Thursday, April 11, 2013

Navigating the complexities of authorship: Part 1 –inclusion


One of the highlights of grad school is publishing your very first papers in peer-reviewed journals. I can still remember the feeling of seeing my first paper appear in print (yes on paper and not a pdf). But what this novice scientist should not be fretting over is which colleagues should be included as authors and whether they are breaking any norms. The two things that should be avoided are including as authors, those that did not substantially contribute to the work, and excluding those that deserve authorship. There have been controversial instances where breaking these authorship rules caused uncomfortable situations. None of us would want someone writing a letter to a journal arguing that they deserved authorship. Nor is it comfortable to see someone squirming out of authorship, arguing they had minimal involvement when an accusation of fraud has been levelled against a paper. How to determine who should be an author can be difficult.






Even though I spell out my own rules below, it is important to be flexible and to understand that different types of papers and differing situations can have an impact on this decision. That said, you do not want to be arbitrary in this decision. For example, if two people contribute similar amounts to a paper, you do not want to include only one because you personally dislike the other. You should have a benchmark for inclusion that can be defended. The cartoon above highlights the complexity and arbitrariness of authorship –and the perception that there are many instances of less than meritorious inclusion.

Journals do have their own guidelines, and many now require statements about contributions, but even these can be vague, still making it difficult to assess how much individuals actually contributed. When I discuss issues of authorship with my own students, I usually reiterate the criteria from Weltzin et al. (2006). I use four criteria to evaluate contribution:
1)   Origination of the idea for the study. This would include the motivation for the study, developing the hypotheses and coming up with a plan to test hypotheses.
2)   Running the experiment or data collection. This is where the blood, sweat and tears come in.
3)   Analyzing the data. Basically moving from a database to results, including deciding on the best analyses, programming (or using software) and dealing with inevitable complexities, issues and problems.
4)   Writing the paper. Putting everything together can sometimes be the most difficult and external motivation can be important.

My basic requirements for authorship are that one of these steps was not possible without a key person, or else there was a person who significantly contributed to more than one of these. Such requirements mean that undergraduates assisting with data collection do not meet the threshold for authorship. Obviously these are idealized and different types of studies (e.g., theory or methodological papers) do not necessarily have all these activities. Regardless, authors must have contributed in a meaningful way to the production of this research and should be able to defend it. All authors need to sign off on the final product.

While this system is idealized, there are still complexities making authorship decisions difficult or uncomfortable. Here are three obvious ones –but there are others.

Data sharing
Large, synthetic analyses require multiple datasets and some authors are loath to share their hard work without credit. This is understandable, as a particular dataset could be the product of years of work. But when is inclusion for authorship appropriate? It is certainly appropriate to offer authorship if the questions being asked in the synthesis overlap strongly with planned analyses for the dataset. Both the data owner and the synthesis architect have a mutual interest in fostering collaboration. In this case every effort should be made to include the data owner in the analyses and writing of the manuscript.

When is it not appropriate to include data owners as authors? First and foremost, if the data is publically available, then it is there for further independent investigation. No one would offer authorship to each originator of a gene sequence in Genbank. Secondly, if it is a dataset that has already been used in many publications and has fulfilled its intended goals, then it should be made available without authorship strings. I’ve personally seen scientists reserve the right of authorship for the use of datasets that are both publically available and have satisfied the intended purpose long ago.

The basic rule of thumb should be that if the dataset is recent and still being analyzed, and if the owner has an interest in examining similar questions, then authorship should be offered –with the caveat that additional work is required, beyond simply supplying the data.

Idea ontogeny
I thought about labeling this section ‘idea stealing’ but thought that wasn’t quite right. An idea is a complex entity. It lives, dies and morphs. It is fully conceivable to listen to a news story about agricultural subsidies, which somehow spurs an idea about ecosystem dynamics. We all have conversations with colleagues and go to talks, and these interactions can morph into new scientific ideas, even subconsciously. We need to be careful and acknowledge how much an idea came from a direct conservation with another scientist. Obviously if a scientist says “you should do this experiment…”,  then you need to acknowledge them and perhaps turn your idea into a collaboration.

Funding
Now here is the tricky one. Often people are authors because they control the purse strings. Yes, a PI has done an excellent job of securing funding, and should be acknowledged for this. If the study is a part of a funded project, where the PI developed the original idea, then the PI fully deserves to be included. However, if the specific study is independent from the funded project in terms of ideas and work plan, but uses funding from this project, then this contribution belongs in the acknowledgements and does not deserve authorship. There are cases where the PI of an extremely large lab gets dozens of papers a year, always appearing last in the list of authors (see part 2 on author order -forthcoming), and it is legitimate to view their contributions skeptically. Their relationship to many of the papers is likely financial and they probably couldn’t defend the science. I had a non-ecologist colleague ask me if it was still the case that graduate students in ecology produce papers without their advisors, to which I said yes (Caroline has several papers without me as an author).

Clearly there are cultural differences among sub disciplines. However, I do feel that authorship norms need to be robust and enforced. Cheaters (those gratuitously appearing on numerous papers –see part 3 on assigning credit; also forthcoming) reap the rewards and benefits of authorship, with little cost. It is disingenuous to list authors that have not have a substantial input into the publication, and the lead author is responsible for the accuracy of authorship. The easiest way to ensure that authors are really authors is to make an effort to include them in various aspects of the paper. For example, give them every opportunity to provide feedback –send them the first results and early drafts, have Skype for phone meetings with them to get their input and incorporate that input. Ultimately, we all should walk away from a collaboration feeling like we have contributed and made the paper better, and we should be proud to talk about it to other colleagues.


Many of these ideas were directly informed by this great paper by Weltzin and colleagues (2006):

Weltzin, J. F., Belote, R. T., Williams, L. T., Keller, J. K. & Engel, E. C. (2006) Authorship in ecology: attribution, accountability, and responsibility. Frontiers in Ecology and the Environment, 4, 435-441.

http://www.esajournals.org/doi/abs/10.1890/1540-9295(2006)4%5B435:AIEAAA%5D2.0.CO%3B2 

Friday, April 5, 2013

Measuring the Pacific extinction spasm


ResearchBlogging.orgIt is a fact that humans have caused numerous extinctions around the globe. Almost all of the large bodied mammals of North America disappeared after the arrival of humans sometime around 20,000 years ago –likely due to compounding effects of hunting and climate change.  This North American example has been controversial, largely because it constitutes a single observation. However, humans colonized the Pacific islands over a span of a couple of thousand years, between 3,500 to 700 years ago. Species extinctions followed these colonizations on each island, confirming the link between humans and extinctions. Yet how many species went extinct? This question may be relatively easily answered for large organisms since evidence of their existence is well recorded, but for small-bodied organisms like birds, this is a difficult question to answer.


