Tomorrow I fly out to Minneapolis for Evolution 2008, the joint annual meeting of the Society for the Study of Evolution, the American Society of Naturalists, and the Society of Systematic Biologists. I’m going to be presenting an ancestral trait reconstruction that traces the origins of the yucca-yucca moth interaction. Should be a blast!
Category Archives: science
Science 2.0 revisited
Back in March, Science ran a Perspectives piece in which computer scientist Ben Shneiderman suggested that the wealth of new data on human interactions provided by the Internet (Facebook, Amazon.com customer records, &c.) would require a new approach to science, which he called “Science 2.0” [subscription]:
… the Science 2.0 challenges cannot be studied adequately in laboratory conditions because controlled experiments do not capture the rich context of Web 2.0 collaboration, where the interaction among variables undermines the validity of reductionist methods (7). Moreover, in Science 2.0 the mix of people and technology means that data must be collected in real settings … Amazon and Netflix became commercial successes in part because of their frequent evaluations of incremental changes to their Web site design as they monitored user activity and purchases.
Science 2.0 sounded, to me, a lot like what ecologists and evolutionary biologists often do – hypothesis testing based on observations, manipulations of whole natural systems in the field, and the clever use of “natural experiments” sensu Diamond [subscription]. I said as much in a post shortly after Shneiderman’s article ran, and also wrote a brief letter to Science.
And now it turns out they’ve published it! My letter, along with a response from Shneiderman, is in the 6 June issue [subscription]. You can read it in PDF format here. In very short form, I say:
… what Shneiderman calls Science 1.0 has always included methods beyond simple controlled experiments, such as inference from observation of integrated natural systems and the careful use of “natural experiments” (1) to test and eliminate competing hypotheses.
Shneiderman’s response concedes the point on natural experiments, but says he was actually talking about manipulative experiments conducted on large online social networks:
Amazon and NetFlix designers conduct many studies to improve their user interfaces by making changes in a fraction of accounts to measure how user behaviors change. Their goal is to improve business practices, but similar interventional studies on a massive scale could develop better understanding of human collaboration in the designed (as opposed to natural) world …
That still sounds to me like ecological experimentation, but with people’s Facebook accounts instead of (to pick an organism at random) yucca moths. Maybe I’m just not getting it, but I don’t see anything in Shneiderman’s description that qualifies as a new kind of science.
References
Shneiderman B. 2008. Science 2.0. Science 319:1349-50.
Diamond J. 2001. Dammed experiments! Science 294:1847-8.
Yoder, JB, and B Shneiderman. 2008. Science 2.0: Not So New? Science 320:1290-1.
Selfishness aids cooperation
In evolutionary ecology, cooperation is a perpetual puzzle. It makes sense for organisms to help each other if they can reliably expect to be repaid in kind some time in the future, but cooperative societies are vulnerable to invasion by folks who selfishly accept help without returning the favor. The classical theoretical result is that, once selfishness evolves in a cooperative society, selfish individuals are able to out-compete cooperative ones, until cooperation (and, potentially, the society) dies away altogether.
One possible way to prevent this outcome is for cooperative individuals to punish selfishness, for instance by refusing to help those who don’t reciprocate. In this week’s PNAS, a new paper suggests that another way to stabilize cooperation is to have selfish individuals punish selfishness themselves [subscription needed].
As the authors put it,
This behavior might seem hypocritical in moral terms, but it makes sense as an evolutionary strategy. It can even be looked upon as a division of labor, or mutualism, whereby cheating during first-order interactions becomes a “payment” for altruism (punishment) in second-order interactions.
In other words, these “selfish punishers” may not return cooperation in kind, but they pay for it by punishing other selfish individuals. Ayn Rand would probably love this stuff, but it puts me in mind not of unfettered individualism but a feudal society – a mass of cooperators working for the benefit of the “greater good,” with a handful of punishers taking the benefits of that work and keeping everyone else in line.
Reference
Eldakar OT and DS Wilson. Selfishness as second-order altruism. PNAS 105(19): 6982-6.
