Nick Matzke posted Entry 2611 on September 30, 2006 02:38 AM.
Trackback URL: http://www.pandasthumb.org/cgi-bin/mt/mt-tb.fcgi/2605

Preview graphic of chart showing hominin cranial capacity over time. Summary: fossil hominid brain size over the last 3 million years. Data from De Miguel and Henneberg, 2001, chart by Nick Matzke of NCSE.  Free for nonprofit educational use.For some time I have been annoyed that charts of the changing cranial capacity of fossil hominin skulls are not more common. There is this chart online at the Talk.Origins Fossil Hominids FAQ, derived from this 1994 PNAS paper, but that is about it. I wanted to make my own chart, but there was no easy way to get all of the relevant data. Then, this week, I ran into this amazing paper (De Miguel and M. Henneberg 2001*), which conviently included a 29-page Appendix listing every known published measurement of a hominin skull older than 10,000 years old.

While killing my brain cells by listening to the radio broadcast of the ID movement presenting cutting-edge research in the USF Sun Dome conducting an old-fashioned creationist revival in the USF Sun Dome,** I schlepped all 602 measurements and metadata into Excel.

I am not complaining here, but I would like everyone to know that this was exceedingly tedious – many specimens have more than one measurement and there are all sorts of notes about various taxon designations, juvenile specimens, specimens confused with other specimens, and the like. I can’t imagine how long it took the authors to assemble the table and the 239 references they cited. But it did dull the pain from the Sun Dome broadcast.

And, once the numbers were in Excel, I was able to recalculate the averages for each specimen, exclude the juveniles and dubious specimens that the authors excluded, and more-or-less reproduce the charts they have in their paper. The big advantages are (a) my chart can be freely reproduced and (b) I can play with it in future blog posts. For now, here is just your basic plain-vanilla chart of cranial capacity vs. time:

Chart showing hominin cranial capacity over time. Summary: fossil hominid brain size over the last 3 million years. Data from De Miguel and Henneberg, 2001, chart by Nick Matzke of NCSE.  Free for nonprofit educational use.

It seems to me that every popular-level discussion of human evolution should use this sort of chart as much as possible. Creationists should be embarrassed and ashamed about the huge mass of evidence they ignore every time they fail to mention the stunning, overwhelming, transitional, gradual, nature of the hundreds of ancient fossil skulls that have been discovered since Darwin and Huxley postulated apelike ancestors for humans back in the 1800s. The evidence is simply an astonishing confirmation of evolution, and the endless pages of creationist diatribes about the lack of transitional hominid fossils are revealed to be mere verbal obfuscation when compared to this simple chart. I suspect that in the entire history of creationist/ID writings, not one of them has been brave enough to show a chart like this to their readers, and then continue to maintain that there are no transitional fossils between humans and their apelike ancestors. Icons of Evolution doesn’t do it. Of Pandas and People doesn’t do it. But I would be happy to be proven wrong.

De Miguel and Henneberg are the same people who authored the 2004 paper “Hominins are a single lineage: brain and body size variability does not reflect postulated taxonomic diversity of hominins.” Here is the abstract:

Henneberg and de Miguel (2004). “Hominins are a single lineage: brain and body size variability does not reflect postulated taxonomic diversity of hominins.” Homo. 55(1-2), pp. 21-37.

Fossil hominin taxonomy is still debated, chiefly due to the fragmentary nature of fossils and the use of qualitative (subjective) morphological traits. A quantitative analysis of a complete database of hominin cranial capacities (CC, n = 207) and body weight estimates (Wt, n = 285), covering a period from 5.1 ma (millions of years) to 10 ka (thousands of years) shows no discontinuities through time or geographic latitude. Distributions of residuals of CC and Wt around regressions on date and latitude are continuous and do not differ significantly from normal. Thus, with respect to these characteristics, all hominins appear to be a single gradually evolving lineage.

Whether or not you agree with scrapping hominin taxonomy (major plus: it would vastly reduce creationists’ ability to transmogrify pedestrian taxonomic hairsplitting into wild declarations of the absense of transitional hominin fossils), a result like this should make it hard for anyone to take seriously the idea that there are major discontinuities in the hominin fossil record. But strangely, this paper is not cited in Casey Luskin’s 2005 analysis of hominid evolution (which I discussed briefly last week). This has not stopped Luskin from keeping up his argument for the special creation of humans by citing the allegedly drastic size difference between Australopithecus and Homo, as he has done several times by putting up this graphic from Hawks et al. (2000)***:

Australopithecus and Homo fossils from Population Bottlenecks and Pleistocene Evolution, from Hawks et al. 2000

Hmm. Is comparing two fossils the best way to assess the question of whether or not there is a huge gap in the hominin fossil record? Lucky for us, Henneberg and de Miguel (2004) put their spiffy database to use, and plot both hominin cranial capacity and body mass in Figure 1:

Fossil hominin cranial capacity and estimated body weight vs. time.  Figure 1 from Henneberg and de Miguel 2004.

This chart is a little more complex to interpret. The top set of points is cranial capacity, corresponding to the vertical axis on the left. This is essentially the same data that I plotted above – it just plots on a straight line here because the authors are using a logarithmic scale for the y-axis.

The bottom set of points is body mass, corresponding to body weight in kilograms (right-hand axis). This is also on a log scale. There are two interesting scientific points here: (1) cranial capacity increased disproportionately compared to a slower increase in body weight during human evolution (which everyone hopefully knew already) and, (2), in fact, contra Luskin, the fossil evidence makes the increase in body mass look pretty darn gradual also.

P.S.: I would like to generate my own spiffy plots of hominin body weight estimates over time, but the dataset seems to have been published in this annoyingly rare publication:

De Miguel and Henneberg (1999). “Variation in hominid body size estimates: Do we know how big our ancestors were?” Perspectives in Human Biology, 4(1), pp. 65-80.

Here is the WorldCat entry for the series. If anyone happens to have it handy, please email me a scan at matzkeATncseweb.org if you get a chance.

Notes

* The paper is: C. De Miguel and M. Henneberg (2001). “Variation in hominid brain size: How much is due to method?Homo 52(1), pp. 3-58.

In this paper, the authors, Carmen de Miguel and Maciej Henneberg of the Department of Anatomical Sciences, University of Adelaide, Australia, conducted a study of the experimental error in researcher measurements of cranial capacity. Although I am not discussing this in detail here, this question is interesting in itself. Basically the authors found that the error is substantial, and due to numerous sources such as different reconstructions of mushed skulls, but (creationists, take note!) despite these errors, the time variable explains 89% of the variance in the dataset. The error is significant, but is still overwhelmed by the time-dependent trend:

When the entire time span of more than 3 Ma is analysed jointly, the date (= time) is responsible for the major portion (89%) of the variation in hominid cranial capacity, while taxa on their own are responsible for a minor portion of this variation (5%), the rest being errors of estimates. (De Miguel and M. Henneberg 2001, p. 16)

The authors conclude that their study supports previous studies indicating that the change in cranial capacity can be explained by “a typical Darwinian mechanism” of exponential increase in a quantitative trait under selection. (Creationists, take note again: “exponential increase” does not mean “sudden” – think of compound interest.)

** Summary of ID Sun Dome broadcast: same ol’, same ol’, but the radio hosts narrated the event like it was a football game, which was hilarious – “Wow, Bob, Jonathan Wells sure answered a lot of tough questions just now, didn’t he?” “Yes, Shelly, isn’t this pure science great? This is really impressive stuff we’re hearing, and it’s all science, not religion!” “Oh, and isn’t it awful how the textbooks and public schools are lying to kids?” “Up next is the famous Michael Behe, but first we’re going to watch a segment from this amazing ID video, which you can get free by signing up with Physicians and Surgeons for Scientific Integrity.” “What’s that website again, Bob?”…etc. This is a paraphrase, but I Am Not Making This Up.)

*** See also this recent debunking at afarensis.

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Comment #136036

Posted by RM on September 30, 2006 5:01 AM (e)

Very nice diagram, indeed. What I hope will be added in the future is where various creationists put in the line showing the sudden appearance of men as distinct from apes.

But then I remember that to a substantial number of that group it is the X axis which is wrong. If the earth is 6-10 thousand years old all of Nick’s dots would be lumped together at the right margin of the diagram.

Comment #136043

Posted by Tiax on September 30, 2006 5:43 AM (e)

“It seems to me that every popular-level discussion of human evolution should use this sort of chart as much as possible.”

Here’s how I would frame the argument. First, point out that a ‘gap’ in the fossil record is a point along the vertical axis that falls within the range of the sizes at which you can draw a horizantal line from the left side of the graph to the right without hitting any points. Then, tell the person asserting that there is a gap to take the image, and draw such a line. Next, explain that a meaningful gap is one where not only can you draw a thin line, but you can fit a bar of significant width.

Comment #136061

Posted by Philip Bruce Heywood on September 30, 2006 6:48 AM (e)

Well- presented charts. They demonstrate something but there are at least three obvious riders:
1). The history of Science is littered with scores of discarded “proofs” as compelling as these.
2). For many species (not to mention higher taxa)in the fossil record, there is no substantial fossil evidence of ordered, sequential, gradual transition, one to another. There is not one proveable gradual transition between what can categorically be said to be different species. What we do have is some sort of a mystifying semblance in the fossil record of life being unfolded in sequence, and it is apparent by studying these sequences that species were employed in some deeply practical way in the revelation of those that followed. A proper title for this could be Evolution, simply meaning, a sequential unrolling or staged revelation.

3). Science wes never served by loud hollering about something when the information isn’t all in. Now the graphs above may be accurate and meaningful. When we see them discussed and (shock! horror!) criticized by cool-minded and detatched people, especially by people whose place in their academic community isn’t threatened if they don’t repeat the “correct” views, then we will sit up and listen to the independent umpire. It is obvious at the outset that statistics such as these will tend to be presented in a way not prejudicial to the personal beliefs of the statistician. The graphs may be accurate. If so, good luck; and if not, good luck. The laws of Science stand regardless. Dogs won’t be giving birth to cats anytime soon, and your great uncle will never be any more like a chimp than will his nephew.

Comment #136074

Posted by wolfwalker on September 30, 2006 7:21 AM (e)

Beautiful work, Nick. Thanks much for taking the time.