In a recent paper in the Proceedings of the National Academy of Sciences, Richard Duncan, Alison Boyer and Tim Blackburn use sophisticated methods to estimate the true magnitude of bird (specifically nonpasserines –i.e., not perching or songbirds) extinctions on 41 Pacific islands (including islands from Hawaii, Melanesia, Micronesia and Polynesia). Estimating the number of extinctions prior to recorded history is an extremely difficult exercise, but Duncan and colleagues use a set of statistical methods (Bayesian mark-recapture) to produce reliable estimates. The data available include a spotty fossil record, and so the researchers needed an appropriate estimate of the number of species present on islands in the past. To do this they examined the fossil record and compared it to species that are found there today. Only a subset was found in the fossil record. From this, they determined how the number of fossils found, body size of the organisms and island size affected detection probability. With these informative detection probabilities, they were able to estimate past richness and compare that to today’s richness – and the difference is the number of extinctions.

Across these 41 islands, Duncan et al. estimate that human colonization resulted in at least 983 extinctions. Nine-hundred and eighty-three species are no longer with us because of the presence of humans. Coupled with human activities elsewhere, from over-hunting, habitat destruction and the introduction of non-native species, we responsible for thousands of extinctions. For the first time in Earth’s history, a single species (us) is the direct cause for thousands of other species going extinct. A paper such as this is an important analysis, but it certainly doesn’t make us feel good about ourselves.

Duncan, R., Boyer, A., & Blackburn, T. (2013). Magnitude and variation of prehistoric bird extinctions in the Pacific Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1216511110

Wednesday, April 3, 2013

Gendered assumptions and science: still a problem

Sometimes I feel like covering sexism and science has the potential to trigger a weary response, a feeling that this is well-travelled territory. And generally, academia is fairly self-aware about the causes and consequences of its current gender gap (see the special issue in Nature). But then I hear or read something that disappointingly reminds me that society as a whole still has a ways to go.

The first was a minor story. The curator of “I f--king love science”, a widely-followed Facebook page on things scientific and otherwise, happened to reveal that they were Elise Andrew--a female. While this seemed to be a non-event, apparently young men everywhere (i.e. on the internet) were shocked that their mental picture of a male scientist was untrue. Many comments fell along the lines of “you’re a girl?!” and “all that time picturing a man!”. Even more frustrating was that commenters also mentioned Elise’s appearance – attractive and female and a scientist--apparently this was so surprising as to be worthy of comment. And while I wanted to dismiss this as being limited to problems with Internet culture and hardly indicative of larger societal trends, something else happened – Yvonne Brill, a brilliant American rocket scientist passed away. Her work on propulsion systems now helps keep communications satellites in orbit, and she was a successful engineer with an interesting career. She clearly deserved a national obituary, and she got one in the New York Times. It started:

“She made a mean beef stroganoff, followed her husband from job to job and took eight years off from work to raise three children. “The world’s best mom,” her son Matthew said.

But Yvonne Brill, who died on Wednesday at 88 in Princeton, N.J., was also a brilliant rocket scientist, who in the early 1970s invented a propulsion system to help keep communications satellites from slipping out of their orbits.”

By way of comparison, not one of Steve Jobs’ obituaries started with a mention of his hobbies or personal accomplishments, or his status as a father. The only other recently (2012) deceased female scientist I could think of, astronaut Sally Ride, similarly received an obituary in the NYT that emphasized her gender - "American Woman Who Shattered Space Ceiling".

The need of society, reporters, and popular culture to reconcile a female scientist’s gender with their occupation appears to still be common. So much so that the one science writer came up with the Finkbeiner Test (Columbia Journalism Review) to point out articles which rely on the “she’s a woman AND a scientist” trope. Such articles tend to mention:
  • The fact that she’s a woman 
  • Her husband’s job 
  • Her child-care arrangements 
  • How she nurtures her underlings 
  • How she was taken aback by the competitiveness in her field 
  • How she’s such a role model for other women 
  • How she’s the “first woman to…” 
The point is not that it is always unacceptable to include such things in articles, but that unless the article is about sexism or balancing work-life balance, these facts are irrelevant when reporting on a scientist's professional accomplishments. Gender shouldn't be the default position when we consider scientists who happen to be women. And apparently this message still needs to be repeated. Some people have suggested that one equalizer is to simply to also ask male scientists about their personal lives more often. However writer Finkbeiner notes that these questions rarely improve science journalism: "They’re [scientists] all normal human beings and the thing that makes them so interesting is the science. So, if you want to humanize them, talk about their motivations. Talk about how they got interested in their field. Talk about the part of their life that led them to become such an interesting scientist—because childcare is not interesting."

Note: while problems with gendered assumptions is a very general societal issue, academia isn't totally blameless. Having served on a number of lecture organizing committees, I've noticed that if the email for speaker nominations doesn't explicitly say that we wish to nominate male and female scientists at the top of their careers, female scientists are rarely nominated. Students' mental image of a top scientist tends to skew male. If that simple note is included though, nominations begin to approach gender ratios for professors at that career stage.

Tuesday, April 2, 2013

Carbon sequestration in boreal forests: below-ground interactions matter


One of the most important developments in plant ecology over the last 20 or so years is the inclusion of belowground interactions with fungi into traditional studies of plant diversity, productivity, and ecosystem functions. Results like those from van der Heijden (1998)--which showed experimentally that the assumed link between ecosystem function and plant diversity was actually driven by arbuscular mycorrhizal fungal diversity (through their effects on plant communities)—must alter how we see plant community dynamics. Not only does this reinforce the importance of complexity in ecology, but more specifically it suggests that if fungi are a necessary component of plant community identity and function, they must be explicitly considered in management and conservation plans.

For example, an important current issue is the question of which ecosystems will be carbon sinks as part of a focus on atmospheric CO2 levels. Understanding the mechanisms by which carbon is stored is therefore an important topic. Boreal forests sequester net amounts of carbon in soil and it is generally assumed that this is as a result of plant litter and organic matter accumulating in soil. Clemmensen et al. (2013) examined soil chronosequences for forested islands in Sweden to test whether this hypothesis held. These islands differed in the frequency of fire occurrences, between large and frequently burnt islands and smaller, infrequently burnt islands.

