Studying the Evolution of Division of Labor with Digital Organisms

This post is by MSU Postdoc Heather Goldsby.

Heather Goldsby, an MSU BEACON postdoctoral researcher working in the Devolab, Kerr, and Hintze labs.

Why do you have different types of cells in your body? Why do honeybees perform different roles, including forager, undertaker, nurse, and queen? Why do factory workers perform jobs as specific as putting on one part for a car? Why do we engineer robots to do different tasks in support of the same mission? All of these are examples of division of labor where individuals take on specific roles and cooperate to survive and thrive. I first became fascinated by division of labor when I realized it underpins all of our economy – and most of our daily interactions at work. My interest only grew as I began to notice it everywhere. Originally, my research started by using division of labor as a tool in algorithms I developed. Then, I started to work on creating evolutionary algorithms that employed division of labor to solve a problem.

As I continued my studies, I learned that division of labor is a key component of major transitions in evolution, and thus of great interest in biology. Major transitions in evolution occur when formerly distinct lower-level entities become linked (either by staying together or by forging bonds) and reproduce and compete as one higher-level entity [1]. For example, major transitions include single cells transitioning into multicellular organisms, solitary insects transitioning into eusocial colonies, and the formation of the eukaryotic cell. For some of these transitions, in particular the ones where genetically similar lower-level entities stay together, a big challenge is how to evolve to specialize and take advantage of the benefits of division of labor.

Because of its importance to science and engineering, I want to better understand how and why division of labor evolves. To do this, I use the Avida digital evolution platform [2]. Its rapid generation times and experimental control enable me to place digital organism (analogous to cells or ants) into groups, apply different evolutionary pressures, and observe how and when division of labor evolves. Using this approach, I’ve studied several aspects of the evolution of division of labor, including: (1) The evolution of temporal polyethism [3]: a form of division of labor used by some bees, where individuals change the task they performed based on their age; (2) The evolution of reproductive division of labor [4]. In particular, we became interested in why do somatic (body) cells evolve when they are evolutionary dead ends? (3) What is the role of task-switching costs in promoting specialization [5]? I’m going to go into greater detail on this question to illustrate how we use digital evolution to study division of labor.

Do task-switching costs promote the evolution of division of labor? Task-switching costs are penalties (in terms of time or resources) associated with changing from performing one type of task to another. For us, they might be the amount of time it takes to shift from checking email or Facebook, to get back to writing a paper. For example, for a bee within a colony, they could include the amount of time it takes to travel from one place in the hive to another, the morphological overhead in changing roles (building new glands, etc.), or even cognitive overhead. To study this question, we placed individual digital organisms into a colony, where the colony as a whole was required to perform a variety of tasks to successfully compete with other colonies. We ran treatments that varied the task-switching costs. We observed that treatments with low task-switching costs evolved generalist organisms: an organism performed many types of tasks. In contrast, when higher task-switching costs were applied, specialist organisms that evolved only one type of task evolved. In an unexpected twist, the specialist individuals also evolved task-partitioning behavior where one individual passed on the results of a task to another individual who used the solution as a building block to perform a more complex task. We see this behavior in both human assembly lines and also insect colonies, such as leaf cutting ants.

Fig. 1. A task-partitioning system evolved by a digital colony. Digital organisms (squares) perform tasks and send messages (solid lines), including task results. In this case, the organisms evolved to send task results to neighbors, who, in turn, used the information to perform more complex tasks.

What fascinated me about the task-partitioning behavior evolved by the individuals within colonies was that while the colony as a whole could perform seven different types of tasks, when placed alone, the individuals could only perform one type of task (Fig. 1). The loss of functionality at the lower-level individual and the emergence of functionality at the level of the colony indicates that task-switching costs could favor both the evolution of division of labor and also a shift in autonomy from a lower-level to a higher-level unit. This shift in autonomy is a fundamental component of major transitions in evolution.

This project highlights how digital evolution can contribute to studies of division of labor and major transitions in evolution. Now, working with colleagues, I’m expanding this research to both understand other evolutionary pressures that favor division of labor and also to see a major transition in evolution unfold in real time.

