Did humans descend from other primates?

[McCulloch]

Man did not descend from the primates.

Did humans descend from other primates?
Are humans primates or should there be special biological taxonomy for humanity?
Please cite evidence.

[Goat]

What ISN"T predicted by the 'creation model' is the fact that the microcephalin common ancestor is from 1 million years ago, a full 800 years before the 'mt-eve' ancestor'...

I'm not sure what you mean by "a full 800 years".

pardon me, and full 800 THOUSAND years before the mtdna ancestor.

Also, the microcephalin common ancestor is not a fact. The authors state:

By using the interhaplogroup divergence test, we show that haplogroup D likely originated (emphasis mine) from a lineage separated from modern humans ~1.1 million years ago and introgressed into humans by ~37,000 years ago.

http://www.pnas.org/content/103/48/18178.full


But this is problematic because if microcephalin introgressed into humans ~37,000 years ago, did humans not have large brains before then?

Their dating methodology also assumes humans and chimpanzees share a common ancestor.

Yes?? And?? How is that not a fact?

Because they used 'likely' rather that 'this is 100% postive and Absolutely true"..

So, they are not absolutely and surely positive about all the details.. but.. the existence of this haploid at all falsifies the creation model. Period.

You can't use a partial piece of the science to promote the 'creation model' , and reject it when information comes to falsifying your religouis beliefs. Science doesn't work that way.

First, the MRCA of all of the chromosomes in the sample was obtained by using chimpanzee sequence as the outgroup. The average sequence divergence separating the MRCA and each of the chromosomes was then calculated. Last, this average divergence was scaled to mutation rate as obtained from human-chimpanzee divergence in the region to produce coalescence time.

Dating was generated by using a simulation software that they wrote.

All software programs developed for the study are available upon request. The coalescent process as implemented in the ms software (31, 32) was used to simulate genealogies under the following parameters ...

In regards to microcephalin, it states:

The gene microcephalin is a critical regulator of brain size. In humans, loss-of-function mutations in this gene cause a condition known as primary microcephaly, which is characterized by a severe reduction in brain volume (by 3- to 4-fold) but, remarkably, a retention of overall neuroarchitecture and a lack a overt defects outside of the brain (26). The exact biochemical function of microcephalin has yet to be elucidated, but this gene likely plays an essential role in promoting the proliferation of neural progenitor cells during neurogenesis (26). microcephalin has been shown to be the target of strong positive selection in the evolutionary lineage leading from ancestral primates to humans (27, 28). This observation, coupled with the fact that this gene is a critical regulator of brain size, suggests the possibility that the molecular evolution of microcephalin may have contributed to the phenotypic evolution of the human brain (27, 28).

A mutation of a gene that causes a small head does not necessarily mean that the mere presense of that gene would cause a larger head.

Further a large head/brain by itself does not mean that something is more intelligent.

In this study, we investigate the origin of the microcephalin D allele in modern humans. We show that the D allele is unlikely to have arisen within a panmictic population. Instead, our data are consistent with a model of population subdivision followed by introgression to account for the origin of the D allele. By this model, schematized in Fig. 4 B, the lineage leading to modern humans was split from another Homo lineage, and the two lineages remained in reproductive isolation for ~1,100,000 years. During this period of reproductive isolation, the modern human lineage was fixed for the non-D allele at the microcephalin locus, whereas the other Homo lineage was fixed for the D allele. These two alleles are differentiated by a large number of sequence differences accumulated during the prolonged isolation of the two populations. At or sometime before ~37,000 years ago, a (possibly rare) interbreeding event occurred between the two lineages, bringing a copy of the D allele into anatomically modern humans. Whereas the original D-bearing Homo population had since gone extinct, this introgressed copy of the D allele in humans had subsequently spread to exceptionally high frequency throughout much of world because of positive selection.

But even if microcephalin is a factor in the development of a larger brain because of associations with microcephaly, then it would only be one of six genes that would be necessary.

"Microcephalin (MCPH1) is one of six genes causing primary microcephaly"
http://en.wikipedia.org/wiki/Microcephalin

A derived form of MCPH1 called haplogroup D appeared about 37,000 years ago (anytime between 14,000 and 60,000 years ago) and has spread to become the more common form throughout the world except Sub-Saharan Africa.

Haplogroup D may have originated from a lineage separated from modern humans approximately 1.1 million years ago and later introgressed into humans.