The authors identified the age since fixation of C found in the chronosequences and used models of C source to look at the relative contribution of the two possible processes: either fixation of C through aboveground plant litter or below-ground inputs through root-associated fungi. Carbon input tended to be higher on the small islands that were burnt less often, and this was associated entirely with root-derived input. Further, DNA barcoding showed that on these small islands, there were mycorrhizal fungi associated with the soil depths where the root-derived inputs were occurring. On islands which burned more frequently, and had lower carbon input, fungi were absent at these depths (figure below). This difference in fungal profile was related to the fact that infrequently burnt islands had older mycelium with low turnover, hence greater carbon sequestration.
From Clemmensen et al (2013). A) Fungal functional groups associated with soil depths on large, frequently burnt islands (panel 1) and small, infrequently burnt islands (panel 2).

The authors convincingly show that, at least in some ecosystems, the view that decomposition of litter primarily drives humus accumulation (and the accompanying carbon sequestration) must be tempered with the knowledge that organic layers also accumulate from below by roots and root-associated fungi. This suggests that there is a need to consider fungal communities as well as plant communities for when managing forests and making inventories of global carbon stores. And probably a need to consider fungi much more often in general.

Monday, March 18, 2013

Evolution on an ecological scale


Andrew Gonzalez, Ophélie Ronce, Regis Ferriere, and Michael E. Hochberg. 2013. Evolutionary rescue: an emerging focus at the intersection between ecology and evolution. Philos Trans R Soc Lond B Biol Sci. 368 (1610).doi: 10.1098/rstb.2012.0404 (Intro to special issue).

David A. Vasseur, Priyanga Amarasekare, Volker H. W. Rudolf, Jonathan M. Levine. 2011. Eco-Evolutionary Dynamics Enable Coexistence via Neighbor-Dependent Selection. The American Naturalist, Vol. 178, No. 5, pp.E96-E109.

Ecology and evolution are often treated as connected but ultimately discrete areas of study. Ecological processes are usually the main source of explanation for ecological patterns and  ecologists may ignore evolutionary processes under the assumption that these are most important over longer time scales than are of interest (e.g. speciation). However, there is also an increasing recognition that rapid evolutionary dynamics can contribute to ecological observations. In a time where rapid changes to climate and habitat are the greatest threats to most species, the suggestion that rapid evolution might play a role in extinction prevention and diversity maintenance is an important one.

Increasingly researchers are exploring this concept. The concept of evolutionary rescue (ER), has been particularly championed by Andy Gonzalez and Graham Bell of McGill University. ER results when evolution occurs fast enough to arrest population declines and allow populations to avoid extinction in the face of changing conditions. Changing conditions resulting in maladapted populations should result in population declines followed by extinction. However, if selection for resistant types (which are present in the population, or result from mutations) occurs, population declines can be countered. The result is a characteristic u-shape curve, showing the initial geometric decline, followed by a geometric increase – escape from extinction is then a balance between rates of evolution and success of resistant types compared to rates of population decline.
From Bell & Gonzalez 2009.
The question of whether evolution may have relevance to population declines is not precisely new, but it is especially relevant given we are in a period of habitat changes and extinction. A special issue of Proc B is focused only ER, on the question of its importance, prevalence, and predictability. Many of the articles extend theory, exploring assumptions about the type of environmental change, type and extent of the threat, presence of dispersal, spatial gradients, etc. A few articles attempt the more difficult task of testing for ER in natural systems and assessing its likely prevalence and value to conservation activities. It is an interesting journal issue and a great example of the importance of context in determining when an idea takes off. The theoretical background for evolutionary rescue has existed for many years, but it took the context of climate change (and perhaps the collaboration of an ecologist and evolutionary biologist?) for it to gain ground as an area of ecological research.

Another interesting paper, this one linking evolutionary dynamics with community coexistence, is from Vasseur et al. (2011). In this case, the authors suggest an evolutionary mechanism that could augment coexistence when ecological conditions allow for niche partitioning and that could allow coexistence when ecological conditions lead to competitive exclusion. If species exhibit tradeoffs between traits that are optimal for intraspecific interactions and traits that are optimal for interspecific interactions, evo-ecological dynamics can produce coexistence. Such tradeoff means that a species will be a superior interspecific competitor when rare and a poor interspecific competitor when common. Such a tradeoff creates neatly alternately selective pressures depending on whether a species is common (fitness declines) or rare (fitness increases). This is presented as a theoretical model, but it seems like in a tractable system one could easily test for changes in ecological and evolutionary pressures as predicted by the model.

No one would argue with the conclusion that a closer relationship between ecology and evolutionary biology would be beneficial for both. But in practice this seems to be the exception rather than the rule. "Evolutionary ecology" as it exists is fairly restricted, and if complaints about seminar topics is to provide a hint, most ecologists feel disconnected from evolutionary topics and vice versa. If evolutionary dynamics are relevant on an ecological scale, it seems that we should at least attempt to understand their prevalence and importance in natural systems.


Monday, March 11, 2013

Ecology in everyday life: Monday links

To start, it’s reassuring to know that honeybees like caffeine too. So as you sip your coffee, know that you aren’t the only species who benefits from a little something to start the day.

Citizen science success. iNaturalist.org provides a platform for interested citizens to collect and submit observational data for a huge variety of taxa. This creates an expanding database of species IDs and geographical locations across the US. At present, they have 200,000 observations, which is pretty amazing.

Beautiful wildlife gifs, a reminder that nature is an astonishing place.

Predator/Prey. For some ecologists, work and creative undertakings overlap. So with this in mind, I wanted to point out a band that has taken this marriage of art and ecology to the extreme. Predator/Prey is a Canadian band headed by Dak de Kerhove and Adam Phipps that has released an album built around the concept of species interactions. Dak de Kerkhove is a PhD student studying predator-prey interactions between fish with Peter Abrams and Brian Shuter, so in this case art imitates life.

Most of the songs take inspiration from a combination of emotional subtext and ecological theory. For example, “A Run of Rabbits” focuses on prey dynamics and red queen, with the prey ever running to stay in one place. “Plump of Grouse” is inspired by death and predator prey cycles and written from the perspective of a predator. Because de Kerkhove's work has taken him to the far North, the band can't tour, and instead decided to release a web game that allows you to experience predator-prey interactions from the perspective of a fox. Pretty cool.

