What’s happening here?

January 3, 2018 • 9:00 am

by Matthew Cobb

This photo by R Fontaine (aka @Tenfon2 on Tw*tter) contains a complex set of interactions, involving two kingdoms and two classes, with two orders within one of those classes, and two genera or perhaps species within the other. Your task is to describe them. You don’t need to use fancy latin names, but there will be extra marks for those who do. My answer will be posted at noon Chicago time.

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AAAS refuses to consider population growth as a cause of environmental degradation, and promotes Catholic point of view

May 24, 2016 • 10:00 am

I’ve had my worries about the American Association for the Advancement of Science (AAAS), especially its cozying up to religion. They’ve collaborated with Templeton in funding an accommodationist program, the Dialogue on Science, Ethics, and Religion (DoSer), and have engaged in other religion-coddling activities unseemly for a secular science organization (see, for instance, herehere, here, and here). I’m not sure why that is, unless somehow the AAAS wants to court popularity by making nice with faith.

But when I saw a new “editorial” in the AAAS’s journal Science, I was gobsmacked. The piece, “Pursuit of integral ecology,” is clearly labeled as an “Editorial” (which means its message has the approval of Science), and was written by Monsignor Marcelo Sánches Sorondo, Chancellor of the Pontifical Academies of Science and of Social Science, and Veerabhandran Ramanathan, a climate scientist at UC San Diego and a council member of the Pontifical Academy of Sciences.

The editorial, part of a special Science Issue on “Urban Planet,” is basically a paean to the Pope’s views on environmentalism, and really says nothing more than this: “We like the Pope’s views that pollution, environmental degradation, and so on, impacts people differently, with the poor suffering the brunt of the damage.” Fine, but that’s been said over and over again. There’s nothing remarkable or new in the piece. But there’s also a notable inclusion and a notable omission.

The inclusion (my emphasis):

The Paris agreement was signed by 195 nations to limit global warming to well below a 2°C increase. These global acknowledgements of systemic ecological and social problems have opened a window of opportunity to focus on how problems of poverty, human well-being, and the protection of creation are interlinked. The real innovation is this new synergy between science, policy, and religion.

What the hell is the notion of “creation” doing in a science journal? It’s this kind of wording that got the Los Angeles County Museum of Natural History in trouble for referring to its Nature Lab exhibit (funded by a donor) as helping celebrate “God’s creatures.” On the curators’ insistence, that sign was quickly taken down. Why does Science, then, allow mention of “creation,” a clearly religious concept, in an “editorial”?

And the notable omission: there is not a single word in the Science editorial about population growth as a cause of environmental damage, nor about population control. No surprise, given who wrote it! The Catholic Church has of course refused to connect population growth with environmental damage—perhaps the most important nexus between society and ecology—because the Church wants its warren to breed like rabbits. And no condoms or pills! Instead, the piece simply praises Pope Francis as being prescient:

Indeed, 1 year ago, Pope Francis emphasized, in the encyclical Laudato Si, that complex crises have both social and environmental dimensions. The bond between humans and the natural world means that we live in an “integral ecology,” and as such, an integrated approach to environmental and social justice is required.

Where is the social dimension of birth control?

Others have noticed the AAAS’s reluctance to even discuss birth control. In a piece called “AAAS wields the censor’s hammer on U.S. population issues,” Stuart Hurlbert, emeritus professor of biology at San Diego State, writes a “J’accuse” piece on the AAASs apparent accommodationism:

Over the last four years three different population-focused NGOs have tried to have exhibitor booths at AAAS meetings. All have been turned down. The 2011 battles by Californians for Population Stabilization and Population Institute Canada to have booths at the 2012 AAAS meeting in Vancouver have been recounted elsewhere (1), as has AAAS’s exclusion of substantive discussion of U.S. population growth and policies from its flagship journal, Science.

Most scientists scream bloody murder when others suppress knowledge. But a few are in fact happy to censor when it suits their own ideological predispositions.

The positive consequence of those earlier battles was the formation of a new national NGO, Scientists and Environmentalists for Population Stabilization (SEPS). SEPS now educates people not only on population issues but on the problem of censorship by scientists of other scientists as well.

SEPS applied for a booth at the 2014 AAAS meeting in Chicago and was rejected. So when it applied for one at the 2016 AAAS meeting in Washington, D.C., it listed in its application the 19 scientific societies that since 2012 have warmly welcomed SEPS exhibitor booths at their meetings. No society other than AAAS has ever rejected a booth application from SEPS.

