Human Evolution Q&A

[sayak83]

I am currently reading up a lot of resources on human evolution. The current scientific evidence points to

1) A divergence between ancestral chimpanzee line and ancestral human like around 6 million years.
2) Increasing adaptation to bipedal locomotion and open woodlands. Multiple species with several bipedal strategies present all over africa (upto 2.5 million years)
3) Beginning of tool use and brain size increase from 2.5 mya. Subsequent adaptation to open savanna
4) Spread out of africa (1.7 mya appx.) and colonization of Europe and Asia
5) Multiple species evolve everywhere
6) Archaic modern humans rise in Africa (200,000 yrs) and spread out to Europe and Asia with limited crossbreeding with other local species.
7) Development of culture around 80,000 and rapid growth after 40,000.

Would like to know about your views on the scientific discourse on human evolution.

[pax]

We conclude that, at least for life history characters such as development time, unconditionally advantageous alleles rarely arise, are associated with small net fitness gains or cannot fix because selection coefficients change over time.

Ok. These were fruit flies. But I think the same principle should apply to humans.

Then there is The Rise and Fall of Skull KNM-ER 1470

It is unbelievable the difference between how the skull was first presented and what it looks like now.

What does that prove?

Hominid reconstruction is a very subjective discipline.

Then there is a series of frauds in the first half of the 20th century.

Bottom line: Not much credibility left in the hominid evolution camp.

I don't even take what those guys say with a grain of salt. I just pretty well ignore it.

[sayak83]

We conclude that, at least for life history characters such as development time, unconditionally advantageous alleles rarely arise, are associated with small net fitness gains or cannot fix because selection coefficients change over time.

Ok. These were fruit flies. But I think the same principle should apply to humans.

Then there is The Rise and Fall of Skull KNM-ER 1470

It is unbelievable the difference between how the skull was first presented and what it looks like now.

What does that prove?

Hominid reconstruction is a very subjective discipline.

Then there is a series of frauds in the first half of the 20th century.

Bottom line: Not much credibility left in the hominid evolution camp.

I don't even take what those guys say with a grain of salt. I just pretty well ignore it.

Well you did not follow up thoroughly enough

http://blogs.discovermagazine.com/gnxp/ ... evolution/

and more accessibly

http://www.nytimes.com/2010/09/21/science/21gene.html

One well-known path to change is a heavily favorable mutation in a single gene. But it may be well known only because it is easy to study. Another path is exploitation of mildly favorable differences that already exist in many genes.

In sequencing their subjects genomes, the researchers found that a soft sweep was indeed responsible for the earlier hatching. No single gene had swept through the population to effect the change; rather, the alternative versions of a large number of genes had become slightly more common.

And such soft sweeps is what happened in human evolution according to genetic data!

Jonathan Pritchard, a geneticist at the University of Chicago, wrote this year that there seem to have been surprisingly few hard sweeps in recent human evolution, and that therefore much early human adaptation to novel environments since the dispersal from Africa may have been mediated by soft sweeps. In addition, soft sweeps could explain the apparent speed of human evolution, because they work on the genetic variation already present in a population, without having to wait for a novel mutation to arise. The fruit fly experiment shows that natural selection can indeed work through soft sweeps, at least for certain traits.

As in this paper
http://www.ncbi.nlm.nih.gov/pubmed/20178769

Homo Rudolfensis skull reconstruction has always been subject to debate. Initially a 700-800 cc brain size should make it a homo unless it was a large specimen, without lower skeleton one cannot tell. This is well known. Its 1.9 mya...either a late large brained robust Australopithecus or an early species of Homo. Since one evolved from the other its difficult to seperate them at this point.

http://archaeologyinfo.com/homo-rudolfensis/

This is very bad for credibility because?

[pax]

We conclude that, at least for life history characters such as development time, unconditionally advantageous alleles rarely arise, are associated with small net fitness gains or cannot fix because selection coefficients change over time.

Ok. These were fruit flies. But I think the same principle should apply to humans.

Then there is The Rise and Fall of Skull KNM-ER 1470

It is unbelievable the difference between how the skull was first presented and what it looks like now.

What does that prove?

Hominid reconstruction is a very subjective discipline.

Then there is a series of frauds in the first half of the 20th century.

Bottom line: Not much credibility left in the hominid evolution camp.

I don't even take what those guys say with a grain of salt. I just pretty well ignore it.

Well you did not follow up thoroughly enough

http://blogs.discovermagazine.com/gnxp/ ... evolution/

and more accessibly

http://www.nytimes.com/2010/09/21/science/21gene.html

One well-known path to change is a heavily favorable mutation in a single gene. But it may be well known only because it is easy to study. Another path is exploitation of mildly favorable differences that already exist in many genes.