**The ecological connections are sometimes subtle, so here is the cheat sheet I was given**
Unkindness of Ravens (INTELLIGENCE / MUTUALISM)
Bed of Mussels (ENDURANCE / PASSIVE FORAGING)
Sounder of Boar (REVENGE / LOSS OF TRAITS UNDER DOMESTICATION)
Knot of Snakes (DESIRE / MATE COMPETITION)
Skulk of Foxes (LOSS / MONOGAMY)
Rout of Wolves (POWER / SOCIAL HIERARCHY)
Priory of Panthers (COOPERATION / GAME THEORY)
Plump of Grouse (DEATH / PREDATOR PREY CYCLES)
Mischief of Mice (OVERWHELMED / COMPETITION)
Shoal of Fish (DEDUCTION / CREPUSCULAR FORAGING)
Run of Rabbits (FEAR / RED QUEEN)
Gang of Elk (ACCEPTANCE / SELFISH HERD)
Piteousness of Doves (LOSS / GAME THEORY) 
                           ****

Wednesday, March 6, 2013

Can you lecture through Twitter?

The question is intriguing, and recently David Shiffman taught a marine bycatch lecture entirely on Twitter. It seems like an excellent way to reach a broad audience and a novel use of social media. I would be interested to know how the participants felt about the content detail. Universities have been diminishing the classroom experience, in favor of online courses, but this Twitter exercise maintains contact with the instructor (as opposed to pre-recorded videocasts with discussion boards monitored by a TA).

Tuesday, March 5, 2013

Evolution of conservation – what counts?

Winter, M., Devictor, V. and Schweiger, O.. 2013. Evolutionary diversity and nature conservation: where are we? Trends in Ecology and Evolution. http://dx.doi.org/10.1016/j.tree.2012.10.015

and the response:

Rosauer, D.F. and Mooers, A.O. 2013. Nurturing the use of evolutionary diversity in nature conservation. Trends in Ecology and Evolution. http://dx.doi.org/10.1016/j.tree.2013.01.014

The problem has been called the agony of choice – available resources for conservation are dwarfed by need. And as a result, we are forced to prioritize, to save some species and lose others. Much of the attention given to phylogenetics in ecology lately is on its use, questionable or otherwise, in ecophylogenetic metrics. However the important and useful research being done relating evolutionary information to conservation decisions deserves more attention.

This work has created a recurrent and sometimes contradictory discussion about whether evolutionary relationships contribute complementary information to traditional conservation targets (e.g. biodiversity, habitat types) and whether such information can easily be incorporated into conservation activities (e.g. Rodrigues et al. 2005; Faith 2008; Rodrigues et al. 2011; Tucker et al. 2012 etc.). A couple of papers recently in TREE are continuing this discussion and together do a nice job of summarizing the state of evolutionarily informed conservation practices. Most interesting about the article and the response is that even the opposing sides of the discussion appear to be converging on the same conclusion—that evolutionary diversity should be incorporated into conservation decisions—and differ primarily in how they justify this and the extent to which they feel it will be useful.

Phylogenetic diversity (PD) can be defined specifically as a measure of evolutionary diversity, however here it is more generally defined as the evolutionary information (e.g. phylogenetic relatedness) represented in a community and a common measure of evolutionary information. A community with high PD might include many distantly related species and hence represent many branches in a phylogenetic tree. The simplest argument for why PD might inform conservation is that maximizing PD will maximize the range of species’ ecologies and function that is conserved. In contrast, species richness targets have no relation to a community’s functionality.

Although the conservation literature includes many studies of phylogenetic diversity that are oriented towards real-world applications, in practice, conservation activities rarely incorporate PD. Winters et al. seem lukewarm about the value of phylogenetically informed approaches (one header is “A promising but yet ambiguous additional biodiversity component for conservation”). They suggest that there are a number of ways in which phylogenetic diversity can be informative: it can act as a measure of rarity and facilitate decision-making if rarity is a priority (and perhaps other measures of rarity not available) (e.g. http://www.edgeofexistence.org/). It may act as additional information to be incorporated with measures of species richness – areas with similar richness may have very different amounts of PD. However, the authors question “But what would the added value of conserving areas or communities of unexpectedly high phylogenetic diversity, or spending money on phylogenetically eroded areas, actually be?” The most common arguments, they suggest, are that phylogenetic diversity is a proxy for functional diversity and/or a measure of the evolutionary potential of a community. However, since ecological/functional similarity is not always correlated with PD, and evolutionary potential is not related to PD in a predictable manner, these are inadequate.

Winters et al. seem to suggest that PD is valuable because it can (but not always) act as a proxy for things we actually want to account for (rarity, etc). This is the point that the response from Rosauer and Mooers has the hardest time with. Why does evolutionary diversity not have intrinsic value if, say, species diversity does? Further, species richness is objectively a poor measure of diversity, since it treats all species as having equal value. In contrast, phylogenetic measures of diversity already account for one difference (evolutionary distinctiveness) between species, and hence should already be more effective in capturing total diversity in an assemblage. Rosauer and Mooers state “In an era of triage, difficult decisions are being made, and we know that inclusion of [evolutionary diversity] could make a substantial difference to the outcome for biodiversity, suggesting that it should be considered as one among many criteria”.

Regardless of differences in motivation, both authors agree that the greatest barrier is actually in bringing these ideas into practice. There are many ways of measuring evolutionary diversity (and species diversity, if we’re being fair) and choosing the correct metric can be a minefield. Calculating measures of evolutionary relationship requires specialized knowledge. On the other hand, it is easier and faster than ever to generate phylogenetic trees using DNA sequence databases and available software. Further, evolutionary information lacks the attractiveness that taxonomic-focused conservation has (it is more exciting to save the tigers than the genes). So what remains is to make the jump from theory and case studies to practice, and to find ways to explain why an echidna should receive more protection than all the other rodents. But if evolutionary information makes the agony of choice a little less, it is a worthy goal.
The power of phylogenies?
(Lanna Jin)
Cited
Faith D.P. (2008). Threatened species and the potential loss of evolutionary diversity: conservation scenarios based on estimated extinction probabilities and phylogenetic risk analysis. Conservation Biology, 22, 1461-1470.
Rodrigues A.S.L., Brooks T.M. & Gaston K.J. (2005). Integrating evolutionary diversity in the selection of priority areas for conservation: does it make a difference? In: Phylogeny and conservation (eds. Purvis A, Gittleman JL & Brooks TM). Cambridge University Press Cambridge, UK, pp. 101-199.
Rodrigues A.S.L., Grenyer R., Baillie J.E.M., Bininda-Emonds O.R.P., Gittleman J.L., Hoffmann M., Safi K. & al. e. (2011). Complete, accurate, mammalian phylogenies aid conservation planning, but not much. Philosophical Transactions of the Royal Society, London, B, 1579, 2652-2660.
Tucker C.M., Cadotte M.W., Davies T.J. & Rebelo A.G. (2012). The distribution of biodiversity: linking richness to geographical and evolutionary rarity in a biodiversity hotspot. Conservation Biology, 25:2.
Vane-Wright (1991). What to protect - systematics and the agony of choice. Biological conservation, 55, 235-254.