On the state of American (well, Idahoan) education
As part of a bet, a friend of mine in the department put the following question on the final for her introductory biology class:
Plans are living organisms – True, or false?
9.5% of her students answered FALSE. For added perspective, 12% forgot to bring a pencil to the final exam.
First Joshua tree article online
The first publication from the Pellmyr Lab’s study of Joshua trees and their pollinators, in which we demonstrate significant, potentially coevolved, morphological differences in Joshua trees pollinated by different species of yucca moths, is now online at the American Naturalist’s website. My understanding is that it’ll be in the print edition this June.
Godsoe W, JB Yoder, CI Smith, and O Pellmyr. 2008. Coevolution and Divergence in the Joshua Tree/Yucca Moth Mutualism. The American Naturalist 171.
Global weirding: bats dying off
NY Times: bats are dying off in huge numbers throughout the Adirondacks. No one seems to know why, but symptoms include low fat reserves and susceptibility to some sort of superficial fungus. Puts me in mind of colony collapse disorder in honeybees – another unexplained disaster befalling ecologically critical species.
It’s frankly scary. This is the kind of thing we might expect as a result of climate change and a general increase in human interference in natural systems: gradual changes having sudden, nonlinear effects. We’re dismantling our own life-support system for parts, and we don’t even know which bits are important.
Science 2.0? New data, but not new methods
In a Perspectives piece in this week’s Science, Ben Shneiderman argues that we need a new kind of science [subscription] to deal with human interactions via the Internet. He calls this “Science 2.0”:
The guiding strategies of Science 1.0 are still needed for Science 2.0: hypothesis testing, predictive models, and the need for validity, replicability, and generalizability. However, the Science 2.0 challenges cannot be studied adequately in laboratory conditions because controlled experiments do not capture the rich context of Web 2.0 collaboration, where the interaction among variables undermines the validity of reductionist methods (7). Moreover, in Science 2.0 the mix of people and technology means that data must be collected in real settings (see the figure). Amazon and Netflix became commercial successes in part because of their frequent evaluations of incremental changes to their Web site design as they monitored user activity and purchases.
Good evolutionary ecologist that I am, I read this and said to myself, “Science 2.0 sounds like what I already do.” Biologists have been using methods beyond controlled laboratory experiments and collecting data in “real settings” to test hypotheses since Darwin’s day and before (see Jared Diamond’s discussion of natural experiments found in “real settings” [subscription]).
As an example of Science 2.0 methods, Shniederman shows a chart mapping collaborations between U.S. Senators, a version of which is available here. It’s an informative picture – you can see immediately that “independents” Joe Lieberman and Bernie Sanders are a lot more connected to the Democrats than the Republicans, and that a relatively small number of senators act as “bridges” between the two parties. But it’s not clear to me why this represents a new method (apart from the visualization technology behind it) – couldn’t the same graphic have been compiled from paper voting records in 1920? It might be easier to produce now, but I don’t think the diagram represents a new scientific method. (An analogy: it might be really easy for me to do ANOVAs now, but these statistics pre-date my laptop and R.)
Shniederman also suggests that Science 2.0 will be interested in different kinds of things than hoary old Science 1.0:
Science 1.0 heroes such as Galileo, Newton, and Einstein produced key equations that describe the relationships among gravity, electricity, magnetism, and light. By contrast, Science 2.0 leaders are studying trust, empathy, responsibility, and privacy.
He cites a “fivefold growth of research on privacy and trust,” based on a literature search, but doesn’t elaborate on how these topics require truly new methods. Again, I’d suggest that Science 1.0 was interested in human interactions, too (just ask a Sociobiologist), but it didn’t have the data provided by the Internet until, well, about 10 years ago. I’d wager that none of the studies turned up by Shneiderman’s lit search do anything radically new, methods-wise.
