Monday, May 28, 2012

Horseshoe Crabs And Other Stories By Richard Fortey

OnPoint Radio had palaeontologist Richard Fortey for a talk on his new book Horseshoe Crabs and Velvet Worms: The Story of the Animals and Plants That Time Has Left Behind .

The lead in talks about how in the history of life species have come and gone except for some remarkable survivors who persist today almost unchanged in appearance since when they first originated hundreds of millions of years ago. These kind of creatures whose morphology resembles that of their ancestors are called "living fossils" and Richard Fortey gives quite a few examples in this entertaining talk. He is a good speaker. He qualifies the term unchanged through time by clarifying that these creatures have evolved, maybe not in morphology, but certainly at a molecular level. The talk has a lot of information about the habitats, life history and idiosyncrasies of life style and biochemistry of many of these organisms.

One important point is never made in the talk. What are you referring to when you use the term "survivor"? The talk compares for example the coming and going of different species like the mastodon and musk ox with the persistence of say horseshoe crabs suggesting that survivors means individual species.

The term survivor though refers not to individual species but a lineage.

Think about your own family. Say you have well kept records that traces your genealogy to 700 years ago. You could say that my family is a survivor from before the days of the black plague. But it would be absurd to suggest that you have in your family someone living today who was born in the 1300's. Every individual in your family lived within the normal range of humans lifespans. Your family lineage though represents an unbroken chain of descendants of which you are a living relative today.

Species too have lifespans just like individuals. They originate at a point in geologic time and then go extinct at some later date. The lifespan may be a few million years or so with a lot of variation amongst different types of creatures. Mammal species seem to have a lifespan of a million or two million years. Marine invertebrates may have a life span up to 10-11 million years. Horseshoe crabs are marine invertebrates and a type of arthropod. This group of arthropods originated in the Late Ordovician, about 450 million years ago. That first species i.e. the founder of the group of horseshoe crabs gave rise to descendant species and those descendant species gave rise to more recent species and so on in an unbroken chain of species until today.  As a group the horseshoe crab has survived until today but earlier species within that group are now extinct. The living representatives (species) of the persisting lineage of horseshoe crabs may have evolved just a few million years ago.

So today's horseshoe crabs are not really creatures that time left behind. They are a lineage that like any other lineage has been evolving and budding of descendant species although it may be that the lineage of horseshoe crabs is not particularly speciose i.e. it does not bud of too many species. Today, biologists can recognize 4 living species of horseshoe crabs, which means that morphological diversification in this lineage continues, although at a slower rate than many other types of organisms.

Without this distinction, throughout the talk, the longevity of a group was being compared to the longevity of a species; for example a comment was made that sponges (the group) are 600 million years old but Homo sapiens (species) are just a hundred thousand years old. That is an unfair comparison and Richard Fortey surely knows that but he let it pass.

That is not to say that these lineages don't have an important story to tell about the reasons behind their resilience. But they are not some kind of frozen Jurassic Park.  

Listen / Download

Monday, May 21, 2012

Revenge Of The Underpaid Professor

I couldn't beat the author's title so I kept it. There is an interesting article in The Chronicle by Kevin Carey on new online education software and how it might transform the fortunes of the underpaid under appreciated teaching faculty.

He profiles Udemy, a web company that enables teachers to build customized courses along with an avenue to sell these courses to students.  He envisions a future wherein the best teachers will have the option to opt out of the traditional University setting and to market their teaching services globally.

One can imagine many scenarios unfolding. Professional and scholarly organizations might come together to create coherent curricula and endorse certain professors and courses. Old-fashioned guilds might become modern again. People without traditional scholarly credentials will have more access to the college teaching market. The effect on the existing professoriate will be asymmetrical, with the most-skilled teachers doing much better and the least effective losing their jobs. Those who seize the opportunity won't have to donate years of semi-unpaid labor in order to secure tenuous employment positions with organizations that don't value what they do in the first place.

This is mostly about improving undergraduate education. I can imagine a day when more and more students do buy a course or two from talented teachers. For many, they would still need to go to a physical building for lab courses. Maybe a degree might involve having the option of taking the lecture part from one of the many online choices available and then buying lab time from a University. That would mean though that Universities will have to hire faculty just to take lab work. I am reminded of just such a class of faculty known as "demonstrators" when I attended college. They were decent teachers but were underpaid and under appreciated.

Wednesday, May 16, 2012

Would It Matter Where You Placed The Anthropocene?