Monday, February 25, 2013

Assorted links: predictable evolution, why the US government maybe the best thing for open access, and the lab junk drawer

A few interesting places to start the week. Probably these are worthy of full blog posts, if only I had the time.

A recently published paper in PLOS Biology shows that in multiple experiments, independent  populations of E. coli showed similar processes driving adaptive diversification. That is, similar ecotypes of E. coli arose from different populations, sometimes as a result of the exact same mutations at the same nucleotide position. A really cool result.

Good news on the open access front - the US government revealed a new policy stating that publications from taxpayer-funded research should be made free to read after a year’s embargo. It will remain to be seen how this plays out for most researchers, but it appears to be an important step, and one inline with European policies. It seems like steps made by big governments and universities will ultimately be what will create a new normal in publishing.

Why do biology labs tend to have hoarder-esque tendencies? Even newish labs seem to have a junk drawer of equipment that may or may not work inherited from past tenants, half used primers, ancient samples in a freezer somewhere, and more sharpies that don't work than do. An amusing list of the usual suspects was complied in this comment thread.



Friday, February 22, 2013

Academic ambivalence, part 2: poor prospects

The topic of Caroline's excellent post on why we choose grad school and an academic career seems to be hitting an on-line crescendo. A number of blogs and numerous posts to the ECOLOG listserve have been arguing and lamenting the state of job prospects and the grad school experience in general. What has been lacking is an analysis of the job numbers. In a case of perfect timing, Jordan Weissmann, and The Atlantic, has posted an excellent analysis of the numbers of recent PhDs employed across fields. The general message is: the number of fulltime, permanent jobs waiting for PhDs has been declining. However, the proportion of PhDs taking up post-doctoral postions has not declined (and in fact has increased for many disciplines).

From PhD comics

People in graduate school need to be cognizant of the available options, but it seems that if there is an emerging bottleneck, it certainly is not at the postdoc stage (the proportion of postdocs has not changed recently). Of course, the academic stream is but one option for recent PhDs, and the loss of other opportunities is a serious concern. The graphs in the Weissmann post enumerate full-time jobs, and I wonder how many people are taking up part-time, sessional positions as a way to move forward? Regardless, employment opportunities are changing.

My feeling is that academic institutions should be doing a better job of researching, and presenting viable career options to their graduate students. There are a number of industry, governmental and non-governmental postions out there, but people in academia often have a very limited understanding of these types of positions -where they are, how many are available and what kind of training they are looking for.

Perhaps it is time for graduate programs institute real career training.

Tuesday, February 19, 2013

Academic ambivalence: why do we want to join the academic pipeline?

(This is inspired by a few related posts, and the ongoing discussion in the comments and elsewhere...
http://deepseanews.com/2013/02/19294/)

At the foundations of the University is the concept of academic freedom, unhindered exploration. At their best, universities are reservoirs for society’s brightest and most creative thinkers, people who might not otherwise have the opportunity to explore their intellectual potential. Despite the worst things we might say about academia, it is a place with unmatched room for the exploration. And as a result, academic positions are in constant demand from bright, thoughtful people.

As every grad student learns, academia’s popularity greatly outstrips the availability of research funding and academic positions. Last year there was a string of articles declaiming graduate school as a mistake, a pyramid scam, and an institution in drastic need of rethinking. It’s also a place where students interact with like-minded peers for possibly the first time, succeed or fail at independent research, and experience more responsibility for their own success than many full-time employees ever will. Depending on who you listen to, it will be the best, or the worst, experience of your life.

And then there are tenure track positions. These are the holy grail of the academic pipeline. Advertised positions in ecology often get more than 100 applications for a single job. And yet everyone knows that these jobs are accompanied by a list of problems. They are unremittingly--exhaustingly--competitive, and for that reason, they are associated with long working hours and no concept of “overtime”. The frequent moves between universities mean that relationships can be strained or disrupted, the long hours make family life complicated, and women faculty especially face balancing pregnancy and childrearing with academic demands.

And yet. Hundreds of applicants for every position. So this is the ambivalence about academia: is it one of the best jobs in the world or the worst ones? An (admittedly ridiculous) article in Forbes about how faculty jobs are among the least stressful received rapid condemnation. But this must be reconciled against the fact that many professors choose to remain active years after retirement, and that faculty jobs are often ranked among the most fulfilling.

One consequence of this system of concurrent reward and punishment, with its supply of many similarly-talented people and stochastic element, is a strange culture of competitive martyrship. This shows up in many subtle and less-subtle ways on job boards, in personal conversations, on panels and discussions, in the comments on blog posts. The funniest example I’ve experienced was the comment from a grizzled prof that having a dog would decrease my publication output by one paper a year (I can’t imagine how much a baby would set it back). The saddest examples are people who emphasize that they work 12, 14, 16 hours a day, at the cost of seeing their children and/or spouses. These statements are always made with the confidence that this is the necessary sacrifice for success, that people not willing to give up on balance and hobbies and everything else in life are deserving (or at least risking) failure. The people who make these claims are survivors of the academic arms race. They found one strategy (immense hard work combined with talent) that got them through. But this can create the attitude that those not able or willing to sacrifice aren’t deserving of a position – rather than that the position may demand too much of people.

Such people also tend to be more vocal than other survivors of this arms race who had more success balancing the personal and professional. If you are lucky as a grad student, you know some faculty members who had families, hobbies, personal interests, and managed to be successful academics. This suggests that the dichotomy between personal and professional success is not absolutely necessary.