The 2016 application also listed 40 current or former presidents of scientific societies who were endorsing SEPS’ application. These included several distinguished past and present members of my own San Diego scientific community such as: Michael Soulé, former UCSD professor and founding president of the Society for Conservation Biology and the Wildlife Network; Margaret Leinen, director of the Scripps Institute of Oceanography and current president of the American Geophysical Union; John Rieger, former SDSU grad student and founding president of the Society for Ecological Restoration; Peter Jumars, former SIO grad student and past president of the American Society for Limnology and Oceanography; Edith Allen, former SDSU professor and past president of the Soil Ecology Society, and Dennis Murphy, former SDSU grad student and past president of the Society for Conservation Biology.

But no luck. The narrow-mindedness of AAAS staff once again trumped the judgment of large numbers of top scientists both in and out of SEPS, including the meeting organizers of 19 other societies.

Pretexts offered by AAAS for application rejections have been diverse, disingenuous and puzzling.

For the 2016 meeting, AAAS CEO Rush Holt claimed that rejection of SEPS’ application was  “based on the mission, focus and actions of your organization.”

So let’s see what is causing all this fear and trembling at AAAS.

SEPS mission statement as given on its website is this: Our mission is to improve understanding within the U.S. scientific, educational and environmental communities of the fact of overpopulation and its social, economic and environmental consequences at both national and global levels. We advocate for U.S. population stabilization followed by its gradual reduction to a sustainable level by humane, non-coercive means.

Hurlbert ends this way:

Such discussions seem destined to never be had in an AAAS exhibition hall.

The problem here is far bigger than rejection by AAAS of booth applications from a few NGOs. The AAAS staff and board of directors seem to have decided, surreptitiously, to exclude substantive discussion of U.S. population issues from all AAAS venues. An independent board of inquiry is needed. This behavior by AAAS has already been discussed by the board of the Council of Scientific Society Presidents. Perhaps they will bite the bullet and take up the task.

For some reason the AAAS, like the Pope and the Pontificating Academy of Partial Sciences, doesn’t want to bring up population control as an important social issue affecting the environment. I get why the Catholics don’t do that, but why a respected scientific organization? How do they benefit from censoring discussion of population growth?

h/t: Anne

Space Girl goes on a Marine Environment junket

May 21, 2016 • 10:00 am

JAC: Melissa Chen is a doctoral candidate in genetics at MIT, and, like me, a moderator of the Global Secular Humanist Movement Facebook site. She recently went on a cool NASA-sponsored trip from Wood’s Hole, and when she volunteered to write about her adventures here, I of course said, “Sure.” Here they are.  (By the way, Melissa’s alter ego is “Space Girl,” which she assumes, as you see below, by putting on a fake NASA helmet.)

The Adventures of Space Girl: What’s in a NAAMES?

by Melissa Chen

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With Prof. Craig Carlson and Jason, both researchers on the NAAMES mission, about to embark on a 26-day journey to sea

Space Girl was invited by NASA for a “social” which was essentially a press junket for social media “influencers” to aid the agency in disseminating information and publicizing its research. In particular, this was an insider’s look into NAAMES (North Atlantic Aerosols and Marine Ecosystems Study), a 5-year study to understand processes that govern ocean ecosystems and their influence on atmospheric aerosols—which in turn affect clouds and Earth’s climate.

NASA’s scientific portfolio is usually dominated by the “sexy” space sciences which involves research about other planets, asteroids, galaxies and the fundamental nature of our universe. It conjures up enthralling images of space exploration, rocket launches and spacefaring missions that captivate the public mindset and stoke the flames of science-fiction fantasies. But what about our own planet, the pale blue dot that we call home? Probing outer space for an extraterrestrial sanctuary for our species seems prudent, but why not spend some resources to save the one we live on now? To do so, we’ll have to understand the problems that plague Earth first.

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I arrived early at the NASA Social hosted at Woods Hole Oceanographic Institute. Check out all the NASA swag laid out for bloggers and guests!

This is exactly what NAAMES, the first earth-suborbital mission focused on studying the coupled ocean ecosystem and atmosphere, intends to do. Fortunately for us, NASA has an Earth Sciences division that is funded to the tune of USD$2 billion. Dr. Paula Bontempi spoke to us about this terrestrial niche, one that gets scant attention compared to the titillating and awe-inspiring space sciences. Further exacerbating this is the fact that the research they do, particularly in areas like ocean sciences and biogeochemistry, have been caught up in the culture wars of our time. There’s no question that the earth sciences tend to be held to a much higher and more rigorous standard due to the stubborn pervasiveness of climate-change denialism among some factions of the American public. Funding is scarce and press coverage virtually non-existent.

“Which is why Space Girl was here to save the day,” I mused to myself as I sat in the conference room on a warm spring morning at Woods Hole Oceanographic Institute.

