Readings: Earth's Ice, Neanderthal Women, Indian Monsoons

Some good stuff from the past few weeks.

1) How much of the Earth's Ice is Melting? Sid Perkins writes about the variety of methods of estimating ice loss from the high latitudes. These methods are showing where and how much melting is taking place, in turn, helping scientists make predictions of future sea level rise. The overall scenario is rather gloomy. 

2) The Lives of Neanderthal Women. "Archaeology is no exception to biases against women’s interests across science and the humanities". Archaeologist Rebecca Wragg Skykes expertly constructs a picture of what the lives of Neanderthal women might have been like.

3) Indian Monsoon Across Millennia. Stalagmites from a cave in Meghalaya, NE India are giving paleoclimatologists information about monsoon variability over a thousand years. Their geochemistry points to periodic deadly droughts that coincide with phases of major social and political turmoil in India. Paper authors Gayatri Kathayat and Ashish Sinha describe their research. 

 

Readings: Deep Time Mexico, Neanderthals, Early Mammals

Relish these articles.

1) Mexico City Deep Time Sickness.  Modern day Mexico City is built on the bed of lakes that formed around 2 million years ago. The Mexica people in the 14th century constructed a series of dams and dykes partitioning salt water and fresh water areas. They developed agriculture called as 'chinampas' on islands made up of mud and organic debris. This region became the city state of Tenochtitlan. Later in the 16th century this vast lake was drained by Spanish Conquistadors. Over time, extraction of groundwater is causing compaction of the soft sediment. The ground is subsiding unevenly across different parts of the city. Ground shaking by frequent earthquakes is making the problem worse. As cracks grow and widen, buildings tilt, and the ground shakes, the citizens have become acutely sensitive or "tocado" to geology altering their everyday lives.

"Deep time is often framed as something antithetical to immediacy, something totally separate not only from everyday experience, but also the idea of history itself. But if we are living in a moment in which experiential time, historical time and deep time are colliding, which of these times are being written onto the walls of Mexico City apartments?" 

A beautiful and unnerving article by Lachlan Summers.

2) Did Neanderthals Speak? Archaeologist Anna Goldfield summarizes our current state of understanding of the throat anatomy of Neanderthals and how they might have sounded. There is a nice audio clip too! 

3) Warm Blooded Mammals. When did warm bloodedness or endothermy evolve in mammals? Katherine Irvine writes about a new study of ear canal bone structures indicative of endothermy. An analysis of fossils suggest that warm bloodedness, along with a host of traits typically associated with mammals, arose by around 233 million years ago. 

Articles: Herculaneum, Magma Ascent, Early Human Migration, Indian Cheetah

Some interesting articles on a variety of topics that I came across in the past few weeks.

1) What Really Happened at Herculaneum?

This off course refers to the violent eruption of Mount Vesuvias in 79 A.D.  A new study analyses the way bone and soft tissue react to extreme heat and proposes that the people found dead at Herculaneum did not vaporize but died of asphyxiation.

2)  The long wait and rapid rise of deep magma.

Magma can reside in deep chambers at the boundary between the crust and mantle for thousands of years before rising to the surface rapidly in a matter of a few days.

3) Neanderthal Genes Hint at Much Earlier Human Migration From Africa.

It was thought that 60,000 years ago modern humans migrated out of Africa and interbred with Neanderthals beginning around 40,000 years ago. As a result all non-Africans carry some Neanderthal DNA. A new DNA analysis technique now suggests that an earlier wave of humans migrated out of Africa some 200,000 years ago and interbred with Neanderthals. Their descendants back migrated to Africa carrying with them the legacy of this earlier mating. As a result, Africans too carry a genetic legacy of Neanderthals.

4) Introduce the cheetah, with caution and guidelines.

There is a proposal to introduce the African cheetah into the Indian landscape. Neha Sinha argues that a grasslands policy needs to be put in place first.
 

Dating Rock Art

I love it when science is explained with a well thought out and cleanly drawn illustration.

A commentary in Nature News and Views by David G. Pearce and Adelphine Bonneau presents this diagram on dating rock art.

Two recent studies on dating cave paintings from Spain are discussed.

Who were the artists?

The oldest minimum age for the paintings is 66 ka (thousand  years) leading to speculation that they might have been drawn by Neanderthals. The earliest presence of modern humans in Spain is from  40 ka. This would imply independent evolution of symbolic behavior in Neanderthals.  However, the same painting throws up a range of minimum dates from ~ 60 ka to ~ 3 ka making an exclusive link  to Neanderthals problematic.

