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Member (Idle past 4726 days) Posts: 283 From: Weed, California, USA Joined: |
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Author | Topic: The Common Ancestor? | |||||||||||||||||||||||
anglagard Member (Idle past 858 days) Posts: 2339 From: Socorro, New Mexico USA Joined: |
barbara writes: I'm sorry I thought that all breeds of dogs was man's creation All dogs are from wolves as has been recently shown through genetic examination. It is obvious that such a symbiotic relationship was of great help in a hunter-gatherer society, to both species. Now the real question is - considering the selfish gene - which one initiated the process and which one benefited the most? May I suggest Dawkins for the question and Diamond - considering all domesticated species, including plants - for one potential answer? The idea of the sacred is quite simply one of the most conservative notions in any culture, because it seeks to turn other ideas - uncertainty, progress, change - into crimes. Salman Rushdie This rudderless world is not shaped by vague metaphysical forces. It is not God who kills the children. Not fate that butchers them or destiny that feeds them to the dogs. It’s us. Only us. - the character Rorschach in Watchmen
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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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caffeine Member (Idle past 1046 days) Posts: 1800 From: Prague, Czech Republic Joined: |
The dog ancestry is a dead end. Apparently the specific breed ancestry was never documented. I'm not sure how this is supposed to be important, but the specific ancestry of many dog breeds is documented. I was reading about Alsatians the other day, for example, as a friend recently bought one. Alsatians are all descended from a few, closely related German working dogs intentionally inbred at the turn of the 20th century. Even details like the name of each dog are recorded by breeding societies. With the obsessiveness of some hobbyists and recording in breed registries, it's probably possible to trace the exact ancestry of certain modern dogs back to the founders of the breed a century ago.
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Dr Jack Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: Member Rating: 8.4 |
his 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. No-one is arguing for a single, unique common ancestor. Nor a single common ancestor to whom all genes can be traced. 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. Nothing about this suggests that aren't many, many more individuals involved in the population genetics of chimps and humans or that this individual is the only such individual.
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Blue Jay Member (Idle past 2719 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, Barbara.
barbara writes: I'm sorry I thought that all breeds of dogs was man's creation Man "created" dogs by selecting for the traits they wanted in the dogs. This is called "artificial selection." Artificial selection works basically the same way as natural selection, except that artificial selection doesn't just favor survival and reproductive ability: it could favor any number of things (aesthetics, or human utility, for example). It's still evolution. And, it's a great example of common ancestry for diverse forms of life. -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
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Coyote Member (Idle past 2127 days) Posts: 6117 Joined: |
In an experiment that shows how dog domestication could have been done, Russian scientists have done the same thing with the fox.
Domesticated silver fox - Wikipedia Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
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caffeine Member (Idle past 1046 days) Posts: 1800 From: Prague, Czech Republic Joined: |
Artificial selection works basically the same way as natural selection, except that artificial selection doesn't just favor survival and reproductive ability: it could favor any number of things (aesthetics, or human utility, for example). This seems to me a pretty artifical distinction. What's being selected for in artificial selection is still reproductive ability, it's just taking place in an environment where reproduction is controlled by humans. It seems silly to say it's aesthetics that's being selected when some human only allows dogs who look in a certain way to breed, whlist it's reproductive ability being selected when some female wolf only allows wolves that look a certain way to mate with her. In both cases the animal being selected is the one best able to reproduce in its own environment.
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New Cat's Eye Inactive Member |
There's actually a cool youtube video about those tamed russian foxes:
https://www.youtube.com/watch?v=enrLSfxTqZ0 I found it particularly interesting that selection for tameness also yielded changes in coat color, etc.
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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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Blue Jay Member (Idle past 2719 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, Caffeine.
caffeine writes: It seems silly to say it's aesthetics that's being selected when some human only allows dogs who look in a certain way to breed, whlist it's reproductive ability being selected when some female wolf only allows wolves that look a certain way to mate with her. But it's far from silly to say that it's aesthetics that's being selected for when humans choose who breeds, while it's reproductive ability being selected for when a population becomes dominated by females that give birth to larger litters. Edited by Bluejay, : No reason given. -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
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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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barbara Member (Idle past 4823 days) Posts: 167 Joined: |
According to this it says there is a 30% difference between chimps and humans. Differences in chromosome 1,4,5,9,12,15,16,17,18. On chromosome 2 in humans are scattered among parts of several cats and rat chromosomes of these species. They mention the human/rodent ancestor now.
This website mentions many differences between human and chimp such as single base pair substitutions, amino acids changes, inserts/deletes diff, etc. We are closer to a rat that is 88% identical compared to a chimp 70% identical. Common ancestry is not very convincing to me at all.
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Coyote Member (Idle past 2127 days) Posts: 6117 Joined: |
We are closer to a rat that is 88% identical compared to a chimp 70% identical. Common ancestry is not very convincing to me at all.
I think you should demand a recount on those numbers. Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
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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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caffeine Member (Idle past 1046 days) Posts: 1800 From: Prague, Czech Republic Joined: |
PaulK mentioned Orrorin tugenensis (Message 4). Perhaps this will be a good beast with which to begin? So, what do we know about him? Not a great deal. It was found in Kenya, and there are thirteen bones believed to come from about 5 individuals. They're dated to around 6 or 7 million years ago, which is about the same or slgihtly older than the usual molecular clock estimates for the human/chimpanzee split. The fossils include two femurs, which are claimed to show that they were supporting an upright body, but this is a bit controversial, I think. The teeth indicate they ate mostly fruit and veg, with some meat. You can see a quick summary of the claims of the discoverers here
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