[_ Old Earth _] This is what a common ancestor is (non-pedantic).

[The Bible Thumper]

'Our common ancestor' has to begin first with a question: Who, exactly, is 'our' in the first place?
The answer is this: 'our' would include all great apes. Who is a great ape? A comprehensive list:

1. Man
2. Chimpanzee
3. Bonobo
4. Gorilla
5. Orangutan

So indeed we have the definition to that first question of 'our' that evolutionary scientists have included us into.
Now that we know who 'our' is, who is 'our' common ancestor? Our common ancestor would be that ancestor that shares traits that are common to the great apes. A non-comprehensive list:

1. Absence of tails for balance
2. Same number of hair follicles across the skin surface
3. Same rate for atavism; same identifiers for vestigial appendages

Now we have an idea of whom our common ancestor should be: he should be an animal that lived 6 million years ago, had no tail for balance, roughly the same number of hair follicles as us (man, chimp, gorilla) and no doubt an appendix that was seeing the last days of service.
This animal was given the name, aegyptopithecus.

How did a simple baboon-like animal called aegyptopithecus give rise to man? Or chimp, for that matter?

If we look at the speciation idea set fourth by Charles Darwin we will arrive at an answer: certain of aegyptopithecans emigrated from their native mid-African habitat and found the means to 'speciate' beyond. One group speciated to the higher mountain ranges to adapt and evolve to a diet rich in vegitation; he bacame the gorilla. Another speciated to the eastern coastal regions and adapted to the climate and that environment; he became the chimpanzee (a river and around 1 million years separates the chimpanzee form the bonobo).

Still yet, a group found their way up north, where the climate is far harsher than that in the south (Saharan desert). There, the group had to evolve the necessary means to withstand the climate. Evolving an opposeable thumb would make tool-making easier (this means that females preferred males who had the more opposeable thumb, and was the more dexterous with his hands), and with it: a brain to handle the capacity of this handiwork.

 

[The Bible Thumper]

I believe we are evolving into a taller, more-slender species. Evidence I may submit for my assertion is the fact that female humans often wear high-heeled shoes to give them a perceived advantage in height. "By wearing these shoes that give me an additional two inches in height," she implores, "I will certainly attract males of my (human) species that are around two inches above the mean height for my genetic code. That means, that when I'd ordinarily attract a male individual who's, say, 5' 10" tall, these high-heeled shoes will give me the advantage of attracting males who are 6' 1" tall."

Thus homo sapiens gets taller, and taller, and taller, and taller, and taller, and taller, and taller, and taller, and taller, and taller, and taller, and taller, and taller, and taller, and taller, and taller, and

Whether it's through a God-willed evolutionary process or through the outright deception of a woman wearing high-heeled shoes, we are evolving into the taller species. I still do not know why this is. I also know it's futile to question the mind of God. Why God wants humans to keep getting taller is beyond my very considerable comprehension.
Sooner or later, if this evolutionary force is allowed to go on unimpeded, we will be dinosaur-sized, God willing. Why God want's a bunch of 30-foot tall people lanking around on the earth I have no idea!

If I had it my way, we'd be evolving into a more gentile, gracile species, built on the notions set fourth in the Gospel of Jesus Christ. This to me is true human endeavor and true human evolution.

But God wants a bunch of 40' freaks roaming the earth for some reason.

 

[lordkalvan]

This article http://researchnews.osu.edu/archive/medimen.htm has an interesting study of height patterns in humans from medieval times. I doubt the trend that you project is as limitless as you suggest it may be. There are many limiting factors to the practical height an individual can reach, not least of which would be skeletal strength and bone-size/density/cross-section. Most changes in average height seem to be related to diet and social conditions, a fact reflected by the decrease in average height in Europe during the period of industrialisation in the 18th and 19th centuries.

 

[The Bible Thumper]

This article http://researchnews.osu.edu/archive/medimen.htm has an interesting study of height patterns in humans from medieval times. I doubt the trend that you project is as limitless as you suggest it may be. There are many limiting factors to the practical height an individual can reach, not least of which would be skeletal strength and bone-size/density/cross-section. Most changes in average height seem to be related to diet and social conditions, a fact reflected by the decrease in average height in Europe during the period of industrialisation in the 18th and 19th centuries.

