It’s election season here in the U.S., and the rules for who can vote when and where can be pretty confusing. Here’s a set of infographics from NPR that show voting-related dates for each state.
For Florida, here’s the graphic:
By Greg Henderson and Alyson Hurt. Copyright NPR.
So as of today, Floridians have 11 more days to register to vote. Those already registered can request an absentee ballot right away, or early vote in-person from Oct. 27 through Nov. 3. Florida ballots will be crazy long this year (as in 5-10 pages!), so Floridians should really consider exercising one of these options.
This is timely, since Florida’s first cyclone threat of 2012 is churning toward us in the Caribbean.
Want to see a map of every hurricane tracked since 1851? This is a really cool visualization of this data, though it may take a minute to orient yourself to the map projection:
Click to enlarge. Image copyright IDVsolutions .
Really, this should be called a cyclone map, because it includes all cyclonic storms: both tropical storms and hurricanes/typhoons/cyclones, depending on linguistic preferences. But it’s an American map, so the creator apparently chose to go with “hurricane.” A blog post in which the creator talks about making the map is here.
The brightness intensity of the Atlantic & E. Pacific storms seems enhanced compared to that of the W. Pacific and Indian Ocean storms. I suspect this is because tracking of these storms by NOAA (which is where the dataset comes from) started rather late. It’s a bit unfortunate, because one of the things people will do is compare the prevalence of cyclones in various regions, and the Philippine Sea, S. China Sea, and W. Pacific are very active regions for cyclones. So the overall effect is to give an unbalanced view of the activity in various regions. (Admittedly, I haven’t looked at the data myself, so my concern might be unfounded here.)
One of the questions I’m interested in is how changes in the technology available to create science visualizations have affected the final products. While there are obvious differences related to the final display media- like paper and ink vs. monitors and pixels- other “hidden” technologies also play a part in creating visualizations.
Let’s look at the case of visualizations for which you need to do some sort of math in order to create. These include graphs and charts, but also less obviously number-based visualizations, like those showing the relationships among species.
Essentially, we base our understanding of the relationships among species upon how similar they are. Today, this means classifying many traits of different species, creating a table of the different types of traits each species has, and determining what percentage of traits they share in common.* Then we compare the percent similarity among each species, and use that information to construct phylogenetic trees- visualizations of the relationships among the species.
Example of a phylogenetic tree (c) Surachit CC-BY-SA 3.0
Clearly, some mathematical calculations need to be done here. And the more traits and species you are trying to deal with, the more complex the calculations become. Today’s biologists use computers- and even supercomputers- to help them crunch all the numbers they need to be crunched. Once that step is done, other computer programs help them construct the phylogenetic trees.
So, let’s step back in time to the early days of evolutionary biology. In Darwin’s day, this mathematical approach to evolutionary biology didn’t exist. Species were classified in a more qualitative way, but one that was still based upon similarities and differences. This approach relied more on the judgement of the individual scientist in determining which species were most closely related, rather than a compilation of percentages. The visualizations that resulted relied less on math, and more on individual judgment and traditional conventions of design.
But does this mean that early biologists didn’t use math when creating visualizations? Not at all. Most probably used math at least in some amount to help them figure out relationships between species. And (to get a bit off-topic) they also used complex math for other aspects of biology, such as determining population densities. To help them in this task, they actually had a fair array of tools, such as logarithmic tables, Napier’s bones, slide rules, and possibly even mechanical calculators.**
Modern slide rule (c) ArnoldReinhold CC-BY-SA 3.0
But were these tools really widespread among biologists? And did the introduction of more powerful calculating devices help spur the change in biology that led to the number-heavy world of today? I suspect the answer to the latter question is yes.
So, getting at the title of this post, did Darwin use a slide rule? My (admittedly limited, so far) research hasn’t been able to turn up any examples of this. However, I did find an autobiography of his fellow biologist, Alfred Russel Wallace, that talks about using a slide rule as a boy:
“My brother had one of these rules, which we found very useful in testing the areas of fields, which at that time we obtained by calculating the triangles into which each field was divided. To check these calculations we used the slide-rule, which at once showed if there were any error of importance in the result. This interested me, and I became expert in its use, and it also led me to the comprehension of the nature of logarithms, and of their use in various calculations.” (From Wallace, A. R. 1905. My life: A record of events and opinions. London: Chapman and Hall. Volume 1. via Charles Darwin Online)
If Wallace used a slide rule, it’s reasonable to think Darwin might have too. And early visualizations of evolution probably did use tools other than pens, ink, and straight brainpower.
