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The New York Times has a piece with the title A Rebel Filmmaker Tilts Conservative. What conservative tilt is being displayed here? It’s Pandora’s Promise, a film which serves as a sort apologia for nuclear power from environmentalists concerned about climate change. What confuses me is that I don’t understand the specifically conservative tilt here, as I have many friends who evince a nuclear-friendly tilt without seeming politically conservative. Perhaps a generation ago anti-nuclear sentiment was strongly ideological colored, but more recently there has been a boomlet on the enviro-Left in favor of nuclear energy.

The GSS has two variables which query this issue crossed with ideology rather well. Here’s the query so you can replicate:

Row: NUKEELEC NUKEGEN

Column: POLVIEWS(r:1-3″Liberal”;4″Moderate”;5-7″Conservative”)

Selection filter(s): year(2010-*)

Views on nuclear energy N ~ 400
Lib Mod Cons
Strongly favor 16 13 12
Favor 49 50 64
Oppose 28 27 16
Strongly oppose 7 9 8
Nuclear power dangerous to the environment N ~ 1300
Lib Mod Cons
Extremely dangerous 26 23 16
Very dangerous 25 29 23
Somewhat dangerous 33 32 31
Not very dangerous 14 13 22
Not dangerous 3 3 8

As you can see liberals do tend to be more skeptical of nuclear energy, but it is not stark. In fact, attitudes toward nuclear power seem to be as strongly, if not more so, variant on a populist vs. elite axis than conventional ideology. Here’s the second question replicated for education:

Nuclear power dangerous to the environment N ~ 1300
No college College
Extremely dangerous 26 11
Very dangerous 27 21
Somewhat dangerous 31 34
Not very dangerous 11 28
Not dangerous 4 7

But, when you look only at college educated individuals the ideology divide doesn’t go away. In fact, it seems more extreme.

Nuclear power dangerous to the environment N ~ 370
College educated only
Lib Mod Cons
Extremely dangerous 14 16 5
Very dangerous 28 22 14
Somewhat dangerous 38 35 28
Not very dangerous 15 24 42
Not dangerous 5 4 11

That’s strong circumstantial evidence that the gap here is one of cultural norms and values, and not facts.

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Environment, Nuclear Energy 
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Credit: Tierrascott

In the 1980s I was fascinated by the pictorially oriented books on the wildlife of the world which dated to the 1960s and 1970s. One of the great conservation success stories of that era were the Saiga antelope of Eurasia. In 1920 there were only 1,000-2,0000 Saia left in the world. By the 1960s their numbers were in the millions. And so it was until the 1980s.

But the combination of the collapse of the Soviet Union, for which the Saiga was a notable conservation success, and the rise of the Chinese economy, have resulted in another crisis for the Saiga. Today their number is between 10,000-50,000, in a few fragmented regions. And yet this is still higher than their early 20th century bottleneck! The Saiga clearly have the capacity to recover from dramatic population crashes. The key, to be frank, is to keep the Saiga a viable population as China ascends up Maslow’s hierarchy of needs.

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Conservation, Environment 
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Image credit: Mister-E.

It has recently come to my attention that there is wide variation in the frequency of tuskless male elephants across populations. These individuals are termed maknas. To review, while both male and female African elephants have tusks, prominent tusks are only a feature of males in Asian elephants. Yet among wild Sri Lankans, which number on the order of ~5,000 individuals, tuskless males are ~90% of the population! Similar population frequencies have been reported in the few Chinese elephants than remain in Yunnan province. Tuskless apparently also may be a heritable trait among some African elephant populations. I think you know where I’m going with this. Seeing that China’s demand side appetite for ivory is resulting in more poaching, and is unlikely to abate over the next 10 years or so, the heritable variation which results in lack of tusks in elephants may be a possible glimmer of hope. Of course, elephant generations are long, so I’m not offering an adaptive panacea. Just a likely prediction.

Literature: Tuskless bulls in Asian elephant Elephas maximus. History and population genetics of a man-made phenomenon.

Addendum: I am aware that this does not address habit destruction.

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Environment 
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Not dead yet

The new book Never Look a Polar Bear in the Eye: A Family Field Trip to the Arctic’s Edge in Search of Adventure, Truth, and Mini-Marshmallows, by Zac Unger, has made some waves because it suggests that there has been some alarmism as to the extinction likelihood of this charismatic megafauna within the next 50 years. The public debate on this issue has veered between grave worry, to some guarded optimism. A moderately alarmist book to set against Unger’s would be Richard Ellis’ On Thin Ice: The Changing World of the Polar Bear, from 2008. Ellis was very dismissive of those who might suggest that polar bears might be able to adapt to changing conditions. For him the gates of scientific debate had closed.


Of course in the end Unger takes the threats to the polar bear, and the arctic biome, seriously too. But, he emphasizes that he wishes that scientists might focus on the descriptive aspects of science, rather than becoming prescriptive in their pronouncements. When one makes a scientific inference confidence is rarely assured. Rather, there are a range of likely outcomes, of decreasing probability, around an expected value. In some cases it makes rational sense to emphasize the worst case scenario, because of the downside risks are so great. But the problem in the public discourse is that this condition is often elided or ignored, and the worst case scenario becomes the expected scenario. And if that worst case scenario does not pan out (and, if it is a worst case scenario, it is highly like not to come about), then the public may begin to doubt future predictions.