The image above is the male species of the Proboscis monkey. The image below is the female of the same species:

Notice how natural selection selected for a highly unusual and even more highly non-functional nose in the male of the species. The nose serves no function except a cosmetic one. Who is to say that the females of our own species will not choose an equally absurd height in the male of our species? As it stands, we're tall enough, and just getting taller, and to an impractical extreme (our teeth are likewise impractically garish-looking). What makes you think this freakish trend will not continue?

Picture below: Image of oversized teeth in our species; widely regarded as beautiful, and equally as impractical:

 

[lordkalvan]

My argument isn't that a trend to a slightly greater average height does not exist, but rather that there are practical limits to what that height may be. Evidence from history and archaeology suggests that average height has varied and that the trend in humans has not been inexorably towards being taller. Average height decreased from Palaeolithic to Neolithic times, for example, and there is also the example of Europe that I cited before. It is also the case that, as you increase height you also increase weight, requiring stronger bones and greater musculature to bear that extra weight. This inevitably increases body mass further requiring yet stronger bones and yet greater musculature to bear it. As volume (mass) increases as the cube of size, it is easy enough to calculate that, if i was 3.4m tall instead of 1.7m and retained much the same (quite slim) body proportions, I would weigh 520kg instead of 65kg.

 

[The Bible Thumper]

My argument isn't that a trend to a slightly greater average height does not exist, but rather that there are practical limits to what that height may be. Evidence from history and archaeology suggests that average height has varied and that the trend in humans has not been inexorably towards being taller. Average height decreased from Palaeolithic to Neolithic times, for example, and there is also the example of Europe that I cited before. It is also the case that, as you increase height you also increase weight, requiring stronger bones and greater musculature to bear that extra weight. This inevitably increases body mass further requiring yet stronger bones and yet greater musculature to bear it. As volume (mass) increases as the cube of size, it is easy enough to calculate that, if i was 3.4m tall instead of 1.7m and retained much the same (quite slim) body proportions, I would weigh 520kg instead of 65kg.

After the cambrian explosion, G-d had no problems with creating enormous fauna; damn the 'practical limits' (the fauna to which I refer, of course, are the dinosaurs).
There is also the obverse of island dwarfing--any animal living in the environment where there are lots of recources and (a perceived) lots of predation will evolve to the larger morphological species. With man, the predation is actually fancied, and not real. Watch the 5:00 news--where perfectly innocuous individuals--are illustrated as being a threat to the man even when there is no real predative threat.
Women wearing high-heeled shoes (for the dectively illusory gain in physical height) and running personal advertisements listing physical height as the highest priority in a quality of a mate tells me that 'reverse island dwarfing'is quite alive and well in the human genome.
It could be arguedthat the sensationalist media is responsible for this abbaration in the immediate development in human evolution, since the media portrays many individuals as being a threat to the life of any given person walking down, say, a dark alley at night (xenophobia).

 

[lordkalvan]

After the cambrian explosion, G-d had no problems with creating enormous fauna; damn the 'practical limits' (the fauna to which I refer, of course, are the dinosaurs).

People are not dinosaurs. What is your evidence that there were no 'practical limits' to the size of dinosaurs? Were all dinosaurs 'enormous'? If not, why not? The largest animal ever to have lived is still with us - the blue whale; why has no land animal reached the size of the blue whale?

There is also the obverse of island dwarfing--any animal living in the environment where there are lots of recources and (a perceived) lots of predation will evolve to the larger morphological species.
Do you have examples of what you are referring to?

...Women wearing high-heeled shoes (for the dectively illusory gain in physical height)....

But not actually physically any taller in actuality.

....and running personal advertisements listing physical height as the highest priority in a quality of a mate tells me that 'reverse island dwarfing'is quite alive and well in the human genome....

But not every female regards height in a sexual partner as the overriding quality. Therefore there is no inexorable trend towards increased height in the human species as the result of sexual selection. And even if a woman chooses a taller partner than herself, given that any offspring are a combination of the genetic material from both their parents that determine the height they may achieve, it is equally possible that they will inherit the 'shorter' genes from their mother as opposed to the 'taller' ones from their father.

 

[The Bible Thumper]

People are not dinosaurs. Were all dinosaurs 'enormous'?

People aren't dinosaurs (in other words, homo sapiens is not a 'terrible lizard'), true, but both humans and dinosaurs are considered animals. Not all dinosaurs were like huge, but some were, which tells us that the practical limit on human height development may proceed to at least the size of the largest dinosaurs.