* I’m oversimplifying this a bit, because another important thing to consider is whether the traits are based on shared ancestry, rather than convergent evolution, and some other factors. Because of these factors, some of the traits in your table are more important than others, so are “weighted” more heavily in your calculations.
** Charles Babbage of Difference Engine fame was a contemporary of Darwin’s, and they even corresponded about his calculating devices.
Metaphors in science can be powerful things- they can provide unifying frameworks for thinking about the world, suggest exciting new insights, or at times color our interpretations so that what we see is what we expect to see. Science is communicated to non-scientists largely through metaphors. Sometimes these communication strategies work, and at other times they don’t.
One of the key metaphors used to describe the pattern of descent with modification or evolution over time is the image of a branching tree. I’ve discussed some of the limitations of the tree metaphor in a previous post; essentially, it’s difficult for us to discard the misleading aspects of the tree metaphor while using other associations to communicate about the pattern of evolution. A current PLoS Biology paper by David Penny points out the problems of conflating a branching pattern of evolution in general with cultural associations of a “tree of life” (an image found in varying forms in several cultures), and points out that the tree metaphor only gives us part of the picture.
But do we have to use a tree metaphor at all? Certainly, the tree does a good job of illustrating common descent, and an okay job of showing the formation of new species (species can form through mechanisms like hybridization that the tree isn’t good at depicting). But no metaphor is perfect. Biologists have used other visual metaphors in the past, such as complex systems of symmetry-based relationships, or maps based on ecological affinities of species, but these have their problems as well.
In my graduate work, I’m using digital tools to expand the range of metaphors we have to communicate about evolution, by creating a dynamic evolutionary map. I’m focusing on avian evolution and the pattern of diversification of bird orders over time. I’ll be writing more about this project in the upcoming months, but in this post I want to share the basic draft pattern of the visualization.
The visualization spans a time period from the Cretaceous (in which we see the hypothesized origin of birds) to the present. This series of gifs is the draft version of the evolution of bird orders over time; each dot represents an order (with some exceptions). When the project is finished, viewers will be able to animate the orders forward in time, as well as examine relationships among orders and the evidence for shared descent. I’m already planning some changes near the beginning of the sequence, based on recent molecular studies. The numbers and cross-hairs will also not be in the final version (I’ve been using them to help me keep track of all the orders as I animate it). You should be able to get a sense for how the animation progresses by clicking through this slideshow:
I ran across this animated GIF today, via Southern Fried Scientist, that vividly illustrates the effects of a century of overfishing on the biomass of fish in the North Atlantic. It’s a pretty stark visual depiction of changes that have happened to the oceans worldwide, in just the past century.
This image wascreated by Information is Beautiful‘s David McCandless from a PEW report on historic declines on several fish species. He posts about the image here, and includes a link to the cited report. In his post, McCandless points out that even by the 1900s, we had had a huge effect on the number of fish (and whales, and turtles, and seals, and sea cows, and so on…) in the sea. So one important thing to keep in mind for context is that the fish abundance from 1900 is not a “pre-human impact” point in time.
I just came across this infographic about the environmental and economic benefits of buying locally-produced products via Food and Tech Connect. The argument here is that we gain disproportionate environmental, economic, and social benefits from purchasing locally-sourced products (mainly food) or purchasing goods from locally-owned businesses, rather than purchasing goods produced far away or from large retail chains.
I don’t disagree with the general argument of the graphic, though I will point out that there are additional nuances to these issues that this graphic doesn’t explore. For example, the environmental costs of shipping produce a long distance via ship can be lower than shipping it a shorter distance via truck. But these types of arguments are notoriously difficult to make in a small space, and this graphic probably serves a purpose in getting people who are completely unaware of these issues to think about them.
