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
Selection filter(s): year(2010-*)
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.
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.
Addendum: I am aware that this does not address habit destruction.
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.
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.
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….
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:
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?”
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.
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:
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.
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?
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:
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.
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?
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.
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.
* 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).
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
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.
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.