I have warned against confusing the normative with the positive in cultural anthropology. The issues in biology are somewhat less fraught, because there is less of a human rights concern with animals. But the field of conservation genetics and ecology is unfortunately characterized by a tendency to confuse a statistic such as effective population or the shannon index of diversity with a “good” or “bad” value. Even a concept such as mutational meltdown, which is wrapped in a terminology which alarms, is not necessarily “good” or “bad,” aside from the values which we impute toward it. For example, a mutational meltdown of mosquito populations, implausible as it might see, would be “good.” A mutational meltdown of most other organisms might be “bad.” Not because of science, but because of human values.

The point is not that science can not inform policy. It is simply that policy is by nature normative, so when the boundaries between science and policy are blurred, then the boundary between the positive and normative are blurred. This does not redound to the benefit of science, because science’s prestige is accrued from the fact that it presumes to be an objective, cold, and dispassionate observer as to the state of the world. There are surely enough activists in the world that scientists might think it would be wiser to expend their capital more prudently. The grandeur of science is not that it can speak truth to power with the prophetic voice of Elijah, it is that it is inhumanly blind to human concerns.

Finally, in regards to the science it seems likely that the currently lineage of polar bears dates to ~500,000 years before the present, with some admixture with brown bears. This is important, because it means that polar bears survived through the Eemian interglacial ~125,000 years ago. Let me quote:

At the peak of the Eemian, the northern hemisphere winters were generally warmer and wetter than now, though some areas were actually slightly cooler than today. The Hippopotamus was distributed as far north as the rivers Rhine and Thames…Trees grew as far north as southern Baffin Island in the Canadian Arctic Archipelago instead of only as far north as Kuujjuaq in northern Quebec, and the prairie-forest boundary in the Great Plains of the United States lay further west — near Lubbock, Texas, instead of near Dallas, Texas, where the boundary now exists. The period closed as temperatures steadily fell to conditions cooler and drier than the present, with 468-year long aridity pulse in central Europe…and by 114,000 years ago, a glacial period had returned.

This does not prove that polar bears today would be resilient toward abiotic environmental changes, but, I think it cautions us not to deny out of hand those who might assert this proposition. But, as you likely know I do not believe that most megafaunal extinction in the past ~100,000 years were due to abiotic factors. Humans reshape the parameters of extinction probability because of our resource utilization ad encroachment upon organisms which are under exogenous stress.

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Environment, Environmentalism 
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I realized that my post on David Attenborough simply presumed you know who the man is. The reality is who he is is less critical than what he’s done. If you haven’t seen it, you need to see The Living Planet. Or you can read the book of the same name.

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Environment 
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Recently David Attenborough made the news because he expressed some old fashioned population alarmism. I say old fashioned because we’ve come a long way since Paul Ehrlich’s Population Bomb was published. It’s been 44 year since the original edition, and it hasn’t aged well. Not only is the world healthier and wealthier than it’s ever been, but population growth is likely to taper off in a stabilization by the mid-21st century. If there are resource scarcity issues it won’t be because of human numbers, it will be because of the unsustainability of per capita consumption. And that doesn’t take into account technological change and innovation. Agricultural inputs aren’t static.

The real issue here is one of values. It probably is difficult to not have reduced biodiversity as humans have to exploit more and more of the world to maintain their lifestyles. A “population bomb” in the sense of the impending end of civilization is probably not a good medium term (i.e., ~50 years) prediction. But for large to medium sized non-human organisms we are a bomb or plague. The irony here is that a concern for the environment is to a great extent a post-materialist value, which emerges in the wake of the affluence which may be the greatest threat to biodiversity….

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Culture, Environment 
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One of my major gripes with my friends in ecology is that there is a tendency to look at every problem through the lens of ecological models. Garrett Hardin, who popularized the term “tragedy of the commons” is an exemplar of this. People in ecology often get irritated by the public confusion between it, a positive scientific discipline, and environmentalism, a normative set of beliefs (it doesn’t help when some environmentalist groups have names like “ecology movement”). But the fact is there are deep commonalities in terms of prior assumptions by both ecologists and environmentalists. Despite evolutionary ecology, the reality is that ecologists seem to be characterized by a mindset which posits limits to growth and a finite set of responses to the challenges of scarce resources. That is, the Malthusian paradigm.

I bring this up because despite the similarities between ecology and economics it strikes me that ecologists often have a difficult time admitting that the parameters of the model which they think they have a good grasp of may not always be fixed. Incentives and innovation can shift the dynamics radically. Consider George Monbiot’s about face on “peak oil,” We were wrong on peak oil. There’s enough to fry us all:

A report by the oil executive Leonardo Maugeri, published by Harvard University, provides compelling evidence that a new oil boom has begun. The constraints on oil supply over the past 10 years appear to have had more to do with money than geology. The low prices before 2003 had discouraged investors from developing difficult fields. The high prices of the past few years have changed that.

Maugeri’s analysis of projects in 23 countries suggests that global oil supplies are likely to rise by a net 17m barrels per day (to 110m) by 2020. This, he says, is “the largest potential addition to the world’s oil supply capacity since the 1980s”. The investments required to make this boom happen depend on a long-term price of $70 a barrel – the current cost of Brent crude is $95. Money is now flooding into new oil: a trillion dollars has been spent in the past two years; a record $600bn is lined up for 2012.