I’m also not sure I like the top-down viewpoint and general “sprawl” of the graphic. Granted, it does a good job of conveying far-flung supply chains, but I’d probably want to create something a bit more compact. At any rate, it’s interesting to take a look at.
(Click to view larger original version at eLocal.com.)
One version of the tree of life, by Ernst Haeckel (Wikipedia)
The evolutionary “tree of life” is a well-known metaphor for the broad scope and branching pattern of evolution over time. This metaphor was first developed by Charles Darwin in On the Origin of Species, as a way to help shape his ideas about evolution by natural selection.
Darwin used several of different metaphors in Origin, but the tree of life is key in that it presents his central organizing vision of shared descent, the idea that all species are related and ultimately evolved from a common ancestor in the distant past. From a single starting point in this image, genetic changes in different populations send species down different evolutionary paths. Some of these “branches” survive, and split in turn to end off new branches. Other branches wither, and species become extinct. The species we see today are represented on the tree by new budding twigs, and those species that have become extinct are represented by the woody branches.
The idea that all species are related by common descent from a single ancestor is quite a profound difference between Darwin’s ideas about evolution and other ideas about evolution that had come before. This is probably the aspect of his theory that has been resisted the most by the general public. If all life is related by common descent, what does this imply about humanity and our place in the world? In Darwin’s view of nature, humans are an integral part of the natural environment, rather than in a separate, special position. Because Western religious traditions emphasize a separation between humans and the rest of nature, Darwin’s ideas were (and have remained) controversial.
Cartoon of Darwin as an ape-man, with a tree in the background. (Wikipedia)
In fact, Darwin’s metaphor of the tree of life was so influential in his lifetime that caricatures mocking his idea of common descent generally feature a tree somewhere in the image (while the other common motif is Darwin himself pictured as an ape-man).
What type of tree do you picture when you think about the tree of life?
While the tree of life does a good job of illustrating common descent, this metaphor, like all metaphors, has a few limitations. For one, the tree in the metaphor is often depicted as a temperate tree like an oak, with a thick central trunk. This thick, woody trunk doesn’t map well to what we know about early evolution- for example, we now know that there were probably many instances of gene transfer among different groups of organisms early in the history of life. Some biologists have suggested replacing the traditional oak tree with an image of a mangrove, with many interconnected branches and roots near its base, in recognition of this early complexity in the history of life.
While modern research gives insights into the evolutionary history of life that Darwin could only have dreamed of, his broad metaphor of a tree still seems to be going strong. Regardless of its ultimate shape, the tree of life seems poised to remain with us for a long time to come. However, this does not mean that there aren’t alternative ways to picture evolution. Could an alternative metaphor to the tree of life help us make mental connections about evolution in different ways? This is a question I hope to answer in my own research.
References:
Gruber, Howard E. “Darwin’s ‘Tree of Nature’ and Other Images of Wide Scope.” inHoward E. Gruber and Katja Bodeker (eds.) Creativity, Psychology and the History of Science, pp 241-257.New York: Springer, 2005.
Gruber, Howard E. “Ensembles of Metaphors in Creative Scientific Thinking.” inHoward E. Gruber and Katja Bodeker (eds.) Creativity, Psychology and the History of Science, pp 259-270.New York: Springer, 2005.
Larson, Barbara, and Fae Brauer. The Art of Evolution: Darwin, Darwinisms, and Visual Culture. Hanover, NH: Dartmouth CP, 2009.
Stevens, Peter F. “Pattern and Process: Phylogenetic Reconstruction in Botany.” in Henry M. Hoenigswald and Linda F. Weiner (eds.) Biological Metaphor and Cladistic Classification. pp. 155-179. Philadelphia: U of Pennsylvania, 1987.
One of the more prominent science-related news topics lately has been the radiation emitted from the Fukushima Daiichi nuclear power plant. Coverage of this issue has been mixed in the press, with some stories providing an accurate context for the radiation amounts being reported, and other stories providing lurid and sensationalist uncontextualized commentary. For a roundup of the latter, see the “Journalist Wall of Shame” on the JPQuake Wiki (they also have a “Good Journalism” space).