That first graph reminds me of the first time I saw the Hawaii Center for Volcanology’s nifty graph of age vs. distance for the Hawaiian volcano chain. It’s as much a killer argument against YECism as your graph is against “no transitional hominids.”

The second chart is interesting for an entirely different reason: why is the correlation coefficient for body mass so much lower than the coefficient for cranial capacity?

I’d also be curious to see both charts broken down further by genus: Ardipithecus, Australopithecus, Paranthropus, and Homo.

Comment #136085

Posted by ben on September 30, 2006 7:38 AM (e)

The history of Science is littered with scores of discarded “proofs” as compelling as these.

A scientist was wrong once, ooo, don’t believe anything they say! BTW, anyone who talks about “proof” in science is an obvious numbskull.

A proper title for this could be Evolution, simply meaning, a sequential unrolling or staged revelation.

Except that evolution doesn’t mean “a sequential unrolling or staged revelation” in any usage, anywhere, except inside your head. When you need to invent usage just to make your point, you don’t have one.

Science was never served by loud hollering about something when the information isn’t all in

Science hasn’t explained everything, therefore it hasn’t explained anything! Why would you publish any paper that didn’t present the finalized, “proven,” comprehensive Theory of Everything? This just just shows the desperation of science, in my opinion.

PBH’s camp, OTOH, has published the one scientific, peer-reviewed document that does explain every scientific observation ever made–the bible! Want to know the value of pi? Check the bible–it’s 3! What to know what the smallest seed in the world is? Check the bible–it’s the mustard seed! Want to know about the digestive processes of rabbits? You guessed it! Bible! [disclaimer, anything found in the bible that cannot be reconciled with observation, well, they were just being figurative, silly!]

Dogs won’t be giving birth to cats anytime soon

Why don’t you go post your vacuity at evolutionmeansdogsgivebirthtocats.com, since nobody here ever claimed evolution had anything to do with dogs spawning cats, and the fact that you even mention it shows clearly just how little integrity and intelligence you actually possess?

Comment #136091

Posted by Mod on September 30, 2006 7:55 AM (e)

ben wrote:

Except that evolution doesn’t mean “a sequential unrolling or staged revelation” in any usage, anywhere, except inside your head.

Just an FYI, that is exactly where the word evolution comes from. Check out the etymology:

Latin ēvolūtiō, ēvolūtiōn-, from ēvolūtus, past participle of ēvolvere, to unroll

Darwin wasn’t pleased with the term for this very reason, but caved to popular usage - thought you might like to know :)

Comment #136096

Posted by ben on September 30, 2006 8:03 AM (e)

Etymological point taken, but I meant usage within the field being discussed. PBH’s was just another lame attempt to weaken a theory he doesn’t like by redefining its own terminology in a way that seems to support his perspective, similar to the strawman of evolution having anything to do with dogs giving birth to cats. Which would be pretty cool, as an aside. That would pretty much blow both sides of the argument right out of the water, wouldn’t it?

Comment #136098

Posted by Kim on September 30, 2006 8:10 AM (e)

Nick, would you mind to share the data with me, the way to estimate whether two size variables change relative to each other is to produce a log-log plot, and perform a linear model 2 regression on the log-log data (either Reduced Major Axis or Major Axis). If there is a relative change, the slope will deviate from x = y.

Comment #136100

Posted by Kim on September 30, 2006 8:13 AM (e)

Oeps, somewhat to quick. I had to mention that a slope of one is expected is both size measurements are in the same magnitude, if one is quadratic or cubed, or any wierd cmbination of that, the slope is expected to change accordingly, but in a predictable manner.

Comment #136122

Posted by Larry Gilman on September 30, 2006 8:44 AM (e)

The diagram is a thing of beauty, Nick. It fills a pedagogical need and is going to be reproduced many times. A worthy “icon of evolution,” and not one that people like Wells are going to be able to swiftboat easily. Thanks for doing the homework.

By the way, isn’t it a fairly weak argument (if Henneberg and de Miguel are making it) that continuity in a fossil set of two summary or bulk characteristics—cranial volume and body weight—points to a single lineage? Didn’t paleontologists used to arrange the Eohippus–>Equus series as a single lineage on bulk continuity grounds—smooth-looking variation of size and form—only to find out later that these fossils are really chronologically ordered samples from different twigs of a ramifying bush? So the continuity of size and weight numbers for hominins does not seem, from where I’m sitting up here in the peanut gallery (“I’m an engineer, not a biologist!”), to argue against a bush-like taxonomy. More precisely, could it be said that the failure of this data to “reflect postulated taxonomic diversity of hominins” is neither here nor there? That one would not necessarily expect such diversity to be manifest as discontinuities in these parameters?

Is this mere amateurish confusion on my part, or does it resemble any real concern in the field?

Regards,

Larry

Comment #136128

Posted by Kim on September 30, 2006 8:58 AM (e)

Nick, the fastest way is probably to contact the authors for a pdf of the article you want…..

Comment #136130

Posted by Philip Bruce Heywood on September 30, 2006 9:05 AM (e)

Hey Ben., if it’s too much to look up the meaning of a word in a dictionary, and too much to look up science history and find out what various and respected scientists have thought about things, why cloud the issue? In fact, there were and are respected scientists who did and do question whether one species can give birth to another. Some of these scientists were/are evolutionary biologists and palaeontologists.

Comment #136132

Posted by Bob O'H on September 30, 2006 9:15 AM (e)

Kim - the two size variables are plotted on the log scale in the second figure, so cranial capacity is increasing more rapidly. To be more formal, the equations are:

log(CC) = a_C + b_C*Time
log(Wt) = a_W + b_W*Time

or CC = a_C*(Time^b_C) and Wt = a_W*(Time^b_W). So, the ratio is CC/Wt=, or on the log scale

log(CC) - log(Wt) = (a_C - a_W) + (b_C - b_W)*Time

From the graphs it’s clear that b_C > b_W, so the ratio is increasing with time.

Gah! The paper doesn’t give the estimated curve for weight. For cranial capacity, the coefficient is 0.254 (in a slightly different model). I don’t know if the coefficient for weight can be found elsewhere in the literature.

Bob

Comment #136140

Posted by N.Wells on September 30, 2006 9:41 AM (e)

Nick,
My thanks too - that’s a lovely graph.

Could you please make available the Excel file with the data? The reason I ask is that although simply seeing the graph will be important in most teaching situations, I think it would be even more effective in classes that are teaching about graphing (either math classes or biology classes) - teachers might like to use this as a multiple-purpose exercise where the students encounter the results by plotting them and then discuss the sort of issues raised by Tiax in comment 136043.

Comment #136141

Posted by Alann on September 30, 2006 9:43 AM (e)

I wonder if you can successfully impregnate a dog with a fertilized cat embryo just to keep creationist from using the inane dog->cat analogy.

As for great uncles, making some assumptions for the mathematics (only 4 million years, 1 generation every 20 years) they are typically 0.001% more chimp (actually the common chimp-human ancestor) like than their great nephew.

Comment #136150

Posted by Salvador T. Cordova on September 30, 2006 10:09 AM (e)

The graph may arguably reflect how well enforced the possibly false dating of fossils is done to fit a pre-conceived viewpoint. :-)

A Cornell PhD disputes the dating. See : Forbidden Archaeology

Over the past two centuries researchers have found bones and artifacts showing that people like ourselves existed on earth millions of years ago. But the scientific establishment has ignored these remarkable facts because they contradict the dominant views of human origins and antiquity. Cremo and Thompson challenge us to rethink our understanding of human origins, identity, and destiny. Forbidden Archeology takes on one of the most fundamental components of the modern scientific world view, and invites us to take a courageous first step towards a new perspective.

I’m not saying Cremo and Thompson are necessarily correct, but seeing the data like the above is promoted by die-hard Darwinists like Reiner Protsch (a known fraud), the data is already suspect from the get go.

Have a nice day.

Comment #136156

Posted by k.e. on September 30, 2006 10:22 AM (e)

Don’t worry Sal your CC doesn’t actually indicate brain size, empty space possibly, have you considered exercising your brain to beef it up?

Try getting it to do sit ups while you wait for the demise of ‘Darwinism’ there should be plenty of room.

Have a naive day.

Comment #136162

Posted by Nick (Matzke) on September 30, 2006 10:34 AM (e)

The second chart is interesting for an entirely different reason: why is the correlation coefficient for body mass so much lower than the coefficient for cranial capacity?

It looks to me like:

1. The slope of the regression is lower, i.e. closer to zero, so less variability in the sample can be explained by the trend, and

2. If the trend is removed from each dataset, there is somewhat more variability in the body size sample. This is probably several things, including (1) skulls are actually relatively commonly preserved compared to the body, (2) body size estimates can be made with just a bone or two, but not without error, (3) experimental error due to measurement technique, extrapolation technique, etc.

Comment #136164

Posted by Nick (Matzke) on September 30, 2006 10:42 AM (e)

I think the reactions of the creationists in this thread are beautiful and show exactly the main point in this debate – they talk about scientific evidence, but they actually don’t care one whit about it. This was the same point demonstrated with the immune system cross at the Dover trial. They are just willfully oblivious to data.

Here, with the data right in front of them, you can see them switching over to denial mode. There is nothing they can say scientifically, so they just desperately grasp at conspiracy theories or desperate hopes that the data will all disappear one day because scientists have been wrong before. Or “cats don’t give birth to dogs.”

We even have this one creationist repeating ignorant ID/creationist talking points about the lack of transitional fossils, even when the data are right in front of him!!

Creationists, whatever happened to your high-minded jabber about the importance of the data? Why haven’t creationists ever put this sort of chart up in their books and lectures? Are you afraid of what your followers will think?

Comment #136173

Posted by qetzal on September 30, 2006 11:15 AM (e)

Philip Bruce Heywood wrote:

Dogs won’t be giving birth to cats anytime soon…

Why not? Isn’t that exactly what ID predicts? New complex creatures should appear suddenly in a single generation due to intervention of the Intelligent Designer, right?

So the failure of dogs to give birth to cats (or dats), is evidence against ID. Surely you’ll agree with that, right Phil?