What we really need is less rhetoric and more open debate about what is acceptable and what is appropriate in academia, and how to shift the culture to be aligned with this. This is difficult, but also not impossible. For example, departments can decide that they want to encourage a particular atmosphere within the department. For example, EEB here at the University of Toronto has decided that they want to support families: as a result, there is a move to provide some maternity funding for graduate students, and provide income for faculty on maternity leave to hire a postdoc during this time. The hope is that this postdoc will help reduce the publication gap that having children can cause by maintaining research activities, while also providing support to current undergraduate and graduate students. Obviously this is only a drop in the bucket. But what matters is that we recognize that academia combines both good and bad, and merely selecting for those people who can survive the bad isn’t optimal. Instead, we can try to make academia a place where the best people can thrive. In this I am, and hope to remain, an idealist.


Monday, February 11, 2013

The birds and the bees and the microbes

Vannette et al. 2013. “Nectar bacteria, but not yeast, weaken a plant-pollinator mutualism”. Proceedings of the Royal Society B-Biological Sciences.

"When we try to pick out anything by itself, we find it hitched to everything else in the Universe."- John Muir

You can’t help but marvel at the complexity of ecology, at the intricacy and multiplicity of species interactions. But this complexity is also problematic. For many ecologists, it becomes necessary to focus on a single type of interaction, or on interactions limited to only a few species. But real ecological systems are hardly ever limited to a single important process. They might include competition, mutualism, facilitation, predation, environmental constraints and fluctuations, additive and interactive effects, nonlinearities, thresholds and emergent properties. Can knowledge of  omplexity emerge from simplicity? Can simplicity emerge from complexity? These are important and longstanding questions in ecology, the focus of some of our smartest minds. We may not have the answer yet, but if nothing else, it is helpful when experimental work in community ecology attempts to explore multiple interactions.

For example, some of the work from Tadashi Fukami’s lab is focused on how communities of microorganisms (yeast and bacteria species) assemble in Mimulus aurantiacus nectar. In the past, this work has focused particularly on priority effects and resource competition, which plays an important role in structuring these communities. While past work has suggested the importance of pollinators as a dispersal vector for microorganisms, fascinating new work suggests that microbial communities have important effects on pollinators and their mutualistic interactions with the host plant as well.

Vannette et al. (2013) focused on the effects of the two most abundant species in Mimulus nectar, Gluconobacter sp., an acid-producing bacteria, and Metschnikowia reukaufii, a yeast. They then looked at three related questions – how do nectar microbes affect nectar chemistry, how do they affect nectar removal by hummingbird pollinators, and how to they affect pollination success and seed set. Basically, do nectar microbes disrupt important mutualistic interactions between the plant and their pollinators, or are their effects neutral?

This is where the story becomes interesting. Both types of microbes altered nectar chemistry, but in different ways. The bacteria acidified the nectar (to ~ pH 2.0) far more than the yeast species, and tended to also reduce the sugar content of the nectar far more than the yeast. Hypothesizing that these changes could ultimately affect pollinator preference, the authors then filled artificial flowers with nectar containing either the bacteria, yeast, or no microbes. Half of these flowers were bagged to prevent hummingbird access. Compared to the bagged controls, flowers with bacteria-inoculated nectar had less nectar removed than either yeast-inoculated or sterile nectar. It appeared that nectar removal was related to the changes in chemistry driven by bacterial growth in the nectar. Finally,  the authors looked pollination success in relation to microbial inoculation. Flowers inoculated with bacteria did indeed have less pollination success (measured as the number of stigmas closed) and had decreased seed numbers. Microbial communities were not isolated from the ecology of the plant.

Perhaps none of this is that surprising – hummingbirds are intelligent and will preferentially feed, and pollinator choice is important for plant fitness. However, these bacteria and yeast species are specialized for growth in the hypertonic nectar environment and their continued presence in the ecosystem depends on dispersal from one flower to the next before their host flower dies. The transient nature of this nectar habitat suggests that obtaining a dispersal vector should be important. The fact that Gluconobacter alters nectar chemistry in a way which negatively affects their likelihood of movement to other patches suggests an interesting paradox and a complicated relationship between plants, their nectar microbes, and pollinators. Gluconobacter species growing in Mimulus flowers produce acidifying H+ ions and reduce sugar concentrations in nectar – this increases their likelihood of winning competitive interactions with other microbes in the nectar, which should select for the maintenance of acidifying, sugar-reducing characteristics. But on the other hand, these characteristics reduce the likelihood of being transported to new flowers and persisting in the metacommunity. Further, these pollinator-decreasing characteristics may result in selection by the Mimulus plants for nectar compounds that reduce microbial contamination. So understanding competitive interactions in microbial communities, or understanding pollinator-plant interactions, or understanding pollinator-microbial interactions on their own might be inadequate to understand the important ecological and evolutionary processes structuring the entire system.

Given that the question of simplicity vs. complexity is still so difficult and at least for me, uncertain, I would hesitate to draw a general conclusion about whether this is the kind of work all community ecologists should strive for. But it seems that recognizing ecological and evolutionary context is key, whether you work with Arabidopsis, microcosms, or tropical forests.



Friday, February 1, 2013

Travel the world with the Carnival of Evolution

The latest edition of the Carnival of Evolution, hosted by Lab Rat, is online. Take an evolutionary journey around the world.

Wednesday, January 30, 2013

Exploring biodiversity science: The BioDiverse Perspectives blog

A network of graduate students has started a new blog called 'BioDiverse Perspectives'. The purpose of this blog is to explore and compile seminal papers in biodiversity science.  In some ways this mode of knowledge gathering replaces existing 'Foundations of...' compilations of classic papers. Instead, this blog creates an ever-evolving dialogue about our understanding of the different dimensions of biodiversity. Check it out!

Tuesday, January 29, 2013

A different kind of ecological diversity: on sticking out in academia


This is a guest post from Sarah Hasnain, currently a PhD student in ecology at Queen's University. Sarah did her MSc at the University of Toronto with Brian Shuter on the interplay between environmental and evolutionary processes underlying thermal response in freshwater fish. Sarah was an office mate of mine for a while at the University of Toronto, and we had some interesting conversations about balancing cultural backgrounds and academia.

By the time that I was nine years old, I already knew that I wanted to do something in science. By the time I was eleven, my grandparents had patiently explained that in order to be a research scientist, I need to complete something called a PhD. And by thirteen, after brief flirtations with physics (which seemed cool at the time, and still is), mathematics, and history, I had decided to pursue a career as an ecologist.