References:

  1. J. Maynard-Smith and E. Szathmáry, The major transitions in evolution. New York, NY, USA: Oxford University Press, 1997.
  2. C. Ofria and C. O. Wilke, “Avida: A software platform for research in computational evolutionary 
biology,” Journal of Artificial Life, vol. 10, pp. 191–229, 2004.
  3. H. J. Goldsby, N. Serra, F. Dyer, B. Kerr, and C. Ofria, “The evolution of temporal polyethism,” Artificial Life, vol. 13, pp. 178–185, 2012.
  4. H. J. Goldsby, D. B. Knoester, C. Ofria, and B. Kerr, “The evolutionary origin of somatic cells under the dirty work hypothesis,” PLoS Biol, vol. 12, no. 5:e1001858, 2014.
  5. H. J. Goldsby, A. Dornhaus, B. Kerr, and C. Ofria, “Task-switching costs promote the evolution of division of labor and shifts in individuality,” Proceedings of the National Academy of Sciences, vol. 109, no. 34, pp. 13686–13691, 2012.
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Evolution’s Pet Cemeteries: museum collections are haunted by ghosts of natural selection

This post is by MSU Postdoc Eben Gering.

Dr. Helen James. The Smithsonian bird collection Curator in Charge

Several of my most exciting workdays last year were spent rummaging through drawers of dead birds. I was on the hunt for a few dozen of the 640,000 specimens that makeup the world’s third largest bird collection. This collection resides within the Smithsonian National Museum of Natural History, but one could also say that it “lives” in the minds of the investigators who study it… Because there, like the cast of Milan Trenc’s A Night at the Museum, evolutionary processes spring to life from the inanimate artifacts that life leaves behind.

A curious biologist could easily dedicate her professional life to studying and curating such a treasure trove as the Smithsonian bird collection, and during my visit there I met two remarkable women who have done precisely that. I had already made an appointment to meet with one of them, Dr. Helen James to ask what could be learned about the biology of feral chickens (the focus of my current research) from several dried specimens in the Smithsonian collection. I’ll save the details for another day; the short answer is: a lot!

Dr. Carla Dove, the Department of Vertebrate Zoology Program Manager at the Smithsonian

Dr. James is among the world’s leading avian paleontologists, a reputation that rests upon decades of extraordinarily resourceful work. From meticulous studies of tiny bits of bone, she has pieced together much of the previously unknown evolutionary history of Pacific Oceania’s birds. Dr. James’ capabilities and reputation are likely what led someone from another museum to drop by her office during our meeting. They had brought with them several 100 million year old feathers that had been trapped (in breathtakingly pristine condition), in a recently discovered Burmese amber deposit. Would I mind if Helen took our conversation over to the feather forensics lab to have a look? No… I would not mind. For me (and probably also for you, if you are reading this blog), this was the stuff of childhood dreams.

Aircraft can occasionally ingest birds into their engines.

As Dr. James, her guest, and a postdoc excitedly examined the ancient feathers and sought “matches” from more recently collected material in the collections, I had an opportunity to meet the manager of the feather forensics lab, Dr. Carla Dove. Dr. Dove explained to me that, while the ancient feathers were a treat to examine, her lab is usually occupied by the study of younger, less well-preserved samples. Specifically, her team dedicates much of their effort to identifying birds from the fragmentary evidence that survives birdstrikes. These sometimes fatal accidents occur when aircraft ingest birds into their engines. Knowing the species (and therefor the biology) of the birds involved helps air traffic controllers, pilots, and engineers anticipate and avoid them.

The Smithsonian has Big Bird feathers in their collection!

Studies of birdstrikes offer a very compelling and straightforward example of why natural history collections, and the taxonomic experts who maintain them, are so important. Unfortunately many scientists and citizens are losing sight of the value of scientific collections. In my opinion a visit to a natural history collection is a must for any evolutionary biologist, no matter what animal, vegetable, or pathway s/he studies. We owe the very discovery of evolution to Darwin’s analysis of bird collections, and they offer unlimited opportunities for future breakthroughs.

Before leaving the museum, I asked Dr. Dove if she could share any interesting facts about chicken feathers. It turns out, she informed me, that barbules (tiny feather substructures) in the group of birds to which chickens belong (Galliformes), are unique in possessing multiple ringed nodes whose function is still unclear. Since a chicken feather was not at hand, Dr. Dove invited me to examine a relative’s feathers under the microscope. Yes…

Galliformes ringed barbules

SMITHSONIAN HAS BIG BIRD FEATHERS IN THEIR COLLECTION! And so at the close of a perfect day, I was able to view the Galliformes ringed barbules (image 5) because, it turns out, the immortal and monotypic Big Bird shares surprising morphological homology with Meliagris, the turkey.

