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SALT LAKE CITY — A team of researchers from the University of Utah have used chemical isotopes in ancient African soil to determine what environment early humans lived in during the past 6 million years.
In a study published Wednesday in the prestigious scientific journal Nature, the group concludes that early man and apes lived in grassy savannas, dotted by trees, in eastern Africa. "Wherever we find human ancestors, we find evidence for open habitats similar to savannas," said senior author Thure Cerling, a distinguished professor of geology, geophysics and biology at the University of Utah.
Cerling said fossils of early humans and their relatives have been found in both wooded and open environments. But the contents of grasses in their diets indicate they spent time in grassy landscapes. This environment could have influenced in human development of upright walking, increased brain size and tool use, he said.
The new study shows that grasslands and wooded grasslands have prevailed for more than 6 million years in the area of eastern Africa some scientists call "the cradle of humanity." The new isotope method used in the current study indicates that savannas existed in the area as much as up to 7.4 million years ago.
"This study shows that during the development of bipedalism (about 4 million years ago) open conditions were present," Cerling said.
The study was conducted with the help of U. graduate students William Mace (geology), Anthony Macharia (geography), Christopher Remien (mathematics) and former Utah geology graduates Jonathan Wynn, Naomi Levin and Jay Quade. Biologists from the Kenya Wildlife Service also aided the study.
The study was funded by the National Science Foundation and the Leakey Foundation. Cerling is currently in Kenya continuing his research.
