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Member (Idle past 5030 days) Posts: 283 From: Weed, California, USA Joined: |
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Author | Topic: The Common Ancestor? | |||||||||||||||||||||||
Jon Inactive Member |
Easy. I agree with your statements. I just found your explanation funny.
![]() Jon "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
Response to diagram on common ancestry. Could you please now add in Australopithecus, Homo habilis, Homo Rudolfensis, Homo Erectus, Homo Ergaster, Homo Heidelbergensis, Homo Neanderthal, Homo Cro-magnom, woodland apes. and then modern humans. I don't think that'd be necessary for this discussion. It's well established that the critters you listed did not appear until long after the speciation events. (BTW: I'm also stumped on the woodland apes reference. I googled them, but the closest thing I could find to a mention was listed as being in a book about human violence.) Jon "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
For now, let's go for a weaker proposition: there was at least one individual having two children one of whom was ancestral to some or all living humans but no chimps/bonobos, and the other of whom was the ancestor of some or all living bonobos/chimps but no humans. While such an individual may have existed, I don't see why it is at all necessary or even reasonable to assume she did. What defines one as human vs. chimp is not locked away in a single gene. The speciation event would have taken many generations, during which input from any member of C (to use your example) could have occurred (which would make that person a B). It would be something like the following (P = Proto-):
PC PB PH \ / \ /\ \ / \ / PH PC PH | | | | / \ / \ / C B B H | \/ | |\ ?? /| C \ / \ / H ? ? So while we may have an ancestor in common, the question is with whom? With one another, sure; but with chimpanzees? I find it unlikely; not because we could not pinpoint the ancestor, but because the ancestor (singular) doesn't exist, at least not in any meaningful way. Who's the CA in the above diagram? Jon "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
Then we are only looking at the species that contains the most synapomorphies which still does not guarantee direct ancestry to any living organism, human or chimp. It will be an okay first start though, no? ![]() "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
Who's the CA in the above diagram? PB is. Okay, that makes sense; but only as far as my chart goes, and the real process being not so neat, my chart is not representative of much other than a fantasized simplification. What if there are (and in reality, I'd think this likely) humans that have no input from PB@t1? Let's say we can extend as follows (I switched some more things to ?):
PC PB PH t1 | \ / \ /\ | \ / \ / PH PC P? P? | | | | | | / \ / \ / \ PC C B B H H t2 | | | | | | | |\ ? ? /| | PC C \ / \ / H H | | ? ? | | | | | | | | / \| |\ |\/ \ / \ PC C ? ? ? ? H H t3 | \_|_____ _______/| (from C@t3 to C@t4 crosses OVER | | \ / | PC@t3 to ?@t4; they do not connect) PC C ?_________H t4 \ / | C H t5 What is the CA for H and C at t5? I see we can find some ancestors in common, and naturally there must be (they are related species after all). But you cannot find a single one that shares all in common, unless you cut out some input from your consideration. If we answer CA for H&C@t5 as PB@t1, then we cut out CA for PH&PC from our consideration. It is an ancestor in common, but is it the most recent? Is it the most ancestral?
Assuming time is supposed to be read down the diagram. Correct.
What are question marks supposed to be? They are uncertainties as regards their classification. Jon Edited by Jon, : Can't cross a T if it isn't there... "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
Genetics claim that a fresh water dolphin is not related to the salt water dolphin so do you really expect me to believe we are related to chimps based on a silly diagram? Please stop turning evolution into a religion before its loses all credibility. Common ancestry cannot be proven so why waste your time? Common ancestry is a fact.
Today's DNA between them are not identical or even close. There are no fossils of gorilla and only a few of orangutan. The fossils of chimps look very much like they do today. Too bad that's all false. Jon "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
caffeine writes: What I think [Jon] is discussing (correct me if I'm wrong!), is the idea that two populations may diverge, and then start to change such that they're recognisable as distinct populations, without genetic flow between them ceasing. So we'd have our protochimps and protohumans, still occasionally interbreeding for many, many generations even after recognisably seperating. This doesn't change the fact that the populations eventually do seperate completely with no further interbreeding, and there must at some point be the final ancestor who has both human and chimp descendants, but whose children do not. This is roughly my argument, yes. Our 'final ancestor' though is not likely to be a single individual, but a group of individuals, which may be representative of one or the other of PH or PC or B; in fact, it is likely that the 'final ancestors' (or common ancestral genetic pool) contained all three types of individuals. And if we decide to settle on just the last contributing one of these, it is not going to be properly representative of the common ancestral pool. Unless we just want to call our common ancestor the last beast that contributed anything at all to each specieseven if its children contributed more to one than to another (that is, more variation than was previously present in that populationnot the same child, but different children who contributed solely to one species each), we have to accept that there is not likely to be a single form to the common ancestor, but that the common ancestral pool consisted of a large variety of beasts. The other option is to go way back to before the beginning of the speciation event, but then the question we must ask ourselves is whether or not such a population represents the most recent common ancestor. It would clearly be less recent than any of the others, but also clearly more ancestral. The closer we get to the speciation (i.e., the more recent the ancestor is for which we are looking), the less homogeneous the common contributing populations become. At the point of speciation, we have to ask ourselves if we can really stick on a single beast form as representative of the common contributing ancestor, or concede that there are many forms of contributing ancestorsno one form will be solely representative of the ancestral group, so that the OP's question would be best asked in the plural. The more recent we get, the less contribution the ancestor found is likely to have given toward one species or the other. The more recent the ancestor, the less ancestral; the more ancestral the ancestor, the less recentas a matter of probability. I think this is reasonable to posit given the messy nature of evolution and speciation. Jon "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
This sounds good but in order for this to happen these several beasts would have to be able to sexually reproduce offspring. This is entirely plausible; the initiation of speciation does not instantly put an end to all breeding across the to-be-distinct species. Jon "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
Apparently the specific breed ancestry was never documented. LOL... Yes; it's too bad they didn't put to bark their mamas' namesit was a pun, get it ![]() Edited by Jon, : No reason given. "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
barbara writes: I'm sorry I thought that all breeds of dogs was man's creation Just the same; even if true, the presence or absence of documentation does not change reality. "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
No-one is arguing for a single, unique common ancestor. Nor a single common ancestor to whom all genes can be traced. Of course not; that would be ridiculous.
No. What we're arguing for (now Dr. A convinced me) is that there exists at least one individual who is a common ancestor of both humans and chimps and who has children of whom at least one is ancestor of humans and not chimps, and at least one is ancestor of chimps and not humans. This is inevitable. I don't see how making a claim that is already implied by the very definition of evolution advances us anywhere. Nevertheless, then the question does become: what were the common ancestors? So, let's start throwing some critters into this discussion. What did they look like? How were they different from one another? When did they live? How much did they contribute to each species? Jon "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
All this stuff about dogs...
Are we going to talk about human/chimp ancestors? Jon "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
Are we going to deal with the topic and lay out some of the critters for consideration in common human/chimp ancestry, or are we going to let Barby here keep throwing this thread off topic with unrelated silliness?
PaulK mentioned Orrorin tugenensis (Message 4). Perhaps this will be a good beast with which to begin? So, what do we know about him? Jon "Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer "Dim bulbs save on energy..." - jar
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Jon Inactive Member |
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