Dance of the phytoplankton

The NAAMES mission is not only multi-disciplinary but also multi-modal, using ships, aircraft and satellites simultaneously. A C-130 Hercules airborne laboratory that deploys from St. Johns, Newfoundland will rendezvous with the R/V (research vessel) Atlantis which departs from Woods Hole, MA, along a route in the North Atlantic that takes it to the tip of Greenland.

One of the major biological events of the year is the phytoplankton bloom that takes place in the North Atlantic ocean. Below, you’ll notice the mesmerizing swirls of green biomass, reminiscent of a dreamy Van Gogh painting; they form the basis for the entire marine food chain. Satellites pick up the climax of blooms from April-May and were previously attributed to the same seasonal processes that cause terrestrial plants to flower in spring – namely, the gradually warming temperatures and increasing sunlight.

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Under this hypothesis however, warmer oceans should produce larger phytoplankton blooms, which means more carbon-rich fuel for zooplankton and the other marine creatures that depend on them. That goes against what we observe, however.

According to Mike Behrenfeld from OSU (pictured below), a researcher in the NAAMES study, phytoplankton actually bloom when conditions are “worse” for growth, i.e., during the dead cold and stormy swells of winter in the North Atlantic. It follows that global warming would produce smaller and smaller blooms, reducing photosynthesis and drastically limiting the ocean’s food supply and the foundation for the entire ocean ecosystem.

How biology influences cloud science

Another way these phytoplankton blooms affect global climate is by affecting aerosols and hence cloud formation. Clouds are made up of many tiny droplets of water condense from water vapor onto microscopic particles floating in the Earth’s atmosphere. Plankton essentially help to provide clouds with these nuclei to form around by “aerosolizing” to form airborne particles. It’s akin to how crystallization of a supersaturated liquid requires a “seed.”

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The more dissolved organic material in the ocean, the more particles get aerosolized in the atmosphere, which encourages cloud formation. Warming of the oceans could lead to decreased phytoplankton blooms, which, in turn, would decrease aerosols in the marine layer, thereby decreasing cloud formation. This further accelerates warming, resulting in a positive-feedback loop!

One of the NAAMES scientists showed us a neat demo which illustrates this point: holding a piping hot cup of tea on a particularly crisp cold day with minimal pollution (virtually no airborne particles), no ghostly streams of steam were detected emanating from his mug. When he blew onto the beverage surface or tried perturbing it with a lighter, hazy white ribbons of steam immediately formed.

In addition, large phytoplankton blooms are what causes the oceans to act as carbon sinks, since via photosynthesis, these micro plant cells convert CO2 to sugar that form the basis for all marine life.

R/V Atlantis: a floating laboratory

After the briefing, the participants were led on a tour of the R/V Atlantis, which was poised to embark on a 26-day mission the following day. This is no cruise – it’s a utilitarian research vessel that functions as a floating science laboratory, carrying 33 scientists and 26 crew.

There wasn’t an idle soul on board – everyone was industriously bustling about, tending to their respective duties or calibrating scientific instruments. We walked through the main lab space where we got a sense of what each group was studying, from the genomic sampling of the phytoplankton to the biogeochemistry of the oceans. It was clear to me that the only way to successfully carry out research on a ship that will, at times, be rocking quite violently, is to be fastidious and neurotic about securing everything with cable ties and rope.

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Out on the deck, we had to be very careful as we moved around, for the floor of a research vessel is a booby trap for those who, like me, have two left feet. Rows of plastic incubators were being set up to see how phytoplankton respond to various conditions like osmotic shock or varying degrees of sunlight.

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Biologists setting up a series of incubating tanks to learn more about the variables that affect phytoplankton growth. Check out that scientist’s (right) T-shirt!

Toward the bow of Atlantis, several modular ship containers (below) are perched side by side, each masquerading as mobile science laboratories. Inside, instruments like mass spectrometers and flow cytometers haphazardly corralled together from spare parts were whirring noisily as researchers were doing their final preparations.

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The NAAMES study involves some really unique and expensive instruments to take measurements. The CTD “rosette” (left) is basically a glorified sample collection device with multiple cylinders. When it is carefully hauled back on deck, the scientists gather around it with their containers in a ritual that is known on board as “milking the cow.” Then there are the “floaters,” (right) which is a little bit of a misnomer because they actually sink quickly and slowly rise as they collect data about the water column and transmit the information back to the ship. Each of these costs USD$30,000 and are for single use only!

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Off the ship, we saw the deep-sea sub named Alvin, who works with the R/V Atlantis for scientific research and exploration. He was in the dry dock because his ability to operate under immense pressures and total darkness was not needed for the NAAMES mission. Of his 4,400 dives, the most famous was probably the exploration of the wreckage of RMS #Titanic led by Dr. Robert Ballard in 1986.

