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Author | Topic: Show one complete lineage in evolution | |||||||||||||||||||||||||||||||||||
Asgara Member (Idle past 2323 days) Posts: 1783 From: Wisconsin, USA Joined: |
Ahhh but is your most recent ancestor MY most recent ancestor? I stand by "recent".
Asgara "Embrace the pain, spank your inner moppet, whatever....but get over it" http://asgarasworld.bravepages.comhttp://perditionsgate.bravepages.com
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RAZD Member (Idle past 1425 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Stand if you must, I still say that terminology is confusing. what we are both saying is {{an ancestor old enough to be a common ancestor to all humans but no older}}. Personally, I don't find recent or oldest or earliest to have all the connotations needed to fully express the image.
Note that it does not (cannot? need not?) account for multiple interrelations -- as in mom and dad are both related to the same person on the Mayflower. Article does say that men having many wives might explain why the "y-chromosome adam" calculates younger than eve -- evading the possibility that men just don't evolve as fast as women .... Note also that a "bottleneck" event (mentioned in the wikipedia article) apparently happened some 100,000 years ago: BBC - Science & Nature - The evolution of man
At one point, the numbers of modern humans living in the world may have dwindled to as few as 10,000 people. "Our data suggests there was a bottleneck that was not that recent," says Goldstein. The genetic data puts the likely date for this event at just before 100,000 years ago. And this would also affect the calculations -- a comparison from just before that event would likely result in an older "most recent oldest possible common maybe ancestor" genetically modern type person. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}
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John Williams Member (Idle past 5019 days) Posts: 157 From: Oregon, US Joined: |
Well, I think everyone knows by now that the case for macro-evolution is not very well supported.
No species evolved to from an entire other group of species. We simply do not have the physical evidence of this. I would like someone to show me clear evidence of one species transitioning into another with clear stages of skeletal development etc. I will be open minded, without saying it's impossible. But at this point I really am not convinced that macro evolution took place.That's my 2 cents worth.
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RAZD Member (Idle past 1425 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Have you tried the Therapsids tonight?
they have a flavour reminiscent of chicken ... seriously, they show evolution from a reptilian ear structure to a mammal ear structure, complete with intermediate double jointed jaw. http://www.geocities.com/...naveral/Hangar/2437/therapsd.htm we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}
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RRoman Inactive Member |
quote:What the F%&$! Did you even read this thread!?!? quote:*goes off and repeatedly bangs head against wall * quote:Dude, please tell me you're just joking? Perhaps re-read the thread. "Knowledge is Power" - Francis Bacon Roman's drum blog
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crashfrog Member (Idle past 1487 days) Posts: 19762 From: Silver Spring, MD Joined: |
Well, I think everyone knows by now that the case for macro-evolution is not very well supported. Here's 29 evidences for macro-evolution:
29+ Evidences for Macroevolution: The Scientific Case for Common Descent No species evolved to from an entire other group of species. No, this has happened hundreds of times under observations, and countless billions of times throughout the history of life. After all, why wouldn't it? All it takes is reproductive isolation to form new species. But you don't have to take my word for it:
Observed Instances of Speciation No webpage found at provided URL: http://www.talkorigins.org/faqs/speciation.html I would like someone to show me clear evidence of one species transitioning into another with clear stages of skeletal development etc. Skeletal development has nothing to do with new species. Skeletons can change within species. You only get a new species when reproductive isolation occurs. New species have nothing to do with morphological change; significant morphological change can occur within species.
But at this point I really am not convinced that macro evolution took place. Certainly not as you've defined it, no. Nonetheless, all species past and present are the decendants of a common ancestor. This is the conclusion of a vast weight of evidence and is simply not refutable from what we know now.
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mark24 Member (Idle past 5215 days) Posts: 3857 From: UK Joined: |
John Williams,
I would like someone to show me clear evidence of one species transitioning into another with clear stages of skeletal development etc. Vertebrates/Craniates represent a tiny, tiny portion of the total diversity of life on earth. Why on earth are you limiting yourself to them? Secondly. Given that the fossil record is poor (he says nonchalantly) at the 10k/year resolution. Why do you think you would see such a thing? Wouldn't it be best to ask for evidence that exists within geological bounds? Because if you do, it is irrefutable. Mark There are 10 kinds of people in this world; those that understand binary, & those that don't
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Snikwad Inactive Member |
RAZD writes: Even after radiometric information was available some of the, by then, 'institutionalized' mindset continued to prevail. Nice. This is what I was asking about. I wasn't aware that there was an "institutionalized mindset." I thought that, despite the use of a steady rate in calculations, everyone accepted a variable rate--even the phyletic gradualists. It's like when classical mechanics is used as opposed to relativistic physics because of convenience--i.e. the mathematics isn't nightmarish. The discrepancy between the answer obtained via classical mechanics and the one given by relativistic physics is so small for all practical purposes, it makes more sense to use the easier method. But does this necessarily mean that those using it accept the notion of absolute time? No, of course not. Does using F = ma warrant a restatement of relativistic physics? I'm guessing, "no." Similarly, I thought that geneticists used a steady rate in their calculations out of convenience, not because they didn't accept that a variable rate actually existed. But, of course, the existence of this "institutionalized mindset" lays waste to my crass assumptions. Ah well.