Let’s take Monbiot’s assertion as a given, that we are not entering an era of hydrocarbon scarcity. Why? As he outlines increasing demand, flat supply, and higher profits, stimulated exploration and innovation, generating more supply. This isn’t rocket science, critics of peak oil were pointing out this likelihood back in the mid-2000s. What this reminds me of is evolution. A eternal and circuitous race across a fluctuating ‘adaptive landscape,’ with fitness target constantly shifting.

Of course evolutionary process is not such that anything is possible. This is still science, and science has limits. But evolutionary process is often surprising in its ingenuity. Similarly, over the past 250 years or so human ingenuity has been surprising. This doesn’t mean we should bet on this lasting forever, the Malthusian condition has been the norm for almost all of human history. But, we should never forget the power of innovation and incentives when we consider policies at the intersection of the environment and economics. I don’t get irritated when the general public operates with Malthusian assumptions. But I do get irritated when biologists, and especially ecologists, seem to act as if human economic history since 1800 simply hadn’t happened.

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Ecology, Environment, Environmentalism 
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Once Hidden by Forest, Carvings in Land Attest to Amazon’s Lost World:

For some scholars of human history in Amazonia, the geoglyphs in the Brazilian state of Acre and other archaeological sites suggest that the forests of the western Amazon, previously considered uninhabitable for sophisticated societies partly because of the quality of their soils, may not have been as “Edenic” as some environmentalists contend.

Instead of being pristine forests, barely inhabited by people, parts of the Amazon may have been home for centuries to large populations numbering well into the thousands and living in dozens of towns connected by road networks, explains the American writer Charles C. Mann. In fact, according to Mr. Mann, the British explorer Percy Fawcett vanished on his 1925 quest to find the lost “City of Z” in the Xingu, one area with such urban settlements.

In addition to parts of the Amazon being “much more thickly populated than previously thought,” Mr. Mann, the author of “1491,” a groundbreaking book about the Americas before the arrival of Columbus, said, “these people purposefully modified their environment in long-lasting ways.”

If one wants to recreate pre-Columbian Amazonia, most of the forest needs to be removed, with many people and a managed, highly productive landscape replacing it,” said William Woods, a geographer at the University of Kansas who is part of a team studying the Acre geoglyphs.

“I know that this will not sit well with ardent environmentalists,” Mr. Woods said, “but what else can one say?”


There are two descriptive models which have to be interpreted in different normative frames. First, there is the model whereby before the arrival of the Europeans the New World was lightly populated by indigenous groups which had a minimal impact upon the environment. This is the description. Before the 1960s this was viewed by the mainstream culture as a rationale for the justified conquest of the New World by Europeans, who put the land to productive economic usage, whereas before it had been fallow and under-untilized. After the 1960s many, especially in the environmental movement, inverted the moral valence of the description. Instead of being primitive savages, the native peoples were at balance with the environment. Rather than an outmoded way of life to be superseded, they were a potential model for the future.

The second descriptive model is the one that Charles C. Mann outlines in 1491: New Revelations of the Americas Before Columbus. It posits that in fact the New World was much more heavily populated and its environment more impacted by humanity than we had thought previously. Rather, it suggests that the introduction of Old World diseases resulted in massive population crashes, subsequent to which there was a “re-wilding” of much of the Americas. Mann focuses more on the period before the arrival of Europeans, but if you read the scholarship on the arrival of Paleo-Indians there is a fair amount of evidence that even their appearance resulted in a massive change in the suite of fauna which characterized the New World (e.g., the gray wolf and American bison are also Holocene newcomers, just like man).

Some have argued tat Mann has taken a maximalist position (in fact, some readers have lied and stated that Mann argued that the Amazon was as populated as Bangladesh!). But even granting that Mann may be sampling from the more revisionist tail of the scholarship, I think it is creditable that we need to move away from the extreme position of the first descriptive model. There is a fair amount of circumstantial evidence that New World civilizations had not attained the same level of sophistication and complexity as Old World civilizations (see Guns, Germs, and Steel for some of the reasons why). But it is also likely that the Aztecs and Incas were not sui generis aberrations, but rather one point along the spectrum of social complexity which characterized the New World.

This is a subtle point though, because the new model also has normative ramifications. I state above that New World civilizations were not as complex or developed as Old World ones, and that is not a position that many are comfortable with. Rather, they may want to assert that the New World societies were just as complex and sophisticated as the Old World civilizations, that fundamentally all civilizations have equal value and similar character. Therefore, these partisans are particularly enthusiastic about the model which Charles C. Mann popularizes in 1491, as it reverses the narrative of noble simple savages, projecting the indigenous as highly cultured, and only brought down by the biological weapons which Europeans brought.

Where does that put those who wish to construct a plausible model of reality, rather than a mythic history for purposes of ideology? It is lazy to simply pick the position in the middle, but in this case that’s probably the most prudent unless you want to dive into the primary literature yourself. I don’t accept the old model anymore for a variety of reasons, not just having to do with the natural history of the New World. But, I can’t personally assess in detail the magnitude of the numbers that some of the scholars Mann relies upon to revise upward population estimates. So I take the revision with a grain of salt and some caution.

I would conclude that there is one reason I can think of why the Amazon basin might have been more suitable for human habitation that some other wet tropical zones in the Old World: the relative lack of disease. Many wet lowland zones which would otherwise be suitable farmland are lightly populated due to malaria, but this was not an issue in the New World before 1492.

