Wednesday, September 17, 2014

Live Fast, Die Young: Evolutionary Outcomes of an Asteroid Impact

Figure 1 Visual representations of trait changes across the KPB.
Figure 1: (A) "Dryophyllum" subfalcatum, (B) unknown nonmonocot,
(C) "Ficus" planicostata, (D) "Populus" nebrascensis
A new semester has started and with it an influx of new students into the lab has begun. Busy has become my middle name. So when I was looking around for a paper to write about I wanted something different and cool. Not exactly hard to find in science. The asteroid known as 2012 DA14 will narrowly miss Earth this Friday, the closest known asteroid flyby on record. And by close we’re talking within the orbits of many communications satellites. This got me thinking about and looking for recent papers about asteroids. It didn't take me long to come by an interesting new paper about the dino-killing Chicxulub bolide impact.

As of now, it is widely accepted that an epic asteroid collision ended the 135 million year reign of the dinosaurs. The Cretaceous-Paleogene boundary (KPB) extinction event is marked by the Chicxulub (CHEEK-sheh-loob) impact on the Yucat√°n Peninsula in Mexico. This asteroid or comet is estimated to have been about 6 miles (10 km), releasing as much energy as 100 trillion tons of TNT that caused a crater more can 110 miles (180 km) across! This impact coincides with a mass extinction event that includes the dinosaurs. Dramatic climate swings caused by the dust kicked up into the atmosphere were likely the culprit behind many of these extinctions. Before we go further, take a second to think about what you know about this extinction event. You probably think of the mass die-off of the dinosaurs and the subsequent rise of the mammals, right? But, as I have in the past, I’ll now pose a question: What about the plants?

A new paper published yesterday in PLOS Biology asks just that question. We know that in temperate North America the Chicxulub impact resulted in the extinction of over 50 percent of the plant species. From an evolutionary and ecological stand-point, that’s a lot of competitors that were taken out of the game. However, the environment was dramatically altered as well, changing to a cold and dark “impact winter.” Combined, these factors created a unique selection scenario for certain ecological strategies. The new paper takes a close look at the functional traits associated with these strategies.

The researchers measured fossil leaf assemblages spanning a 2.2 million year interval across the KPB, assessing four differing selection scenarios for functional traits. First, wrap your head around the concept of “functional traits.” These are characteristics that define species in terms of their ecological roles. In the case of leaves, these include leaf mass per area (LMA; Do you make a big, expensive leaf or a light, cheap one?) and leaf minor vein density (VD; Do you have more veins to transport lots of water?), among many others. Because leaves are the food producers, these traits are linked to plant growth and fitness. Next, you can relate these traits to the “leaf economic spectrum” (LES) that contrasts species with inexpensive short-lived leaves with fast returns on carbon and nutrients (deciduous, angiosperm, broadleaf) to costly long-lived leaves with slow returns (coniferous, gymnosperm, evergreen). The former is typically selected for in a less resource variable environment and vice versa. From this, you can get a more global perspective on changes in species composition.

The researchers measured LMA and VD for fossil leaf assemblages spanning the KPB. To do this they digitally photographed specimens that could be measured and confidently reconstructed. Then they used Photoshop to digitally separate the leaf from its rock matrix. For LMA they used ImageJ to calculate leaf area and petiole width, and then ran these numbers through empirical scaling functions (a.k.a. equations). For VD, they used a MATLAB line-counting program to isolate the veins and then manually counted the number of vein-line intersections, computing the mean distance between veins  as the sum of all line counts divided by the sum of all distances (a.k.a. a slightly less complicated equation). They ran a few scenarios to account for site and region plant specificity as well.

They found LMA to decrease and VD to increase across this time period. Even changes just these two traits reflect large physiological and biological shifts in plant functioning over a relatively short period of time. According to their data, the Chicxulub impact led to the selective extinction of species with slow strategies. This caused a directional selection away from evergreen species along with a stabilizing selection of deciduous angiosperms. The authors pose a few hypotheses in their discussion that are worth mentioning. The higher observed VD in angiosperms, and their ensuing selection, could have been driven by declining atmospheric carbon dioxide (CO2), which selects for higher hydraulic capacity. This CO2 hypothesis would, of course, not really hold water (no pun intended) for nonangiosperms and shade species, but the authors suggest that the observed increase in VD is more likely to be a direct consequence of the impact selecting for specific leaf economic strategies rather than ongoing-longer term climate change.

