Wednesday, May 29, 2013

HUGE CLUES ABOUT EVOLUTION BY THE RECENT FINDS OF THE TINIEST BONES IN THE HUMAN BODY -- THOSE OF THE MIDDLE EAR

Darryl de Ruiter, a professor in the Department of Anthropology at Texas A&M, and colleagues from Binghamton University (the State University of New York) and researchers from Spain and Italy have published their work in the current issue of PNAS (Proceedings of the National Academy of Science).

The team examined the skull of a hominin believed to be about 1.9 million years old and found in a cave called Swartkrans, in South Africa. Of particular interest to the team were bones found in the middle ear, especially one called the malleus. It and the other ear bones - the incus and the stapes - together show a mixture of ape-like and human-like features, and represent the first time all three bones have been found together in one skull.

The malleus appears to be very human-like, the findings show, while the incus and stapes resemble those of a more chimpanzee-like, or Ape-like creature. Since both modern humans and our early ancestors share this human-like malleus, the changes in this bone must have occurred very early in our evolutionary history.

"The discovery is important for two reasons," de Ruiter explains."First, ear ossicles are fully formed and adult-sized at birth, and they do
not undergo any type of anatomical change in an individual lifetime. Thus, they are a very close representation of genetic expression. Second, these bones show that their hearing ability was different from that of humans not necessarily better or worse, but certainly different. "They are among the rarest of fossils that can be recovered," de Ruiter adds.


http://www.eurekalert.org/pub_releases/2013-05/tau-tas051313.php

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