Despite such an esteemed track record and illustrious career, Alvin is of course, still subject to what the internet does best – poking fun at things. Fittingly, he has been christened “Subby McSubface” (below) by an eager engineer wielding a label-maker.

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Like the ocean ecosystem that the NAAMES researchers were studying, the entire ship and its inhabitants are a kind of ecosystem as well, each part of a teeming organism whose lifeblood is the desire to learn and discover. It was all quite beautiful, like a symphony in perfect harmony or a stage of dancers in exquisite synchronicity.

Theirs is a devotion to science on a level that I have never known despite having worked in wet labs in academia for many years: crammed sleeping quarters, narrow and dim hallways, and huge logistical challenges plaguing the most basic everyday routines. Scenes from disaster movies such as “The Perfect Storm” are not just fiction to those on board – the maniacal stirrings of the North Atlantic occasionally toss people and things around. Motion sickness notwithstanding, the crew has to also “do science” under these conditions! Because of the variable working (and funding) conditions, many of the NAAMES scientists have mastered the art of “MacGyvering,” one even repurposing an engine from a Dodge truck to power sea water ionization.

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One of the NAAMES scientists was specifically looking out for Space Girl and wanted this photo. I told her that SHE was the real “celebrity” here!

The day ended with lunch at Captain Kidd’s next to WHOI where we were all still riding on the kind of high you can only get from being inspired by science. All this data from NAAMES will not only tell us so much about what processes trigger the yearly pattern of phytoplankton blooms, but also connect the dots between the blooms, aerosols and clouds. This information will in turn, help us to refine our climate models so that we can make better predictions on how marine ecosystems will be affected by climate change.

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Thank you to NASA for inviting me. I met some amazing people like mega space dork Jason Major who’s a social media rockstar and blogs at lightsinthedark.com; Michael Finneran from NASA Langley Research Center; Nichole Estaphan, reporter from WCVB and a journalist who embedded with the NAAMES mission during its November mission. She wrote about her experience as a science journalist who spent her free days roughing it out on the rough sees on the Atlantis instead of kicking it back on vacation in the Carribean at journalistatsea.com. Why? To tell the stories of the men and women who put it all the line for the sake of knowledge and discovery.

 

Reader wildlife photo

March 30, 2016 • 1:30 pm

by Greg Mayer

My Okinawa correspondent sends a happier picture than last time, this one of a living longhorn beetle, a member of the family Cerambycidae. Note the very long antennae, and the impressive tarsi. Cerambycids are often brightly or contrastingly colored.

An Okinawan longhorn beetle, 30.iii.2016.
An Okinawan longhorn beetle, 30.iii.2016.

Normally I’d have no idea what particular genus or species an Okinawan insect would be– I was happy I recognized the order and family!– but this seems to be an Asian longhorned beetle, Anoplophora glabripennis, which has become an invasive species in the US, Canada, Trinidad, and several European countries. The larvae feed on the sapwood of maples, elms, and other trees. If a reader more knowledgeable about Okinawan or East Asian insects has an opinion, please weigh in.

Richard Levins, 1930-2016

February 12, 2016 • 11:00 am

by Greg Mayer

Richard ‘Dick’ Levins, the John Rock Professor of Population Sciences at the Harvard School of Public Health, died on January 19 of this year. He was one of the most influential population biologists of the 20th century, and a close colleague and associate of Dick Lewontin, Jerry’s doctoral advisor.

Richard Levins, 1930-2016
Richard Levins, 1930-2016

Levins was an early and active participant in the group of biologists that, in the early 1960s, worked to unite ecology, evolutionary biology, and genetics into a unified and theoretically-rich science of the biology of populations. Included among this group was Dick Lewontin, Larry Slobodkin, E.O. Wilson, and, perhaps most saliently for Levins, Robert MacArthur.

Both Levins and MacArthur were skilled in mathematical theory, and both wanted to develop a unified, general, and realistic theory of ecology and evolution. They collaborated on a number of seminal papers, and Levins (1966) wrote an important exposition and defense of the style of modeling that he and MacArthur favored, and which proliferated throughout population biology. The self-conscious unification of ecology and evolutionary biology in which Levins participated was an important event in the history of the field, but it has received little attention from historians. Sharon Kingsland touches on it in her Modeling Nature, but the most extensive treatment I know of is in E.O. Wilson’s memoir, Naturalist (though see note below.)

Wilson had a spectacular falling out with Levins and Lewontin in the 70s, so other accounts would be welcome. Some flavor of the movement, its goals, and participants, can be found in the 1968 symposium volume Population Biology and Evolution, edited by Lewontin, which included contributions by Levins, MacArthur, and Slobodkin, and which was favorably reviewed by Wilson in Science.

