Excellent one at A Primate of Modern Aspect:

Okay, so we’ve got lots of increases in brain size, and a few decreases. In the cases where we have decreases, we usually have body size decreases as well. More often than not, we have body size decreases which result in a disproportionately large brain size, but occasionally we have a body size increase which results in a disproportionately small brain size. And all of that brings us to the Hobbit.
The authors looked at Homo floresiensis in relation to the Dmanisi hominids, Homo habilis, and a Homo erectus from Ngangdong and found that if we use Dmanisi or habilis as an ancestor, the decrease in brain size and body size isn’t exceptionally weird when compared to other primate groups. The mouse lemur decreased in both to a greater degree, for example.
But if you use the Ngangdong erectus as the ancestor, it is a really weird decrease.
So, I guess the question is, is it reasonable to use Dmanisi or Homo habilis as the ancestor and not Homo erectus? And of course, we don’t know that yet!

What is the single best reference for refuting the notion that “race is only a social construct” for a non-scientist? I don’t know. (Suggestions welcome in the comments.) But Neven Sesardic (previously praised here) does a marvelous job in “Race: A Social Destruction of a Biological Concept,” (pdf) Biology and Philosophy (2010, forthcoming).

It is nowadays a dominant opinion in a number of disciplines (anthropology, genetics, psychology, philosophy of science) that the taxonomy of human races does not make much biological sense. My aim is to challenge the arguments that are usually thought to invalidate the biological concept of race. I will try to show that the way ‘‘race’’ was defined by biologists several decades ago (by Dobzhansky and others) is in no way discredited by conceptual criticisms that are now fashionable and widely regarded as cogent. These criticisms often arbitrarily burden the biological category of race with some implausible connotations, which then opens the path for a quick eliminative move. However, when properly understood, the biological notion of race proves remarkably resistant to these deconstructive attempts. Moreover, by analyzing statements of some leading contemporary scholars who support social constructivism about race, I hope to demonstrate that their eliminativist views are actually in conflict with what the best contemporary science tells us about human genetic variation.

Nothing new for the GNXP faithful, but the presentation is clear and compelling throughout. He opens with “Those who subscribe to the opinion that there are no human races are obviously ignorant of modern biology.” — Ernst Mayr, 2002. Great quote!

I’ve got a few installed now. Has anyone had any issues with performance yet? I recall back when I used Firefox that was the main downside of having extensions.
If you don’t know what I’m talking about, see TechCrunch. Or just update your browser and Google will start telling you all about it, in Settings -> About Google Chrome.

Mike the Mad Biologist points me to an interesting article in Wired, Uranium Is So Last Century — Enter Thorium, the New Green Nuke. Of course Wired is a booster of many things which never take off, but in general I think it’s probably safe to bet on nuclear power becoming more prominent in the near-to-medium-future. I recently have been reading a bit about oil, stuff that’s not written by Daniel Yergen, and was fascinated by this chart of long term crude prices:

The inflation adjusted values are of interest. But look at the lack of volatility before 1974! My whole life has been characterized by volatility of crude oil prices, so I simply assumed that that was the nature of the beast….

A supplement to the previous two posts. Below are maps which are shaded proportionally. Note how New York seems to be the abortion capital of the USA. Total surprise to me. Remember that these data are for white females from the ages of 15-19.

A reader pointed to this post in Free Exchange:

Here are the 15 states with the biggest percentage drop from 1988-2005 in the ratio of teen abortions—the percentage of teen pregnancies that ended in abortion, not counting miscarriages. Crudely put, these are the states where pregnant white teens stopped having abortions between 1988-2005.

1. Kentucky
2. Nebraska
3. Arkansas
4. Oklahoma
5. South Dakota
6. Tennessee
7. Kansas
8. Iowa
9. Texas
10. North Dakota
11. Alabama
12. Indiana
13. Missouri
14. North Carolina
15. Utah

I have 2008 exit poll data handy by state, as well as the 2005 birth and abortion data. Abortion ratio = (Abortion rate)/(Abortion rate + Birthrate); basically pregnancy rate minus miscarriages. “Teen” here defines females in the age range 15-19. As you’d expect:

1) Whites voting Democrat is correlated with lower white birthrates
2) Whites voting Democrat is correlated with higher white abortion rates
3) Whites voting Democrat is correlated with higher white abortion ratios

#3 is stronger than #2, and I believe that’s because teen pregnancy rates are lower in areas where whites are strongly Democrat, so the abortion rates are also going to be lower. The abortion ratio is somewhat normalized to pregnancy rate.

NASA to Review Human Spaceflight:

The National Aeronautics and Space Administration is preparing for a major evaluation of its human spaceflight program, even as many who will conduct the survey have yet to be informed of the agency’s revised mission.
…
The administration might also enlist the help and financing of other nations to handle parts of space exploration — perhaps giving the European Space Agency the job of building a lunar lander, for example.

Perhaps China vs. the world? Fodder for near-future science fiction.