Evolution, on the other hand, predicts much more gradual change over time. Like, say, a gradual increase in hominid cranial capacity over the past 3 million years. I wonder if anyone’s ever tried to graph that out….

Comment #136183

Posted by Nick (Matzke) on September 30, 2006 11:40 AM (e)

By the way, isn’t it a fairly weak argument (if Henneberg and de Miguel are making it) that continuity in a fossil set of two summary or bulk characteristics—cranial volume and body weight—points to a single lineage? Didn’t paleontologists used to arrange the Eohippus–>Equus series as a single lineage on bulk continuity grounds—smooth-looking variation of size and form—only to find out later that these fossils are really chronologically ordered samples from different twigs of a ramifying bush?

Yes, but the horse thing was done by only looking at a small subset of the horsey fossils that fit the pattern. With the hominin skulls we’ve got a graph of *everything discovered* (excluding juveniles and a handful of hopelessly partial/mislabeled duplicates/etc.).

Also, horses go back 55 million years, so the equivalent for humans would be all old-world monkeys or some such.

So the continuity of size and weight numbers for hominins does not seem, from where I’m sitting up here in the peanut gallery (“I’m an engineer, not a biologist!”), to argue against a bush-like taxonomy. More precisely, could it be said that the failure of this data to “reflect postulated taxonomic diversity of hominins” is neither here nor there? That one would not necessarily expect such diversity to be manifest as discontinuities in these parameters?

Not necessarily, but according to Henneberg and de Miguel, apparently the taxonomists have often used brain size and body size (two of the most basic measurements) as key features to split apart taxa. Elsewhere in their work they make the point that these distinctions are sometimes drawn on measurement differences that are lower than experimental error.

The way the authors put it, if hominin taxonomy was meaningful, they hypothesized that these basic data ought to be able to falsify the null hypothesis of continuity. But instead the null hypothesis was confirmed.

As you say, there might be other characters on which to base the distinctions, but it is worth taking all of the “bushy” models with a grain of salt. We might perceive a distinct “lineage”, i.e. with Neandertals – but should differences that are basically subspecies-level distinctions really be represented as an offshoot branch? Was interbreeding really halted? These are tough questions.

There is another huge but very academic debate with the meaning of “species” in a gradually changing series of fossils ilke this. Something I would like to see discussed more is what cladistics should do in a situation like this, where we may well really be able to say, “this species is descended from that fossil species,” or at least consider such a statement a very close approximation of the truth. Cladistics may not be the best model for within-lineage evolution.

Comment #136190

Posted by Nick (Matzke) on September 30, 2006 11:58 AM (e)

Nick, the fastest way is probably to contact the authors for a pdf of the article you want…

I emailed them, but no result so far. The journal/book series does not have an online database so they are no more likely to have a PDF than anyone else I think.

Requests for the Excel spreadsheet – email me if you want it. Creationists have to promise to put my chart up on their website and explain why this data doesn’t destroy their position, and why creationists never show such charts to their followers even though they have been around for decades in the scientific literature. There should be few errors since I copied-and-pasted the data from a readable PDF, but I still had to manually fix line breaks etc. so there might be some.

I am thinking of doing some updates:

1. Chart with the different species shown with different graphics (how to deal with multiple designations for a specimen?)

2. This would be a lot of work, but it would be fun to translate the citation for each specimen into the year of publication, and then construct a time series of charts showing the fate of the “gaps” over the decades.

3. Adding fossils published after 2000 would be nice, is there a place where people could add the new finds as they come up? (this thread, or wikipedia or something?) It would be especially fun to plot each new fossil on the chart to see where it fits.

Other suggestions welcome.

Nick

Comment #136192

Posted by KevinD on September 30, 2006 12:02 PM (e)

There is a bit of confusion between regression and correlation going on here. First I am not sure why Henneberg and de Miguel (in figure 1 from their 2004 paper shown above) present a figure derived from a regression analysis and then present numerical statistics from a correlation analysis.

There is a simple mathematical relationship between a correlation coefficient and the slope coefficient in a linear regression. However the two coefficients measure different things.

A regression coefficient is measuring the slope of a line. The larger the coefficient the more rapidly the dependent/Y variable increases as the independent/X variable increases.

A correlation coefficient is measuring the tightness of fit to the line. The line can have any slope.

Figure 1 presented here does not compare the slopes of the lines at all. It is merely reporting a strong and positive relationship of both cranial capacity and body mass with date. The slope of the lines on figure 1 are both unit dependent and as cranial capacity and mass are measured in different units and on different axes you can’t conclude that one slope is larger than the other from the information given here (I haven’t looked at the paper itself).

To compare the slopes you could do one of a couple of things. Kim’s suggestion of reduced major axis regression will tell you about the allometric relationship of cranial capacity and mass. I think you would have to convert cranial capacity to brain mass (which should be straightforward) so that both variables would be measured in the same units. An alternative is to do an analysis of covariance in which you look at the relationship of cranial capacity to date and then include body mass as a covariate. This would tell you if any of the increase in cranial capacity is explained by date after you take body mass into account.

The difference in size of the correlation coefficients is interesting. As Nick states, the lower r value for body mass could be the result of an inherently larger measurement error in estimating body mass from fossils than in estimating cranial capacity. Alternatively it might mean that body mass varies more with local environment than cranial capacity.

Comment #136193

Posted by Nick (Matzke) on September 30, 2006 12:09 PM (e)

Very nice diagram, indeed. What I hope will be added in the future is where various creationists put in the line showing the sudden appearance of men as distinct from apes.

Also a good idea. I could add columns for each major creationist reference and then note their categorization of each fossil into human or ape. I believe the common pattern is that creationists only discuss a few of the most prominent fossils.

But it would be somewhat tedious to gather this info, is there a way to make a collaborative online repository for this stuff also somewhere, so that people can add to it as they come across new examples?

Comment #136197

Posted by mplavcan on September 30, 2006 12:21 PM (e)

I’m a little surprised that this stuff is not more familiar to a wider audience (point taken – we who teach this stuff need to stop assuming that “everybody knows THAT”…). The data presented here are very familiar to most anthropologists, and there has been a running argument about how to interpret it for many years. You need to keep in mind that the chart includes several different taxa that are not uniformly distributed through time, and overlap each other an several cases. Therefore, even though the graph clearly and unambiguously demonstrates a TREND for an increase in brain size over time, it is not accurate in representing variation in rates of change within each taxon over time. This leads to some taxa with relatively “stable” brain size values (in some cases this can be attributed to a narrow time range or small sample size in the early taxa), and others, as in the Homo series, showing a gradual transition with no clear boundary in this character between taxa. I believe that Steve Leigh published a paper in the American Journal of Physical Anthropology in the mid-1990’s using spline regressions (linear regression is not necessarily appropriate for the above data), concluding that the data are inadequate to determine the exact rate of change in cranial capacity. [For those creationists reading, please save yourself the embarrassment of thereby claiming that the data are punctuational – this will only demonstrate the you have no idea of what you are talking about.]

The suggestion that the chart is evidence that hominins represent a single species is not particularly strong, because it relies on a single character – a perilous proposition in any phylogenetic or taxonomic analysis. A glance at Paranthropus and Australopithecus skulls side by side should convince anyone except a die-hard ideologue (*ahem*) that these are different taxa by any common zoological standard. Nevertheless, the point that cranial capacity does not provide an unambiguous trait for delimiting species is not particularly contentious.

As for Mr Cordova’s comment about radiometric dating – give me a break. Do you have even the slightest inkling of just how stupid and insulting that comment is? That Cremo and Thompson BS in Forbidden Archeology is utter crap. The “evidence” in that book has been refuted so many times that it is difficult to read it simply because it is so boring at this point (it used to be funny, but any joke looses its humor after being repeated a thousand times). The dates used in the above graph have been derived from multiple sites by multiple independent labs using multiple dating techniques, and have been INTENSELY scrutinized, re-analyzed, re-dated and re-tested over decades. If the dating techniques were so bad, then the data above would come out as a noisy, random blob – garbage in, garbage out. And don’t give that crap about people selecting dates to correspond to their preconceived notions of the evolutionary scenario. Most folks in this business would love nothing more than to get solid data that would overthrow an accepted view. The reality is that bad dates are just that – bad.

Comment #136199

Posted by Scott Hatfield on September 30, 2006 12:31 PM (e)

Nick:

Scott Hatfield here! Sure wish I could afford to join you guys at NCSE. This was a tremendous post! I of course swiped your graph for use in my high school science class. Wonderfully persuasive! Keep up the good work….SH

Comment #136206

Posted by Greg on September 30, 2006 1:04 PM (e)

I was wondering, were these dates done with traditional carbon 14 dating or something else. It didn’t really specify in the abstract. Thank you.

Comment #136210

Posted by Torbjörn Larsson on September 30, 2006 1:22 PM (e)

Nick, really nice job! This time you have exceled your usual high standard posting.

Though I think there has been a lot said about ‘hypothesis testing’ by regression lines, it seems hard to fit anything else than an exponential growth here. That is perhaps strongly indicative of a gradual hypothesis - wouldn’t we expect a power law relationship if the growth had been by observing markedly different species from a bushy evolutionary tree? Perhaps mplavcan can explain why not.

It is amazing that we are still on the growth portion of cranial capacity. After all, the body mass grows slower, and the pelvic/foetus construction to handle birth should have tough constraints to work with.

Tiax, nice take on “a gap” definition.

Comment #136211

Posted by RBH on September 30, 2006 1:23 PM (e)

qetzal wrote

Why not? Isn’t that exactly what ID predicts? New complex creatures should appear suddenly in a single generation due to intervention of the Intelligent Designer, right?

In fact, Kurt Wise has made exactly that argument. According to Wise, shortly after the Flood new species were popping up daily and weekly, born of other species. IIRC correctly (I can’t bear to listen to it all again right now) the MP3 of Wise’s talk is here.

RBH

Comment #136213

Posted by RBH on September 30, 2006 1:30 PM (e)

Greg asked

I was wondering, were these dates done with traditional carbon 14 dating or something else. It didn’t really specify in the abstract. Thank you.