Though both Levins and MacArthur were accomplished theoreticians, both also had a natural-historical side (MacArthur, famously, “really knew his warblers“), and it is in fact Levins’ empirical side that first attracted my attention. Levins had a farm in Puerto Rico, and later was professor at the University of Puerto Rico. While there, he had a collaboration of many years with Harold Heatwole, documenting the biogeography of the biota of Puerto Rico and the nearby Virgin Islands, which involved substantial field work.

Levins was most interested in the insects, while Heatwole is a herpetologist. As Heatwole put it, this field work taught Dick “to love ants for themselves.” (There is no good online list of Levins’ papers, but those written with Heatwole are listed at the latter’s website.)Their 1981 paper with Michael Byer is rich in data and modestly synthetic, with a good bibliography. Their work was of great interest to me, as my dissertation field work was concentrated in the Virgin Islands, and my 2012 paper cited below is basically an update of the herpetological data parts of their 1981 paper.

But there was also one important theoretical paper, “On the distribution of organisms on islands”, that came out of their island collaboration. Published in 1963 in the Caribbean Journal of Science, it contains, in capsule form, the equilibrium theory of island biogeography, deriving the species species richness of an island biota from the balance of extinction and colonization.

This is of course, the theory made famous by, and now universally associated with, MacArthur and Wilson, who also first published on it in 1963, but in the more prestigious journal Evolution. The Levins and Heatwole paper has been almost universally overlooked. (Ilkka Hanski and I have cited it.) This could be a lesson in choosing your publication outlets wisely, but, in fairness to MacArthur and Wilson, their paper was more comprehensive, and explored more ramifications. Given the close connections among Levins and the latter two, it would be interesting to know how the ideas developed so as to result in near simultaneous publication of the same basic idea.

Levins did later develop some of the theory from his and Heatwole’s paper into the theory of metapopulations, which looks at a species’ distribution over a region as a “population of populations”– some populations going extinct, while new ones form by colonization, leading to a dynamic landscape of the species’ presence and absence. In fact, the basic metapopualtion model is to this day called the “Levins Model”.

When I was a graduate student, including doing some work in Lewontin’s lab in the Museum of Comparative Zoology, Levins had students based with Lewontin at the MCZ, but, being across the Charles River at the School of Public Health himself, I rarely saw him, and never discussed with him either his field work in Puerto Rico and the Virgin Islands, or the circumstances surrounding the development and publication of his and Heatwole’s version of the equilibrium theory of island biogeography, a failing which, to this day, I regret.

Levins was a lifelong communist, which was evident in his activities with groups such as Science for the People, and his affinity for Cuba and North Vietnam. I could not detect any hint of his political philosophy in his biological work, but John Maynard Smith, perhaps the greatest British evolutionary biologist of the second half of the 20th century, and himself an ex-Marxist who became disillusioned by communism, thought otherwise:

Levins was a Marxist before he was a biologist, and all his work shows it. His book Evolution in a Changing Environment, although it avoids the usual jargon, is the work of a conscious Marxist. I also think that it was a major contribution to ecology…. It is perhaps ironic that he made extensive use of mathematical techniques borrowed from capitalist economic theory: I cannot criticise because I have done the same. Since that time, he has worked more on applications of ecological theory. The essays in this book [The Dialectical Biologist] on pesticides, on Latin community health, and on applied biology in the Third World, reflect these interests. They illustrate the power of Marxism in the right hands. I have long thought of Levins as a rare example of a scientist whose work has been strengthened by adherence to a philosophy – Marxism or any other – and this book has confirmed that view.

Like Ernst Mayr before him– a synthesist of an earlier generation– Levins was able to participate in a symposium and celebration of his life’s achievements– “The Truth is the Whole”– organized at Harvard by his colleagues and students in the year before his death. Reminiscences by a number of his colleagues have been posted at the symposium website.

Richard Levins in Maricao, Puerto Rico, in the early 1950s (from radicalismojudio.org).
Dick Levins in Maricao, Puerto Rico, in the early 1950s (from radicalismojudio.org).

Heatwole, H. R. Levins and M.D. Byer. 1981. Biogeography of the Puerto Rican Bank. Atoll Research Bulletin 251. pdf

Kingsland, S. 1985. Modeling Nature. University of Chicago Press, Chicago.

Levins, R. 1966. The strategy of model building in population biology. American Scientist 54:421-431. pdf

Levins, R. 1968. Evolution in Changing Environments. Princeton University Press, Princeton, N.J.

Levins, R. and H. Heatwole. 1963. On the distribution of organisms on islands. Caribbean Journal of Science 3:173-177.

Levins, R. and R.C. Lewontin. 1985. The Dialectical Biologist. Harvard University press, Cambridge, Mass.

