Evolution news: punctuated speciation and the fittest wins only sometimes

We all (except a handful of fanatics) agree that evolution happens. What is not fully clear are the details of how it happens. These days two new researches challenge some conceptualizations and support others instead.

Evolution is not constant but punctual.

That is what Stephen A. Smith (left) and colleagues have discovered when analyzing the phylogeny of angiosperms (flowering plants). They found that the conceptualization of evolution as punctuated rather than constant seems to be correct, and also that the characteristics of a new taxon evolve in a single population or root species before diversification (radiation) occurs.

The research has been published in the American Journal of Botany (open access) and a synthesis appears at Science Daily.

Perfectly fit? Maybe not needed.

A simplistic school promotes the idea that given enough evolutionary time in a simple ecological niche only one competitor will survive: the fittest one.

However this does not seem to be the case. Research by Robert E. Beardmore and colleagues, published in Nature (ppv), vindicates previous research in which optimal efficiency coexists with suboptimal one:

The fit use food well but they aren't resilient to mutations, whereas the less efficient, unfit consumers are maintained by their resilience to mutation. If there's a low mutation rate, survival of the fittest rules, but if not, lots of diversity can be maintained.

Full story at Science Daily.

Texan evidence of pre-Clovis North-Americans

Clovis (L) and Buttermilk (R) toolkits

Several news sites have announced today what is arguably the first consolidate archaeological evidence of human population of North America before the emblematic Clovis culture: the Buttermilk Creek culture of Texas, dated to c. 15,500 to 13,200 years ago.

This site adds to others more or less accepted ones from North and South America, clearly establishing that the colonization of the double continent happened at least several millennia before the emblematic Clovis culture, which is dated around 13,500 and 13,000 years ago.

Source: Science News.

Archaeonews from South Asia

The latest Archaeonews bulletin is full of interesting information on South Asian prehistory, from Nepal to Kerala:

Nepal mountain burials

27 people buried in caves at c. 4000 meters above sea level have been found in the Himalayan country and dated between 3000 and 1500 years ago. 

67% of the bodies were defleshed, a mysterious burial practice, which may relate to a contemporary Tibetan one (sky burial) or, alternatively,  Zoroastrian rituals (who in the past defleshed the bodies and fed the meat to animals - nowadays they feed the whole bodies to vultures in special grounds). 

Full stories at República and National Geographic.

Kerala Megalithic dome

A new Megalithic tomb has been found at Kodiyeri with a curious pillar (left), a similar dome is recalled to have been found 40 years ago (but nobody seems to know its destiny anymore).

Full story at The Hindu.

Kerala claims oldest non-African Paleolithic site

With and age of 1.83 million years at the deepest layer, Bukit Bunuh may be one of the first homes of our cousins Homo erectus (or H. georgicus or...), when they migrated to Asia.  The site was apparently chosen for its excellent ecology that would have provided our cousins with all they needed for a living: fresh water, hunt, plants and stone to make handaxes. 

The site also shows more recent inhabitation dates of 40,000 and 30,000 years ago which surely belong to modern humans.

Protection from UNESCO as World Heritage Site has been requested. 

Full story at University Sains Malaysia and Asia Research News.

Note (Mar 31):

I wrote earlier in regards to this Indian site: Also, maybe more in detail, at Ancient Indian Ocean Corridors (by archaeologist Michael Petraglia, who includes a link to a relevant paper in press).

But this one is actually another site, in nearby Tamil Nadu, with a confirmed age of 1.6-1.4 million years on a more careful (and hence credible) measure. David Sánchez has an excellent review of this finding and its implication in Spanish language today.

Violence among early Scotland farmers

Early farmers of Scotland died violently... but then they were buried in a monument, the Tomb of the Eagles (left), at Isbister.

Out of 85 burials in this tomb, 16 have clear evidence of head trauma caused by weapons. Some of these injuries were healed but others not, meaning that they were killed by them (or related violence).

The tomb's age is of c. 3000 BCE, a few centuries after farming began in the area.

Full story at Daily Mail.

Also in Scotland it has been announced the discovery of rock art that could be Neolithic near a recently discovered chambered tomb (dolmen) at South Ronaldsay, Orkney, reports Orknejar.

Original source: Stone Pages Archaeonews bulletin.

Provenzal genetic data... and weird speculations

The following paper offers some information on the genetics of Provenzals and some specific populations of Turkey (Foça, Izmir) which is compared with older studies (on Turkey and Greece) to reach quite unfathomable conclusions:

Roy J. King et al., The coming of the Greeks to Provence and Corsica: Y-chromosome models of archaic Greek colonization of the western Mediterranean. BMC Evolutionary Biology, 2011. Open access.

