Chimp Taxonomic Classification

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Anonymous

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I guess this thread is a suitable place to mention today's news story that chimps and humans 'should share grouping'.

Scientists from the Wayne State University, School of Medicine, Detroit, US, examined key genes in humans and several ape species and found our "life code" to be 99.4% the same as chimps.

They propose moving common chimps and another very closely related ape, bonobos, into the genus, Homo, the taxonomic grouping researchers use to classify people in the animal kingdom.

I would say that this is generously unanthropocentric of us to share our genus, except that it would surely be less taxonomic hassle to rename us "Pan sapiens"?
 

Anome

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JamesM said:
I would say that this is generously unanthropocentric of us to share our genus, except that it would surely be less taxonomic hassle to rename us "Pan sapiens"?
Actually, there is a matter of precedence.

Jared Diamond covers this in The Rise and Fall of the Third Chimpanzee. Using the oft cited figure of 98% commonality between humans and chimps (now somewhat discredited) and a similarity of about 95% with gorillas, these three apes should be reclassified as species of the same genus (using the same classification guidelines as are used for non-hominid species). Which genus (Homo, Gorilla, or Pan) would we classify them under?

Historically we have used the genus that was defined first, simply because it has precedence. In this particular case, that would be Homo as we classified ourselves before we (Europeans) knew that either Pan or Gorilla existed. Therefore, we would reclassify Chimps and Gorillas as Homo Troglodytes and Homo Gorilla (with the corresponding sub-species for Bonobos and highland versus lowland gorillas).
 

stu neville

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Bump

Split off from Oliver! Humanzee! thread on Crypto.

Stu
 
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Apparently Linnaeus, the inventor of the binomial taxonomic system we use today, placed chimpanzees in genus Homo and named them Homo troglodytes in 1758.

The chimpanzee's genus was then changed to Simia in 1775, and to Pan in about 1816.

Some cladistic systems of classification have lumped chimpanzees and bonobos together with Man for several years now...

"Cladistic Classification:"
Superfamily Hominoidea
.....Family Hylobatidae
...............Genus Hylobates (gibbon)
.....Family Hominidae
..........Subfamily Ponginae
...............Genus Pongo (orangutan)
..........Subfamily Homininae
...............Genus Gorilla (gorilla)
...............Genus Homo (two species of chimp and humans)

and for good measure- genetic engineering story
 

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Originally posted by JamesM
I would say that this is generously unanthropocentric of us to share our genus, except that it would surely be less taxonomic hassle to rename us "Pan sapiens"?

I agree but remember

'Humans are not proud of their ancestors, and rarely invite them round to dinner.'
Douglas Adams
 

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Closer to man than ape

· DNA study supports call to reclassify chimpanzees
· 'Historic differences' may not be so great, tests find

Ian Sample, science correspondent
Tuesday January 24, 2006
The Guardian

They already use basic tools, have rudimentary language and star in TV commercials, but now scientists have proof that chimpanzees are more closely related to humans than other great apes.

Genetic tests comparing DNA from humans, chimps, gorillas and orang-utans reveal striking similarities in the way chimps and humans evolve that set them apart from the others.

The finding adds weight to a controversial proposal to scrap the long-used chimp genus "Pan" and reclassify the animals as members of the human family. The move would give chimps a new place in creation's pecking order alongside humans, the only survivor of the genus Homo.

The biologist Soojin Yi's team at Georgia Institute of Technology in Atlanta compared 63m base pairs of DNA from different species, where each base is a letter in the animal's genetic code. They then analysed the DNA to look at what evolutionary biologists call the molecular clock, the rate at which an animal's genetic code evolves. The speed of the clock shows how the span of a generation has changed over the millennia.

The tests showed that even though humans and chimps split from a common ancestor between 5m and 7m years ago, the rate at which their genetic codes were evolving was extremely similar, differing by only 3%, and much slower than gorillas and orang-utans.

A slow molecular clock suggests that the time between generations is long, something that has historically set humans apart from the great apes. Team member Navin Elango said: "We found that the chimpanzee's generation time is a lot closer to that of humans than it is to other apes."

According to the scientists, whose study appears today in the US journal Proceedings of the National Academy of Sciences, the finding suggests some human traits only emerged 1m years ago, a fleeting moment on evolutionary scales.

"This study provides further support for the hypothesis that humans and chimpanzees should be in one genus, rather than in two different genuses, because we not only share extremely similar genomes, we share similar generation time," said Dr Yi.

Doubts over the chimp's position in the evolutionary tree have been around from the start. In 1775, when scientists first got around to naming the chimpanzee, they noted the similarity with people and placed them next to humans under the genus Homo. But by 1816 chimps had been pushed out into their own genus, Pan, which has survived to this day.