Ionizing radiation is scary; it’s something we don’t generally think about on a day-to-day basis, it’s invisible, and it can harm us in unpredictable and deeply personal ways. I’m specifying ionizing radiation here because it’s this type of radiation- mainly gamma rays and x-rays- that can damage cells; there’s an entire range of radiation that’s non-ionizing and not harmful in this way- heat, visible light, etc. This may seem a bit pedantic, but the more mysterious and rarefied “radiation” seems, the more potentially troubling it becomes. Once people realize that they interact with many types of radiation constantly, the word “radiation” becomes a little less intimidating. Hopefully, that helps us put the dangers of ionizing radiation into context with a little less fear of the unknown complicating our understanding.
Xkcd radiation dose chart
At any rate, one of the things that makes ionizing radiation, like that emitted from the Fukushima plant, hard to put into context is our lack of day-to-day experience with it. Reporters commonly compare radiation exposure levels to numbers of chest x-rays, or public exposure of people after the Chernobyl disaster. But it’s still hard to put those doses of radiation into context. The graphic on the right, from the Xkcd webcomic folks, does a really good job of putting these numbers into a visual context (click on the thumbnail to go to Xkcd.com and a full-size version).
I like this graphic for a number of reasons. First, it’s generally easier to compare a wide range of numbers visually, rather than numerically. Second, the author compares ionizing radiation to everyday non-ionizing radiation, which provides us with familiar context. He also compares the Fukushima event to the disasters at Three-Mile Island and Chernobyl, which lets us make our own comparisons between the three events. Fourth, he gives us references and links to his sources. He also calls attention to uncertainty- e.g., in places near the Fukushima plant where measured levels of radiation are fluctuating.
So, an interesting example of informal science communication. Check it out!
Because this was a very preliminary study, I only had 9 participants, mainly fellow students in the T&T program (and a last-minute addition of some family members). My main goal was to see if this would actually work, and I wasn’t really expecting dramatic results. Which is what happened- generally, there weren’t significant differences in the maps that the interactive and non-interactive viewers drew. This probably happened because the description of how to read a phylogenetic tree was too thorough (which, unfortunately, I realized after the fact…). If I do something like this again, I’ll definitely make this orientation info less detailed.
Overall, there were big differences in how well people remembered the two big groups on the tree- land birds and shorebirds- shorebird families were apparently much more challenging to remember. This result was correlated with how well people reported that they know birds in general: more general bird knowledge was related to doing better at remembering the shorebird part of the tree. One thing I might do differently would be to give people a list of family names- that way, at least terminology wouldn’t be an issue.
Some open-ended questions that I asked gave me more useful ideas for designing a future study. For example, several people said that they learned that specific families were related, but wanted to see more information on either the names of the branch groupings, or the common ancestor of related species. This raises a few interesting points, because higher-order taxonomy is often different than genetic differences (so there aren’t necessarily names for branches), and ancestral species are really hypothetical last common ancestors, not known species. It would be interesting to think of ways to communicate this to people in a diagram like this.
So, the upshot is that this project gave me some new ideas about how to design a study like this, even though it didn’t give me very conclusive results. Obviously, just adding interactivity to a phylogenetic tree won’t magically make people learn it better- it would be surprising if it did.
I probably won’t be working in interactive phylogenetic trees for my dissertation- there are a number of people working on that at the moment, but I’m think of working on something related. I’m sure I’ll be talking more about that here as my ideas come into shape.
For those interested: here’s the list of references I used in this project:
Baum, David A., Stacey D. Smith, and Samuel S. S. Donovan.“The Tree-Thinking Challenge.” Science 301 (2005): 979-980. Web.
Baum, David A., and Susan Offner. “Phylogenies and Tree-Thinking.” The American Biology Teacher 70.4 (2008): 222-229. Web.
Carrizo, Savrina F. “Phylogenetic Trees: An Information Visualisation Perspective.” Yi-Ping Phoebe Chen, ed. Conferences in Research and Practice in Information Technology 29 (2004): 315-320. Web.
Cranfill, Ray, and Dick Moe. Deep Green-Hyperbolic Trees. Web. 20 September 2010.
Liu, Zhicheng, Nancy J. Nersessian, and John T. Stasko. “Distributed Cognition as a Theoretical Framework for Information Visualization.” IEEE Transactions on Visualization and Computer Graphics. 14.6 (2008): 1173-1180. Web.