 

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Publicizing Your Research

This post is by MSU Media Communications Manager/Spartan Science Storyteller Layne Cameron.

First of all, allow me to introduce myself. I’m Layne Cameron, the Spartan Science Storyteller.

Layne Cameron, Spartan Science Storyteller, shares a few tips on working with the media and publicizing research.

My job is to help publicize the research that is being conducted at MSU. I write about your work for MSUToday, but I also pitch my stories to media outlets – from the New York Times and National Geographic to the local National Public Radio affiliate – to get reporters to cover the great science that’s happening at MSU.

I’ve worked with quite a few researchers from BEACON. The research that you do there is compelling, and your ability to translate the science for a general audience is first-rate. So, for the people I’ve helped, please keep the stories coming my way. And for those I’ve yet to meet, I looking forward to hearing from you.

MSU scientists often ask where I get my story ideas. My answer is, “From you.” I’d like to hear from you when:

  • You land a large grant to fund your research
  • You publish a paper in a peer-reviewed journal
  • Hear news coverage that’s related to your research
  • When you snap a cool image that captures an aspect of your work
  • When you’re being interviewed for a story

In all of those situations, I can help publicize your work and coordinate media coverage and social media strategy.

When you land a grant or publish a paper, you’re often told: “YOU CAN’T TALK TO ANYONE ABOUT THIS!!” That’s true; you can’t talk the media until you have the OK from granting organization or the embargo lifts for your paper.

However, you can talk to me beforehand—I am a media relations manager NOT a reporter. I can meet with you to prepare talking points, news release, take photos, and rough out a media and social media strategy in advance of any grant or embargo. I will hold all of the work until the embargoes are lifted. (And with papers in journals such as Science, Nature and PNAS, I can even pitch the stories to a handful of trusted, national science reporters, who will then hold their stories until the appointed time.)

You don’t need to write a news release, either – that’s my job! Simply drop me an email or give me a call. Send me a copy of your grant application or paper with a layman’s description, and we’ll get started.

To give you a better idea of what I do, I’ve included a couple of links to stories that I’ve covered recently.

I’m always open to meet with anyone to discuss the ins and outs of working with the media. If you have an idea, let’s talk. Over coffee. In your lab. Wherever.

If you’re still unsure, feel free to cyber-stalk me on Twitter. I’m at SpartnSciStorytellr or @LayneCameron1. (I’ll take all the followers I can get!)

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Point Break: My experiment with dropping PowerPoint in a large lecture course

This post is by MSU Associate Professor Chris Waters.

A Change is necessary

I am the course administrator and sole instructor for the junior/senior level course “MMG 431:Microbial Genetics” of about 150 students at Michigan State University. Entering my seventh year of teaching this course in the Fall of 2015, I began to reevaluate my approach. Previously, I had implemented a fairly standard lecture course with PowerPoint slides interspaced with active learning “think:pair:share” exercises that utilized iClickers for students participation. The students were given the PowerPoint slides before class, and these were intended to be an outline for further note taking during class.

But each year the complaints of the students were the same: “too much material…”, “the instructor goes too fast…”

From my perspective, I was frustrated that half the class was clearly not paying attention, but rather felt that the 50 minutes of class time were ideal for catching up on Facebook, Instagram, or their favorite electronic distraction.

To address both of these problems, I decided to stop using PowerPoint (with a few exceptions for complicated structures or diagrams) and rather present information in a “chalk-talk” style where the students take notes as I write everything from scratch. Do any of you remember those days, say from the beginning of time until the year 2,000, when you came to class with a blank notebook, two pencils, and a readiness to take notes! Here is how this experiment unfolded last Fall…

Choosing a format

Although I refer to this style as chalk-talk, no chalk was actually harmed during the making of my course. Rather, I decided to use my touch-screen laptop and project what I was writing on two screens in my lecture hall. This has several advantages including more color options, the ability to switch between formats (the rare PowerPoint slide, online videos, etc.), and it allowed me to save every lecture so I could reference exactly what I had presented. I explored different formats but eventually decided to use OneNote 2013. OneNote allows you to have an infinitely large screen that you can zoom in/out, it has many colors and pen styles, and it nicely organized for keeping track of each lecture as a separate entry. To prepare for class, I would basically transcribe my old slides into handwritten notes in a bound notebook, and use this to give my lecture. Being my seventh year, I know the material inside and out so this was easy for me to do (it would be much harder starting out with a new course).