Shouldn't MCPH1 be common among all humans living in the world, not just particular regions of the world?

Our results not only provide genetic evidence in support of the possibility of admixture between modern humans and an archaic Homo lineage but also support the notion that the biological evolution of modern humans might have benefited from the contribution of adaptive alleles from our archaic relatives.

If MCPH1 causes a reproductive advantage, how can it be explained the ancestor of it has become extinct?

Because there are more than one factor than a single gene. For example.. the neanderthal was build was strong, but not as agile as modern man. One thing that happened around the time Neanderthal disappeared is that the forests of Europe became more plains.. and their genotype was more successful in a forest environment where they could get closer to prey, rather than be observed from a distance. The modern man basically out competed Neanderthal for resources. They also didn't fully disappear.. they interbred with modern man.. Neanderthal genes still exist (1 to 4% of the genes in modern Asian and Europe populations are Neanderthal)

One thing you are doing is using a distortion of the science involved to promote 'the creations model', yet reject the exact same science when it falsifies the creation model.

And, no., that halogroup D was reintroduced into the human population about 37000 years ago. It has not yet gotten to the entire human population. It might...eventually, since it is now in 80% of the population. however, it would 'spread' from the place where the archaic humans and the modern humans came into contact and interbred. .. and spread out from there. come back in 20,000 years to see if the other halogroups get replaced, or if a competing mutation happens.

[nygreenguy]

Also, the microcephalin common ancestor is not a fact. The authors state:

Do you know how we do this genetic work to reconstruct phylogenies? If you did, this wouldnt be a surprise to you. Im curious, why would you attack something before first trying to understand how it works?

Their dating methodology also assumes humans and chimpanzees share a common ancestor.

Its not an assumption if it is based upon past evidence.

[SailingCyclops]

When you say "ever-evolving", wouldn't all species be ever-evolving according to evolutionary theory?

Of course.

When you say "species", would hominids constitute different species?

How would you define "hominid"?

Yes many species; all the great apes, of which we "humans" are one particular species.

hominids, also known as great apes[notes 1]) form a taxonomic family, including four extant genera: chimpanzees, gorillas, humans, and orangutans.[1]

Is the distinction of humans based only on technological capabilities (mastering fire and tool making)?

I see fire and tool making a sign of human intelligence even though it pre-dates modern humans by some 2 million years during the Paleolithic period.

For me a few other requirements like having at least a rudimentary language, cooking food, developing a culture, art, burying their dead along with artifacts, and having a modern anatomy would define modern humans..... It's a bit arbitrary I know, and some may draw the line elsewhere. Since evolution is a very slow process, and precise definitions can vary, it's hard to say exactly where modern humans began. The best evidence suggests this stage of anatomical, mental, technological, and social development was reached some hundreds of thousands of years ago.

This from the Smithsonian explains it better than I:

The species that you and all other living human beings on this planet belong to is Homo sapiens. During a time of dramatic climate change 200,000 years ago, Homo sapiens (modern humans) evolved in Africa. Like other early humans that were living at this time, they gathered and hunted food, and evolved behaviors that helped them respond to the challenges of survival in unstable environments. Anatomically, modern humans can generally be characterized by the lighter build of their skeletons compared to earlier humans. Modern humans have very large brains, which vary in size from population to population and between males and females, but the average size is approximately 1300 cubic centimeters. Housing this big brain involved the reorganization of the skull into what is thought of as "modern" -- a thin-walled, high vaulted skull with a flat and near vertical forehead. Modern human faces also show much less (if any) of the heavy brow ridges and prognathism of other early humans. Our jaws are also less heavily developed, with smaller teeth. Scientists sometimes use the term anatomically modern Homo sapiens to refer to members of our own species who lived during prehistoric times.

Bob

[otseng]

I just ran the model and (somewhat amazingly) the number of surviving lines did drop to 1, after approx 14600 generations. Is this unexpected? Didn't we establish that lines dying out is a predictable outcome?

Is there any way I can see your source code? Also, I think I might have to write a simulation myself to see what would happen.

The algorithm is as follows (parameters can be changed) (person means breeding female):

Start with 5000 lines
For each generation:
- For each line, each person in the line generates 0 to 3 offspring at random
- Set a population target p (e.g. 5000 + generations/2)
- For each person, kill them with probability (1-p)/total population

That's the whole thing. I will send you the actual program via PM (as my implementation runs fairly slowly after a while).