In sequencing their subjects genomes, the researchers found that a soft sweep was indeed responsible for the earlier hatching. No single gene had swept through the population to effect the change; rather, the alternative versions of a large number of genes had become slightly more common.

And such soft sweeps is what happened in human evolution according to genetic data!

Jonathan Pritchard, a geneticist at the University of Chicago, wrote this year that there seem to have been surprisingly few hard sweeps in recent human evolution, and that therefore much early human adaptation to novel environments since the dispersal from Africa may have been mediated by soft sweeps. In addition, soft sweeps could explain the apparent speed of human evolution, because they work on the genetic variation already present in a population, without having to wait for a novel mutation to arise. The fruit fly experiment shows that natural selection can indeed work through soft sweeps, at least for certain traits.

As in this paper
http://www.ncbi.nlm.nih.gov/pubmed/20178769

Homo Rudolfensis skull reconstruction has always been subject to debate. Initially a 700-800 cc brain size should make it a homo unless it was a large specimen, without lower skeleton one cannot tell. This is well known. Its 1.9 mya...either a late large brained robust Australopithecus or an early species of Homo. Since one evolved from the other its difficult to seperate them at this point.

http://archaeologyinfo.com/homo-rudolfensis/

This is very bad for credibility because?

You just about had me convinced until I saw the artwork. No lower skeleton? I have to wonder where that artist got that lower body from. (Probably from a serious consult with Larry Flint.) Whenever I see a human body with a monkey head, or a monkey body with a human head, I know I am being sold a bill of goods.

[sayak83]

Why is the picture on the top relevant? Is Quantum Mechanics wrong because textbooks often use simplifies sketches of atoms in the undergrad colleges?

You have already decided on this issue and will not believe anything. Why bother then?
Repeat ....Rudolfensis is a skull without a lower skeleton and the skull is not of an ape (an fairly diff. from early australopiths or later homo). Its clearly a hominid skull. The only question is which group it lies on.

Monkeys are very different from apes you know. And also humans ARE APES (universally recognized fact in all biology).

[pax]

Why is the picture on the top relevant? Is Quantum Mechanics wrong because textbooks often use simplifies sketches of atoms in the undergrad colleges?

You have already decided on this issue and will not believe anything. Why bother then?
Repeat ....Rudolfensis is a skull without a lower skeleton and the skull is not of an ape (an fairly diff. from early australopiths or later homo). Its clearly a hominid skull. The only question is which group it lies on.

Monkeys are very different from apes you know. And also humans ARE APES (universally recognized fact in all biology).

Is it belief that is being asked of me? or a study of the evidence and agreement with the conclusions? In order for science to be healthy free discussion must take place. When science becomes dogmatic it ceases to be science. How much evidence do we really have for hominid evolution? How is that evidence interpreted? (Yes. I said "interpreted.") Are there other interpretations that are more valid?

This is what I mean by loss of credibility:

Many apemen are merely apes that evolutionists have attempted to upscale to fill the gap between apes and men. These include all the australopithecines, as well as a host of other extinct apes such as Ardipithecus, Orrorin, Sahelanthropus, and Kenyanthropus. All have obviously ape skulls, ape pelvises, and ape hands and feet. Nevertheless, australopithecines (especially Australopithecus afarensis) are often portrayed as having hands and feet identical to modern man; a ramrod-straight, upright posture; and a human gait.

The best-known specimen of A. afarensis is the fossil commonly known as Lucy. A life-like mannequin of Lucy in the Living World exhibit at the St. Louis Zoo shows a hairy, humanlike female body with human hands and feet but with an obviously apelike head. The three-foot-tall Lucy stands erect in a deeply pensive pose with her right forefinger curled under her chin, her eyes gazing off into the distance as if she were contemplating the mind of Newton.

Few visitors are aware that this is a gross misrepresentation of what is known about the fossil ape Australopithecus afarensis. These apes are known to be long-armed knuckle-walkers with locking wrists. Both the hands and feet of this creature are clearly apelike. Paleoanthropologists Jack Stern and Randall Sussman2 have reported that the hands of this species are surprisingly similar to hands found in the small end of the pygmy chimpanzee"common chimpanzee range. They report that the feet, like the hands, are long, curved and heavily muscled much like those of living tree-dwelling primates. The authors conclude that no living primate has such hands and feet for any purpose other than to meet the demands of full or part-time arboreal (tree-dwelling) life.

Despite evidence to the contrary, evolutionists and museums continue to portray Lucy (A. afarensis) with virtually human feet (though some are finally showing the hands with long, curved fingers).

http://www.answersingenesis.org/article ... -creatures

http://www.answersingenesis.org/outreac ... enton/bio/

[LiamOS]

Again, sayak83's quantum mechanics analogy is valid.
Do I complain because physicists draw atoms? No, of course I don't, because it has no bearing on the science behind it.