Volcanism And The Demise Of Neanderthals

In addition to the many proposed reasons, something more to think about:

From Geology (early edition)-

Campanian Ignimbrite volcanism, climate, and the final decline of the Neanderthals - Benjamin A. Black, Ryan R. Neely, and Michael Manga

The eruption of the Campanian Ignimbrite at ca. 40 ka coincided with the final decline of Neanderthals in Europe. Environmental stress associated with the eruption of the Campanian Ignimbrite has been invoked as a potential driver for this extinction as well as broader upheaval in Paleolithic societies. To test the climatic importance of the Campanian eruption, we used a three-dimensional sectional aerosol model to simulate the global aerosol cloud after release of 50 Tg and 200 Tg SO2. We coupled aerosol properties to a comprehensive earth system model under last glacial conditions. We find that peak cooling and acid deposition lasted one to two years and that the most intense cooling sidestepped hominin population centers in Western Europe. We conclude that the environmental effects of the Campanian Ignimbrite eruption alone were insufficient to explain the ultimate demise of Neanderthals in Europe. Nonetheless, significant volcanic cooling during the years immediately following the eruption could have impacted the viability of already precarious populations and influenced many aspects of daily life for Neanderthals and anatomically modern humans.

Widely varying climatic conditions and resource availability may have hit Neanderthals more than "modern" humans. A number of reasons are given including the ability of "modern" humans to set up long distance networks facilitating exchange of technology and ideas.... Off course some would argue that the Neanderthals  never really became extinct. Their genetic legacy lives on in us. There is no doubt that interbreeding between the two human populations means that Neanderthal genes are with us today, but certainly a way of life, a particular morphology, social mores and perhaps a unique language (s) did disappear.

Creationist Version Of Neanderthal Human Interbreeding

via The Panda's Thumb..

Had to put this up. Apparently creationists have their own take on the recent findings that Neanderthals interbreed with modern humans.

Svante Paabo who has led the effort to sequence the Neanderthal genome and has a popular book about it writes:

There were many others who were interested in the Neanderthal genome – perhaps most surprisingly, some fundamentalist Christians in the United States. A few months after our paper appeared, I met Nicholas J. Matzke, a doctoral candidate at the Center for Theoretical Evolutionary Genomics at UC Berkeley. Unbeknownst to me and the other authors, our paper had apparently caused quite a flurry of discussion in the creationist community. Nick explained to me that creationists come in two varieties. First, there are “young-earth creationists,” who believe that the earth, the heavens, and all life were created by direct acts of God sometime between 5,700 and 10,000 years ago. They tend to consider Neanderthals as “fully human,” sometimes saying they were another, now extinct “race” that was scattered after the fall of the Tower of Babel. As a consequence, young-earth creationists had no problem with our finding that Neanderthals and modern humans had mixed. Then there are “old-earth creationists,” who accept that the earth is old but reject evolution by natural, nondivine means. One major old-earth ministry is “Reasons to Believe,” headed by a Hugh Ross. He believes that modern humans were specially created around 50,000 years ago and that Neanderthals weren’t humans, but animals. Ross and other old-earth creationists didn’t like the finding that Neanderthals and modern humans had mixed. Nick sent me a transcript from a radio show in which he [meaning Hugh Ross] commented on our work, saying interbreeding was predictable “because the story of Genesis is early humanity getting into exceptionally wicked behavior practices,” and that God may have had to “forcibly scatter humanity over the face of the Earth” to stop this kind of interbreeding, which he compared to “animal bestiality.”

Clearly our paper was reaching a broader audience than we had ever imagined.

Aha.. so that's why humans colonized the entire planet. It was punishment for engaging in bestiality.

There is also a transcript of a bizarre conversation between creationists trying to answer the deep question that while there are references in scripture of God destroying angel-human hybrids, Neanderthal -human hybrids eventually died out too, leaving humans to be with humans only.

Psycho-Shrinking The Neanderthals

On Quirks & Quarks host Bob McDonald and psychologist Prof. Frederick Coolidge have an entertaining discussion on Neanderthal behavior.

Apparently, the fossil record suggests that the Neanderthals recovered from injuries sustained above the waist. Injuries to the foot though were generally fatal. Prof.  Frederick Coolidge suggested that while Neanderthals took care of their injured, a foot injury meant that that individual couldn't take part in a hunt and move around with the band and may have been left behind to die.

I don't get this. If empathy was extended to individuals who were injured above the waist and presumably couldn't be useful in a hunt in that state and possibly had to be helped move from place to place, why would that empathy stop below the waist?

Here is one for keeps. Frederick Coolidge agrees with Bob McDonald that the Neanderthals would have had a sense of humor, but a slapstick kind of a humor. More like the Three Stooges. They would be lost on puns and word play.

I wonder if Prof. John Hawks considers this damaging enough to be placed in his Neanderthal anti-defamation files!