Fig. 1. The classic Hershey-Chase experiment. Sidenote: Alfred Hershey obtained his PhD from the Microbiology Dept. at MSU!

Here is an example of my description of the classic Hershey-Chase experiment utilizing phage to elucidate DNA as the hereditary material (Fig. 1). It doesn’t look like much, but remember I am drawing this from scratch explaining what is happening as I go along so hopefully the student’s versions would be filled with all kinds of additional comments that I only verbally present.

How did it work?

At the start of the semester I was quite nervous about pulling this off, especially given my tendency for sloppy hand-writing. But I quickly became comfortable with the new approach, and I grew to love teaching this way. I was more able to emphasize important points and comments, and as one student mentioned, “it’s very interesting to see the way your thought processes unfold when you provide illustrations”. Another fantastic aspect of this method is that is allowed me much more freedom to take the class in new directions or present a new idea on the spot. Unlike with PowerPoint, I was not fixed to a given order, and the students did not know what was coming next. Many times during the course I improvised in ways which I had not been able to do before. I loved the freedom! It also allowed me to better query the students and report their responses. For example, I could ask “What are some of the potential uses and drawbacks of CRISPRs?” and the students were not able to merely reference the next slide in that day’s lecture.

Importantly, the students were all “locked-in” during class! The unfocused, inattentive student had magically vanished. Check for solving my past complaint. And, let me tell you, it takes a heck of a lot longer to draw something out rather than flash up a PP slide. Not surprisingly, I quickly got behind my normal course schedule and had to adjust the information that I presented to cut details or additional examples. I would estimate I that I trimmed 35% of the material that I had given in the prior year, and students complained much less on the amount of content and lecture speed. Check for addressing the student’s complaints.

Quantitative data: student response and effectiveness

It is all well and good that I liked teaching in a chalk-talk style, but more importantly how did the students respond to it and was it effective?

Fig. 2. Student’s numerical review scores 2013-2015.

To address these question, I analyzed the student’s evaluations and course scores from 2013-2015. This entails the three years that I have been the sole instructor of MMG431. Scores are ranked from 1 to 5 with 1 being the best and 5 being the worst. The questions can be grouped into 6 categories such as “Instructor Involvement”, “Student Interest”, etc. Although 2013 and 2014 were fairly equivalent (both “normal” PowerPoint lectures), every single category improved last Fall with the implementation of the chalk-talk format (Fig. 2)! The biggest gains occurred in “Course Demands” and “Student Enjoyment”, historically the two weakest categories.

Fig. 3-Categorizing specific student comments.

In addition to these numerical scores, I also evaluated specific student comments from the last three years, grouping them into whether they had an overall negative, positive, or neutral view of the course. The results were striking with a huge increase in positive responses from 18-30% to almost 70% associated with a corresponding decrease in negative responses from 65-66% to 21% (Fig. 3).

Clearly the new approach resonated with the students. Examples of specific comments that I received were “It is extremely easy to take notes”, “I think the changes made on how to teach this course were super effective”, and “I wish all my classes would go back to teaching instead of reading material off of slides”. And the most surprising comment, which I have never seen a similar one in 7 years, actually wanted class to be longer: “If only classes ran 1 hour and 20 minutes 3 times a week instead of 50 minutes so we could cover more.”

Fig. 4. Student’s unadjusted final scores.

But how effective was the chalk-talk style? The hope is that they retain more information. To answer this question, I compared the final, unadjusted grades from 2013-2015. These are the raw grades at the end of the semester without any adjustment for overall course difficulty (Fig. 4). Although there was a small increase in the 4.0 group, it was not as dramatic as other groups, suggesting to me that the top students will do well regardless of what format you use. But the largest increases were seen in the 3.5 and 3.0 categories. These are students who likely would have in the past received 2.0 or below who were able to be more successful with the new style. Most dramatically was the decrease in the number of failing students, which has been one of my long-term goals for this course.