The complaints regarding sketches and drawing are moot unless the paper or scientists are putting forth that it is an accurate representation, which they rarely(if ever) are.

[sayak83]

Please post papers please to support your claims that they are knuckle walkers....this is patently untrue. It is a characteristic feature of all homonins that they ARE NOT KNUCKLE WALKERS but have bipedal gait when on ground. Australopithecus afarensis (Lucy) had a very well developed bipedal gait (as evidenced by pelvis and hip bones). It is not necessary for them to walk just like us to abe able to walk on two legs (esp. if they were also able to climb trees at night.)

Well apparently you are being misled
http://www.talkorigins.org/faqs/homs/a_piths.html

That neatly takes care of your objections. Now lets see if Australopithecus Afarensis was bipedal or not

Begin here
http://elucy.org/Main/WhatIsBipedalism.html
Next a good overview here
http://books.google.com/books?id=PrJ1lm ... es&f=false

Next if you can get a hand on it this paper is a good one,
Fossils, feet and the evolution of human bipedal locomotion
W E H Harcourt-Smith and L C Aiello

It is imp. to note that the ancestral apes did not have knuckle walking abilities and chimpanzees and gorillas developed knuckle walking separately.

Finally the Laetoli footprints are by bipedal australopiths

Paper (2010)
Laetoli Footprints Preserve Earliest Direct Evidence of Human-Like Bipedal Biomechanics (David A. Raichlen1*, Adam D. Gordon2, William E. H. Harcourt-Smith3,4, Adam D. Foster1, Wm. Randall Haas Jr1)

These are not chimpanzees or any ape walking on two legs.

Bipedal but not fully human
[i]Ichnotaxonomy of the Laetoli trackways: The earliest hominin footprints
D.J. Meldruma, , , Martin G. Lockleyb, Spencer G. Lucasc, Charles Musibad
[/i]

The intermediate feature include:- 1) tapered heel 2) Flexible mid arch 3) Less developed balls of foot 4) concave forefoot 5) longer toes (but smaller than apes)


Now that footprints have been identified as bipedal lets look at what the foot of afarensis looked like. Well it had human like arches designed for bipedal locomotion,
http://www.bbc.co.uk/news/science-envi ... -12412662

Main Paper:-
Complete Fourth Metatarsal and Arches in the Foot of Australopithecus afarensis
Carol V. Ward1,*, William H. Kimbel2, and Donald C. Johanson2

By the way this same dig site has revealed bones belonging to 250 seperate individuals, all afarensis. So these bones are clearly Afarensis.

Next up. There were hominins at the same time that had a different locomotor gait. These were found in a different location and are clearly not Afarensis.

http://www.bbc.co.uk/news/science-environment-17533826

This bloke climbed on trees (with divergent toes) and also walked bipedally on ground when necessary. But it was more efficient at trees than Afarensis and clumsier on the ground. Again not an ape.

[sayak83]

One general comment.

It is always wise to crosscheck the interpretations of scientific findings made by any ideologically driven website (theist or atheist). There is always a tendency to over-represent favorable data and comments and under-represent unfavorable ones. I already saw in your part 3 such mistakes in this topic,

1) You misunderstood the implications of the paper on hard sweep/ soft sweeo
2) You misunderstood the implications of the uncertainties in determining the taxa of the KNMR rudolfensis skull that were mostly due incomplete nature of the evidence and difficulties in dating the fossil (widely acknowledged in journals since 1988. The dating has finally been fixed to 1.9 mya after a lot of effort.)
3) You are now trusting a source on Homonin bipedality that completely misrepresents what is known about the Australopiths without checking if their arguments are authentic or not. Anybody can say anything in any website, it is the outcome of seriously sustained dialogue and follow up research to clarify sources of controversy in interpretation that matters.

[sayak83]

Earliest Homonin:- Sahelanthropus (7 million)

This guy would be very near the base of the homonin-chimp divergence. Found in Chad, its skull slots it in the homonin group and appears to have some adaptations to bipedal locomotion.

"Nature 434, 755-759 (7 April 2005) | doi:10.1038/nature03397; Received 17 September 2004; Accepted 25 January 2005

Virtual cranial reconstruction of Sahelanthropus tchadensis[/size]

Christoph P. E. Zollikofer1, Marcia S. Ponce de Len1, Daniel E. Lieberman2, Franck Guy2,3, David Pilbeam2, Andossa Likius4, Hassane T. Mackaye4, Patrick Vignaud3 & Michel Brunet3

But till now the fossils are too few and fragmentary to make specific claims
http://australianmuseum.net.au/Sahelant ... tchadensis