But not every female regards height in a sexual partner as the overriding quality. Therefore there is no inexorable trend towards increased height in the human species as the result of sexual selection.

Ad hominem. Just because not all women are attracted to tallness does not mean that tall males are not preffered over shorter males.

And even if a woman chooses a taller partner than herself, given that any offspring are a combination of the genetic material from both their parents that determine the height they may achieve, it is equally possible that they will inherit the 'shorter' genes from their mother as opposed to the 'taller' ones from their father.

The offspring from the female who acquired the taller male (any male taller than the woman's biological father) will grow taller if the female can convince the tall male that she is desirous. One way to achive this objective is to wear high-heeled shoes, to bring her height closer to the range of the children she will sire..

 

[lordkalvan]

People are not dinosaurs. Were all dinosaurs 'enormous'?

People aren't dinosaurs (in other words, homo sapiens is not a 'terrible lizard'), true, but both humans and dinosaurs are considered animals. Not all dinosaurs were like huge, but some were, which tells us that the practical limit on human height development may proceed to at least the size of the largest dinosaurs.

Agreed, but not all mammals are humans, either, and yet many mammals are much latger than humans (blue whales, elephants, rhinos, etc). The existence of larger mammals than humans is not evidence that humans have the potential to grow as large as those mammals. I agree that there is a trend towards slightly increased average height, but I suggest that those factors are largely the result of factors other than genetic. The height potential of an individual is genetically limited.

[quote:3m0fg6xf]But not every female regards height in a sexual partner as the overriding quality. Therefore there is no inexorable trend towards increased height in the human species as the result of sexual selection.

Ad hominem. Just because not all women are attracted to tallness does not mean that tall males are not preffered over shorter males.[/quote:3m0fg6xf]

I don't think this is an ad hominem argument; it certainly wasn't my intention to attack you rather than your argument. I was trying to point out that sexual partners are not selected by women solely on the criterion of greater height. And if sexual selection amongst humans is such that women tend to prefer taller partners, the trend you suggest should be identifiable throughout the existence of homo sapiens. We know this trend has, in fact. been in the opposite direction during significant periods.

[quote:3m0fg6xf]And even if a woman chooses a taller partner than herself, given that any offspring are a combination of the genetic material from both their parents that determine the height they may achieve, it is equally possible that they will inherit the 'shorter' genes from their mother as opposed to the 'taller' ones from their father.

The offspring from the female who acquired the taller male (any male taller than the woman's biological father) will grow taller if the female can convince the tall male that she is desirous. One way to achive this objective is to wear high-heeled shoes, to bring her height closer to the range of the children she will sire..[/quote:3m0fg6xf][/quote]

From personal experience, this is not so: my father is taller than my maternal grandfather; my mother is taller than my paternal grandmother. I am not taller than my father. As current research indicates that many different genes contribute to controlling what our potential height may be, it is entirely the case that tall parents can produce children who are shorter than they are. You may find this Stanford School of Medicine article interesting:

http://www.thetech.org/genetics/ask.php?id=98

 

[The Bible Thumper]

This may sound half-baked, but think about it: the best indicator of the vector of human evolution can best be determined by what the median of all female respondants say they most prefer in a mate (male).
If, for example, a scouring of the Personals reveals more females desire height in a potential mate, we can guess that humanity is for the most part evolving into a taller version of itself. Likewise, if females express a desire for males with tiny toes, it stands to reason that that's the vector the direction our evolution is taking.

In this regard, G-d's work (evolution) seems painfully crude and primitive, and has outlived its usefulness as far as our species is concerned; and stands as a grotesque caricature in front of the backdrop of the beauty of quantum mechanics and cosmology. Evolution has worked for life on earth--until now. I believe humans can take over G-d's Work with our increasing knowledge in genetic research, and do a better job at it than G-d.

G-d wants man to turn into a grotesquely tall rodent with two enormous rodent-like front teeth. I believe that man will change this vector that G-d has planned and genetically mold us in the beautiful image of Christ himself: compassionate, caring and sensitive.

 

[The Bible Thumper]

In light of the fact that we do have these two absurdly large front teeth, we now must consider our species as that of rodentiae.
Thus, because G-d willed it for some reason and women desire it, we must now call ourselves, "homo sapiens-rodentiae".