I've looked at the program and there are several things that I've noticed that are suspicious. So, I do not think his simulation is a good model to go by. If any are curious, I'd suggest you ask Zeeby for a copy of his simulation.

I am glad you are also considering writing a simulation - I will be interested to see if you obtain different results.

I think the logic would be fairly simple for a basic simulation. Basically all you need is to use the exponential growth equation and plug in possible growth rate values. And throw in some random population reducers (war, famine, epidemics). For those populations that have positive growth rates, those lines will survive. To expect that one line will not survive will mean they've experienced negative growth rates, or was very unlucky in a random population reducer. Probably the closest value to determine the population growth rate would be a function of the fertility rate minus the infant/child mortality rate. Looking at the 2009 estimates by country, if it maintains over a 2.0 rate, that population will not die out. So, by looking at country data, it is highly unlikely that it will ever be reduced to just one country (or population) in the future.

[otseng]

Yes?? And?? How is that not a fact?

Because they used 'likely' rather that 'this is 100% postive and Absolutely true"..

It should not require exaggerating a position to support a point. You've stated something is a fact, where in actuality, the authors only state it is likely.

You can't use a partial piece of the science to promote the 'creation model' , and reject it when information comes to falsifying your religouis beliefs. Science doesn't work that way.

I've presented logical arguments against their hypothesis. I have not presented any religious statements as arguments against it.

For example.. the neanderthal was build was strong, but not as agile as modern man.

Evidence for this assertion? Also, even if true, it cannot be demonstrated that being more agile is a reproductive advantage.

And, no., that halogroup D was reintroduced into the human population about 37000 years ago. It has not yet gotten to the entire human population. It might...eventually, since it is now in 80% of the population.

And so the other 20% would have smaller brains?

Also, the microcephalin common ancestor is not a fact.

Do you know how we do this genetic work to reconstruct phylogenies? If you did, this wouldnt be a surprise to you. Im curious, why would you attack something before first trying to understand how it works?

I'm simply pointing out that the authors do not state that it is a fact. Are you disputing this?

As for being able to attack it, I've read most of what was presented. And I can certainly question points that I feel are weak.

[nygreenguy]

I'm simply pointing out that the authors do not state that it is a fact. Are you disputing this?

You pointed out the autors said it wasnt a fact, this is because of the process for which it is calculated. You tried to poision the well by saying "its not a fact" which is irrelevant. What if something was a 99% probability. Isnt that pretty close to a fact? Or 99.9? Or 99.5? How do you know what is conseidered acceptable and what is not?

As for being able to attack it, I've read most of what was presented. And I can certainly question points that I feel are weak.

You cant attack an argument if you dont understand it and the mechanisms involved. This is why articles go through a peer review and not a random lay-person review.

[otseng]

I'm simply pointing out that the authors do not state that it is a fact. Are you disputing this?

You pointed out the autors said it wasnt a fact, this is because of the process for which it is calculated. You tried to poision the well by saying "its not a fact" which is irrelevant. What if something was a 99% probability. Isnt that pretty close to a fact? Or 99.9? Or 99.5? How do you know what is conseidered acceptable and what is not?

Pointing out an exaggeration is not poisoning the well. Also, where does it say in the article that it has a 99% probability (or any probability) of it being a fact?

You cant attack an argument if you dont understand it and the mechanisms involved. This is why articles go through a peer review and not a random lay-person review.

Just because a peer reviewed article is presented doesn't mean it's a gospel fact and cannot be even questioned by others.

Also, I don't need to fully understand something to be able to question it. If this is the requirement, then very few of us, if any, can debate about the topics on this forum.

[Grumpy]

otseng

Evidence for this assertion? Also, even if true, it cannot be demonstrated that being more agile is a reproductive advantage.

You are probably mistaking an effect for a cause. Neandertal adult males needed 5000 calories per day , over 85% of which was meat(Neandertals were the most carnivorous species of man known). The adult male Cro Magnon required 2500, almost exactly half the calories, of which only about 35% was meat. When herds grew scarce the cro magnon was able to survive much better.