My family supported me in my goal of being a scientist, even though they didn't  know what an ecologist was. And as an undergraduate in Canada’s largest, most multicultural city, I didn’t stand out from my fellow classmates, who similarly came from all over the globe. And yet surprisingly, in addition to the usual student woes about finding scholarships, funding and the right academic advisors, the fact that I am a Pakistani female (and until recently a Hijabi) always seemed to play a role in how people responded to my goals. I continue to be asked to explain my career choice and my passion for science on a  regular basis by colleagues, faculty members and visiting scientists  which was and continues to be emotionally exhausting. For example, a senior faculty member followed me to the lab that I worked in as an undergraduate research student, to confirm that I actually worked there. People always came to my posters at conference poster sessions, but a number of them wantied to tell me that they are very glad to have someone “like you” here. One of the determining factors for which PhD labs I wanted to be in was that during the interview, at no point did the potential supervisor asks what made someone from my cultural, ethnic and religious background decide to pursue ecological research. This actually knocked a few labs out of the running.

I understand that my career choice is interesting, considering that ecology is not a field that has historically attracted many Pakistani women. And it’s undeniable that these comments and questions are about people wanting to be open and accepting and welcoming to me. But I can’t help but feel that the constant questions about my background insinuate, probably unintentionally, that my ethnic, religious and cultural affiliations are more interesting than my research. As an ecologist belonging to a minority group, these questions can have the opposite effect – instead of feeling accepted by their interest, I feel like I am constantly justifying my existence in this field. I imagine that for many minority ecologists, the underlying message is that they don't belong here.

Of course I don’t represent all minority, or Pakistani female ecologists. Probably some individuals would appreciate this interest in their background. But others, like myself, may not. Regardless of ethnic, cultural or religious affiliations, ecology is not the expected career choice in North American society. Why is someone like me interested in ecology? Because I like it. Just like everyone else here. 











Wednesday, January 23, 2013

Understanding modern human society through the lens of evolution



We often think about the ways in which evolution has shaped this world, from the amazing diversity of cichlid fishes in the African Great Lakes, to Australian marsupials that seem to replicate strategies that placental mammals have evolved elsewhere (e.g., Tasmanian tiger and the North American wolf). We even look at our own bodies or behaviors to find evolution’s imprint –why do I have a non-functional appendix attached to my intestine? However, we seldom look to important events in human history to examine the effects of evolution, yet, according to Edmund Russell, human history can be better understood through evolution –like my appendix.

Russell is advocating for a new field of inquiry within the study of human history –namely, evolutionary history. When I first read the book jacket, I must admit that I was skeptical. However, this book makes the compelling case that historians gain a much fuller understanding past events by including evolution. Russell’s main claim is that modern civilization is the product of an evolution revolution. Even Russell’s unremarkable dog “Riley, like all dogs, is a testament to the extraordinary power of human beings to shape the evolution of other species”. While citing dogs may seem like a trivial example, it was coevolution that shaped this relationship. Wolves that were less aggressive and less fearful, which tend to be more puppy-like, found benefits by associating with human groups. Human groups that tolerated the presence of these wolves were likely alerted to approaching threats. Even the fact that dogs bark is a product of this relationship. This evolution revolution can similarly explain the domestication of other animals and plants, and ultimately produces the necessary conditions for permanent large settlements.

An important and intriguing underlying theme of this book is that these evolutionary revolutions are not often the product of conscious effort. We are used to the narrative that highlights humans as selecting individuals and driving the evolution towards some goal. But this would require early peoples knowing what they wanted in the end, having a specific goal. In the dog example, do we really think that early humans thought ‘hey, I would like a poodle’? No, the reality is that canines and human changed with one another producing a mutually beneficial outcome. Even the domestication of many of the earliest crop species likely resulted from lazy and sloppy humans. Lazy because humans probably harvested the easiest, most accessible fruits and seeds –selecting for bigger, easily removed fruits that ripened at the same time. Sloppy because seeds were discarded around settlements. Then that laziness again means we looked to those nearby plants for harvesting. Thus evolution has continually informed the development of human civilization and produced the much of the cultural norms today.

While modern cultures may consciously drive evolution through selective breeding and genetic engineering, we are immersed in an evolving world. Diseases that are resistant to drugs, pest that are immune to pesticides, and commercial fish that are now smaller and reproduce earlier are examples of important evolutionary changes that affect human activities and economics. Russell provides evidence that evolution is in part responsible for the industrial revolution, due to some varieties of cotton evolving particular features.

Taken all together, Russell admirably succeeds in his goal of convincing the reader that evolution has influenced much of human civilization. Moreover, his intended audience of historians should be re-assessing previous explanations of important human events by asking the basic question: how has evolutionary change influenced major changes in human history.




Edmund Russell. 2011. Evolutionary History. Cambridge University Press.

Tuesday, January 22, 2013

Bob Paine's footprint

A great post by Ed Yong on Bob Paine's influence on ecology -both conceptually and numerically, with a large number of academic children and grandchildren.

Thursday, January 17, 2013

Who are you writing your paper with?


Choosing who you work with plays an important role in who you become as a scientist. Every grad student knows this is true about choosing a supervisor, and we’ve all heard the good, the bad, and the ugly when it comes to student-advisor stories. But writing a paper with collaborators is like dealing with the supervisor-supervisee relationship writ small. Working with coauthors can be the most rewarding or the most frustrating process, or both. Ultimately, the combination of personalities involved merge in such a way as to produce a document that is usually more (but sometimes less) than the sum of its parts. The writing process and collaborative interactions are fascinating to consider all on their own.

Field Guide to Coauthors
The Little General
The Little General is willing to battle till the death for the paper to follow his particular pet idea. Regardless of the aim or outcome of an experiment, a Little General will want to connect it to his particular take on things. Two Little Generals on a paper can spell disaster.
Little General
The Silent Partner
These are the middle authors, the suppliers of data and computer code, people who were involved in the foundations of the work, but not actively a part of the writing process.
Silent Partner
The Nay-sayer
These are the coauthors who disagree, seemingly on principle, with any attempt to generalize the paper. Given free rein, such authors can prevent a work from having any generality beyond the particular system and question in the paper. These authors do help a paper become reviewer-proof, since every statement left in the paper is well-supported.
Nay-sayer

The Grammar Nazi
The Grammar Nazi returns your draft of the paper covered in edits, but he has mostly corrected for grammar and style rather than content. This is not the worst coauthor type, although it can be annoying, especially if these edits are mostly about personal taste.
Grammar Nazi
The Snail
This is the coauthor that you just don’t hear from. You can send them reminder emails, give them a phone call, pray to the gods, but they will take their own sweet time getting anything back to you. (And yes, they are probably really busy).