The mark of a creationist’s “innocent” question is to ask if carbon-14 dating was used to ascertain dates >50Kya. We now see all three main tactics of creationist denial in this thread: Heywood (deny inferences from the plain data), Cordova (accuse scientists of faking the data), and Greg (plain ignorance).

RBH

Comment #136215

Posted by Nick (Matzke) on September 30, 2006 1:45 PM (e)

I think it is better to assume that Greg is not a proud-to-be-ignorant fundamentalist who prefers literal Bible interpretation above physical evidence (Sal, however, has shown his cards above, and now we all know we can’t believe him when Sal says he values scientific data, likes science, and thinks we should follow the data wherever it leads).

I was wondering, were these dates done with traditional carbon 14 dating or something else. It didn’t really specify in the abstract. Thank you.

Carbon-14 has a half life of 5,000 years, which means that C-14 decays away to 0 at about 50,000 years. So C-14 can only date things back to 40-50,000 years, after that the answer you get is just “older than 50,000.”

But, contra the almost universal misperception of creationists, C-14 is not the only way to date fossils. In fact there are dozens of methods based on dozens of different radioactive isotopes and other clocks. This page from a scientist who is an evangelical Christian is a decent summary. The creationist treatment of dating techniques is of course an unremitting travesty that will stain the antievolution movement until the unlikely day when antievolutionists uniformly and unhesitatingly denounce the young-earthers for the frauds they are and for the delusions that they sold, under the guise of piety, to millions of evangelicals in this country. See the TalkOrigins Age of the Earth FAQs and this webpage on radioisotope half-lives.

Comment #136216

Posted by Nick (Matzke) on September 30, 2006 1:47 PM (e)

It is amazing that we are still on the growth portion of cranial capacity. After all, the body mass grows slower, and the pelvic/foetus construction to handle birth should have tough constraints to work with.

If you were to zoom in on the last 50,000 years I think you would find that the growth has leveled off. Our brains are actually slightly smaller than Neandertal brains.

Comment #136217

Posted by MarkP on September 30, 2006 1:50 PM (e)

I wonder if the creationists can explain to me why my cat yawns the same way I do when they trot out their ignorant tripe.

Comment #136218

Posted by Anton Mates on September 30, 2006 1:51 PM (e)

Salvador T. Cordova wrote:

The graph may arguably reflect how well enforced the possibly false dating of fossils is done to fit a pre-conceived viewpoint. :-)

A Cornell PhD disputes the dating. See : Forbidden Archaeology?

Um, Sal, that link is to a book by a guy who thinks he was able to write as an infant due to literary skills from previous reincarnations, and who believes “humans like ourselves have existed on this planet for tens of millions of years.”

But yes, the other author’s obviously an expert in paleontology and archaeology since he holds a Ph. D. from Cornell!!

(Wait for it…)

…in math. Oh, and believes UFOs visited ancient India a lot.

I’m trying to figure out how this supports ID or YEC or TE, and it’s just not coming to me. Your post was the equivalent of “So, you think you’ve refuted my argument? Well…look over there! A stray cat! And he’s vomiting! What do you think of that, eh?”

Comment #136220

Posted by Bob O'H on September 30, 2006 1:54 PM (e)

Nick Matzke wrote:

2. This would be a lot of work, but it would be fun to translate the citation for each specimen into the year of publication, and then construct a time series of charts showing the fate of the “gaps” over the decades.

That doesn’t sound too bad using something like R. It’s a dialect of the S language, which is a stats programming language. Hmmm, expect an email from an Anon. soon.

Oh, and add my name to your list of admirers. All I can say is that the Sun Dome broadcast must have been very entertaining if it stopped your brains from dribbling through your ears doing all that typing (been there, done that, now I’ve made sure I get other people to do that, and I ge the fun of torturing the data :-))

KevinD wrote:

The slope of the lines on figure 1 are both unit dependent and as cranial capacity and mass are measured in different units and on different axes you can’t conclude that one slope is larger than the other from the information given here (I haven’t looked at the paper itself).

You can compare the slopes, becaues the y-axes are both on the log scale. So an increase of 1 unit means that the variable (CC or Wt) increases e^1 times. So the units don’t matter, except that they move the plots up or down by a different amount.

Bob

Comment #136221

Posted by Anton Mates on September 30, 2006 1:57 PM (e)

Nick (Matzke) wrote:

Not necessarily, but according to Henneberg and de Miguel, apparently the taxonomists have often used brain size and body size (two of the most basic measurements) as key features to split apart taxa.

I’m yet another total non-expert here, but I gotta say, I’ve pretty much never seen that in a paleoanthropological paper. (Admittedly, I’ve only seen a couple dozen.) Classification’s always involved a host of other morphological features, such as torsion of the humerus or ulna or size ratios between skull, mandible and cheek teeth.

I could certainly be wrong, but glancing over the Henneberg/de Miguel paper, it doesn’t look like they really support the idea that brain/body size are the most commonly-used taxonomic characters.

Comment #136228

Posted by Dave Carlson on September 30, 2006 2:20 PM (e)

Philip Bruce Heywood wrote:

Dogs won’t be giving birth to cats anytime soon, and your great uncle will never be any more like a chimp than will his nephew.

Oh, I see. You don’t actually know anything about evolutionary biology. If you did, you would know not to to say something as utterly ridiculous as the above. Huh. Typically, when I’m completely ignorant on a topic, I tend not to pontificate on it in front of people who know a lot about it. Different strokes for different folks, I suppose. Just don’t expect to be taken seriously around here.

Comment #136233

Posted by Nick (Matzke) on September 30, 2006 3:08 PM (e)

You know you’re a total non-expert when you get corrected by a self-described total non-expert, as here:

I’m yet another total non-expert here, but I gotta say, I’ve pretty much never seen that in a paleoanthropological paper. (Admittedly, I’ve only seen a couple dozen.) Classification’s always involved a host of other morphological features, such as torsion of the humerus or ulna or size ratios between skull, mandible and cheek teeth.

I could certainly be wrong, but glancing over the Henneberg/de Miguel paper, it doesn’t look like they really support the idea that brain/body size are the most commonly-used taxonomic characters.

Well, I didn’t say “most common”, but I probably overstated it. But I was thinking of stuff like this in their paper:

The number of taxa of hominins is still debated between those who postulate the presence of just a few chronospecies and those who advocate the existence of many often coeval and sympatric genera and species (Tattersal 1987; Wolpoff 1996–1997; Wood & Collard 1999; Eckhard 2000; Wood & Richmond 2000). Primate species adapt to different conditions. These differences are reflected in morphometric characters, including brain size (Oxnard 1983; de Winter & Oxnard 2001) and body size (e.g. Rowe 1996). Thus, had the taxonomic diversity of hominins
been real it should be reflected in heterogeneity of brain size and body size distributions.

So they are arguing (a) primate species adapt to different niches, (b) body size and brain size are important adaptive characters, therefore © if there really were a whole bunch of hominin species we should see this in the brain size/body size data, but (d) we don’t.

Therefore, they say:

The level of coeval variation of CC and body size within hominins seems to be appropriate for slight adaptive differences between geographic populations of a single species rather than for interspecies differences. Were speciation amongst humans true, it would have to be due to small magnitude, largely unexplainable processes as intricate as some morphological descriptions that justify division of human fossil record into multiple taxa. Parsimony being one of the major principles of scientific explanation, we find it hard to justify coeval human taxonomic diversity.

Variation within the basic type, anyone?

Comment #136235

Posted by waldteufel on September 30, 2006 3:19 PM (e)

Thanks for the very interesting graphs. I’ve already saved them and plan to send to my son and a couple of friends who are also interested in matters biological.

Philip Bruce Heywood sure sounds like a Kent Hovind sock puppet.

Comment #136237

Posted by RBH on September 30, 2006 3:32 PM (e)

waldteufel wrote

Philip Bruce Heywood sure sounds like a Kent Hovind sock puppet.

Naw, Heywood is more literate (if not more knowledgeable) than Hovind. See here for a dissection of Hovind’s writing style. Now, I don’t say Heywood’s not echoing Hovind, but at least he writes better.

RBH

Comment #136238

Posted by Sir_Toejam on September 30, 2006 3:38 PM (e)

It might also be a good idea to put in error bars where you took the average to represent a data point.

moreover, can a parametric analysis be done correctly with this dataset? the lack of replication for many points suggests a non-parametric analysis might be a better fit.

Requests for the Excel spreadsheet – email me if you want it.

i would, but you don’t have a PM or an email addy listed on PT.

Is it over at NCSE?

Comment #136240

Posted by wolfwalker on September 30, 2006 3:56 PM (e)

One other point regarding the creationist moldy-oldie of asking about “carbon dating of fossils”: fossils can’t be dated using carbon-14 at all. Radiocarbon dating works only on unaltered organic remains. Fossils such as most of the specimens in Nick’s data are dated using other techniques.

Comment #136241

Posted by Greg on September 30, 2006 4:26 PM (e)

Nick Matzke wrote:

Carbon-14 has a half life of 5,000 years, which means that C-14 decays away to 0 at about 50,000 years. So C-14 can only date things back to 40-50,000 years, after that the answer you get is just “older than 50,000.”

Ok, I understand that, and I’m not a creationist, but I was merely curious of how those dates were arrived at. I would’ve though that it would’ve been carbon, but apparently, I was wrong. So, were other, various, methods of dating used for the different fossils, or another way, like, using the strata?

Comment #136242

Posted by afarensis, FCD on September 30, 2006 4:29 PM (e)

I wouldn’t mind a copy of the spreadsheet myself (and if possible the two articles you mentioned). Thanks for mentioning my debunking of Luskin!

Comment #136244

Posted by mplavcan on September 30, 2006 4:39 PM (e)

Nick:

Sorry, but the assertion that one should see de facto variation in brain size and body size if there is taxonomic diversity in extinct species is simply wrong. Speciation in primates, as with many other mammals, is not necessarily correlated with morphological divergence in a particular set of characters. For example, I have craniometric data on about 150 species of primates. Plotting body size estimates versus cranial size estimates most often yields a slurry blob, with little taxonomic differentiation. Often times in anthropology, analyses will focus on taxonomic distinctions between gorillas and chimps alone, but an argument can be made that these are relic taxa from a wider past radiation, and do not represent a good model for a radiation (the argument can be made the other way though). Anyhow, the general rule is that when using just a few characters, one should expect to underestimate diversity in the fossil record. Conversely, multivariate analysis (usually discriminant functions) using larger character arrays often can yield separation amongst closely related taxa. But that is a case where one has multiple characters. Furthermore, when dealing with the fossil record, one has to make a clear distinction between the ability to statistically detect significant differences in a character amongst living species, versus whether taxonomic differentiation in a character is great enough to sort taxa accurately into discrete groupings. Brain size and body size alone are relatively poor indicators of taxonomic diversity for this purpose.

