Piltdown and the search for Human Ancestors

[rmwilliamsll]

ONe of the interesting things i see in this and several related things is the long term effects of a scientific education.
Part of it is certainly the ability to understand the technical side of the discussion, something i think is lacking in several posters on the issue of HERV's, simple put i don't think they understand what they are reading.

But this is something else here as well. How to judge the relative importance of information, how to prioritize pieces of theory so that you look at the most important first and give them the attention they deserve while not worrying about the little things. It has to be the result of getting a systematic viewpoint into your head, understanding how the big pieces fit together and how new data potentially effects them.
this is important, the role of HERV's as a 3rd independent clade is far more important than how the human brain tripled in size in a few million years. why?
i can't put my finger on it exactly, but it has something to do with how the system of TofE is put together and how the pieces hold together. but for me it is more intuitive then something i can point at.

 

[Chalnoth]

I would claim that it has to do with the fact that it is very easy, in evolutionary terms, to change body proportions. Just look at dogs to see evidence of this.

 

[JohnR7]

I would claim that it has to do with the fact that it is very easy, in evolutionary terms, to change body proportions. Just look at dogs to see evidence of this.

Why ist it easy to change proportions? What controls all of the proportions so that they are in proportion with each other. I have never seen anyone who had feet and hands that were way out of proportion with each other. How can a mutation still be in proportion with everything that is already there? Don't mutations cause body parts to grow in inconsistant places? Why is it that we do not ever see anyone with feet or hands growing where there ears should be?

 

[Chalnoth]

JohnR7, human beings have a very homogeneous genome. This is because we experienced a genetic bottleneck about 70,000 years ago, where the worldwide human population was reduced to roughly 2000 individuals (apparently due to an ice age brought on by a supervolcano explosion in Sumatra). I have read that one population of chimpanzees has more genetic diversity than all of humanity.

Now, take a look at dogs. Look at the tremendous variation in size, shape, temperment, and intelligence. Need some help? Here's a Google image search:
http://images.google.com/images?q=dog

And all of these are one, single species. They are so genetically similar that they can all interbreed (though there are obvious size constraints between the smallest and largest, you could still get a chihuahua pregnant with the sperm of a mastiff...though that would be a very cruel thing to do to the poor chihuahua), and can even breed with a number of canines that live in the wild.

Humans have manged to change the body proportions of dogs through selective breeding by tremendous amounts, and all of this within only about 130,000 years. Just 130,000 years. And yet there are doubts that the human brain could have tripled in size in 5-8 million? Give me a break.

 

[rmwilliamsll]

and all of this within only about 130,000 years. Just 130,000 years.

there is a lot of interesting canine genetics being written.

A larger genetic variation in East Asia than in other regions and the pattern of phylogeographic variation suggest an East Asian origin for the domestic dog, ~15,000 years ago.

the 135K comes from:
Given the relatively short time since their. domestication [the oldest estimate is 135000 years ago. calculated from mtDNA sequence data (Vilà et al. 1997)
http://mbe.oxfordjournals.org/cgi/content/abstract/22/12/2541

the best generally available article is at:
http://www.canineworld.com/ngsdcs/Origin.of.the.Dog.pdf

The statement "Man domesticated the wolf," implying human proactive effort,
appears in most speculations about DD origin. Vilà et al. (1997) conclude that the DD
may have originated from tamed wolves 135,000 YBP, when Homo sapiens was a young
species (Wolpoff & Caspari 1996). This hypothesis has conceptual gaps. The question of
how humans created a domesticated wolf between 15,000 YBP, the oldest estimate from
the fossil record for DD (Clutton-Brock 1995), and 135,000 YBP, the highest estimate for
separation of DD/wolf from mtDNA (Vilà et al. 1997), is rarely addressed.
Further, the reasons for wolf domestication need to be analyzed in the context of
human cultural evolution. The value of domesticating such an animal is generally
assumed to be to assist with large game hunting or to act as guards (e.g., Clutton-Brock
1977, 1995; Olsen 1985; Wayne 1986; Cohn 1997). Wolves hunt large prey
cooperatively, thus some propose wolves easily adapt to hunting as human partners
(Olsen 1985; Clutton-Brock 1999). The time of separation of DD and wolf is estimated to
be between 76,799 YBP to 135,000 YBP from mtDNA (Okumura et al. 1996; Vilà et
al.1997). At that time, humans had only clubs, axes, spears and knives (Gowlett 1993).
With these tools, stealth and ambush are used to secure large prey. Wolves are extremely
difficult to condition to reliably inhibit inherent behavior (Fox 1973; Frank & Frank
1983, 1987). They instinctively chase large prey, and thus would hinder humans hunting
cursorial game, rather than assist. Wolves are also extremely food-possessive
(Klinghammer & Goodman 1985; Goodman & Klinghammer 1990; Koler-Matznick
personal observation). If hungry tamed wolves did secure prey, humans would have to
fight them for it.