I have been listening to an absolutely riveting series of talks hosted at Generation Anthropocene. This is a project dreamed up by young Stanford University researchers and it involves interviewing scientists working on the broad theme of human impact on ecology and environment and consequentially the question of whether there is now a case to be made for defining a new geologic epoch called the Anthropocene.

The answers to where one would place the Holocene-Anthropocene boundary usually converges to either the beginning of Agriculture or the Industrial Revolution because both involve big changes to various aspects of the earth's environment. While these two, especially the Industrial Revolution, came through as a strong candidate, the most thought provoking answer was given by ... well off course .. a geologist... Jon Payne.

He suggested we take a methodological approach and understand how geological boundaries are defined. There has to be a distinctively recognizable sedimentary section which contains evidence of a faunal break i.e. a change in the earth's biota marked by the extinction of some species or the appearance of some new species.  We subdivide geologic time by recognizing that there has been some change in the earth's biota. Looking way back in the earth's past, sedimentary sections containing these transitions cover time periods well beyond the human time scale i.e. the sedimentary layers may represent a time passage of thousands of years.

Sediments usually accumulate in layers quite slowly over time periods longer than the scale of historical events. So, taking a long view, choosing as the beginning of the Anthropocene either the Industrial Revolution or World War II  won't matter, since all these events will collapse as one instance of sediment deposition. A geologist looking back several million years from now won't be able to discriminate events that took place a few tens of years apart.

In my opinion that doesn't make the concept of Anthropocene a useless exercise. For example, the boundary between the Pleistocene and the Holocene is defined by the disappearance of two foraminifera species and is dated as 10,000 BP radiocarbon years. These events mark a passage of few tens of years. Similarly,  today there would be sediment accumulating in a lake or a quiet deep sea that contains very thin layers that mark a sudden rise in a geochemical indicator of the Industrial Revolution or some other human activity.

We may mark that as a beginning of Anthropocene today. These deposits may even get preserved into the geological future. It's just that millions of years from now absolute dating methods like carbon14 that may discriminate events on the order of few tens of years will be useless on these deposits and the error bar on the dates obtained for these rocks will be on the order of hundreds to thousands of years. As a physical entity, the boundary in deep future may be recognizable as a sedimentary layer marking the disappearance of a significant number of species, although correlating that boundary with a specific historical event may not be possible.

Other talks that I liked were by Jon Christensen who talked about the myth of the American Frontier, Rodolfo Dirzo who talked about tropical biodiversity and Doug Bird who spoke about the native Martu peoples of Australia and their history of landscape management.

One refreshing aspect of these talks are that the hosts are all graduate students. What an opportunity to have an extended chat with your intellectual mentors and find inspiration in their work.

And who knows... start thinking of a career in science journalism.

Highly highly recommended.

Monday, May 14, 2012

Making Paleoanthropology A Real Science

There is a strengthening movement towards introducing more transparency in science by making data and papers produced from publicly funded research more readily available to all those interested. Paleoanthropology which includes the study of ancient human fossils has been an especially secretive field with researchers zealously guarding their fossils until they have completed their studies and published their results.

Kate Wong in Scientific American blog writes about recent efforts to end this culture of secrecy:

...Kivell thinks concerns about sharing fossil data are misplaced. “You don’t have to worry about getting scooped,” she says, explaining that a lot of the science of interpreting fossils lies in comparing them with other fossils, which is time-consuming work. “Good science in paleoanthropology is highly comparative, highly descriptive and cannot be done fast,” Hawks agrees. “If it’s not done with extensive comparison and careful description, it’s not going to be good.”

Hawks observes that genetics had the same problem paleoanthropology has with making data accessible. But eventually the geneticists “got over it as a culture.” Indeed, it has become standard practice among geneticists to upload new sequence data to a public database before submitting a paper on the findings to a journal for publication. “I really think most people want to see things more open than they are,” Hawks says. “[Paleoanthropology] should be a real science just like genetics is a real science.”

Saturday, May 12, 2012

Debunking Miracles May Get You Jail Time In India

Another normal day in India:

Early in March, little drops of water began to drip from the feet of the statue of Jesus nailed to the cross on the church of Our Lady of Velankanni, down on to Mumbai's unlovely Irla Road. Hundreds began to flock to the church to collect the holy water in little plastic bottles, hoping the tears of the son of god would sanctify their homes and heal their beloved. 

