A University of Pittsburgh anthropologist argues in a paper published today that humans most likely share a common ancestor with orangutans, and not chimpanzees, which is the prevailing belief.
Jeffrey H. Schwartz hopes the paper will get researchers to practice fundamental science and question some assumptions.
“What I’ll be happy with is if people actually think out of the box and consider alternative theories of human relationships with apes,” Schwartz said Wednesday in a phone interview from Zagreb, Croatia.
He concedes it won’t happen overnight, but the paper in the Journal of Biogeography that he co-authored could help, said Schwartz, who’s the president of the World Academy of Art and Science.
“We’ve done the analysis,” said John Grehan, who is the paper’s other co-author, director of science at the Buffalo Museum in New York and a research associate at the Carnegie Museum of Natural History.
Jeffrey L. Boore, an adjunct biology professor at the University of California-Berkeley who specializes in interpretive genome sequences, said he knows of no strong reason to discount the DNA studies that have demonstrated chimps and gorillas are more closely related to humans than orangutans.
“The overwhelming majority of those studies have given very strong support to excluding orangutans from the human-chimp-gorilla group,” said Boore, who’s also CEO of Genome Project Solutions, Inc., in Hercules, Calif.
“If people disagree with it, they need to put out their evidence and let it go back and forth,” said Grehan, an entomologist who also studies the origin and evolution of animals and plants. “But I think a lot of people are incapable of dealing with it.”
That’s because for years most of the scientific community accepted DNA analyses that suggest humans are most closely related to chimps, Schwartz and Grehan said.
But an examination of fossil and other evidence shows humans and orangutans share 28 features — including reproductive systems, tooth structures and mouth palates, the scientists say.
Schwartz and Grehan write in their paper that humans share only two features with chimpanzees and seven with gorillas.
“In science, you must integrate the fossil record with the living record,” Grehan said. “That’s what we’ve done.”
They propose a scenario that explains the migration of the human-orangutan common ancestor from Southeast Asia, where modern orangutans are from.
The molecular evidence that scientists commonly cite to demonstrate the link between humans and chimps is flawed, Schwartz said.
“Only 2 percent of the entire human genome can be verified,” he said. “But people are saying that chimps and humans share 98 percent of some portion of that 2 percent to make their case.”
That’s not good science, said Malte Ebach, a paleontologist at Arizona State University’s International Institute for Species Exploration, who, like Grehan, studies the origin and evolution of animals and plants.
“People think DNA data is better because they perceive it as technologically superior and more progressive,” Ebach said. “But technology doesn’t make data better.”
Schwartz proposed his human-orangutan theory in 1982. He wrote the book, “The Red Ape: Orangutans and Human Origins,” in 1986 that expanded on those ideas. In 2005, Schwartz published and revised an updated version of the book.
The work was ignored as molecular studies came out that showed the similarity between chimps and humans.
Grehan said alternative views should not be dismissed when a theory becomes so accepted.
During the mid-20th century, scientists so fervently disagreed with Barbara McClintock’s theory that genes could move along a chromosome that she stopped publishing, Grehan said. In 1983, McClintock won a Nobel Prize for her research in “jumping genes.
Archive for the ‘Orangutan’ Category
As science experiments go, it was real hoot.
Researchers mapping the evolution of laughter gently tickled the feet, palms, necks and armpits of baby humans and apes.
By analysing the sounds the animals made – giggles, hoots, grunts and pants – they concluded that laughter can be traced back some 16million years, and that it evolved along the same pathway as our evolution.
In the first study of its kind, Portsmouth University researchers tickled three human babies and young orangutans, gorillas, chimps and bonobos and recorded their ‘laughter’.
They then teased apart the different sounds in the recordings and mapped the similarities between animals. The result looked like the evolutionary family tree, in which humans are most closely related to chimps and bonobos and most distanced from orangutans.
And it showed that laughter evolved gradually over the last 10million to 16million years, reports the journal Current Biology.
Primatologist Dr Davila Ross said: ‘Our results on laughter indicate its pre-human basis.
‘This is important for emotional research in humans and animals as well as for the management of primates in captivity and in the wild.’
The analysis also revealed that gorillas and bonobos have some control over their breathing – a skill that was thought to be unique to humans and to have played an important role in the evolution of speech.
Dr Ross said that apes use laughter differently to humans, adding: ‘Although we can use it to mock each other, previous research has indicated it developed in our ancestors as a play tool.
‘Apes like to play with each other and sometimes this can get out of hand so their form of laughter is used to prevent them getting over aggressive.’Â
Jaak Panksepp, a scientist from Washington State University in the U.S. who studies laughter-like responses in animals, said the findings were exciting.
His work has suggested that even rats ‘laugh’ in response to play and tickling – producing chirps too high-pitched for people to hear.
Other studies have shown that young chimps can outperform people in memory games, completing them more quickly and with fewer mistakes.
Scientists have also observed chimpanzees making a ‘toolbox’ of items when foraging for food and gorillas using branches to test the depth of water they plan to wade through.