A number of two-million-year-old fossils, including three bone part of the eardrum, is currently the subject of research on human ancestor hearing ability during the early evolution of chimpanzees.
A study published recently, which involves two species of South Africa that Australopithecus africanus and Paranthropus robustus, concluded both able to hear better than chimps or humans in a specific frequency that is likely to make them able to communicate in the savanna habitat.
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| The framed hominid fossil "Lucy" -- the first Australopithecus afarensis skeleton ever found -- is seen at a exhibition at the Ethiopian Natural History Museum in the Ethiopian capital of Addis Ababa. (Picture from: http://bit.ly/1L0wbYD) |
Both species have a mixture of ape and human anatomy. Both also inhabit grasslands, in contrast with the descendants of the early humans who inhabit the forest.
Both species had a maximum frequency hearing sensitivity which is somewhat higher than the chimpanzee. Both also hear better than chimps and humans in frequency of 1.0 to 3.0 kilohertz, said Rolf Quam paleontologists from the University of Binghamton in New York.
The voices are included in the range are all vowels and some consonants, said Quam.
"Apparently, the pattern of this hearing may be more favorable to life in the savannah. In the space more open, sound waves do not move so far in the woods so that good communication over short distances in the savannah," said Quam.
Human lineage separated from chimpanzees about five to seven million years ago, said Quam, and hearing abilities begin to adapt to changes in lifestyle.
Middle Ear Bones
To study the ability of hearing the two species, the researchers analyzed a number of fossils including small bones of the ear drum section called "ossicle." They then reconstruct the internal anatomy of the ear with a computer.
Our species, Homo sapiens evolved around 200,000 years ago, is very different from most other primates because they hear better in a wider frequency between 1.0 to 6.0 kilohertz. In this range, humans can hear a lot of noise produced verbal language.
"I want to emphasize we are not doubting human ancestors have their own language," said Quam. "Obviously they can communicate by voice. All primates do that. But human language emerged after being human evolution."
Juan Luis Arsuaga, a Spain paleontologist said the hearing ability of the two species indicated that their vote "would sound strange to us, half human half chimpanzees." And the results of this research were published in the journal Science Advances. *** [EKA | FROM VARIOUS SOURCES | VOA NEWS]
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