Sanal Edamaruku, the eminent rationalist thinker, arrived at the church a fortnight after the miracle began drawing crowds. It took him less than half an hour to discover the source of the divine tears: a filthy puddle formed by a blocked drain, from where water was being pushed up through a phenomenon all high-school physics students are familiar with, called capillary action. 

For his discovery, Mr. Edamaruku now faces the prospect of three years in prison — and the absolute certainty that he will spend several more years hopping between lawyers' offices and courtrooms. In the wake of Mr. Edamaruku's miracle-busting Mumbai visit, three police stations in the capital received complaints against him for inciting religious hatred. First information reports were filed, and investigations initiated with exemplary — if unusual — alacrity. 


Friday, May 4, 2012

Violence Part Of The Social Experience In Indus Valley Civilization

Researchers Gwen Robbins Schug and Veena Mushrif Tripathy in an interview with Anthropology news have this to say about Harappan society:

It was argued that Harappa was a rare example of a peaceful, heterarchical state. The human skeletal material was never consulted to address this question. Based on our evidence for both exclusion and social differentiation in the mortuary practices at Harappa, we argue that Harappa was not entirely peaceful and social differentiation was part of life. We hope archaeologists working in this area will plan future excavations to include the peripheral areas outside the cities; excavation outside the city walls will tell us more about Indus society.

We are using the human skeletons as artifacts of the social experience. We used the concept of structural violence in our most recent work because it accounts for the clear distinctions we see in the burial practices, ritual aspects, prevalence of trauma and infection. The mortuary and bioarchaeological evidence at Harappa suggests that the social experience in South Asia was not exceptionally different from other early urban civilizations; the kinds of suffering and the patterns of violence present at Harappa suggests structural violence—unequal power, uneven access to resources, and oppression that leads to denial of basic needs and even violence.

Lest some people get too excited about the use of the words Harappa and violence in the same sentence, let it be made clear that this violence refers to interpersonal violence present in any complex society and not violence inflicted by outsiders during war.
 

Thursday, May 3, 2012

ExxonMobil Were Playing Both Ways On Global Warming All Along

Fresh Air has an absolutely fascinating interview with journalist Steve Coll who has written a new book on ExxonMobil.

For many years ExxonMobil engaged in a campaign to downplay the human role in global warming and tried to discredit the science of recent climate change.

And yet:

GROSS: Just one more thing about climate change. During the period when ExxonMobil was trying to defeat global warming science, at the same time scientists within Exxon were trying to figure out, well, if the planet is warming, how can we profit from that? So they work in both fronts at the same time.

COLL: Well, that's right. They're a science-based organization. They employ a lot of geologists, and the mission of those geologists is to understand the Earth's structure and how changes in temperatures, geology, technology, could intersect to create opportunities to find oil. And as the book reports, geologists in some of their most important kind of discovery departments were looking at how warming might unlock oil reserves and positioning ExxonMobil with advice about how to think about that.

GROSS: So in other words, Exxon wanted to defeat global science because that says that fossil fuels, burning fossil fuels is warming the climate and creating weather changes and climate change, and that would mean problems for Exxon because it's the fossil fuel industry.

But at the same time, its own scientists were saying, well, it looks like the Earth is warming, so let's see what new oil reserves that might open up to us.

Those new reserves that might open up were under the Arctic sea bed, made more accessible as increased summer melting of the Arctic sea ice makes it easier to explore and eventually exploit those resources.

There are a lot more interesting tidbits in this long interview including ExxonMobil's tussle with the U.S. government over human rights issues in oil rich countries like Chad and the company's increasing interest in unconventional oil and gas resources.


Map Of Potential Carbon Dioxide Storage Sites In U.S. Sedimentary Basins

via Nobel Intent:



Potential carbon dioxide sequestration sites are shown in blue.

Carbon capture and sequestration (CCS) is a climate change mitigation measure. Carbon dioxide emitted by power plants is compressed into a supercritical fluid and injected in deep saline aquifers with an impermeable geological capping layer that prevents the liquid CO2 from escaping.

Does U.S. sedimentary basins have enough storage capacity to make a difference in emissions? From the abstract published in PNAS:

We show that in the United States, if CO2 production from power generation continues to rise at recent rates, then CCS can store enough CO2 to stabilize emissions at current levels for at least 100 y.  This result suggests that the large-scale implementation of CCS is a geologically viable climate-change mitigation option in the United States over the next century.

Will it be economically viable though? There seems to be no hurry in the climate change policy environment in making CO2 emissions expensive enough for companies to turn to CCS.