SCIENTISTS PUSH BACK PRIMATE ORIGINS FROM 65 TO 85 MILLION YEARS AGO
CZECH
SCIENTISTS PUSH BACK PRIMATE ORIGINS FROM 65 TO 85 MILLION YEARS AGO |
CZECH
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New paradigm New research that accounts for gaps in the fossil record challenges traditional methods of interpreting fossils and constructing evolutionary trees. Applying a new statistical approach to primates demonstrates that this group-from which humans developed- originated 85 million years ago rather than 65 Mya, as is widely accepted. New theory This revision has implications throughout the evolutionary tree of primates Key findings from the new approach to interpreting the fossil record include: Primates originated while dinosaurs still roamed the earth. This challenges the accepted theory that primates could not establish a foothold until at the end of the Cretaceous (65 Mya) when an asteroid cleared the way by hitting the earth and wiping out dinosaurs. If times of divergence within the primate tree are revised accordingly, humans probably diverged from chimps about 8 Mya rather than 5 Mya. Using the fossil record to date the origin of any group for which the fossil record is sparse (including other mammals, such as bats) is unreliable. |
Consequences "Current interpretations of primate and human evolution are flawed because paleontologists have relied too heavily on direct interpretation of the known fossil record," says Robert D. Martin, VP academic affairs at The Field Museum and co-author of the research published in Nature April 18. The research has ramifications throughout paleontology, anthropology and primatology and requires rewriting the story of primate evolution. For example, if primates originated 85 Mya, then continental drift that broke up Gondwanaland probably contributed to primate divergence. Existing primates divided into six subgroups: lemurs, lorises, tarsiers, New World monkeys, Old World monkeys, and apes and humans. Their 85-million- year-old earliest common ancestor probably looked like a primitive, small- brained version of today's dwarf lemur, Martin says. That animal would probably have been nocturnal and tree-living, weighing 1-2 pounds, with grasping hands and feet. It probably had large forward-facing eyes for stereovision. It inhabited tropical/subtropical forests, feeding on a mixed diet composed mainly of fruit and insects. Like humans, it probably had a slow breeding pace characterized by heavy investment in a small number of offspring. (according to CCNet 49/2002 from April 17, 2002) |