Levins, R., and R.H. MacArthur. 1966. The maintenance of genetic polymorphism in a spatially heterogeneous environment: variations on a theme by Howard Levene. American Naturalist 100:585–589.

Lewontin, R.C., ed. 1968. Population Biology and Evolution. Syracuse University Press, Syracuse, N.Y.

MacArthur, R.H., and R. Levins. 1967. The limiting similarity, convergence and divergence of coexisting species. American Naturalist 101:377–385.

Mayer, G.C. 2012. Island lists of West Indian amphibians and reptiles. Puerto Rico and the Virgin Islands. Bulletin of the Florida Museum of Natural History 51:136-147. pdf

Maynard Smith, J. 1986. Molecules are not enough [review of The Dialectical Biologist]. London Review of Books 8(2):8-9. link

Wilson, E.O. 1994. Naturalist. Warner Books, New York.

Wilson, E.O. 1969. The new population biology [review of Population Biology and Evolution]. Science 163:1184-1185.

* N.B. This book– Slack, N.G. 2010. G. Evelyn Hutchinson and the Invention of Modern Ecology. Yale University Press, New Haven, Conn.– may treat this important episode: Hutchinson was MacArthur’s thesis advisor, but I have not read it.

Nature to launch new ecology and evolution journal

November 16, 2015 • 8:30 am

This hasn’t been officially announced yet, but I learned about it last week and it’s not really a secret given that Nature is already advertising for editors (here and here) for a new journal whose description is in the second ad:

Nature Ecology and Evolution — the latest member of the Nature family — will be published from January 2017, and we are now looking for editors to complete its launch team. The journal will publish the most significant research across the breadth of whole-organism and environmental biology, and will bring together all of the sub-disciplines of ecology and evolution, including palaeontology, molecular evolution and conservation biology.

We are now recruiting scientists from ecology- and evolution-related disciplines to become Associate or Senior Editors. This is a rare and exciting opportunity to help shape and launch a new academic journal. Candidates must have a PhD in a relevant discipline, and preferably postdoctoral experience, with a strong research record.

This will be a must-read journal for those of us in the field, and it’s also an opportunity for those interested in editing a good journal to apply for jobs now.

The ecology of Heaven

August 6, 2015 • 9:00 am

Here’s a scientifically based cartoon from SMBC about the relationship between ecology and immortality in Heaven. (One might call it “ecological theology.”) Sadly, the r versus k distinction has lost momentum over the years, as they are two ends of a continuum, and there are alternative as well as mixed reproductive strategies for single species. More important, there is a huge biological problem with one of the artist’s assumptions. Can you spot it?1438786209-20150805h/t: Gregg

So what killed the ‘squirrel’ being eaten by the four-legged snake?

August 1, 2015 • 3:30 pm

by Greg Mayer

As the capstone to Snake Week, let’s take a closer look at how the squirrel-like mammal being eaten by Tetrapodophis in Julius Csotonyi’s striking reconstruction died. In my earlier post, I took note of the fact that the describers of the newly discovered four-legged fossil snake had inferred from its skeleton that it was a constrictor (and thus the earliest known constricting snake, implying that constriction is an ancestral characteristic of snakes), and included Csotonyi’s lovely reconstruction showing the four-legged Tetrapodophis doing in and beginning to swallow a squirrel-like mammal. Here’s a reprise of the picture.

A ?multituberculate being eaten by Tetrapodophis. Reconstruction by Julius Cstonyi.
A multituberculate (?) being eaten by Tetrapodophis. Reconstruction by Julius Csotonyi.

The snake killed the ‘squirrel’, so we know who killed it, but what killed the ‘squirrel’? In police procedural talk, we’ve got the murderer, but we want to know the cause of death for the coroner’s report. Coincidentally, a new paper in the Journal of Experimental Biology, appearing at almost the same time as the description of Tetrapodophis, asks exactly that question, and shows via straight-forward and well-done experiments, what, in fact, is the ‘squirrel’s’ cause of death.

It was long thought that constricted prey died of suffocation, but it had also been suggested that the prey died of cardiac arrest due to drop in blood pressure. This had been suggested, in part, by the rapidity with which prey died, seemingly more rapidly than they would suffocate. What Scott Boback and colleagues have shown, using anesthetized rats fed to boa constrictors, with a set of catheters and probes in them to record their heart rates and blood pressures, is that there is a sharp and sudden drop in peripheral arterial pressure, an increase in central venous pressure, and a slowing of the heart rate. They conclude:

[S]nake constriction induces rapid prey death due to circulatory arrest.

I’m not sure if their experiments quite exclude asphyxia as a contributing cause, but it certainly shows the importance of the circulatory crisis caused by constriction.