 The Cheerleader
The Cheerleader can encourage you through a difficult writing process or fuel an easy one. These are the coauthors who believe in the value of the work and will help motivate you through multiple edits, rejections, or revisions, as needed.
Cheerleader
The Good Samaritan
The Good Samaritan is a special type of person. They aren’t authors of your manuscript, but they read it for you out of pure generosity  They might provide better feedback and more useful advice than any of your actual coauthors. They always end up in the acknowledgements, but you often feel like you owe them more.
Good Samaritan
The Sage
The Sage is probably your supervisor or some scientific silverback. They read your manuscript and immediately know what’s wrong with it, what it needs, and distill this to you in a short comment that will change everything. The Sage will improve your work infinitely, and make you realize how far you still have to go.
Sage

There are probably lots of other types that I haven't thought of, so feel free to describe them in the comments. And, it goes without saying that if you coauthored a paper with me, you were an excellent coauthor with whom I have no complaints. Especially Marc Cadotte, who is often both Cheerleader and Sage :)

Thanks to Lanna Jin for the amazing illustrations!














Wednesday, January 9, 2013

Replicable methods

This has been making the internet rounds: If you were being truly honest in your methods, what would you say?
Overly honest methods in science

Mine would probably something like: "We had a sample size of 260 individuals. It may sound like we planned to have 260 plants, but actually 40 seedlings died, luckily leaving us with a nice round number."

A friend joked that hers would be: "All this work was done with a totally different experiment in mind, but this is all I could salvage."

I'm sure everyone has a few of these...

Monday, January 7, 2013

Reinventing the ecological wheel – why do we do it?


Are those who do not learn from (ecological) history are doomed to repeat it?

A pervasive view within ecology is that discovery tends to be inefficient and that ideas reappear as vogue pursuits again and again. For example, the ecological implications of niche partitioning re-emerges as an important topic in ecology every decade or so. Niche partitioning was well represented in ecological literature of the 1960s and 1970s, which focused theoretical and experimental attention on how communities were structured through resource partitioning. It would be fair to say that the evolutionary causes and the ecological consequences of communities structured by niche differences were one of the most important concepts in community ecology during that time. Fast-forward 30 years, and biodiversity and ecosystem functioning (BEF) research slowly  has come to the conclusion that niche partitioning to explains the apparent relationship between species diversity and ecosystem functioning. Some of the findings in the BEF literature could be criticized as simply being rediscoveries of classical theory and experimental evidence already in existence. How does one interpret these cycles? Are they a failure of ecological progress or evidence of the constancy of ecological mechanisms?

Ecology is such a young science that this process of rediscovery seems particularly surprising. Most of the fundamental theory in ecology arose during this early period: from the 1920s (Lotka, Volterra), 1930s (Gause) to 1960s (Wilson, MacArthur, May, Lawton, etc). There are several reasons why this was the foundational period for ecological theory – the science was undeveloped, so there was a void that needed filling. Ecologists in those years were often been trained in other disciplines that emphasized mathematical and scientific rigor, so the theory that developed was in the best scientific tradition, with analytically resolved equations meant to describe the behaviour of populations and communities. Most of the paradigms we operate in today owe much to this period, including an inordinate focus on predator-prey, competitive interactions, and plant communities, and the use of Lotka-Volterra and consumer-resource models. So when ecologists reinvent the wheel, is this foundation of knowledge to blame, is it flawed or incomplete? Or does ecology fail in education and practice in maintaining contact with the knowledge base that already exists? (Spoiler alert – the answer is going to be both).

Modern ecologists face the unenviable task of prioritizing and decoding an exponentially growing body of literature. Ecologists in the 1960s could realistically read all the literature pertaining to community ecology during their PhD studies –something that is impossible today with an exponentially growing literature. Classic papers can be harder to access than new ones: old papers are less likely to be accessible online, and when they are, the quality of the documents is often poor. The style and accessibility of some of these papers is also difficult for readers used to the succinct and direct writing more common today. The cumulative effect of all of this is that we read very little older literature and instead find papers that are cited by our peers.

True, some fields may have grown or started apart from a base of theory that would have been useful during their development. But it would also be unfair to ignore the fact that ecology’s foundation is full of cracks. Certain interactions are much better explored than others. Models of two species interactions fill in for complex ecosystems. Lotka-Volterra and related consumer-resource models make a number of potentially unrealistic assumptions, and parameter space has often been incompletely explored. We seem to lack a hierarchical framework or synthesis of what we do know (although a few people have tried (Vellend 2010)). When models are explored in-depth, as Peter Abrams has done in many papers, we discover the complexity and possible futility of ecological research: anything can result from complex dynamics. The cynic then, would argue that models can predict anything (or worse, nothing). This is unfair, since most modelling papers test hypotheses by manipulating a single parameter associated with a likely mechanism, but it hints at the limits that current theory exhibits.

So the bleakest view of would be this: the body of knowledge that makes up ecology is inadequate and poorly structured. There is little in the way of synthesis, and though we know many, many mechanisms that can occur, we have less understanding of those that are likely to occur. Developing areas of ecology often have a tenuous connection to the existing body of knowledge, and if they eventually connect with and contribute to the central body, it is through an inefficient, repetitive process. For example a number of papers have remarked that invasion biology has dissociated itself from mainstream ecology, reinventing basic mechanisms. The most optimistic view, is that when we discover similar mechanisms multiple times, we gain increasing evidence for their importance. Further, each cycle of rediscovery reinforces that there are a finite number of mechanisms that structure ecological communities (maybe just a handful). When we use the same sets of mechanisms to explain new patterns or processes, in some ways it is a relief to realize that new findings fit logically with existing knowledge. For example niche partitioning has long been used to explain co-occurrence, but with a new focus on ecosystem functioning, it has leant itself as an efficacious explanation. But the question remains, how much of what we do is inefficient and repetitive, and how much is advancing our basic understanding of the world?

By Caroline Tucker & Marc Cadotte