Getting to the point

The data indicate that for myself and my course, the chalk-talk style was highly superior to traditional PowerPoint lectures. There is no question that I will continue teaching in this manner. However, there is clearly still room for improvement.

A number of complaints focused on legibility issues. This comes from my own natural propensity for chicken-scratching and my laptop format, which was somewhat unnatural to write/draw. Before next Fall, I will switch to a tablet format which will hopefully improve these issues. More supplemental slides with complex diagrams was also a common request, and I believe I can make more of these available. Some students had a hard time keeping up with note taking, and I anticipate using two devices next year alternating between two screens so that material is displayed longer. In my opinion, many of them just do not have the experience or skill to take good notes-they have never had to do it before. Perhaps a primer on good note taking would be warranted. Other students such as non-native speakers or students with mental health issues expressed frustration that they would often miss points in class and it was difficult to make them up since I did not post lecture material. I plan to record my lectures and make an audio version available, and I am debating about whether to post lecture notes after the class is over. Any thoughts in the comments section about posting lecture notes are appreciated!

I consider “Point Break” a highly successful experiment that met all of my desired outcomes. On a fundamental level, presenting in a chalk-talk style just made teaching more fun. Consider me a convert.

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Introducing BEACON’s New Science Outreach and Communication Postdocs

This post is by MSU postdoc Travis Hagey.

Late in 2015 BEACON advertised for an Evolution Outreach and Education postdoctoral fellowship. As a result of that posting, we would like to introduce three new postdocs, Dr. Wendy Smythe, Dr. Travis Hagey, and Dr. Alexa Warwick. These new BEACONites will be focusing on diversity outreach (Wendy), communicating BEACON’s research to the public (Travis) and evolution education and outreach (Alexa). We encourage the BEACON community to reach out and strike up new collaborations, taking advantage of the skills and resources these new postdocs bring.

Dr. Hagey studying the ecomorphology of Anolis lizards in the Dominican Republic.

To introduce these new postdocs to the BEACON community, we will be featuring blog posts dedicated to each of their goals and research interests. Today we are focusing on Dr. Hagey. Travis completed his Ph.D. with Dr. Luke Harmon at the University of Idaho in 2013 investigating the evolution, mechanics, and ecology of gecko adhesion (Fig. 1). Travis continued his gecko research at UI for two years as a BEACON funded postdoc As BEACON’s Science Communication Fellow, Travis will be taking over the public communication aspects of BEACON, including the BEACON blog. As result, all blog related inquiries should be directed his way. Travis will also soon be looking for additional blog posts, so if you haven’t ever written one or it has been a while since your last update, take this opportunity to get your research out into the hands of the public.

Travis will also be managing BEACON’s Facebook, Twitter, and yearly newsletter. If you have research, upcoming events, or other information that you think should be featured, please let him know. Public science outreach and communication is an important part of science research. It’s also important to BEACON and NSF. If you have been thinking about public science outreach activities or have one come coming up, let Travis know and he can help get the word out. In addition to disseminating the research occurring at BEACON, Travis will also be collaborating with Jory Weintraub on the Sixth Annual Evolution Film Festival Video Contest. The application deadline to submit your short evolution-themed films is coming up at the end of May! Finalists will be screened at the Evolution 2016 conference.

Travis will also be continuing his previous research working with gecko adhesion. This research blends evolution, mechanical engineering, and ecology. The main questions of Travis’ research focus on how animal performance works and why animals are shaped the way they’re shaped. This research combines work with live animals, biomechanical simulations, and (if he’s lucky) fieldwork to observe animals using their natural habitat.

A 3D reconstruction of Gekko gecko adhesive structures using micro X-ray CT.

Travis is currently investigating the use of high-resolution 3D reconstructions of morphological structures using a suite of different approaches (Fig. 2, confocal microscopy, micro and nano X-ray CT, and photogrammetry). Travis is also working with engineering simulation approaches such as finite element analyses and combining evolutionary and mechanical simulations in software like Open Dynamics Engine. Whenever you mention 3D reconstructions you also have to consider 3D printing! How cool would giant 3D printed gecko toes be?

Travis also has experience with evolutionary comparative methods, fitting models of trait evolution such as Brownian Motion and the Ornstein-Uhlenbeck models. If you’ve got questions, are interested in collaboration, or want to chat about biomechanics let him know.

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