a characteristic of the tribe Hominini from the very start—a pattern that aligns it with what is observed in most other evolutionarily successful groups of mammals.