Another thing to keep in mind here is that we are not dealing with hominin body size in the above graph. That has been estimated using various remains – cranial, dental and postcranial. The body mass estimates in some cases are highly uncertain, with very large standard errors. Therefore, taxonomic conclusions based on estimates of body mass simply introduce an additional level of error variance into the analysis. Taxonomic assessments inevitably include as much metric and qualitative data derived directly from the remains as possible.

The number of taxa that should be recognized in hominin evolution is currently hotly debated. For example, a paper just came out in the Journal of Human Evolution demonstrating that Australopithecus anamensis and A. afarensis represent a smooth transition. However, even the authors of the paper did not agree on how to deal with the taxa in terms of nomenclature, as stated in the paper (hey, they were honest!). Other debates currently center on the taxonomic status of Homo ergaster/erectus/georgicus/habilis/antecessor/heidelbergensis and a few others. This reflects the fact that a lot of new fossils have been found, and our understanding of human evolution has grown more sophisticated, leading to confusion abut how typological, categorical names should be applied to a complex branching pattern of transitional forms. Regardless, the relationship between brain size and body size does not play a singular role in most of these debates (though the character is used in some cases).

So the question of whether all that mess that you see in that graph is variation within a basic type is true at one level, and silly at another. Virtually everyone agrees that the data set above includes some forms that represent an anagenetic lineage, even though there is debate about whether some of those forms should be named as species, subspecies, or whatever. But it also contains forms that the overwhelming majority of paleoanthropologists recognize as unambiguously separate species that are not anagenetically related (e.g. compare any Paranthropus versus any Australopithecus).

Comment #136245

Posted by David B. Benson on September 30, 2006 4:44 PM (e)

A typical method of dating older materials is indeed via the strata. Then it is sometimes possible to use other radio-dating methods, or geochemical methods, to estimate dates for the strata.

As an amateur trying to make sense of some older dates, I want point out that there can easily be systematic errors of one form or another. For example, the last super-eruption of Mt. Toba has been dated to about 71,000 years ago via one technique and to about 74,000 years by another. Unfortunately, the error bars for the two techniques do not overlap…

Comment #136265

Posted by mark on September 30, 2006 5:26 PM (e)

Nice work, Nick. Similar graphs that I have seen (for various features of various species) have normalized one feature (such as brain size) as a function of body size. The same idea is implied by the second graph that includes body weight, but the conclusion (when normalized for body size, cranial capacity still increases over time) is not as obvious.

Comment #136267

Posted by Nick (Matzke) on September 30, 2006 5:41 PM (e)

Sorry, but the assertion that one should see de facto variation in brain size and body size if there is taxonomic diversity in extinct species is simply wrong.

Howdy – technically your argument is with De Miguel and Henneberg 2001, not me. I am agnostic on the “single lineage” idea as I stated before, but I am interested to read your opinion.

As for Paranthropus it seems to appear only a couple of times in the table, under the label A. robustus I think. At one point the authors re-do their analysis while excluding the robust australopithecines and get very similar numbers for the overall pattern.

But it would be useful to talk about this issue: if a figure like the above is to be used for public education, should perhaps the robust Australopithecines be excluded from it? The charts in the new thread break things apart by species so people can get idea of what that would look like.

Comment #136268

Posted by 'Rev Dr' Lenny Flank on September 30, 2006 5:46 PM (e)

Hey Sal, I have about thirty questions for you that you never answered.

Wanna give it a go?

Comment #136269

Posted by Philip Bruce Heywood on September 30, 2006 5:48 PM (e)

So let’s say it in black and white, so the world can be in no doubt.
1). All species grade into each other - correct?
2). This happened by the equivalent of your descendents, in time, just gradually turning into apes, or vice versa - correct?
3). And the engine for this process is time, plus, the natural selective changes we see in the human species - correct?
4). This same engine of natural selection over time produced such obvious and clear-cut species as T. REX and all the others - correct?
5). And it produced a kaleidoscope of complex life-forms within a period almost certainly no longer than 10 mill.yrs, Early Cambrian, when prior to this there was nothing better than organized seaweed - correct?
6). Plus a breathtaking outbreak of flowering plants during the Cretaceous, with scarecely a whisp of flowering plants before - right?
7).And no respected scientist has ever said anything different and if he did or does, he is a fool - correct?

Say it, boys, just say it. Pretty please, confirm your deductions for posterity.

Comment #136309

Posted by Anton Mates on September 30, 2006 6:55 PM (e)

Nick (Matzke) wrote:

You know you’re a total non-expert when you get corrected by a self-described total non-expert, as here:

Oh, I’m not correcting you–I think you summarized the paper quite accurately.

So they are arguing (a) primate species adapt to different niches, (b) body size and brain size are important adaptive characters, therefore © if there really were a whole bunch of hominin species we should see this in the brain size/body size data, but (d) we don’t.

The trouble I see with that argument is, body and brain size don’t have to be particular traits in whch diverging species differ. For instance, if hominin brain development really was driven by a social skills arms race, as is often suggested, then different hominin species might experience roughly the same pressures toward brain growth even as they diversify in other ways. And as they themselves point out, modern humans have a very wide range of brain sizes and cranial capacities are hard to measure reliably; either of those could obscure a slight selection-driven difference in brain size trends between species. Especially if the evolutionary tree is bushy enough that you have several contemporaneous hominin species, with distinct but overlapping brain/body size ranges that all mush together on a plot which doesn’t take other characters into account.

They’re using a phenetic technique, basically–trying to distinguish species on the basis of similarity/difference in a couple of key characters–and according to my professor that often fails on descent patterns that cladistic methods would successfully tease out. Of course, he was…um…a cladist.

Oh, and there’s the extremely minor point (that they couldn’t have foreseen anyway) that if H. floresiensis really is a non-H. sapiens, it’s way off the chart. :)

Therefore, they say:

The level of coeval variation of CC and body size within hominins seems to be appropriate for slight adaptive differences between geographic populations of a single species rather than for interspecies differences. Were speciation amongst humans true, it would have to be due to small magnitude, largely unexplainable processes as intricate as some morphological descriptions that justify division of human fossil record into multiple taxa. Parsimony being one of the major principles of scientific explanation, we find it hard to justify coeval human taxonomic diversity.

I wince when systematists invoke “parsimony” to prove that they’re right. :) Everyone thinks their hypothesis is the simplest, and it’s hard to make a clear call between “lots of species” and “lots of subspecies.”

But I do agree, overall, that drawing fine species lines here is probably unworkable. After all, aren’t most of our modern speciation examples due to small magnitude processes that would be largely unexplainable to a future paleontologist, because they depend on incompatibilities of behavior, genetics, development, etc.? You can’t therefore conclude that hominins didn’t have bunch of different species, just that whatever the barriers to gene flow were, we probably can’t figure them out from the bones.

Comment #136346

Posted by GuyeFaux on September 30, 2006 9:48 PM (e)

1). All species grade into each other - correct?

I have no idea what that means, but I think the answer is no. Cats never “graded into” dogs.

2). This happened by the equivalent of your descendents, in time, just gradually turning into apes, or vice versa - correct?

Sounds right.

3). And the engine for this process is time, plus, the natural selective changes we see in the human species - correct?

No idea what this means.

4). This same engine of natural selection over time produced such obvious and clear-cut species as T. REX and all the others - correct?

Yes, it produced T. Rex. However, even T. Rex underwent considerable morphological change over time. Notably in femur length.

5). And it produced a kaleidoscope of complex life-forms within a period almost certainly no longer than 10 mill.yrs, Early Cambrian, when prior to this there was nothing better than organized seaweed - correct?

Something about the Cambrian explosion, no idea how it relates to previous “points”.

6). Plus a breathtaking outbreak of flowering plants during the Cretaceous, with scarecely a whisp of flowering plants before - right?

Ok, now we’ve switched eopchs…

7).And no respected scientist has ever said anything different and if he did or does, he is a fool - correct?

No, just ignorant. They lived in the wrong century, were not exports in the field, etc.

You consider this a black/white deduction? More importantly you believe it to be an accurate representation of the new synthesis? Please clarify. And next time use words that mean things.

Comment #136368

Posted by Anton Mates on September 30, 2006 11:03 PM (e)

Philip Bruce Heywood wrote:

1). All species grade into each other - correct?

Incorrect. All species’ ancestors grade into each other if you go far enough back. So do yours and mine, but I’m not you.

3). And the engine for this process is time, plus, the natural selective changes we see in the human species - correct?

“Natural selective?”

4). This same engine of natural selection over time produced such obvious and clear-cut species as T. REX and all the others - correct?

Of all the actual clear-cut species you could pick–platypus, gingko–why would you pick that?

T. rex is long-extinct and we only have something like a dozen skeletons. We may never know what its closest relative was and we’ll certainly never know if they could hybridize. It’s the complete opposite of “clear-cut.”

Even among the tyrannosaurid fossils we have found, there’s been plenty of confusion about what belongs with who.

5). And it produced a kaleidoscope of complex life-forms within a period almost certainly no longer than 10 mill.yrs, Early Cambrian, when prior to this there was nothing better than organized seaweed - correct?

Incorrect. The Cambrian “explosion” took more like 40 mya, and well before it there were already large multicellular animals like cnidarians, chordates and whatever it is Dickensonia is.

?7).And no respected scientist has ever said anything different and if he did or does, he is a fool - correct?

Incorrect. No respected modern biologist says different (well, except for the stuff you got wrong.) Modern psychologists and physicists are free to be wrong about biology, and biologists of earlier generations didn’t know about all this yet.

Comment #136375

Posted by djlactin on September 30, 2006 11:25 PM (e)

Great chart, Nick.