I'm split on this paper: on one side it does provide some interesting data and makes some common sense claims (like Provence having been little affected by Neolithic expansion direct colonization) but then you stumble upon absurd ideas, such as Cardium Pottery stemming somehow from "Anatolia":

Using putative Neolithic Anatolian lineages: J2a-dys445=6, G2a-M406 and J2a1b1-M92 the data predict a 0% Neolithic contribution to Provence from Anatolia.

There is absolutely no reason to be looking at Anatolia: the Neolithic wave that arrived to Provence did not originate in Anatolia but in the Western Balcans. It is very possible that Anatolia was the ultimate origin of Greek Neolithic and this was in turn at the origin of Cardium Pottery Neolithic somehow, but the real origin of the Neolithic wave that arrived to Provence must not be looked for in any case in Western Anatolia - that is a total nonsense.

We know way too little as of yet to explain the exact process of cultural transference from West Asia (Anatolia specially) to the Balcans (Thessaly in particular) and from Thessaly to the Adriatic, where the cultural elements are so distinct anyhow. There is no particular reason to expect any arrival directly from Anatolia into Italy or SW Europe in the Neolithic. Any such migration would have been dampened in two filters: one in Greece and another one in the Adriatic Balcans.

From my ongoing (and slow) work of summarizing  European Neolithic in maps:

Here you can see in brown the first area of Cardium Pottery Neolithic: Dalmatia, Montenegro, Coastal Albania, most of Bosnia, Italy (in a second moment)... It has a precedent in Otzaki (Thessaly) and a derived influence in Biblos (Lebanon) but by no means can it be linked to "West Anatolia" of all possible places.

Universities and grants should require that any geneticist doing historical population genetics hire a prehistorian for assessment, sincerely.

Still there is a very interesting amount of data that is of interest, summarized (as I said before) in figure 2 specially. This is an extensive table that I cannot reproduce here with enough resolution without some previous work. So for reason of its relevance and novelty I'll focus on the Y-DNA data of Provence (n=51, only attested lineages shown):

• E1b1b1b1a2 (V13): 4%
• E1b1b1b1c (M123): 2%
• G(xG2a3a) (M201): 8%
• I1 (M253): 2%
• I2(xI2a2,I2b) (M438): 4%
• J1 (M497): 2%
• J2a4h1a (DYS445=6): 8%
• J2a4b(J2a4b1) (M67): 2%
• R1a1a (M198): 10%
• R1b1b2 (M269): 59%

Up 26 to 30% (depending on how you evaluate I2*) of the genetic pool is "Eastern Mediterranean" in Provence. E1b1b1b1a2 (V13) is probably from Albania or other Adriatic areas (see Battaglia 2009). That can also be argued to be the case for all the other "transmediterranean" lineages, which agrees well with a Neolithic origin of all them. However it is not impossible that these Neolithic arrived in batches and with intermediate stops in Italy for example or, why not, in Phocaea in some cases. 

But the research falls very short from demonstrating what they claim to demonstrate. If they have demonstrated something at all they have failed to explain it properly. So the only interest of this paper is the raw data, which adds to other such data to be integrated into a careful and comprehensive exploration of all (and not just some) data with proper prehistoric assessment. 

It is in any case important to understand that under the Neolithic colonization hypothesis, E1b1b1a2 should not be expected to originate neither in Anatolia nor in Greece but in Albania, Montenegro and Dalmatia. And, if anything, in Greece rather than Anatolia. Attributing European Neolithic directly to Anatolia or West Asia in general is not an acceptable assumption but a wacko fetish that should be discarded altogether.

Early farming was inefficient compared to foraging

Early farming was only able to generate some 60% of what foraging (hunting and gathering) did, according to new research:

Samuel Bowles, Cultivation of cereals by the first farmers was not more productive than foraging. PNAS, 2011. Pay per view (depending on world region and time).

Abstract

Did foragers become farmers because cultivation of crops was simply a better way to make a living? If so, what is arguably the greatest ever revolution in human livelihoods is readily explained. To answer the question, I estimate the caloric returns per hour of labor devoted to foraging wild species and cultivating the cereals exploited by the first farmers, using data on foragers and land-abundant hand-tool farmers in the ethnographic and historical record, as well as archaeological evidence. A convincing answer must account not only for the work of foraging and cultivation but also for storage, processing, and other indirect labor, and for the costs associated with the delayed nature of agricultural production and the greater exposure to risk of those whose livelihoods depended on a few cultivars rather than a larger number of wild species. Notwithstanding the considerable uncertainty to which these estimates inevitably are subject, the evidence is inconsistent with the hypothesis that the productivity of the first farmers exceeded that of early Holocene foragers. Social and demographic aspects of farming, rather than its productivity, may have been essential to its emergence and spread. Prominent among these aspects may have been the contribution of farming to population growth and to military prowess, both promoting the spread of farming as a livelihood.