It’s certainly true that the growth of social networking through the Internet allows scientists access to data that can answer questions we weren’t able to deal with before. For instance, we have real-time records of people interacting with their friends thanks to Facebook (momentarily pretend this doesn’t creep you out). But the actual methods we’ll use to analyze those data are nothing radically new. On that count, Science 2.0 looks a lot like a Microsoft product upgrade – a new interface “skin” on top of the same basic mechanism.
References:
Shneiderman B. 2008. Science 2.0. Science 319:1349-50.
Diamond J. 2001. Dammed experiments! Science 294:1847-8.
Parasites help figs control pollinators
Fresh off the open-access press at PLoS Biology: parasites may help to stabilize the mutualism between figs and fig wasps.
In nature, mutualistic relationships usually conceal a tug-of-war between interacting species. This is especially clear in the case of pollinating seed parasites, like yucca moths (my favorite) and fig wasps. Both these insects pollinate their eponymous host plants, then lay eggs in the fertilized flowers so their larvae can eat some of the seeds produced. Natural selection should push each interactor to overexploit this deal: the pollinator “wants” to lay lots of eggs, but the plant “wants” to get as many seeds as possible. Yuccas keep yucca moths in check by killing off flowers with too many eggs inside [subscription], but there hasn’t been a similar mechanism found in figs.
Until now. In the new paper, Dunn et al. show that the figs might benefit from parasites that attack the pollinating wasps. Fig flowers grow in “synconia,” hollow globes like the one in the photo above, which are lined inside with tiny flowers. Fig wasps climb inside the synconia to pollinate and lay their eggs in the flowers. Another wasp species parasitizes the pollinators by laying its eggs near pollinator eggs, so their larvae can eat the pollinator larvae when they hatch. Turns out, the parasites lay their eggs from the outside of the synconium, and the flowers inside the synconium vary in how close they are to the outer wall. Any pollinator eggs laid too close to the outer wall of the synconium are nailed by parasites – so the pollinators have an incentive to only lay eggs in the innermost flowers. Neato!
Reference:
Dunn, D.W., S.T. Segar, J. Ridley, R. Chan, R.H. Crozier, D.W. Yu, and J.M. Cook. 2008. A Role for Parasites in Stabilising the Fig-Pollinator Mutualism. PLoS Biol 6(3): e59.
Hey! I know that tree!
Tonight’s All Things Considered hits a long overdue topic as part of NPR’s ongoing “Climate Connections” series: the fate of Joshua trees in a warming world. I say overdue, of course, because two chapters of my dissertation will be on the population genetics and phylogeography of Joshua tree, and it’s hard to spend much time with Joshua trees and not wonder about how they’ll hold up under global warming.
I’ve spent two spring flowering seasons in Joshua Tree National Park, where much of the story centers. The Park is right at the southernmost boundary of Joshua tree’s current range, where (all else being equal) you’d expect to see the impact of warming earliest. As the NPR story points out, there does seem to be low recruitment (growth of young trees to replace old ones as they die) in the southern populations. On top of that, drier conditions are contributing to more frequent wildfires across Joshua tree’s range, and sprawl from Las Vegas and Los Angeles is rolling right through Joshua tree woodlands. The Park staff I’ve talked to (including naturalist Joe Zarki, who’s interviewed for the story) are seriously considering that they may have to take drastic measures to prevent Joshua Tree National Park from losing its namesake trees.
Hummingbirds chirp with their tails
Online at Proc. R. Soc. B: high-speed video and experimental results suggest that male Anna’s Hummingbirds use their tail feathers to produce a chirping sound during courtship displays. This sort of thing is known from other bird species (notably two genera of Manakins), but there was some dispute about how Anna’s Hummingbird chirps. The high-speed video is on You Tube, though it basically only shows a male hummingbird flaring its tail at the bottom of a display dive. The experimental evidence apparently consists of air jet and wind tunnel tests on feathers collected (ouch) from wild birds.
Reference:
Clark, C.J., and T.J. Feo. 2008. The Anna’s hummingbird chirps with its tail: a new mechanism of sonation in birds. Proceedings of the Royal Society Series B.