1) Suggest you use EXCEL options to put trendline, equation and r² on it. (Click on chart, select Chart menu, etc.)

2) Stating up front that I am an evolutionist and a Ph.D (in… wait for it… Biology!), and have considerable statistical experience (taught at junior college level for 5 years).

But…

At the risk of providing an ‘out’ for the adversaries, charts like this that pool data from many species, can conceal considerable ‘internal’ information. The true trend COULD be a series of punctuation events, with the resulting lineages persisting and overlapping. (A series of overlapping horizontal lines.) Lumping the data without reference to species names would obscure such leaps and (erroneously) cause us to see continuity.

For example, my eyes see a strange pattern of perhaps 2 ‘leaps’ in the graph: CC was relatively low (ca. 500mL) and increased slowly (if at all) until about 2 MYa; At that point there is a sudden increase in variability, and the trend after about 1.5 MYa seems to emerge from the high end of this range of variability; this second part remains relatively flat until about 50kYa, after which the slope skyrockets. One possible explanation is that there are 3 separate lines here: a flat one from the beginning to about 1.5 MYa; another flat one from ca 2 MYa to ca 50kYa, and a third from 50kYA to now which increases quickly.

I’d be interested in discussing this perception. Does anybody else ‘see’ this? And if its real, how (if at all) are the breakpoints that I “see” correlated with species transitions in the fossil record?

Comment #136400

Posted by Nick (Matzke) on October 1, 2006 12:51 AM (e)

Great chart, Nick.

1) Suggest you use EXCEL options to put trendline, equation and r² on it. (Click on chart, select Chart menu, etc.)

De Miguel and M. Henneberg (2001) (and 2004) actually do a pretty sophisticated regression analysis against time and latitude, and they do anova also. I don’t understand all of it but they do standard things like graphing the residuals (which are normally distributed). They end up fitting a “double exponential” model. I would have to work through the stats section of the papers carefully again to answer the various stats questions we’ve had (and some on Pharyngula also), but suffice it to say they answer most of the basic questions.

Having witnessed a few statistics battles between scientists I know that it is common for everyone to have a strong opinion about what the right method is to use in the statistical analysis, but it is uncommon for everyone to agree on what that is. So, (and I emphasize: go to the paper for a real analysis), in Excel, just for kicks, I did the regression function using a variety of curves. Results:

Linear:
CC = -397.95*date + 1413.2
r2 = 0.8376

Logarithmic:
CC = -188.35*Ln(date) + 796.09
r2 = 0.8019

Power:
CC = 723.45*(date-0.2019)
r2 = 0.7571

Exponential:
CC = 1428.9 *e-0.4541*date
r2 = 0.896

The model the authors report in the abstract is:

CC = 306.63 * (4.83(0.9995^date))

…they say it explains 90% of the variance. So the plain exponential model is almost as good. (They say that n=207, whereas I got n=214 from their table even while excluding the specimens they said they excluded, so there is a slight difference in the datasets as well.)

2) Stating up front that I am an evolutionist and a Ph.D (in… wait for it… Biology!), and have considerable statistical experience (taught at junior college level for 5 years).

But…

At the risk of providing an ‘out’ for the adversaries, charts like this that pool data from many species, can conceal considerable ‘internal’ information. The true trend COULD be a series of punctuation events, with the resulting lineages persisting and overlapping. (A series of overlapping horizontal lines.) Lumping the data without reference to species names would obscure such leaps and (erroneously) cause us to see continuity.

Others mentioned this also, so I posted graphics with the species delimited in the next post.

You make a valid point, but in general what I would really like to see with postulated “punctuation” events is (a) the morphological change is quantified and (b) statistical tests to determine if perceived “jumps” are real or could just be statistical noise etc. If you only have a handful of specimens for a particular species it doesn’t take much for the eye to perceive a slight discontinuity that in reality is just a statistical accident.

(Part of this is my generic hostility to the decades of Punk-Eek abuse that the creationists (and frankly some scientists) have engaged in. AFAIK PE is just allopatric speciation applied to the fossil record to explain quite small discontinuities between closely-related sister species. Somehow the “small” and “closely-related sister species” points are very commonly dropped in discussions (or, sometimes people inappropriately invoke PE for other sorts of discontinuities, e.g. at higher taxonomic levels, which is really a different question with different possible explanations).

For example, my eyes see a strange pattern of perhaps 2 ‘leaps’ in the graph: CC was relatively low (ca. 500mL) and increased slowly (if at all) until about 2 MYa; At that point there is a sudden increase in variability, and the trend after about 1.5 MYa seems to emerge from the high end of this range of variability; this second part remains relatively flat until about 50kYa, after which the slope skyrockets. One possible explanation is that there are 3 separate lines here: a flat one from the beginning to about 1.5 MYa; another flat one from ca 2 MYa to ca 50kYa, and a third from 50kYA to now which increases quickly.

I don’t think there has been an increase from 50kYA to present, I think the actual trend is flat or declining. In the last 50,000 we have many more fossils and subfossils so the huge number of samples for the recent past makes the chart look like we’re still in an upswing, when in fact we just have the tails of the distribution more filled in my more thorough data.

Regardless, a model resembling yours could be tested for its explanatory power. My gut instinct is that it would get an r2 around 0.8 like the other non-exponential regressions; in places, the chart above obscures a number of densely-packed points that follow the trend more closely than the outlier points that the eye picks up on more.

I’d be interested in discussing this perception. Does anybody else ‘see’ this? And if its real, how (if at all) are the breakpoints that I “see” correlated with species transitions in the fossil record?

This is being discussed in the newer thread.

Comment #136401

Posted by Nick (Matzke) on October 1, 2006 12:55 AM (e)

Typo in previous:

“filled in my” –> “filled in by”

Comment #136403

Posted by Pinko Punko on October 1, 2006 1:23 AM (e)

It is the “hockey stick” for BRAINS! BRAAAAAAAAAINNNNNNNNNS!

Comment #136409

Posted by Torbjörn Larsson on October 1, 2006 2:56 AM (e)

“Our brains are actually slightly smaller than Neandertal brains.”

Duh! I should remember that! (I sometimes feel related, since I happen to got especially thick bones, large scull size/eye distance, and long tooth roots - all at about 1 in 1000 statistics. Nothing have broken my bones yet, not for lack of trying…)

“he holds a Ph. D. from Cornell!!

(Wait for it…)

…in math.”

Sadaputa Dasa (Richard L. Thompson) seems to have published his PhD. But no more research I can find. (His probable lack of postdoctorate may explain that - he returned home immediately afterwards.)

“Plotting body size estimates versus cranial size estimates most often yields a slurry blob, with little taxonomic differentiation…. Anyhow, the general rule is that when using just a few characters, one should expect to underestimate diversity in the fossil record. Conversely, multivariate analysis (usually discriminant functions) using larger character arrays often can yield separation amongst closely related taxa.”

I don’t get it. This baseline seems to indicate that the apparent increases are really significant. I’m still not sure why we expect an exponential instead of a power curve.

Comment #136465

Posted by Philip Bruce Heywood on October 1, 2006 7:12 AM (e)

Good heavens. Don’t let the facts get in the way of a good story, they say.

If there were no clear dividing lines between species and their “ancestors”, then there are no clear dividing lines between species. As a generality, if man can interbreed with ape-like ancestor, and ape-like ancestor can interbreed with chimp, then there is the certainty that at some time, possibly but not necessarily now, under certain circumstances, chimnp can interbreed with human. Ditto all other species. If we have no reproductive isolating bar, we have something approaching mayhem. Where is the observed mayhem? Why can I be certain my cattle will not interbreed with other species, and cease to be cattle?

I avoid going further into details of factual errors, save one.

I deliberately didn’t use the term, “Cambrian Explosion”. We shan’t quibble over that term, or proposed time-periods. Give or take a few million, many species and even whole classes, orders, etc., were geologically abrupt arrivals - not only during Cambrian times. There appears to be confusion regarding this, on this page. For instance, no fossils unequivocally displaying the necessary features of complex or animal-grade life (such as marked internal symmetry)have yet been found beneath the Cambrian. Some people who contribute to these pages might like to put them there, but the fossil record stands. There are no unequivocally cnidarian or chordate fossils known from beneath the Cambrian. Representatives of most if not all major divisions of complex or animal-grade life first appear - some in totally incipient or embryonic form - in the Cambrian. Chordates are significant here.

I am at a loss as to why a publication such as T/O aspires to be, has no apparent review of factual input on its pages. No cause is advanced by technical inaccuracy.
Kindly correct me if I present facts incorrectly.

Comment #136470

Posted by Dennis on October 1, 2006 7:40 AM (e)

Verrry nice data! I think someone should study if there is a correlation between the modern 0 mya data below the median, 1200 in ml to 900 in ml, and creationists. This data suggests people who’s brain size would comport with 1 mya to 0.5 mya. It may explain why they can’t accept modern thought.

Comment #136477

Posted by William E Emba on October 1, 2006 8:09 AM (e)

Torbjörn Larsson wrote:

“he holds a Ph. D. from Cornell!! (Wait for it…) …in math.”

Sadaputa Dasa (Richard L. Thompson) seems to have published his PhD. But no more research I can find. (His probable lack of postdoctorate may explain that - he returned home immediately afterwards.)

Old-timers will remember Thompson’s multiple personality but ever faithful disciple Kalki on talk.origins in the early 90s hawking Thompson’s book Mechanistic and Nonmechanistic Science, with promises to post to the group the relevant chapters that were most devastating to existing science, as soon as Thompson returned from a trip and granted permission. Upon return, permission was not granted, but readers were informed of his forthcoming Forbidden Archaeology.

Comment #136479

Posted by William E Emba on October 1, 2006 8:15 AM (e)

Nick Matzke wrote:

I would like to generate my own spiffy plots of hominin body weight estimates over time, but the dataset seems to have been published in this annoyingly rare publication:

Interlibrary loan is your friend. Over the years I’ve gotten copies of articles from some extremely obscure publications. I’ve sometimes resorted to locating copies of books online and just buying one, even if I just want the one article. Every so often I’ve been pleasantly surprised with the result.