The New York Times has a new article, After Long Decline, Teenage Pregnancy Rate Rises. The graphic is OK, but it focuses on aggregate teen pregnancy rates (age group 15-19) instead of splitting it out so as to show births and abortions. The original report is chock full of tables, but not the charts I was looking for. So I decided to go ahead and create them. All the “teen” data is for the 15-19 age range. The trends are a bit difference from that in the chart because I split up births and abortions, and also added in “abortion ratio,” which simply illustrates the proportion of pregnancies which result in abortions excluding miscarriage and stillbirths. The other rates are per 1,000 of females of the given age range. First, the overall trends by time, broken out by race & ethnicity. White = Non-Hispanic white in all that follows.

Since Latinos have high birthrates, so surprise that their abortion rate is higher than whites. On the other hand, the relatively low abortion ratio vis-a-vis white teens points to some cultural expectations among this group which we’d expect from Roman Catholics (though more generally Catholics don’t differ much from Protestants in the United States in regards to abortion, so I think that this is less causal than correlated).

There is also state level data, though it is spotty in regards to abortions. I decided to see if the different groups tracked each other in regards to rates. Here’s what I found:

And the scatterplots, as well as some dot plots which show the ratio of the rates of two minority groups, as a function of geography.

Looking closely at the data it seems that that local state law/and/or/culture matters a lot for teen abortion ratios. Vermont for example has a very high abortion ratio. Might look at it later….

Note: I excluded DC from the state level analysis because it’s a bizarre outlier. White teen birthrates of 1 per 1,000, black & Hispanic above 100.

Is the Hobbit’s Brain Unfeasibly Small?:

Brain expansion began early in primate evolution and has occurred in all major groups, suggesting a strong selective advantage to increased brainpower in most primate lineages. Despite this overall trend, however, Mundy and his colleagues have identified several branches/lineages within each major group that have shown decreasing brain and body mass as they evolve, for example in marmosets and mouse lemurs.
According to Mundy, “We find that, under reasonable assumptions, the reduction in brain size during the evolution of Homo floresiensis is not unusual in comparison to these other primates. Along with other recent studies on the effects of ‘island dwarfism’ in other mammals, these results support the hypothesis that the small brain of Homo floresiensis was adapted to local ecological conditions on Flores.”

The paper will show up in BMC Biology at some point. The main question I have is in regards to the purported tool use of the Hobbits. I can believe that a local adaptation toward small brains, Idiocracy-writ large, occurred. Brains are metabolically expensive, and it isn’t as if the history of life on earth has shown the massive long-term benefits of being highly encephalized (though I think one can make a case that there has been a modest trend, with primates, and especially H. sapiens as extreme outliers above the trend). But could small brained creatures maintain the relatively advanced toolkit which the Hobbit finds have been associated with? Seems to me that there’s a high probability here of some sort of contamination, but I’ll be happy to be put in my place by anthropologists in-the-know….

The debates about the timing of the extinction of the last Neandertals in Iberia seem to one of those interminable disagreements around which paleoanthropologists can’t ever reach a resolution. Another offering from PLoS ONE, Pego do Diabo (Loures, Portugal): Dating the Emergence of Anatomical Modernity in Westernmost Eurasia:

Methodology/Principal Findings
Using AMS radiocarbon and advanced pretreatment techniques, we dated a set of stratigraphically associated faunal samples from an Aurignacian III-IV context excavated at the Portuguese cave site of Pego do Diabo. Our results establish a secure terminus ante quem of ca.34,500 calendar years ago for the assimilation/replacement process in westernmost Eurasia. Combined with the chronology of the regional Late Mousterian and with less precise dating evidence for the Aurignacian II, they place the denouement of that process in the 37th millennium before present.
Conclusions/Significance
These findings have implications for the understanding of the emergence of anatomical modernity in the Old World as a whole, support explanations of the archaic features of the Lagar Velho child’s anatomy that invoke evolutionarily significant Neandertal/modern admixture at the time of contact, and counter suggestions that Neandertals could have survived in southwest Iberia until as late as the Last Glacial Maximum.

The paper is pretty long, and probably as opaque to most readers who are as unfamiliar as I with the nuts & bolts of physical anthropology, so ScienceDaily is worth reading:

These findings have important implications for the understanding of the archaic features found in the anatomy of a 30,000 year old child unearthed at Lagar Velho, Portugal. With the last of the Iberian Neanderthals dating to many millennia before the child was born, ‘freak’ crossbreeding between immediate ancestors drawn from distinct ‘modern’ and ‘Neanderthal’ gene pools cannot be a viable explanation. The skeleton’s archaic features must therefore represent evolutionarily significant admixture at the time of contact, as suggested by the team who excavated and studied the fossil.

Those of you in the “know” could probably guess the relevance, as the Lagar Velho 1 skeleton has an entry in TalkOrigins.
Citation: Zilhão J, Davis SJM, Duarte C, Soares AMM, Steier P, et al. (2010) Pego do Diabo (Loures, Portugal): Dating the Emergence of Anatomical Modernity in Westernmost Eurasia. PLoS ONE 5(1): e8880. doi:10.1371/journal.pone.0008880