(Republished from Discover/GNXP by permission of author or representative)
 
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The figure to the left is from a new paper in Science, When the World’s Population Took Off: The Springboard of the Neolithic Demographic Transition. It reports the findings from 133 cemeteries in the northern hemisphere in regards to the proportion of 5-19 year old individuals. When calibrated to period when agriculture was introduced into a specific region there seems to be a clear alignment in terms of a demographic transition toward a “youth bulge.” Why? A standard model of land surplus explains part of it surely. When farmers settle “virgin land” there is often a rapid “catch up” phase toward the Malthusian limit, the carrying capacity. Another possibility though is that sedentary populations did not need to space their offspring nearly as much as mobile hunter-gatherers. Whatever the details, the facts remain that the data do point to a shift in the age pyramid during this period. The author wonders as to the possible cultural implications of this. There is an a priori assumption that a young vs. old age profile in a society constrains its choices and channels its energies (e.g., think the “baby boom” generation in the USA). A final interesting point is that the authors note that today we are seeing the last gasp of this transition toward large numbers of children, as fertility drops toward replacement all across the world. That too may have some cultural consequences.

Here’s a podcast with the author. Link via Dienekes.

(Republished from Discover/GNXP by permission of author or representative)
 
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Nature has a very interesting piece up right now, Don’t judge species on their origins, which addresses the periodic bouts of hysteria which are triggered by ‘invasive species.’ I’ve addressed before the issue of biological terminology of convenience being transformed into fundamental and principled Truths. The separation between ‘artificial’ and ‘natural’ selection, or more archaically the division between ‘humankind’ and the ‘natural world.’ There are important reasons why these terms emerged the way they did, but we shouldn’t confuse the terminology for the truth. This seems definitely a problem when we humans talk about ‘invasive’ and ‘non-native’ species, as well as whether population X is worth being protected because it is a ‘species’ according to a genetic definition, or whether it is too ‘genetically polluted.’ We are after all an invasive species ourself!

Since the piece is behind a paywall I’ll extract the most relevant paragraphs:

Today’s management approaches must recognize that the natural systems of the past are changing forever thanks to drivers such as climate change, nitrogen eutrophication, increased urbanization and other land-use changes. It is time for scientists, land managers and policy-makers to ditch this preoccupation with the native–alien dichotomy and embrace more dynamic and pragmatic approaches to the conservation and management of species — approaches better suited to our fast-changing planet.

But many of the claims driving people’s perception that introduced species pose an apocalyptic threat to biodiversity are not backed by data. Take the conclusion made in a 1998 paper that invaders are the second-greatest threat to the survival of threatened or endangered species after habitat destruction. Little of the information used to support this claim involved data, as the original authors were careful to point out. Indeed, recent analyses suggest that invaders do not represent a major extinction threat to most species in most environments — predators and pathogens on islands and in lakes being the main exception. In fact, the introduction of non-native species has almost always increased the number of species in a region.

The effects of non-native species may vary with time, and species that are not causing harm now might do so in the future. But the same is true of natives, particularly in rapidly changing environments.

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Environment, Invasive Species 
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A monkey frog

The Pith: The Amazon Rainforest has a lot of species because it’s been around for a very long time.

I really don’t know much about ecology, alas. So my understanding of evolution framed in its proper ecological context is a touch on the coarse side. When I say I don’t know much about ecology, I mean that I lack a thick network of descriptive detail. So that means that I have some rather simple models in my head, which upon closer inspection turn out to be false in many specific instances. That’s what you get for relying on theory. Today I ran into a paper which presented me with some mildly surprising results.

The question: why is the Amazon Rainforest characterized by such a diversity of species? If you’d asked me that question 1 hour ago I would have said that it was a matter of physics. That is, the physical parameters of a high but consistent rainfall and temperature regime. This means the basic energetic inputs into the biome is high, and its consistency allows the organisms to plan their life schedule efficiently, maximizing the inputs. All that naturally produces a lot of diversification in the “climax” ecosystem. To some extent I would acknowledge this was pretty much a “Just-So,” but I’d have thought it was a good shot, and probably representative of the internal logic of many people.

ResearchBlogging.org But no, a new paper in Ecology Letters seems to imply that that the answer we must look to is history and not physics. From the perspective of someone who is rooted in are reductionist conception of evolutionary biology this isn’t the answer I was “rooting” for, but if it is, it is. What’s their logic?

First, the abstract, Phylogenetic origins of local-scale diversity patterns and the causes of Amazonian megadiversity:

What explains the striking variation in local species richness across the globe and the remarkable diversity of rainforest sites in Amazonia? Here, we apply a novel phylogenetic approach to these questions, using treefrogs (Hylidae) as a model system. Hylids show dramatic variation in local richness globally and incredible local diversity in Amazonia. We find that variation in local richness is not explained primarily by climatic factors, rates of diversification (speciation and extinction) nor morphological variation. Instead, local richness patterns are explained predominantly by the timing of colonization of each region, an d Amazonian megadiversity is linked to the long-term sympatry of multiple clades in that region. Our results also suggest intriguing interactions between clade diversification, trait evolution and the accumulation of local richness. Specifically, sympatry between clades seems to slow diversification and trait evolution, but prevents neither the accumulation of local richness over time nor the co-occurrence of similar species

Thankfully species richness is pretty easy to understand. It’s a count of the number of species in a given area. In this case they limited their count to a specific clade, the tree frogs. This clade seems to have a common ancestor ~60-80 million years before the present from which it descends.