Comment #136481

Posted by William E Emba on October 1, 2006 8:27 AM (e)

Salvador T. Cordova wrote:

The graph may arguably reflect how well enforced the possibly false dating of fossils is done to fit a pre-conceived viewpoint. :-)

Ignore the dating and just explain the taxonomy. Which are the “human kind” and which are the “monkey kind”?

Comment #136497

Posted by jeffw on October 1, 2006 10:03 AM (e)

There appears to be confusion regarding this, on this page. For instance, no fossils unequivocally displaying the necessary features of complex or animal-grade life (such as marked internal symmetry)have yet been found beneath the Cambrian.

Eidiacaran fossils - precambrian echinoderms and arthropods. And I supose you’ve never heard of hox genes.

I am at a loss as to why a publication such as T/O aspires to be, has no apparent review of factual input on its pages. No cause is advanced by technical inaccuracy.

You’re blithering again.

Comment #136512

Posted by B. hessel on October 1, 2006 10:55 AM (e)

A similar chart has been published in a 2003 paper by Lee and Wolpoff. You can get it here:
http://www-personal.umich.edu/~wolpoff/Papers/Brain%20Size.pdf

Comment #136520

Posted by GuyeFaux on October 1, 2006 11:45 AM (e)

Jeezus H. Creo, a valid inference by Heywood:

If there were no clear dividing lines between species and their “ancestors”, then there are no clear dividing lines between species. As a generality, if man can interbreed with ape-like ancestor, and ape-like ancestor can interbreed with chimp, then there is the certainty that at some time, possibly but not necessarily now, under certain circumstances, chimnp(sic) can interbreed with human.

Yes, and there’s evidence for this, published in Nature.

Comment #136525

Posted by mark on October 1, 2006 12:41 PM (e)

For the benefit of creationists who believe the “Cambrian Explosion” to be, in effect, a moment of creation, let me point out one (of numerous) article in Science that describes fossils from the Precambrian of China, dating tens of millions of years prior to the Cambrian. Science of 3 June 2004, (Chen &al., p. 219-222):

These fossils provide the first evidence confirming the phylogenetic inference that Bilateria arose well before the Cambrian.

Comment #136576

Posted by Sir_Toejam on October 1, 2006 6:21 PM (e)

Kindly correct me if I present facts incorrectly.

ROFLMAO!

I can’t find anything wrong with this statement, as Heywood didn’t present any facts to begin with.

Aren’t the insane humorous?

Comment #136577

Posted by Nick (Matzke) on October 1, 2006 6:24 PM (e)

A similar chart has been published in a 2003 paper by Lee and Wolpoff. You can get it here:
http://www-personal.umich.edu/~wolpoff/Papers/Brain%20Size.pdf

Heh. They seem to reach pretty similar conclusions (they restrict their analysis to Homo erectus and later Homo specimens):

Sang-Hee Lee and Milford H. Wolpoff (2003). “The pattern of evolution in Pleistocene human brain size.” Paleobiology, 29(2), 2003, pp. 186–196. http://www-personal.umich.edu/~wolpoff/Papers/Brain%20Size.pdf

Abstract. With a sample of 94 Pleistocene cranial capacities between the time period of 1.8 Ma and 50 Ka now known, we consider the evolution of cranial capacity in Homo, with the null hypothesis that the changes over time are a result of one process. We employ a new method that uses a resampling approach to address the limitations imposed on the methods of previous studies. To test the null hypothesis, we examine the distribution of changes in adjacent temporal samples and ask whether there are differences between earlier and later samples. Our analyses do not reject the hypothesis of a single process of brain size change, but they are incompatible with an interpretation of punctuated equilibrium during this period. The results of this paper are difficult to reconcile with the case for cladogenesis in the Homo lineage during the Pleistocene.

Wolpoff even says that he used to favor a punctuated equilibrium model, but changed his mind because of this analysis.

At the end of the paper the authors say their analysis favors the multiregional hypothesis, but that seems to me to be a separate question than that considered in their analysis – “Out of Africa” vs. “multiregional” is (I think) about the origin of the last common ancestral population of currently-living modern humans, 100,000-200,000 years ago, which could be a much different question than the generic origin of the fossil species approximating “Homo sapiens”, which is very likely much older (~500,000 years ago for archaic H. sapiens) than the LCA of extant humans.

Comment #136606

Posted by Torbjörn Larsson on October 1, 2006 8:16 PM (e)

“Our analyses do not reject the hypothesis of a single process of brain size change, but they are incompatible with an interpretation of punctuated equilibrium during this period.”

Well, that answers my question. (Framing the question correctly is always better than framing a specific answer. Another thing I should remember!)

Comment #136621

Posted by windy on October 1, 2006 9:20 PM (e)

Philip Bruce Heywood wrote:

If we have no reproductive isolating bar, we have something approaching mayhem. Where is the observed mayhem? Why can I be certain my cattle will not interbreed with other species, and cease to be cattle?

You can’t be certain, if there are some buffalo around.

Comment #136626

Posted by Anton Mates on October 1, 2006 9:36 PM (e)

Syntax Error: mismatched tag 'quote'

Comment #136627

Posted by Anton Mates on October 1, 2006 9:40 PM (e)

windy wrote:

If we have no reproductive isolating bar, we have something approaching mayhem. Where is the observed mayhem? Why can I be certain my cattle will not interbreed with other species, and cease to be cattle?

You can’t be certain, if there are some buffalo around.

Or wisent, or yaks.

And as I’ve mentioned before, we have mayhem when it comes to canids. Wolves and coyotes are interbreeding like mad in the wild right now, to the point where you can find coyote DNA in most wolves in Eastern North America, and vice versa.

Mayhem!

Comment #136654

Posted by W. Kevin Vicklund on October 1, 2006 11:05 PM (e)

I can see PBH right now:

“There’s no such thing as ligers. There’s no such thing as ligers. Mommy, make the liger go away!”

(For those new to the reference, a liger is a cross-breed between a lion and a tiger)

Oh, and don’t forget mules.

Comment #136762

Posted by Anton Mates on October 2, 2006 9:54 AM (e)

The last reply went into a holding pattern, let’s see if this one gets through:

Philip Bruce Heywood wrote:

I deliberately didn’t use the term, “Cambrian Explosion”. We shan’t quibble over that term, or proposed time-periods.

What’s to quibble with? You said less than 10 mya, it’s actually 30-60 mya or so. Why not accept that and move on?

For instance, no fossils unequivocally displaying the necessary features of complex or animal-grade life (such as marked internal symmetry)have yet been found beneath the Cambrian.

I know you didn’t read the links last time, and you probably won’t read these, but:

No
No
No.

It’s perfectly true that we don’t know how to classify most of the Vendian/Ediacaran fauna. But that’s because there were too many complex body plans in the Pre-Cambrian, making it harder for us to catch sight of and identify the direct ancestors of any modern organism.

Comment #136767

Posted by Darth Robo on October 2, 2006 10:59 AM (e)

Keep plugging PBH. If at first you don’t succeed, try, try again. Remember: GOD LOVES a tryer!

Comment #136805

Posted by Michael Suttkus, II on October 2, 2006 3:03 PM (e)

Philip Bruce Heywood wrote:

Well- presented charts. They demonstrate something but there are at least three obvious riders:
1). The history of Science is littered with scores of discarded “proofs” as compelling as these.

So?

Let me get this straight, your argument here is, “Sure, it’s really compelling and all the evidence suggests it, but MAYBE it will be wrong anyway and SOMEHOW creationism will end up being right despite all the evidence being against it?”

If “it could turn out to be something else” is the best you have, you have nothing. If the evidence changes, science will change. If tomorrow, gravity reverses and apples go flying off to Mars, physicists’ theories of gravity will have to change. If we see cats giving birth to dogs, our current theories of evolution will be scrapped. Unless and until we see something like this, you have to conclude that common descent by evolution by natural selection is the best explanation at our current state of knowledge and that creationism appears, to any objective observer, to be a load of junk.

Philip Bruce Heywood wrote:

2). For many species (not to mention higher taxa)in the fossil record, there is no substantial fossil evidence of ordered, sequential, gradual transition, one to another.

Name some. I can name a few, but then I understand the biases of the fossil record. In my experience, most creationists cannot even name one with a real problem.

Philip Bruce Heywood wrote:

There is not one proveable gradual transition between what can categorically be said to be different species.

There are dozens that have occurred as we were watching them. You’ve been presented with links before, but I can see you haven’t bothered to read them.

Philip Bruce Heywood wrote:

What we do have is some sort of a mystifying semblance in the fossil record of life being unfolded in sequence, and it is apparent by studying these sequences that species were employed in some deeply practical way in the revelation of those that followed.

LOL!

Oh, wondrous, Dr. Pangloss! Let me know what has been revealed to you about the “practicality” of Longisquama and how it was necessary for the “revelation” of that which followed! Can we take this to mean that Amphicyon has made the world safe for dogs and bears? Sheesh!

The only thing apparent here is that you find reality too uninteresting to contain your imaginings.

I love it! It’s just a semblance of evolution. Really. Surely “It just looks like it evolved” is the last desperate gasp of the defeated. Just think how much fun the world would be if we used this standard of evidence for everything.

Serial killer: “Sure, I’m covered in blood, holding the bloody knife over the body of a victim with my fingerprints all over yer, but frankly, officer, it just looks like I murdered her, really, God did it.”

Officer: “Er… I don’t know, the evidence really LOOKS like you did it.”

Serial Killer: “But the key words is ‘looks’. It just looks that way. It isn’t really that way at all. It’s something else.”

Officer: “But, why would God make it look like you killed her?”

Serial Killer: “Well, it’s apparent that each of those stab wounds were employed in some deeply practical way in the revelation of those that followed.”

Officer: “Oh, okay. Here, have your knife back.”

Philip Bruce Heywood wrote:

A proper title for this could be Evolution, simply meaning, a sequential unrolling or staged revelation.

Do you have a clue how nonsensical this is for a sexually reproducing species? This nonsense was debunked centuries ago.

Philip Bruce Heywood wrote:

3). Science wes never served by loud hollering about something when the information isn’t all in.

Another whine of the defeated. The information will never be “all in”. It’s a preposterous concept. Are we supposed to wait until we know everything to reach any conclusions at all? Please, archaeologists, stop making theories about ancient Rome until you’ve found ALL the buildings. Doctors, stop trying to cure diseases until we know EVERYTHING about the human body.