Some of the media coverage has overstated the novelty of this result. For example, National Geographic headlined “Why We Were Totally Wrong About How Boa Constrictors Kill”, while Science, somewhat less over the top, headlined “Surprise: Snakes don’t kill by suffocation“. However, as Boback et al. note, circulatory collapse was first suggested over 80 years ago, and has been a viable idea for quite a while. Harry Greene, our foremost student of snake natural history, taking an ecumenical approach to the cause of death, wrote in his fine Snakes, in 1997, that constriction acted by “interfering with breathing and blood circulation so that the victim is immobilized within a minute or so”, while in a later, standard, herpetology text, Laurie Vitt and Janalee Caldwell (2009) wrote, “The tightening continues, and ultimately, circulatory failure causes death.” So Boback and colleagues have done a fine and needed study, but don’t believe the (media) hype!

In writing this post, I wondered what to call the prey in Csotonyi’s reconstruction. It could not be a rat, as in Boback’s study, as there were no rats, or rodents of any kind, in the Cretaceous. On the other hand, it does look like a squirrel (a rodent as well, again not possible for the Cretaceous), so I settled on ‘squirrel’, with scare quotes. A likely mammal for Tetrapodophis to have eaten is some sort of multituberculate, an extinct type of mammal found in the Cretaceous, and convergent on rodents in their dentition (gnawing incisors with a diastema before the molariforms). And, some of them showed arboreal adaptations, as do tree squirrels, but even more so, having prehensile tails. In the reconstruction below, accompanying a paper by Farish Jenkins and David Krause, the multiberculate Ptilodus is shown to be quite squirrel-like, except for its opossum-like prehensile tail.

Cover illustration from Science by L.L. Sadler accompanying Jenkins and Krause (1983).
Cover illustration from Science by L.L. Sadler accompanying Jenkins and Krause (1983).

Boback, S.M., K.J. McCann, K.A. Wood, P.M. McNeal, E.L. Blankenship and C. F. Zwemee. 2015. Snake constriction rapidly induces circulatory arrest in rats. Journal of Experimental Biology 218:2279-2288. abstract

Greene, H.W. 1997. Snakes: The Evolution of Mystery in Nature. University of California Press, Berkeley.

Jenkins, F.A. and D.W. Krause. 1983. Adaptations for climbing in North American multituberculates (Mammalia). Science 220:712-715. abstract (pdf of JEB commentary)

Vitt, L.J. and J.P. Caldwell. 2009. Herpetology. 3rd ed. Elsevier, Amsterdam.

Why there probably isn’t a ghost ship full of cannibal rats headed for the British Isles

January 25, 2014 • 10:24 am

by Greg Mayer

There’s been a lot of media attention the last few days about the prospect of a derelict Russian passenger ship, the Lyubov Orlova, crossing the Atlantic from Canada (where it was last berthed) and crashing into Ireland or Britain, spilling disease-ridden, inbred, cannibal rats on their shores. The ship was being towed to the Dominican Republic when it broke away and floated off last year. The Sun has had perhaps the most dire take on the story, headlining their piece “Ship of Ghouls“.

LYUBOV_ORLOVA The Sun
A scary picture from the Sun.

That the ship, laden with cannibal rats, might fetch up on shore, however, seems very unlikely. As the Guardian reports, both the Irish and British coastguards downplay the possibility. In particular, Irish officials note that they have looked for it, can’t find it, and suspect that it may have sunk.

But there’s another reason that it is highly unlikely, having nothing to do with whether or not the ship is still afloat, and because it reveals an important biological principle, it’s worth a mention here at WEIT: an ecosystem without primary producers cannot be sustained except for very brief periods of time. Unless those rats have been raising crops on the ship, the last one, cannibal or not, died some time ago.

There are very few “laws” in biology in the strong sense with which the term “law” is used in physics. Mendel’s “laws” of heredity, for example, have numerous exceptions and limiting conditions. When I teach genetics, I refer to them not as “laws”, but as Mendel’s “useful generalizations”. But one of the biological principles that does have law-like status is that primary producers must be at the base of every food web, and that energy is lost at every step in the food chain. Perhaps the reason these principles are law-like is because they derive so directly from the laws of thermodynamics: energy must be put in to a system to avoid entropy increase (so we must have producers to capture energy) and no energy transfer is 100% efficient (so there’s less energy available further up the food chain than at the bottom).

These ecological principles are often expressed in terms of a “trophic pyramid“, a visual representation of the fact that primary producers (usually green plants that capture energy by photosynthesis, but also photosynthetic and chemosynthetic bacteria) outnumber herbivores (primary consumers), who outnumber carnivores (secondary consumers), who outnumber top carnivores (tertiary consumers; there are rarely more than four or five levels in a food chain).