In addition, the Neandertal was built to be an ambush hunter. They were massively muscled but could not run very well(pelvis too wide, limbs too short). They killed their prey by creeping up on or hiding from the target and a massive attack that was just as likely to injure the hunter as the prey at such close quarters. They had to kill their prey immediately, they were much less capable of pursuit of wounded animals. Neandertal skeletons show extremely high rates of healed broken bones in the short brutal 30-40 year lifespans.

The Cro magnon, on the other hand, were probably the best long distance runner in the animal kingdom. Even in modern times man is capable of running down even unladen horses over long distances(American Indians were known to do this). The CM could severely wound their prey in an attack from some distance(spearheads)and then back off and follow the animal(possibly herding it in the direction of their camp)until it died from blood loss. Thus more efficient hunting and lower injury rates(as confirmed by the fossil evidence). It's like the difference between a Boa Constrictor needing to kill their prey immediately(up close and personal)and venomous snakes needing only to make an initial strike(using venom, not weapons)and then tracking the dying prey, avoiding injury.

That seems like a huge evolutionary advantage to me.

Grumpy

[Goat]

otseng

Evidence for this assertion? Also, even if true, it cannot be demonstrated that being more agile is a reproductive advantage.

You are probably mistaking an effect for a cause. Neandertal adult males needed 5000 calories per day , over 85% of which was meat(Neandertals were the most carnivorous species of man known). The adult male Cro Magnon required 2500, almost exactly half the calories, of which only about 35% was meat. When herds grew scarce the cro magnon was able to survive much better.

In addition, the Neandertal was built to be an ambush hunter. They were massively muscled but could not run very well(pelvis too wide, limbs too short). They killed their prey by creeping up on or hiding from the target and a massive attack that was just as likely to injure the hunter as the prey at such close quarters. They had to kill their prey immediately, they were much less capable of pursuit of wounded animals. Neandertal skeletons show extremely high rates of healed broken bones in the short brutal 30-40 year lifespans.

The Cro magnon, on the other hand, were probably the best long distance runner in the animal kingdom. Even in modern times man is capable of running down even unladen horses over long distances(American Indians were known to do this). The CM could severely wound their prey in an attack from some distance(spearheads)and then back off and follow the animal(possibly herding it in the direction of their camp)until it died from blood loss. Thus more efficient hunting and lower injury rates(as confirmed by the fossil evidence). It's like the difference between a Boa Constrictor needing to kill their prey immediately(up close and personal)and venomous snakes needing only to make an initial strike(using venom, not weapons)and then tracking the dying prey, avoiding injury.

That seems like a huge evolutionary advantage to me.

Grumpy

In specific, it is an evolutionary advantage in the more open areas that occurred around the time the neanderthal disappeared. During the previous couple of hundred thousand years, Europe was highly forested.. and those forests disappeared to a large extent at the time Neanderthal disappeared. Prey could see the hunters a lot further off, so it was more difficult to ambush them. Cromagnon also had long distance weapons, which Neanderthal did not.

So, being less bulky was an advantage in the newer environment and climate. The environment changed.. and that is the key. The Neanderthal were better adapted to the heavy forests that no longer existed, and they were out competed by the more agile humans in the new environment.

[nygreenguy]

Pointing out an exaggeration is not poisoning the well. Also, where does it say in the article that it has a 99% probability (or any probability) of it being a fact?

Firstly, who ever exaggerated? Secondly, look in the methods. They have P values of less than .003.

Just because a peer reviewed article is presented doesn't mean it's a gospel fact and cannot be even questioned by others.

Also, I don't need to fully understand something to be able to question it. If this is the requirement, then very few of us, if any, can debate about the topics on this forum.

Fully? You didnt even know statistical methods were used to test this. It directly said it used statistics. Either you didnt read the paper, read selected part, or didnt understand what they are talking about.

Now, there is nothing wrong with not getting these papers. Heck, half of my graduate level classes are spent reading these things and trying to understand them.

Now, as for questions, when it comes to science, you can ask questions. You take it one step further and try to say these people are wrong without understand the science behind it. Why do you think I dont get into debates about geology, physics, etc... Simply because I dont know a whole lot about them and I don't think going on the internet and reading a few articles about them makes me an expert (like many of those on BOTH sides of this issue does).

If we could all be experts by reading stuff on the internet, who bother with doctors, lawyers, and any other profession? You wouldnt try to cure your child by reading stuff on the internet (or hopefully at all) and you wouldnt represent yourself if you were being accused of murder yet you feel totally capable of questions the accuracy and legitimacy of biologists.