Science is served by each generation reaching the conclusions the evidence available to them suggests. We have. You don’t like those conclusions so all you can do is whine, “Maybe we’ll find some more evidence later that will make creationism seem not utterly defeated. We might! We might! You don’t know! Someday we’ll make evolution go away! REALLY! YOU JUST WAIT!”

Sorry, we have work to do, we can’t wait for your lot to catch up to the nineteenth century.

Philip Bruce Heywood wrote:

Now the graphs above may be accurate and meaningful. When we see them discussed and (shock! horror!) criticized by cool-minded and detatched people,

Please tell me this isn’t how you see yourself. *rolls eyes*

Philip Bruce Heywood wrote:

especially by people whose place in their academic community isn’t threatened if they don’t repeat the “correct” views,

The academic community rewards it’s mavericks. That’s why we have Darwin and Einstein on pedestals. I know this concept seems alien to your lot, but we really like our rogues, IF, and this is a big if, IF they can back up their oddball ideas with evidence.

Do you have any?

No, you’re arguing we might someday find some later. That’s not maverick, that’s just empty denial. Learn the difference.

Philip Bruce Heywood wrote:

Dogs won’t be giving birth to cats anytime soon, and your great uncle will never be any more like a chimp than will his nephew.

Dogs and cats aren’t closely related, you know that, right? But let me know where this huge difference between us and chimps is, won’t you? I mean, our brains are larger. We’re taller. Less hairy. Hmm, no huge unbridgeable gap so far.

Mod wrote:

Just an FYI, that is exactly where the word evolution comes from. Check out the etymology:
Latin ēvolūtiō, ēvolūtiōn-, from ēvolūtus, past participle of ēvolvere, to unroll
Darwin wasn’t pleased with the term for this very reason, but caved to popular usage - thought you might like to know :)

Originally, “evolution” referred to the idea that Eve (and the other female animals) were created with egg cells containing the next generation. Inside the female members of said generation were really tiny egg cells containing the members of the subsequent generation. Inside those were still tinier egg cells… So, all of humanity, past, present and future, were there in Eve’s ovaries, just waiting to be revealed “as a scroll is unrolled”.

This has some neat implications. For one thing, there’s no place for male fertilization in this scheme. Don’t worry, though. God knows who all the generations of women will sleep with and just sets up those egg cells before hand to reflect the father.

Better understanding of cell structure and embryonic development made this seem very doubtful and it was dropped, though PBH seems to be echoing it to some extent. With the idea no longer in vogue, the word “evolution” was freed to be reassociated with another idea, which is what happened despite some, like Darwin, familiar with the old usage, fighting it.

It is interesting, to me at least, to note that “creationism” is also a word no distant from its original meaning. Creationism originally referred to the doctrine that God created souls individually at conception (or the quickening) and did not prepare them before hand.

Ironically, while evolution in the original sense was only compatible with modern-sense creationism, original-sense creationism is quite compatible with modern evolution.

Alann wrote:

I wonder if you can successfully impregnate a dog with a fertilized cat embryo just to keep creationist from using the inane dog->cat analogy.

Not likely. Cats and dogs are not closely related, being separately descended from the Miacids very early in the so-called Age of Mammals. Cats are more closely related to civets, mongooses and hyena, while dogs are kin to bears, raccoons and weasels.

Comment #136818

Posted by Nurse Bettinke on October 2, 2006 3:52 PM (e)

Torbjorn:

I happen to got especially thick bones, large scull size/eye distance, and long tooth roots - all at about 1 in 1000 statistics. Nothing have broken my bones yet, not for lack of trying…

And here he is claiming we don’t talk alike enough!

When he is of the jotuns the spitting image–just like Dr. “Lucky” One-Eye that here at Trollheim San. & Ph. the pathology lab used to run!

Comment #136820

Posted by Nurse Bettinke on October 2, 2006 4:06 PM (e)

Torbjorn:

I happen to got especially thick bones, large scull size/eye distance, and long tooth roots - all at about 1 in 1000 statistics. Nothing have broken my bones yet, not for lack of trying…

And here he is claiming we don’t talk alike enough!

When he is of the jotuns the spitting image–just like Dr. “Lucky” One-Eye that here at Trollheim San. & Ph. the pathology lab used to run!

Comment #136821

Posted by Nurse Bettinke on October 2, 2006 4:07 PM (e)

For the multiple posting, I very sorry am.

How you say, here and now? That fruggin’ Degas?

Comment #136861

Posted by Torbjörn Larsson on October 2, 2006 6:52 PM (e)

“When he is of the jotuns the spitting image”

Jotuns??? Oh, norwegian giants of the asa religion. (World wide wikipedia to the rescue.) Thank you, no one have called me giant before! Nor neandertal - I’m coordinated and pretty nice on the outside despite the robust combination if I may say so myself. I happened to talk with a similar person once, and you couldn’t tell on him either. And he had also happened to weather some accidental long falls and heavy crush situations without any damage at all. Perhaps we were just in luck, and surely we looked for such happy confirmation, but…

But I do get ‘looks reliable’ a lot, seems like large eye distance easily render that as a first impression. (Hah! Little do they know! ;-)

Comment #137212

Posted by Philip Bruce Heywood on October 4, 2006 7:35 AM (e)

Well I could start quoting SCIENTIFIC AMERICAN and a few authoritative geology textbooks but I suspect it would be as wasted here as it would be with the diehards at AIG.
Tell me, would running buffalo with domestic cattle ultimately result in one herd of cross-breeds (like mongrel dogs when they cross-breed) or would two discreet populations persist? If the two “dissolve” into one, then they are the same species; if they ultimately remain distinct (say like horses when run with donkeys)then they are different species. Has this ever been tested under natural conditions over time?

If anyone wishes to actually start quoting facts, I’ll accommodate you; I have wasted time with people such as AIG.

Comment #137216

Posted by Michael Suttkus, II on October 4, 2006 8:26 AM (e)

Philip Bruce Heywood wrote:

Tell me, would running buffalo with domestic cattle ultimately result in one herd of cross-breeds (like mongrel dogs when they cross-breed) or would two discreet populations persist?

You know, five minutes on wikipedia before you post would help you immensely.

And your attempt to draw distinctions between persistant populations and occasionaly breeding successes is artificial. The whole point is that the degree of barrier between populations is variable, that’s how insipient speciation happens. You’re attempt to categorize this development amounts to a circular argument.

Comment #137332

Posted by 'Rev Dr' Lenny Flank on October 4, 2006 6:35 PM (e)

Hey Heywood, you’re still, um, ya know, blithering.

Comment #137343

Posted by Steviepinhead on October 4, 2006 7:24 PM (e)

Torbjorn:

Jotuns??? Oh, norwegian giants of the asa religion. (World wide wikipedia to the rescue.) Thank you, no one have called me giant before!

I gather from this response that Torbjorn may not be the super value-sized model, however ruggedly he may otherwise be constructed.

IIRC, however–and I’m sure Nurse Bettinke, were she not so distracted by her multiply-escaped trolls, will be the first to correct me–but in the Marvel Comics version of Aasgaard, at least (hey, one plucks one’s authorities where one may…), Loki was reputedly a jotun–or half-jotun, or something–but was still depicted as “normal” Norse-godling size.

So, on the authority of the unimpeachable Lee & Kirby, it would certainly be possible for Torbjorn to exemplify jotun, um, over-engineering, without necessarily exemplifying jotun, um, stature.

In any event, it’s abundantly clear–whatever weight one wishes to assign to Nurse Bettinke’s professional opinion– that Torbjorn has no wisp of troll about him whatsoever.

Comment #145564

Posted by Maciej Henneberg on November 20, 2006 9:41 PM (e)

Thanks for appreciation of our work. I stand by all we have published. I can send you difficult to get papers (PDF) by e-mail. What is your adress?

Comment #145582

Posted by Nick (Matzke) on November 20, 2006 10:50 PM (e)

Posted by Maciej Henneberg on November 20, 2006 9:41 PM (e)

Thanks for appreciation of our work. I stand by all we have published. I can send you difficult to get papers (PDF) by e-mail. What is your adress?

Wow. PT has been honored by the visit of Dr. Henneberg!

(make sure you look at the subsequent posts if you get a chance:
http://www.pandasthumb.org/archives/2006/09/fun_with_homini_1.html
http://www.pandasthumb.org/archives/2006/10/fun_with_homini_2.html )

My email is: matzke[at]ncseweb.org. Someone actually got the 1999 Perspectives in Human Biology paper and sent me a scan; however, what I was sent did not include a data table listing estimated body masses – so if you are willing to give that out, I would be very appreciative.

It may also be that you have some tips about measurements published since 1999 – I know some new crania have been discovered.

Comment #145630

Posted by Maciej Henneberg on November 21, 2006 5:50 AM (e)

I agree with Nick’s general line of argument. I will send him, and anyone who writes to me at “maciej.henneberg@adelaide.edu.au” PDF s of my papers , including those difficult to find on internet.

I have been fighting (with scientific arguments, like those in my published papers cited above) the proliferation of “species” by colleagues studying hominid fossils. Erection of multiple hominid species perpetuates the creationist approach: Abel beget Ezekiel who beget Isaac …. (as my friend and colleague Bob Eckhard says). The process of evolution, including human evolution, is basically occuring in a chain of generations, parents producing offspring, this offspring becoming parents and producing new offspring etc. This way is the only way for life to continue (forget IVF). From generation to generation reproduction of parental characters is not perfect and thus offspring differs somewhat from parents. And so on…..

In human evolution it was not, for instance Australopithecus africanus that appeared suddenly from nowhere beside Australopithecus anamensis who also appeared from nowhere. Individuals of each of those kinds had parents and offspring. Human fossil record is full of specimens assigned by various authors to different taxa. The reson is that many specimens display a mixture of characters - they are transitional. Actually all individuals are transitional as they are but links in the long chain of generations from ancestors to descendants. Platonic idealism in observation of the dense fossil record “creates” species by averaging sets of characters seemingly common for groups of specimens. No specimen is a perfect example of a particular species. No species can exist outside of individuals that were assigned to it.