Below is a phylogenetic tree (scaled to time on the horizontal) representing the relationships of contemporary tree frog species, as well as a distribution of the species across the world:

Visual inspection tells you immediately that Amazonia is overloaded with tree frog species. But to get at the question of what explains the variation in species richness the authors used standard statistical techniques relating predictors such as temperature and precipitation values to the outcome, species richness. The authors did find a relationship between precipitation and temperature and species richness. But once they controlled for phylogeny in their regression, that is, take into account history, the relationship went away. In other words the correlations may have been an artifact of the fact that the Amazon is warm and wet and rich with species. Controlling for the phylogeny of the clade, which is a record of contingent history, the expected picture relating physical parameters to diversification changes. The two panels above and to the left show the relationships between species richness (y-axis) and first colonization event. The left panel is pegged from the first colonization of any tree frog lineage, while the second sums up distinct colonization events by different clades (so the x-axis has a larger magnitude). The r-squared, the proportion of the variance of y explained by variance in x, is nearly 0.50 in the left and 0.70 in the right. That’s pretty good.

There’s some interesting material in the paper sympatry vs. allopatry in regards to the tree frogs. Basically, how they vary in size and diversity as a function of whether they co-occur in the same ecosystem or whether they’re physically separated (so allopatric speciation is when two lineages are separated while sympatric is when they are geographically overlapping but diverge anyhow, perhaps through occupation of differing niches).

But that’s not my primary concern or interest. How generalizable are these results form tree frogs? I don’t know this literature well. Surely someone has done a phylogenetic least squares with a lot of different clades and checked for this? If the results here are generalizable then the diversity of the Amazon ecosystem is in large part a function of its longer term stability and persistence. I have posited that at the “end of history” natural selection will have shaped an exceeding simply and energetically optimized biosphere, dominated by a few species. But in Amazon is a case in the opposite direction, as clade diversification increases as a function of the time of ecosystem integrity. Is this monotonic? In other words, is there going to be a time when a rare evolutionary event may given rise to a species which sweeps away all the accumulated variation?

Those are questions for the future I suppose.

Citation: Wiens JJ, Pyron RA, & Moen DS (2011). Phylogenetic origins of local-scale diversity patterns and the causes of Amazonian megadiversity. Ecology letters PMID: 21535341

Image credit: Colin Burnett

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Diversity, Ecology, Environment, Speciation 
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Image Credit: Stefan Kuhn

I was at a coffee shop recently and a SWPL couple (woman had dreads to boot!) a number of tables away were reading a newspaper, and the husband expressed worry about the Fukushima disaster. The wife responded that “now other people will understand how dangerous nuclear power is,” with a sage nod. They then launched into twenty minutes of loud righteous gibberish about chemicals (I had a hard time making sense of it, despite the fact that I learned a lot about chemicals in the past due to my biochemistry background). Because they’d irritated me I was curious and I tailed them as they left. Naturally they had driven to get coffee in a S.U.V. of some sort (albeit, a modestly sized one which looked like it was more outfitted for the outdoors’ activities common in the Pacific Northwest; they’d probably done their cost vs. benefit about those chemicals!).

In terms of radiation fears, I suspect that if more people just automatically knew the inverse-square law in relation to the drop off of its effects we’d be in a whole lot less public relations trouble. More obviously there is clearly a salience problem with nuclear disasters; people always notice them. For fossil fuels the negative environmental consequences usually don’t get so in your face as ‘fracking’. Or, they’re only really evident in godforsaken places like the Niger Delta. Of course people in Louisiana are well aware of the ‘Cancer Corridor’, but they seem to take it as the cost of doing business by and large. I have a hard time imagining such an equanimous attitude toward nuclear power. So I thought I’d pass on the 1000th article reiterating the obvious, Fossil fuels are far deadlier than nuclear power:

The explanation lies in the large number of deaths caused by pollution. “It’s the whole life cycle that leads to a trail of injuries, illness and death,” says Paul Epstein, associate director of the Center for Health and the Global Environment at Harvard Medical School. Fine particles from coal power plants kill an estimated 13,200 people each year in the US alone, according to the Boston-based Clean Air Task Force (The Toll from Coal, 2010). Additional fatalities come from mining and transporting coal, and other forms of pollution associated with coal. In contrast, the International Atomic Energy Agency and the UN estimate that the death toll from cancer following the 1986 meltdown at Chernobyl will reach around 9000.

In fact, the numbers show that catastrophic events are not the leading cause of deaths associated with nuclear power. More than half of all deaths stem from uranium mining, says the IEA. But even when this is included, the overall toll remains significantly lower than for all other fuel sources.

So why do people fixate on nuclear power? “From coal we have a steady progression of deaths year after year that are invisible to us, things like heart attacks, whereas a large-scale nuclear release is a catastrophic event that we are rightly scared about,” says James Hammitt of the Harvard Center for Risk Analysis in Boston.

In other news, Vive la France!