In this case, slow and steady did not win the race.

  ResearchBlogging.orgBlonder B, Royer DL, Johnson KR, Miller I, & Enquist BJ (2014). Plant Ecological Strategies Shift Across the Cretaceous-Paleogene Boundary. PLoS biology, 12 (9) PMID: 25225914

(image via above citation)

Thursday, September 4, 2014

The Simple Western

Another addition to the creative and fun science ad category.

a.k.a. Buy our really expensive stuff.

Wednesday, September 3, 2014

Pipette Tip Personalities

Apparently I'm Predictable. Might try The Artist this week though.

(via Lab Humor)

Monday, August 25, 2014

Spoiler Alert!: Are You Wasting Your Time Avoiding Spoilers?

Spoiler Alert
Lately I have been cranking though a lot of media – TV, movies, books, podcasts, etc. To the point that I start to wonder how I have time for actual life. During this mass consumption of media, I've been thinking about, and discussing with friends, the topic of spoilers. Bring up this topic with just about anyone and you’ll find that it’s actually a pretty controversial one. As for me, I fall in the no spoilers category. Spoil one of my beloved TV shows and you will go from friend to “friend” just that fast. But I know that there are those out there that don’t mind being spoiled or actually prefer it. That got me to thinking back to a study from few years ago about this topic. The study got quite a bit of attention from the media, specifically applying the findings to film and TV. After doing some searches on Web of Science for similar studies, I can see why. There just aren’t any – to the point that even this older study has only been cited 3 times, and not by other media related studies. So, well, what the heck?

In 2011, a short little study published in Psychological Science by Leavitt and Christenfeld asked if spoiling a story decreased peoples’ pleasure in it. The universal element of all types of media is story. When you talk about spoilers you are inherently talking about changing someone’s enjoyment of the story. The study asked 176 males and 643 females (just a little sex biased and not broken down by any other demographics) to take part in three experiments in which they read three different sorts of short stories selected from anthologies: (1) Ironic-twist stories, (2) Mysteries, and (3) Evocative literary stories. For each of the stories, some of the participants’ stories included a spoiler paragraph that summarized the story and gave the outcome. Afterwards, the participants were asked to rate the story for enjoyment on a 10 point scale – a “hedonic rating.” They found that the participants significantly preferred spoiled over unspoiled stories in all categories and reported that the spoiler paragraph was not out of place or jarring.

Figure 1 from the study. These are hedonic ratings of the individual spoiled and unspoiled stories.

Considering all of the attention this study got when it was published and the applications made to a variety of media, I’m going to throw in a little more personal critique than I do normally. Start out by asking: Are their data wrong? Well, no. But there are some methodologies and assumptions that I question. They assume that I have the same experience each time I read a story. The authors do focus on that first reading but also state that “people’s ability to reread stories with undiminished pleasure, and to read stories in which the genre strongly implies the ending, suggests that suspense regarding the outcome may not be critical to enjoyment and may even impair pleasure by distracting attention from a story’s relevant details and aesthetic qualities.” As someone who rereads her favorite books over and over again, I say “not so!” Their statement suggests that I did not enjoy the shock of a scene the first time around when in fact I did. You know what I mean: that “holy-crap-did-that-just-happen?!!!” moment. Am I saying that twist is all there is? Of course not, but one of the memorable parts of the first reading - the surprise - would not have been the same without it. Upon rereads, my undiminished pleasure comes from the writing and spending more time in a world with characters that I love (or love to hate).

The study’s authors conclude that “people are wasting their time avoiding spoilers,” but go on to say that that their data “do not suggest that authors err by keeping things hidden.” They point out that readers who read stories that open with the outcomes still anticipate additional revelations at the end. To me, this statement suggests that readers still expect twists in the story even though they've just read all of them, that they are waiting for the shock, the twist. A good example might be someone who is seeing a film adaptation of a book they've read; they are looking for the differences in the movie. Considering this, I think would have liked more detail in the methods about how their spoilers were presented. I wonder if a big “Spoiler Alert” warning on that summary paragraph would have made a difference – one that labeled and explained it as something that spoiled everything. Perhaps this would remove this erroneous anticipation? Or what about a before questionnaire that scored anticipation levels? Personally, I am way more upset if someone spoils something I've been looking forward to compared to something I could care less about. What about gauging viewpoints on spoilers by asking a simple question like: Do you read the last chapter of a book first to see what happens?

