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Author Topic:   Why are there no human apes alive today?
Meddle
Member (Idle past 1270 days)
Posts: 179
From: Scotland
Joined: 05-08-2006


Message 44 of 1075 (512751)
06-20-2009 3:16 PM
Reply to: Message 39 by Blue Jay
06-20-2009 8:39 AM


Re: misreading? or trolling?
There is no such thing as "Archapitetus."
Could Doubletime be referring to Ardipithecus ramidus? It was originally classified as an Australopithecus due to similarities in dentition, but as more finds were discovered enough differences were observed that it was classified in its own genus. It is still considered a close relative of Australopithecus, but its anatomy puts it closer to the chimpanzee/human common ancestor.

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Replies to this message:
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Meddle
Member (Idle past 1270 days)
Posts: 179
From: Scotland
Joined: 05-08-2006


Message 787 of 1075 (623436)
07-10-2011 1:58 PM
Reply to: Message 778 by Mazzy
07-10-2011 3:11 AM


But as pointed out in the article you cited, the locations of the PtERV sequences are not shared across the genomes of the species which possess them. This is what you would expect if these sequences originated from separate infection events by random insertion of retroviruses.By comparison other families of ERV sequences can be found in exactly the same locations over the genomes of numerous species. This is what would be expected if the ERV sequences were inherited from a common ancestor.
It is also important to remember that since ERV sequences are derived from retroviruses they possess genes capable of multiplying themselves through the host genome, and that over time this ability is lost due to acquiring more mutations. Again these specific mutations in the ERV sequences are also shared between species who shared a common ancestor.

This message is a reply to:
 Message 778 by Mazzy, posted 07-10-2011 3:11 AM Mazzy has not replied

Meddle
Member (Idle past 1270 days)
Posts: 179
From: Scotland
Joined: 05-08-2006


(2)
Message 1006 of 1075 (626290)
07-28-2011 8:55 AM
Reply to: Message 997 by Mazzy
07-28-2011 12:40 AM


Re: Moderator Advisory
No, actually what is astonishing is your trying to show how an ERV ends up in the 'right place' in two species while using an ERV that does not link humans and chimps as an example to demonstrate it.
You need to keep up with your own argument. You originally brought up the ptERV sequence as evidence against common ancestry as it was an ERV found in disparate old world (specifically African) monkeys and apes but not humans. If ptERV was transmitted vertically transmitted to these species through inheritance it would completely contradict our understanding of the relationships between primate species, including ourselves. But of course if they were transmitted they would be found in the same places of the genomes of all those species i.e. the sequences would be orthologous as Taq has repeatedly pointed out. Instead the ptErv sequences are inserted randomly inserted, as expected if these were separate infection events after the species had separated, so the sequences were NOT spread through inheritance. This is why ptERV is not used for evidence of common ancestry, because it did not originate in a common ancestor.
Now ptERV is only one example of an ERV sequence. Many other ERVs do exist which can be used for evidence of common ancestry because they have been inherited from a common ancestor. We know this because the insertion points are shared across species. Your argument for this has been that separate infection events in different species have inserted in exactly the same position. But here ptERV can be used as an example of what to expect if your conjecture was true, but the pattern from infection as seen in ptERV is different from the pattern seen in inheritance. It also stands to reason that species with greater sequence divergence between species will also affect retroviral insertion sites. Of course Taq has also posted that excellent article on HIV insertions which shows the relative randomness in insertions.
And just as an aside, I had a quick look over the link to the guinea pig article and could find no comparison to a human ERV, orthologous or otherwise. It is recommended that you read the links you are citing to make sure it says what you think it says, otherwise people will be more skeptical of other evidence you post.
As for the source of seven shared ERVs between humans and chimps, the link only leads to a deleted blog post so can't confirm the veracity. It could be referring to ERVs only shared by chimps and humans but not any other apes, so occurred after the human/chimp common ancestor split off from other ape species.

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Meddle
Member (Idle past 1270 days)
Posts: 179
From: Scotland
Joined: 05-08-2006


(1)
Message 1036 of 1075 (626466)
07-29-2011 1:16 PM
Reply to: Message 1023 by Mazzy
07-28-2011 10:57 PM


Here is an image that will hopefullly show up.
http://www.talkorigins.org/faqs/homs/15000_med.jpg
It looks more like an ape than a human. Given that reduced facial morpholy is puroprted in the ape, Lluc, I suggest and reduction you thing you see is no more than the variation within the ape kind and is outside the variation of any race of human today.
Personally, I think that skull looks more like this:
than it looks like this:

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Replies to this message:
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Meddle
Member (Idle past 1270 days)
Posts: 179
From: Scotland
Joined: 05-08-2006


Message 1063 of 1075 (626647)
07-30-2011 7:41 PM
Reply to: Message 1056 by Mazzy
07-30-2011 3:50 PM


These are very obviously apes to me. They show huge discontinuity to mankind today and appear to be demonstrating nothing more than the sexual dimorphism that may be expected within ape variation. Although this is not always clear cut, I am curious why these have not been classified as the decsendants of chimps or some other non-human primate.
Well that second image is a Neanderthal and not Homo erectus. In Message 1036 the skulls I posted for comparison were of a Neanderthal and Chimpanzee (so not a ploy by me to use an extreme example as you suggested). In comparison to Homo erectus, the Chimpanzee skull has an extended snout and a much smaller cranial capacity. In fact we see this general trend in the skulls ascribed to human evolution of a gradual increase in cranial capacity and reduction in the length of the snout. I would guess that these are two of the criteria used by palaeontologists/anthropologists to identify and differentiate species. Of course they would also look at clues from the rest of the skeletons as well, which would also preclude them being descendants of modern Chimpanzees.

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Replies to this message:
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Meddle
Member (Idle past 1270 days)
Posts: 179
From: Scotland
Joined: 05-08-2006


Message 1066 of 1075 (626916)
07-31-2011 8:57 PM
Reply to: Message 1064 by Coyote
07-30-2011 8:04 PM


Re: Morphometrics
Thanks for the information, when I was writing my post I was thinking you'd probably be the one to know about this stuff. I did try google but obviously didn't have the right keywords. I'm glad at work I only have to deal with biochemical tests for identifying bacteria

This message is a reply to:
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