Image Credit: Ichabod Paleogene, Krzysztof Kori

Here’s a scatter plot I generated using NationMaster:

Note, I am not from 1950, and I do not believe that nuclear power will be the “miracle energy of the future.” I am no nuclear power maximalist. Rather, I think that we should enter into a calm and medium-term time scale cost vs. benefit analysis, and not react and respond based on our rough reflex heuristics which to me seem more rooted in pre-scientific intuitions and biases, rather than a rational calculus of the positives and negatives. A nuclear meltdown is the sort of danger we were evolved to detect and react to (the analogy would be to a fire). False positives have a much lower downside than false negatives in the environment of evolutionary adaptedness. In contrast, the morbidity inducing consequences of exposure to fossil fuel pollution are “time released” in their impact, with many of them coming to “fruition” after our reproductive peak (I won’t even get into other negative externalities).

A rational weighting of any such global-consequential decision has to be grounded in “doing the sums,” and not allowing our mystical conceptions of contagion to overwhelm our higher faculties. Electricity is electricity, and moves across borders. The ad hoc response of European nations is grounded in local politics of fear, not global assessments of reason. For example, France does export electricity to Germany which is originally nuclear power derived. So in the developed world there is clearly some transparent NIMBY aspect to this, in addition to the psychology of fear.

(Republished from Discover/GNXP by permission of author or representative)
 
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Last month in Nature Reviews Genetics there was a paper, Measuring selection in contemporary human populations, which reviewed data from various surveys in an attempt to adduce the current trajectory of human evolution. The review didn’t find anything revolutionary, but it was interesting to see where we’re at. If you read this weblog you probably accept a priori that it’s highly unlikely that evolution “has stopped” because infant mortality has declined sharply across developed, and developing, nations. Evolution understood as change in gene frequencies will continue because there will be sample variance in the proportions of given alleles from generation to generation. But more interestingly adaptive evolution driven by change in mean values of heritable phenotypes through natural selection will also continue, assuming:

1) There is variance in reproductive fitness

2) That that variance is correlated with a phenotype

3) That those phenotypes are at all heritable. In other words, phenotypic variation tracks genotypic variation

Obviously there is variance in reproductive fitness. Additionally, most people have the intuition that particular traits are correlated with fecundity, whether it be social-cultural identities, or personality characteristics. The main issue is probably #3. It is a robust finding for example that in developed societies the religious tend to have more children than the irreligious. If there is an innate predisposition to religiosity, and there is some research which suggests modest heritability, then all things being equal the population would presumably be shifting toward greater innate predisposition toward religion as time passes. I do believe religiosity is heritable to some extent. More precisely I think there are particular psychological traits which make supernatural claims more plausible for some than others, and, those traits themselves are partially determined by biology. But obviously even if we think that religious inclination is partially heritable in a biological sense, it is also heritable in the familial sense of values passed from one generation to the next, and in a broader cultural context of norms imposed from on high. In other words, when it comes to these sorts of phenotypic analyses we shouldn’t get too carried away with clean genetic logics. In Shall the Religious Inherit the Earth? Eric Kaufmann notes that it is in the most secular nations that the fertility gap between the religious and irreligious is greatest, and therefore selection for religiosity would be strongest in nations such as Sweden, not Saudi Arabia. But as a practical matter biologically driven shifts in trait value in this case pales in comparison to the effect of strong cultural norms for religiosity.

Below are two of the topline tables which show the traits which are currently subject to natural selection. A + sign indicates that there is natural selection for higher values of the trait, and a – sign the inverse. An s indicates stabilizing selection, which tells you that median values have higher fitnesses than the extremes. The number of stars is proportional to statistical significance.


future1

future2

Some of this is not surprising. The age of the onset of menarche has been dropping in much of the world. I suspect this is mostly due to better nutrition, but a consequence of this shift is earlier fertility for some females. The authors are nervous about the robust correlation of higher fertility with lower intelligence, but notice that the pattern for wealth and income is different and more complicated. The key is to look at education. Whether you believe intelligence exists or not in any substantive concrete sense, those who are more intelligent are more likely to have had more education, and there’s a rather common sense reason why investing in more schooling would reduce your fertility: you simply forgo some of your peak reproductive years, especially if you’re female. The higher you go up the educational ladder the stronger the anti-natalist cultural and practical pressures become (the latter is a heavier burden for females because of their biological centrality in child-bearing, but both males and females are subject to the former). As with religion even if the differences have no biological implication because you believe the correlations are spurious or reject the existence of the trait one presumes that parents and subcultures pass on values to offspring. If higher education has anti-natalist correlations we shouldn’t be surprised if subsequent generations turn away from higher education. Their parents were the ones who were more likely to avoid it.

We live in interesting times.

(Republished from Discover/GNXP by permission of author or representative)
 
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I’ve spent most of my life in relatively forested areas, and took forestry courses in secondary school (which is why I can still distinguish doug fir from spruce by looking at the needles). In my youth I even had friends who were loggers during the summer. But I haven’t taken a deep scientific interest in forests for a long time. So I decided to look at the Google public data set to get a sense of long term trends.

As you can see, there hasn’t been much of an aggregate decline in forests. How about the nations with a lot of forest cover?

I was surprised that the slopes didn’t have a stronger negative value. What about you? If this is your area of expertise, what’s going on? Are we trading climax ecosystems for second growth and lumber plantations? I was surprised that the USA had nearly as much forest cover as Canada, but I guess a lot of the Great White North is tundra.

Also, removing Russia to make the scale easier, and adding China and India, you can see the impact of the recent Chinese reforestation drive pretty clearly:

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Environment 
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Here’s an article from Canada on the debate about whether hybridization should be discouraged. I understand the impulse toward preserving nature as it is, but the drive for presumed purity seems almost fetishistic. Consider this sentence: ” Or could hybrids actually weaken genetically pure populations of disappearing wildlife?” What does “genetically pure” mean in a deep sense here? We know what it means instrumentally for the purposes of conservation genetics, but the way people talk about pristine lineages makes it seem an almost ethical concern.