Did I come into this paper with some preconceived notions? Sure, but I seem to have more problems with this study than most. Upon reflection, I think that stems from problems I have with the study's methodology added to the attention it has gotten (it hasn't escaped me that I’m giving it even more with this post). It has been used to justify spoiling a story – a behavior that I typically find to be one of smug superiority. I think it is important to keep in mind that this is a single small study, and one that had I been a reviewer for would have gotten hacked to pieces. I'm a fan of a nice, simple study but I'm not a fan of lack-of-detail, particularly in the methods.

But I'm not a psychologist, what do I know? What do you think? Do you love or hate spoilers? How would you have done a study on this topic?

ResearchBlogging.orgLeavitt, J., & Christenfeld, N. (2011). Story Spoilers Don't Spoil Stories Psychological Science, 22 (9), 1152-1154 DOI: 10.1177/0956797611417007

Here's some of the media attention this study received and a couple other articles on the topic. Spoiler Alert - some of these contain spoilers.

Film School Rejects: "How Bad Do Spoilers Spoil?: A Super Scientific Study
Smithsonian: "Are Spoilers Misnamed?"
UC San Diego News Release: "Spoiler Alert: Stores Are Not Spoiled by 'Spoilers'"
/Film: "Spoilers Are Good For You, Says Study"
The Atlantic: "Here's the Twist: Good Films Are Good Even If They've Been 'Spoiled'"
io9: "The Cultural Curse of Knowledge and Movie Spoilers"
io9: "Why I refuse to watch movies without spoilers"
Vulture: "Spoilers: In Defense of the American Watercooler"
Vulture: "Spoilers: The Official Vulture Statutes of Limitations" (I like this proposes a stature of limitations on spoilers based on the media type) "Spoiler Alert: A Survival Guide to All Things" (also the source of the image)

Wednesday, August 20, 2014

Observing Fangirls

If David Attenborough narrated footage of Fangirls, it might go something like this. Hopefully the BBC won't take it down before you see it :-)

Thursday, August 14, 2014

What Type of Procrastinator Are You?

Joseph Ferrari is a master of procrastination. And by that I mean a Ph.D. in psychology who studies procrastination and task avoidance. Recently, the folks over at OfficeTime used Dr. Ferrari's findings to create a flow chart that helps you to identify what type of procrastinator you are.

Me? Well, I'm a Thrill Seeker.

You can find more over at Life Hacker and Science Dump.

Monday, August 4, 2014

Lego Ladies of Science

Update 8-11-14:

LEGO® Ideas has another awesomely sciency project on the table: The Planetary Exploration set. It was inspired by The Research Institute (below) and features another female minfigure. It has three main elements:a planetary survey vehicle, an unusual rock formation to survey, and an outpost with a native inhabitant of the planet. Show your support by voting for it over at LEGO Ideas and maybe we'll see this idea become another reality.

planetary expedition main

planetary expedition 1planetary expedition 2

Original post:

I've been holding on to this story until it went from an idea/contest winner to an actual product. And now is that time.

LEGO® has announced that its set called The Research Institute is now available. The set was created by real-life geoscientist, Ellen Kooijman (alias:Alatariel), and selected by Lego Ideas members (formerly known as CUUSOO). If includes three scenes of scientific professions including paleontology, astronomy, and chemistry. These scenes also have accompanying scientist minifigures - specifically all female scientists.

These female minifigs are the newest to Lego's line of scientific minifigs -- I highly recommend reading Maia Weinstock's guest blog post over at Scientific American called "Breaking Brick Stereotypes: LEGO Unveils a Female Scientist." In this post, she breaks down the history of scientist minifigs and clearly details the gender gap.

The Lady-Scientist Lego Set Is Now Available!

Here are some good posts/stories on this topic that you will enjoy:

Support good Lego ideas in the at the their Ideas page - Here's one for a Science Lab and Planetary Exporation (unfortunately log in in required)

Maia Weinstock's flickr account featuring custom built scientists minifigures (these should all be mass produced!)

A letter by seven-year-old Charlotte who takes Lego to task for making more "boy people" than "girl people" (thank you Charlotte!)

Oh, and have you heard of this Lego microscope that actually works? Lego artist Carl Merriman built a functional compound microscope that has up to 10X magnification, has course and fine focus knobs, lights and stage clips. He also has an IDEAS page. Go vote!

LEGO Microscope MkII by Carlmerriam

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