Trophic pyramid.
Trophic pyramid.

The exact shape of the pyramids depends on the efficiency of energy transfer between levels, and whether the pyramid is based on number of individuals, biomass, or energy flow units. As a rough guideline, efficiency of transfer between levels is often estimated at about 10%; the efficiency of capture of solar radiation is much lower. These important details can be investigated here and here, for example, but they do not alter the fundamental principles.

Viewing ecosystems in this manner owes much to an extremely influential paper, “The trophic-dynamic aspect of ecology“, by the young limnologist Raymond Lindeman, who tragically died of an obscure form of hepatitis a few months before the paper was published. The very interesting story of how the paper was almost not published, first being rejected by Ecology for being too theoretical, but finally accepted, has been told by Bob Cook.

Raymond Lindeman (1915-1942). He could have told you why there are no cannibal rats threatening Ireland and the UK.
Raymond Lindeman (1915-1942). He could have told you why there are no cannibal rats threatening Ireland and the UK.

So, what does this all mean for the people of Ireland and Britain? You can relax. Although rodents will resort to cannibalism when food supplies run low (though I’ve never seen it in rats myself, which, by the way, are much friendlier and make better pets than mice), an ecosystem based on cannibalism cannot persist, because there is no energy input to the system, and there cannot be a 100% efficient transfer, so the rat-level in the “food chain” will continually decrease in number and biomass. How long a bunch of rats resorting to cannibalism would last depend on details such as the number of rats, their caloric needs, etc., but suffice it to say that no reasonable numbers for those details could get the rats to last nearly a year. The caloric needs of mammals are quite high, and they need to eat a lot. (This may not be a comforting thought, but a ship full of anacondas and reticulated pythons could last a year or more at sea, without even having to eat one another, because of their low caloric needs. They would come ashore hungry, though.) The reason I say “probably”, rather than “definitely”, is because it is conceivable that large stores of food were left behind, and depending on the quantity, these could support a rat population for some time (recall that in most zombie movies the survivors rely on canned goods for survival, although in the last season of the Walking Dead they did begin farming). But since the ship was being towed for salvage, I doubt the kitchens and larders were full.

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Cook, R.E. 1977. Raymond Lindeman and the trophic-dynamic concept in ecology. Science 198:22-26. pdf

Lindeman, R.L. 1942. The trophic-dynamic aspect of ecology. Ecology 23:399-418. pdf

Sterner, R.W. 2012. Raymond Laurel Lindeman and the trophic dynamic viewpoint. Limnology and Oceanography Bulletin 21:38-50. pdf

Python regurgitates dog

September 30, 2013 • 1:01 pm

JAC Warning: This stuff is graphic, so if you are a d*g lover you may not want to watch.

by Greg Mayer

A video of a python disgorging a dog on a street in Bangkok is making the rounds, and has been the subject of an article in the Daily Mail.

The python appears to be a reticulated python (Python reticulatus). The video dramatically illustrates the flexibility and movability of snakes’ jaws. In most reptiles, the lower jaw articulates with the quadrate bone (q in the picture below), a firm part of the upper jaw. In snakes, the quadrate is only loosely attached to the skull, and there are other points of mobility in the skull. In the lower jaw, the anterior tooth bearing bone on each side, the dentary (d in the picture below), does not have a bony suture with its contralateral partner (as you do– feel your chin just below your lower incisors)– but only a soft tissue connection which is quite stretchable, allowing the two sides of the lower jaw to be widely separated.

Snake jaw. The blue ellipses indicate regions of mobility (and note that the lower jaw connection to the other side is only ligamentous. (From http://borbl426-526.blogspot.com/2012/03/lab-6-serpentes-ophidia-dan-paluh-and.html)
Snake skull. The blue ellipses indicate regions of mobility (and note that the lower jaw connection to the other side is only ligamentous. (From http://borbl426-526.blogspot.com/2012/03/lab-6-serpentes-ophidia-dan-paluh-and.html)

The dog, of course, is quite dead, having been constricted before being swallowed. Constriction compresses the thoracic cavity, and leads to cessation of blood flow, killing the prey even before suffocation occurs. The saliva coating and compression of the dog’s body help it slide out backwards, instead of having the limbs get “stuck” somewhere in the snake’s alimentary canal.

 My guess would be that the snake disgorged the prey because it was being harassed or bothered by people in the street. If it had been in the forest, it would have found a quiet nook in which to digest.

For more on snake feeding, see the refs below.

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Ernst, C.H. & G.R. Zug. 2004. Snakes in Question. 2nd ed. Random House, New York.

Greene, H.W. 1997. Snakes: The Evolution of Mystery in Nature. University of California Press, Berkeley.