When it comes to conservation and environmental policy you’re at the intersection of science, norms, and the messy world of human possibility. Perspective matters a lot in how you value or weight the parameters within your value system. To me the preservation of putatively pure lineages immemorial smacks a bit of pre-Darwinian biology, with its focus on systematic analysis of fixed and eternal kinds as well as a descriptive analysis of anatomy and physiology. At the other end is evolutionary biology which is a process, a phenomenon, understood as a flux of gene frequencies and morphs over time. It is by definition a refutation of a static conception of nature. Of course it takes time…but but not that much time. And then there’s the tendency to see humans as apart and beyond nature, exogenous to the system, destabilizing an eternal equilibrium. This is also arguably a false ideal, humans have been part of the ecosystem of every continent excepting Antarctica for at least 10,000 years, Australia for 50,000 years, Eurasia for a million years, and Africa somewhat longer. Modern H. sapiens sapiens has likely reshaped whole ecosystems through predation and fire even before agriculture and dense societies.

Let’s have a more nuanced and subtle conversion here, and put the focus on what our ultimate values are, or at least the ultimate values of the majority. As it is too often it seems to me that we’re not that far from “king’s wood” whereby we view nature as something to be isolated from the common man, who by his presence sullies and contaminates its purity. And now the fixation on distinct kinds and lineages seems to veer in a similar direction, albeit focusing on the purity of species and sub-species rather than nature as a whole.

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Environment, Environmentalism, Ethics, Nature 
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On this week’s ResearchBlogCast we discussed Adaptation, Plasticity, and Extinction in a Changing Environment: Towards a Predictive Theory (see my post reviewing it). The basic idea was to discuss a simple mathematical model which treated biological populations as something more than simply static constants buffeted by changes in physical parameters. In particular there’s often an implicit model that species exist at a particular and precise equipoise with an environment, and that when those environmental parameters are shifted that the species is in jeopardy unless it can track its optimal environment through migration.


In some ways this would be mighty convenient for us if it were so. If species were static we wouldn’t have to worry about weeds becoming resistant to pesticide, or diseases wrecking havoc to our crops, and so forth. But biology is dynamic, both on the life history and evolutionary scale. I think it would benefit us to take this into account when we humans consider the value we place on conservation, and the decisions we make to maintain biodiversity. Kevin Zelnio pointed out that there have been worries about the disappearance of charismatic fauna for about a generation now, and though species such as the tiger and elephant are still endangered (and because of their relatively long generation times this is problematic), many species which we were told as children would become extinct by the time we were adults remain a presence today in the wild. Some of this is surely due to conservation after the awareness of the threats, but another issue may be that some of these species are more resilient than we think, or give them credit for. Dave Munger reminded us that in 2007 100,000 Lowland Gorillas “discovered”, tripling the numbers of the species immediately. One way of looking at it is that these gorillas were mighty lucky that they’d been unnoticed…but another issue may be that gorillas coevoled to some extent with hominids and may have some sense where to go to avoid human habitation.

This is not to recommend complacency. And I haven’t even broached the serious normative issues as to the value of biodiversity outside of its human utilitarian consequences. These are points over which reasonable people can discuss and differ. Rather, when we speak of the environmental and non-human life we often speak as if humanity and physical nature are the two active forces operative on a passive and static biological nature. This is obviously not true. Our species’ mastery of the physical sciences in the past 200 years has given us a sense of power over the biological world, but we shouldn’t get complacent, and we shouldn’t dismiss the resilience and cleverness of nature, though that resilience and cleverness does not always redound to our benefit.

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Biodiversity, Ecology, Environment 
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pleistocene_brain_sizeJohn Hawks has an excellent post rebutting some misinformation and confusion on the part of Colin Blakemore, an Oxford neurobiologist. Blakemore asserts that:

* There was a sharp spike in cranial capacity ~200,000 years ago, on the order of 30%

* And, that the large brain was not deleterious despite its large caloric footprint (25% of our calories service the brain) because the “environment of early humans was so clement and rich in resources”

Hawks refutes the first by simply reposting the chart the above (x axis = years before present, y axis = cranial capacity). It’s rather straightforward, I don’t know the paleoanthropology with any great depth, but the gradual rise in hominin cranial capacity has always been a “mystery” waiting to be solved (see Grooming, Gossip, and the Evolution of Language and The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature). Blakemore may have new data, but as they say, “bring it.” Until then the consensus is what it is (the hominins with the greatest cranial capacities for what it’s worth were Neandertals, and even anatomically modern humans have tended toward smaller cranial capacities since the end of the last Ice Age along with a general trend toward smaller size).


