Among the evidence that supports such chimp evolution is the existence of two species of chimps, the common chimpanzee
and the bonobo.
The team also announced the completion of the 18-fold draft sequence of the Bonobo genome, an endangered ape closely related to the Common Chimpanzee
and distantly to humans.
A new study finds that the common chimpanzee
, despite its inability to speak, shares with people one feature of this anatomical pattern--a structure called the planum temporale is larger on the left side of the brain than on the right.
But Morbeck and Zihlman find that the cranial capacity, tooth size and body proportions of 10 Gombe skeletons lie within the range of 60 common chimpanzee
skeletons from other locations and are distinct from measurements of 25 pygmy chimpanzee skeletons.
Likewise, these factors probably have reduced the bonobo (pygmy chimpanzee) population from 100,000 to 10,000 in the last 25 years, and the common chimpanzees
from 25,000,000 to 200,000 during the last 55 years.
Bonobos are less aggressive than common chimpanzees
- making Bili less likely to commit air rage.
The scientists compared Orrorin's upper leg to corresponding specimens from 130 modern humans, 49 common chimpanzees
, 14 pygmy chimps, 59 gorillas, 32 orangutans, and nine fossil ancestors of people.
Cameroon, Gabon, and Republic of Congo are home to most Central African common chimpanzees
(Pan troglodytes troglodytes).
The closest parallel today to the pattern of dental development of these ancient, two-legged creatures is not in people but in common chimpanzees