looks like there is no generally accepted consensus. with dates from 15Kya to 135Kya.

 

[Tomk80]

ONe of the interesting things i see in this and several related things is the long term effects of a scientific education.
Part of it is certainly the ability to understand the technical side of the discussion, something i think is lacking in several posters on the issue of HERV's, simple put i don't think they understand what they are reading.

But this is something else here as well. How to judge the relative importance of information, how to prioritize pieces of theory so that you look at the most important first and give them the attention they deserve while not worrying about the little things. It has to be the result of getting a systematic viewpoint into your head, understanding how the big pieces fit together and how new data potentially effects them.
this is important, the role of HERV's as a 3rd independent clade is far more important than how the human brain tripled in size in a few million years. why?
i can't put my finger on it exactly, but it has something to do with how the system of TofE is put together and how the pieces hold together. but for me it is more intuitive then something i can point at.

Basically because the increase in brain size still does not falsify the twin-nested hierarchy, while ERV's add a third hierarchy (so you get a triple-nested hierarchy).

In other words, even if the increase in brain size is unexplained, it does not falsify common ancestry. On the other hand, ERV's strengthen the evidence in favor of common ancestry even more, adding a whole new and independent line of evidence to the already exisiting evidence.

 

[USincognito]

I would claim that it has to do with the fact that it is very easy, in evolutionary terms, to change body proportions. Just look at dogs to see evidence of this.

I know that Mark has poo poo'd this point, as he is wont to do, but he's never given me a satisfactory answer for why he seemingly has no problem with shrew like mammals from the Cretaceous evolving into first large terrestrial mammals, then Cetates in 100 million years or so - two major changes in body plan in that time frame - while an existing structure like a brain increasing in size over 7 million years is utterly impossible due to his incredulity.

 

[shernren]

JohnR7, human beings have a very homogeneous genome. This is because we experienced a genetic bottleneck about 70,000 years ago, where the worldwide human population was reduced to roughly 2000 individuals (apparently due to an ice age brought on by a supervolcano explosion in Sumatra). I have read that one population of chimpanzees has more genetic diversity than all of humanity.

Now, take a look at dogs. Look at the tremendous variation in size, shape, temperment, and intelligence. Need some help? Here's a Google image search:
http://images.google.com/images?q=dog

And all of these are one, single species. They are so genetically similar that they can all interbreed (though there are obvious size constraints between the smallest and largest, you could still get a chihuahua pregnant with the sperm of a mastiff...though that would be a very cruel thing to do to the poor chihuahua), and can even breed with a number of canines that live in the wild.

Humans have manged to change the body proportions of dogs through selective breeding by tremendous amounts, and all of this within only about 130,000 years. Just 130,000 years. And yet there are doubts that the human brain could have tripled in size in 5-8 million? Give me a break.

Mind you, mark kennedy doesn't have the luxury of 130,000 years for these genetic changes which I gather is already a breakneck pace for evolution. If he holds to "Biblical chronology", even if he only accepts it from post-Flood 'till today, he has roughly 4,000 years. We're talking about getting chihuahuas and mastiffs from one common ancestor pair (or was it seven? doesn't change the argument much) of the dog kind within 4 millenia or roughly 1,000 generation times. (And getting jackals, wolves, and hyenas from that same kind-ancestor too, while we're at it, and making sure that they are geographically distributed to become indigenous practically everywhere on the globe.)

And you thought evolution was impossible?