But the second issue is particularly confusing, as Blakemore should have taken an ecology course at some point in his eduction if he’s a biologist (though perhaps not). One of the problems that I often have with biologists is that they are exceedingly Malthusian in their thinking, and so have a difficult time internalizing the contemporary realities of post-Malthusian economics (see Knowledge and the Wealth of Nations: A Story of Economic Discovery).Innovation and economic growth combined with declining population growth have changed the game in fundamental ways. And yet still the biological predisposition to think in Malthusian terms is correct for our species for almost its whole history.*

A “tropical paradise” is only a tropical paradise if you have a modicum of affluence, leisure, and, modern medicine. Easter Island is to a great extent a reductio ad absurdum of pre-modern man and gifted with a clement regime. Easter Island’s weather is mild, the monthly low is 18/65 °C/°F and the monthly high is 28/82 °C/°F. The rainfall is 1,118/44 mm/in. But constrained on an island the original Polynesians famously transformed it into a Malthusian case-study. We literally breed up to the limits of growth, squeezing ourselves against the margins of subsistence.

I can think of only one way in which Blakemore’s thesis that the environment of early humans was rich in resources might hold, at least on a per capita basis: the anatomically modern humans of Africa exhibited bourgeois values and had low time preference. In other words, their population was always kept below ecological carrying capacity through forethought and social planning, since there is no evidence for much technological innovation which would have resulted in economic growth to generate surplus. My main qualm with this thesis is that it seems to put the cart before the horse, since one presupposes that a robust modern cognitive capacity is usually necessary for this sort of behavior.

* Malthus’ biggest mistake was probably that he did not anticipate the demographic transition, whereby gains in economic growth were not absorbed by gains in population.

(Republished from Discover/GNXP by permission of author or representative)
 
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Arboreality has allowed for the evolution of increased longevity in mammals:

The evolutionary theory of aging predicts that species will experience delayed senescence and increased longevity when rates of extrinsic mortality are reduced. It has long been recognized that birds and bats are characterized by lower rates of extrinsic mortality and greater longevities than nonvolant endotherms, presumably because flight reduces exposure to terrestrial predators, disease, and environmental hazards. Like flight, arboreality may act to reduce extrinsic mortality, delay senescence, and increase longevity and has been suggested as an explanation for the long lifespans of primates. However, this hypothesis has yet to be tested in mammals in general. We analyze a large dataset of mammalian longevity records to test whether arboreal mammals are characterized by greater longevities than terrestrial mammals. Here, we show that arboreal mammals are longer lived than terrestrial mammals at common body sizes, independent of phylogeny. Subclade analyses demonstrate that this trend holds true in nearly every mammalian subgroup, with two notable exceptions–metatherians (marsupials) and euarchontans (primates and their close relatives). These subgroups are unique in that each has experienced a long and persistent arboreal evolutionary history, with subsequent transitions to terrestriality occurring multiple times within each group. In all other clades examined, terrestriality appears to be the primitive condition, and species that become arboreal tend to experience increased longevity, often independently in multiple lineages within each clade. Adoption of an arboreal lifestyle may have allowed for increased longevity in these lineages and in primates in general. Overall, these results confirm the fundamental predictions of the evolutionary theory of aging.

The same logic probably explains the long lifespans of tortises. Until humans showed up their shells were pretty good at insulating them from the risks of predation.
Citation: Milena R. Shattuck and Scott A. Williams, Arboreality has allowed for the evolution of increased longevity in mammals, doi:10.1073/pnas.0911439107

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Environment, Evolution 
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Owen Lovejoy has some theories which he is using to process the data from the spate of Ardipithecus ramidus papers. When it comes to the argument about social structure based on the anatomy of the extant remains I’m skeptical. I just recorded a diavlog with John Hawks which is 2/3 devoted to Ardi-issues (should be up Saturday), and he pointed out that Lovejoy has been laying out the case for a monogamous social structure for early hominins for years. This is why I’m not that surprised that some of the numbers he cites from the literature are off. He’s probably quoting older values, and hasn’t been tracking updates or revisions.

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Environment, Evolution 
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From Science, Plenty of Cows but Little Profit:

Three years ago, a technological breakthrough gave dairy farmers the chance to bend a basic rule of nature: no longer would their cows have to give birth to equal numbers of female and male offspring. Instead, using a high-technology method to sort the sperm of dairy bulls, they could produce mostly female calves to be raised into profitable milk producers.
Now the first cows bred with that technology, tens of thousands of them, are entering milking herds across the country — and the timing could hardly be worse.
The dairy industry is in crisis, with prices so low that farmers are selling their milk below production cost. The industry is struggling to cut output. And yet the wave of excess cows is about to start dumping milk into a market that does not need it.
“It’s real simple,” said Tony De Groot, an early adopter of the new breeding technology, who milks 4,200 cows on a farm here in the heart of this state’s struggling dairy region. “We’ve just got too many cattle on hand and too many heifers on hand, and the supply just keeps on coming and coming.”
The average price farmers received for their milk in July was $11.30 for 100 pounds, down from $19.30 in July 2008. The retail price of milk has not dropped as much, but it is down 24 percent in a year, to an average of $2.91 a gallon for milk with 2 percent fat.
Desperate to drive up prices by stemming the gusher of unwanted milk, a dairy industry group, the National Milk Producers Federation, has been paying farmers to send herds to slaughter. Since January the program has culled about 230,000 cows nationwide.

From what I know the market for these sorts of products has framed by a lot of subsidies and incentives. Increased productivity through better science should be good for any industry, but here you go slaughtering cattle to reduce production and keep the prices up. OPEC is simple compared to this. These sorts of policies are only practical because we live in a world of surplus food production.

(Republished from Discover/GNXP by permission of author or representative)
 
• Category: Science • Tags: Environment 
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Razib Khan
About Razib Khan

"I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. If you want to know more, see the links at http://www.razib.com"