my dad (PhD biol, taught at UofM and Harvard, retired) remembers being surprised, not by the punkeek theory, but that it was supposed to be something new Yep, my former biology teacher remembers being surprised that it was being presented as something new, too. "Chance is a minor ingredient in the Darwinian recipe, but the most important ingredient is cumulative selection which is quintessentially nonrandom." --Richard Dawkins, The Blind Watchmaker
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RAZD Member (Idle past 1425 days) Posts: 20714 From: the other end of the sidewalk Joined: |
you mean scientists do not divide into camps over competing theories and tend to overstate their cases sometimes? never get hidebound in their thoughts? I shocked!
there are many unspoken assumptions that go into papers and if ones like assuming a constant rate for the purpose of calculation is not mentioned ... personally I think everyone needs their cages rattled from time to time to see if some old assumptions need further study. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}
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Snikwad Inactive Member |
RAZD writes: you mean scientists do not divide into camps over competing theories and tend to overstate their cases sometimes? What is this about scientists "dividing into camps" and having "competing theories?" Whatever happened to the Evilutionist Conspiracy (TM)? They're not in collusion anymore? How sad.
personally I think everyone needs their cages rattled from time to time to see if some old assumptions need further study. Indeed. "Chance is a minor ingredient in the Darwinian recipe, but the most important ingredient is cumulative selection which is quintessentially nonrandom." --Richard Dawkins, The Blind Watchmaker
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Loudmouth Inactive Member |
quote: Here in the US, people are put to death on the strength of forensic science alone. If forensics, which uses the scientific method in the same way as the other sciences, is enough to have people killed then wouldn't you think that biology and geology are also trustworthy? Again, the data is objective, and how that data is put together in a model is what a theory is. This theory is then testable by comparing the model to independent data. Again, please explain why there is a correlation between cladistics and stratigraphy. Please explain why this isn't a test of the theory of evolution and why this correlation shouldn't be considered as being supportive of evolution.
quote: Yes, and the interpretation must be consistent with all of the data, falsified by none of it, and the interpretation must make testable predictions. It is therefore possible for new data, or independent evidence, to test the theory/interpretation. This is how the scientific method works, and the opposite of how creation science works.
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Dr Jack Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: Member Rating: 8.3 |
methinks you mean earliest or oldest common ancestor Most recent common ancestor is correct - the oldest common ancestor is (possibly) an protein chain near a geothermal vent some 3.5 bya.
but they come to virtually the same thing: Absolutely not.
would not the oldest common ancestor of all living genetically modern humans also be a genetically modern human? Yes. But it is only a bound. It is not only possible, but highly likely that there were many generations before 'eve'.
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RAZD Member (Idle past 1425 days) Posts: 20714 From: the other end of the sidewalk Joined: |
the problem I have is with the connotations of "recent" meaning a very ancient (group of) being(s) -- it doesn't really capture the picture. Yes the oldest common ancestor would be the original bacteria 3.5 million years ago. it is a problem of semantics. perhaps one should only say "the comman ancestor" ...
and the genetic age is not a bound but an indicator of a bound: the age is not absolute and depends on the mathematical model to be correct, which in turn depends on a steady rate of genetic change. the 160,000 year old fossils are a bound, and it is highly likely that many generations preceded them.
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Dr Jack Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: Member Rating: 8.3 |
and the genetic age is not a bound but an indicator of a bound: the age is not absolute and depends on the mathematical model to be correct, which in turn depends on a steady rate of genetic change. That doesn't make it not a bound, it just means there is a margin for error on the bound. Although, thinking about it more there is no actual reason that genetically modern humans couldn't post-date the most recent common female or male ancestors.
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RAZD Member (Idle past 1425 days) Posts: 20714 From: the other end of the sidewalk Joined: |
One question that has come to me in the last week, is that if the apparent age of the "genetic adam" is less than the apparant age of "genetic eve" -- would this not argue for more doubling up of genetic markers in the adam lineage than the eve lineage ... and would this not be more indicative of early behavior similar to bonobos (where females roam and join bands where males stay) versus chimpanzees (where males roam and join bands where females stay)?
It would be interesting to do the same kind of analysis on chimpanzees and bonobos to see if there is a trend in this regard. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}
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