In 1991, the Pulitzer prize-winning ecologist Jared Diamond called humans "the third chimpanzee", setting us alongside the common chimp (Pan troglodytes) and its less aggressive but astoundingly promiscuous cousin, the bonobo (Pan paniscus). By 1999 confusion over the biological status of chimpanzees prompted scientists in New Zealand to join forces with lawyers to petition the country's government to pass a bill conferring "rights" on chimpanzees and other primates. The move drew derision. Roger Scruton, the moral philosopher, asked: "Do we really think that the jails of New Zealand should henceforth be filled with malicious chimpanzees? If not, by what right are they to be exempted from punishment?" New Zealand granted great apes legal protection from animal experimentation. British Home Office guidelines also forbid experiments on chimps, gorillas and orang-utans.

In 2003, researchers at Wayne State University in Detroit again ignited the debate when they found that 99.4% of the most critical DNA sites are identical in human and chimp genes, prompting the lead researcher, Morris Goodman, to declare that chimps and humans should be brought together under the same umbrella genus, Homo.

"There have been discussions about whether chimpanzees should be afforded more protection and this might make things a bit clearer in peoples' minds about whether they should have rights of some kind. In terms of life on Earth, chimps and humans are really not that different to each other," said Andrew Rambaut, an evolutionary biologist at Oxford University. Practically, he adds, reclassification could raise the chimp's profile and potentially improve their conservation.

"It seems a bit human-centric to want to put chimps into the 'Homo' genus and not reclassify humans as 'Pan'. But these things are arbitrary, once you've divided it into species. It would become a more political decision than anything else," he said.

www.guardian.co.uk/science/story/0,,1693364,00.html

I always find the arguement for changing the classification rather spurious and alrgely pushed by chimp rights activists. I think we need to make sure human rights are applied to the human race before extending them. That said I do think we need to do something but not just for chimps but other apes and ceteceans too. It would be a crime to allow what appear to be sentient animals with culture to become extinct.
 

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A Recent Split of Humans and Chimps?
By Ann Gibbons
ScienceNOW Daily News
27 February 2007

In recent years, paleoanthropologists have been closing in on the exact time and place where the ancestors of humans and chimpanzees went their separate ways. As they uncovered several types of fossils from the dawn of humankind, they proposed that these early hominids lived between 5 million and 7 million years ago--dates that match up nicely with molecular studies. Now, however, this satisfying consensus is being challenged by a new study that proposes a surprisingly recent separation.
In a report published online in the February issue of PLoS Genetics, Danish postdoctoral researcher Asger Hobolth of North Carolina State University in Raleigh and his colleagues compared 1.9 million basepairs of DNA in four regions of the genomes of humans, chimpanzees, gorillas, and orangutans. They then used a well-known statistical method called the hidden Markov model, which was developed in the 1960s for speech recognition, to help them identify subtle patterns in the genomes of apes and humans. The researchers used the method to quantify how closely humans are related to chimpanzees, gorillas, and orangutans. They also used it to spot how humans and chimps inherited different segments of noncoding DNA, such as tracing stretches of the genome that humans inherited from their last common ancestor with chimps or from earlier ancestors shared with gorillas or orangutans.

More to the point, the researchers could then calculate the order--and relative timing--in which various lineages split apart on the primate family tree, with orangutans appearing first, followed by gorillas, chimps, and then humans. They dated the branching points by using fossils of orangutan ancestors, which were 18 million years old, to set a starting time at the base of the tree for a "molecular clock." Although molecules mutate at various rates, the average is relatively constant if enough time passes--and those mutations can be used like a clock to date how long ago two species split. The team ended up with a date of 4.1 million plus or minus 400,000 years for the human-chimp split. It was so recent it even surprised the authors, says Hobolth.

Some researchers say the date is so recent, something must be wrong with this application of the Markov methodology. It would bump all the earliest fossils out of the human tree--including a 4.1-million-year-old fossil from Kenya called Australopithecus anamensis, which was already well on its way toward becoming human; it already walked upright, which is a defining character of being ancestral to humans, but not apes. "A 4.1-million-year split for humans and chimps ... is hard to defend because fossils practically reject it," says evolutionary biologist Blair Hedges of Pennsylvania State University in State College.

Others, such as geneticist David Reich of Harvard Medical School in Boston, Massachusetts, say that despite the date, the method shows that the genetic makeup of the last common ancestor of humans and chimpanzees--and the last common ancestor they share with gorillas--was more diverse than expected. The findings also support Reich's controversial proposal last year (Science, 19 May 2006:) that the ancestors of chimps and humans might have interbred more recently than previously believed, even after they had begun to head down separate evolutionary paths.

http://sciencenow.sciencemag.org/cgi/co ... 2007/227/2
 
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