A news article is also available at PhysOrg.

Is the alternative explanation correct?

I find this discovery most interesting because the assumption has generally been that automatically farming was more productive than the old human way of life: foraging what Nature had to offer. 

Yet this assumption did not explain why farming had not evolved earlier or why the, generally very pragmatic, peoples of the World, did not adopt it earlier, as they were no doubt aware of how gardening could be done.

It reminds me somewhat of the very much comparable misunderstanding on the transition from the Bronze to the Iron Age: iron had by then been known for very long but it was brittle in comparison with bronze, quasi-bronze (copper and arsenicum) and even the old good flint stone. Actually I read somewhere recently that another good old friend of humankind, obsidian, makes such great blades that compete favorably with steel scalpels.

Things are not so simple: steel began to be developed (as sweet iron is not really good for most uses) after tin resources began to fail in the Eastern Mediterranean, as the communications with Atlantic Europe (where most tin mines were back then) may have collapsed when the two classical Iberian civilizations, El Argar and Zambujal (VNSP), did as well for reasons not well understood and not too relevant to discuss here. 

It was therefore problems in the bronze industry, so critical for the military of the time, what pushed steel technology ahead, inaugurating the Iron Age.

Seed milling was done long before Neolithic too

Therefore I'd like to consider what may have caused people to adopt farming instead of just continue foraging, as they had done successfully until that time. We know that farming was preceded by a period we call Mesolithic and that is characterized by intensive foraging of wild cereals or other foraging behaviors that somehow announce the advent of farming or herding. 

So, in the Fertile Crescent, there was for a time, since about the end of the Ice Age, a focus on a pre-farming type of foraging. As I have not read the paper yet, I do not know if Bowles has factored this period in his equations. As for me, I'd think that this kind of foraging (maybe already associated to some early gardening practices) we call Mesolithic, seems to respond to an ecological pressure of some sort, no doubt related to the then ongoing climate change. 

Another issue I am pondering is that, even before cereal farming was fully developed in Palestine, herding of sheep and goat was adopted in Kurdistan, followed by cow herding in Anatolia (near the well-named Taurus mountains). Maybe herding had to be developed in order to make farming effective? Cattle (be it bovine or ovi-caprine) provides nutrients in form of manure and, goats specially but not only, can also be used to clear up wild vegetation areas, while pigs are great to plow the fields.

So I am wondering if animal domestication was a condition to make cereal (and pulse and flax) farming an economically effective way of life. 

Honestly I prefer a true economic explanation rather than one based on very conjectural preferences about sedentarism, and this may be made up of:

• The push factor of climate change at the end of the Ice Age
• The pull factor of animal domestication, increasing the yields of agriculture until it became economically worthwile

What do you think?

Y-DNA of Khazaks from Altay Republic

Not very clear which is the motivation behind or the peculiar interest of this paper but it should add to the data resources anyhow:

Matthew C. Dullik et al., Y-Chromosome Variation in Altaian Kazakhs Reveals a Common Paternal Gene Pool for Kazakhs and the Influence of Mongolian Expansions. PLoS ONE 2011. Open access.

The data adds to and is compared with previous research (several papers) on Kazakhs from Eastern Kazakhstan. Central and Western Kazakhstan remain pretty much unexplored.

There are some difference in the respective Y-DNA pools but they seem to originate in differential founder effects and not specially in admixture with Altays. Notably:

• Altay Kazakhs are higher in C(xC3c) (24%) and lower in C3c (39%) than other Kazakhs.
• They are also higher in O3 (26%)
• They are also higher in G and J (9%) altogether

SW Altayan Kazakhs may be admixed patrilinearly with native Altayans, while SE Altayan Kazakhs do not show such affinity. This difference may be caused by sampling in a Christian Khazak community living side by side with Altayans and Russians.

Fig. 4 PCA (Y-DNA) of Central Asian and Mongol populations

It is interesting that while the genesis of the Kazakh nation lays historically in separation from Uzbeks, these two Turkic nations do not share almost any lineage.

The poor sampling of Kazahstan and even Kazakhs in China is admitted by the authors as a problem to properly understanding Kazakh genesis. As mentioned before most samples come from Eastern and SE Kazakhstan however most of the country remains unsampled.

Fig. 1  Kazakh populations sampled (5: this paper, * sample localities)

Population density in Central Asia (for reference)