Maddison, David A, Katja-Sabine Schulz, and Wayne P. Maddison. “The Tree of Life Web Project.” Linnaeus Tercentenary: Progress in Invertebrate Taxonomy. Ed. Z.-Q. Zhang and W. A. Shear. Zootaxa 1668 (2007): 1-766. Web.
Rogers, Yvonne, and Mike Scaife. “How Can Interactive Multimedia Facilitate Learning?” In J. Lee, ed. Intelligence and Multimodality in Multimedia Interfaces: Research and Applications. Menlo Park, CA: AAAI Press, 1998. Web.
Scaife, Mike, and Yvonne Rogers. “External cognition: how do graphical representations work?” International Journal of Human-Computer Studies 45 (1996): 185-213. Print.
Stenning, Keith, and Jon Oberlander. “A Cognitive Theory of Graphical and Linguistic Reasoning: Logic and Implementation.” Cognitive Science 19.1 (1995): 97-140. Web.
Tree of Life Web Project. Web. 19 September 2010.
Tversky, Barbara. “Cognitive Maps, Cognitive Collages, and Spatial Mental Models.” A. U. Frank and I. Campari, eds. Spatial Information Theory: A Theoretical Basis for GIS, Proceedings COSIT ’93. Berlin: Springer, 1993. Print.
Yi, Ji Soo, Youn ah Kang, John T. Stasko, and Julie A. Jacko. “Toward a Deeper Understanding of the Role of Interaction in Information Visualization.” IEEE Transactions on Visualization and Computer Graphics 13.6 (2007): 1224-1231. Print.
Zhang, Jiajie, and Donald. A. Norman. “Representations in Distributed Cognitive Tasks.” Cognitive Science 18.1 (1994): 87-122.
This semester, I worked on a small science visualization research project, partly for a course, and partly as a pilot study related to my possible ultimate dissertation research. I’ll probably break up my discussion of this project into a few posts.
I was interested in looking at whether interactivity affects people’s understanding of phylogenetic trees. Phylogenetic trees are one of the key tools used in the field of evolutionary biology to represent hypothesized evolutionary relationships among species or other biological groups. They let us both explore relationships among living species and make inferences about the history of life.
However, interpreting tree diagrams often presents a challenge to students. On trees, the nodes (branch points) symbolize the last common ancestor between the species represented by the branch tips. Inexperienced readers tend to “read” relationships along branch tips, rather than by nodes, which can lead to misconceptions like inferring that species on the tips gave rise to other species (e.g., frogs to snakes to birds). The correct way to read phylogenies is to think of the nodes as focal points that connect related species.
One of the diagrams from the project introduction.
My experiment was designed to test whether making a phylogenetic tree diagram interactive, in such a way as to emphasize the importance of branch-point connections, would help people recall relationships more accurately when drawing the tree from memory. Cognitive theory suggests that interactive science visualizations could be useful for building understanding, because as we manipulate a visualization, we are able to generate slightly different viewpoints of it. We then put these points of view together into a mental model. A number of groups (e.g., here, here) have experimented with interactive trees, but in most of these projects, viewers interact with the tree by selecting branch tips in a higher-level tree, which takes them to a screen with a lower-level tree. With this type of navigation, the viewer effectively zooms in on a specific region of the tree, and the overall context for the tree is lost.
For this project, I created a tree of Florida bird families, based on the information on the Tree of Life website. To help people with unfamiliar families, there was a thumbnail photo of a representative species and a short fact about each family on the tree.
Viewers could click on a node to "open up" a branch.
Viewers were presented with a complete tree (so they didn’t lose the overview of the entire tree), and had the ability to select one node with its connected species to highlight at one time (thus maintaining the importance of reading by nodes).
Example of an "open" branch.The overall non-interactive tree. All photos open-source from Wikipedia.
My experiment worked like this: 1) viewers read a description of how to read a phylogenetic tree, 2) they either interacted with a dynamic tree or viewed a static tree, 3) were asked to draw the tree from memory, and 4) answered some questions about themselves and the tree. They weren’t told ahead of time that they would have to draw the tree from memory. In my next post, I’ll talk about what actually happened…
