News & Events | Data Nuggets

11.1.16

NABT 2016 – BEACON Evolution Symposium

The color polymorphism in bluefin killifish – males display anal fins in blue, red, or yellow.

Why so blue? The determinants of color pattern in killifish

For more information on the NABT 2016 conference, check out their website, here.

Why be blue in a swamp? The evolution of color patterns and color vision in killifish

Animal communication happens when one organism emits a signal, which then travels through the environment and is detected by the sensory system of another. The environment in which signaling occurs can dramatically alter signal transmission and result in selection where different signals are favored in different environments. The bluefin killifish provide a compelling example. Some populations are found in crystal clear springs (where UV and blue light are highly abundant) and others are found in tannin-stained swamps (where UV/blue light is depauperate). Paradoxically, males with blue color patterns are abundant in swamps and are rare in springs. The resolution to this paradox requires a consideration of how genetics and the environment influence trait expression, as well as the direction of natural and sexual selection in different habitat types, and the manner in which animals with different visual systems perceive the same color pattern.

Data Nugget Workshop: Why so blue? The determinants of color pattern in killifish

Data Nuggets are hands-on activities designed to improve the scientific and quantitative skills of students by having them graph and interpret scientific data gathered by practicing scientists. This workshop will provide an overview of Data Nuggets and present a Data Nugget featuring data on the genetic and environmental basis of color pattern expression in killifish. This Data Nugget will allow students to determine whether color pattern expression is due to ‘nature’ (e.g., genetics), ‘nurture’ (e.g. environment), or the interaction of the two.

The materials from the Data Nugget workshop are as follows:

Workshop organized and presented by: Becky Fuller, Elizabeth Schultheis, Melissa Kjelvik, Alexa Warwick, and Louise Mead

BEACON CENTER FOR THE STUDY OF EVOLUTION IN ACTION, MICHIGAN STATE UNIVERSITY & UNIVERSITY OF ILLINOIS

10.21.16

Bon Appétit! Why do male crickets feed females during courtship?

Mating pair of Hawaiian swordtail cricket with macrospermatophore on the male (left). The male and female (right) are marked with paint pens for individual identification.

The activities are as follows:

In many species of insects and spiders, males provide females with gifts of food during courtship and mating. This is called nuptial feeding. These offerings are eaten by the female and can take many forms, including prey items the male captured, substances produced by the male, or parts from the male’s body. In extreme cases the female eats the male’s entire body after mating! Clearly these gifts can cost the male a lot, including time and energy, and sometimes even their lives.

So why do males give these gifts? There are two main hypotheses explaining why nuptial feeding has evolved in so many different species. First, giving a gift may attract a female and improve a male’s chance of getting to mate with her, or of fathering her young. This is known as the mating effort hypothesis. Second, giving a gift may provide the female with the energy and nutrients she needs to produce young. The gift helps the female have more, or healthier, offspring. This is known as the paternal investment hypothesis. These two hypotheses are not mutually exclusive – meaning, for any given species, both mechanisms could be operating, or just one, or neither.

Biz is a scientist who studies nuptial gifts, and they work with the Hawaiian swordtail cricket. They chose this species because it uses a particularly interesting example of nuptial feeding. In most other cricket species, the male provides the female with a single package of sperm, called a spermatophore. After sperm transfer, the female removes the spermatophore from her genitalia and eats it. However, in the Hawaiian swordtail cricket, males produce not just one but a whole bunch of spermatophores over the course of a single mating. Most of these are smaller, and contain no sperm – these are called “micros”. Only the last and largest spermatophore to be transferred, called the “macro” actually contains sperm. The number of micros that a male gives changes from mating to mating.

From some of their previous research, and from reading papers written by other scientists, Biz learned that micros increase the chance that a male’s sperm will fertilize some of the female’s eggs. Also, the more micros the male gives, the more of the female’s offspring he will father. This research supports the mating effort hypothesis for the Hawaiian swordtail cricket. Knowing this, Biz wanted to test the paternal investment hypothesis as well. They wanted to know whether the “micro” nuptial gifts help females lay more eggs, or help more of those eggs hatch into offspring.

Biz used two experiments to test the paternal investment hypothesis. In the first experiment, 20 females and 20 males were kept in a large cage outside in the Hawaiian rainforest. The crickets were allowed to mate as many times as they wanted for six weeks. In the second experiment, 4 females and 4 males were kept in cages inside in a lab. Females were allowed to mate with up to 3 different males, and were then moved to a new cage to prevent them from mating with the same male more than once. In both experiments Biz observed all matings. They recorded the number of microspermatophores transferred during each mating and the number of eggs laid. If females that received a greater number of total micros over the course of all matings produced more eggs, or if their eggs had a higher rate of hatching, then the paternal investment hypothesis would be supported.

Featured scientist: Biz Turnell from Cornell University and Technische Universität Dresden

Flesch–Kincaid Reading Grade Level = 8.9

Additional teacher resources related to this Data Nugget include:

The data in this activity has been published. The citation for the paper, and a link to the PDF, are below:
- Turnell, B.R. and K.L. Shaw (2015) High opportunity for postcopulatory sexual selection under field conditions. Evolution 69(8): 2094–2104
For a popular science article about nuptial feeding in a different system, check out these articles
- “Nuptial gifts and other romantic gestures of the bug world“
- “Ultimate sacrifice: Spider’s post-sex cannibalism aids offspring“

10.13.16

Winter is coming! Can you handle the freeze?

Doug, and two members of his team, setting up the reciprocal transplant experiment in Scandinavia.

Doug with the reciprocal transplant experiment in Scandinavia.

The activities are as follows:

Doug is a biologist who studies plants from around the world. He often jokes that he chose to work with plants because he likes to take it easy. While animals rarely stay in the same place and are hard to catch, plants stay put and are always growing exactly where you planted them! Using plants allows Doug to do some pretty cool and challenging experiments. Doug and his research team carry out experiments with the plant species Mouse-ear Cress, or Arabidopsis thaliana. They like this species because it is easy to grow in both the lab and field. Arabidopsis is very small and lives for just one year. It grows across most of the globe across a wide range of latitudes and climates. Arabidopsis is also able to pollinate itself and produce many seeds, making it possible for researchers to grow many individuals to use in their experiments.

Doug, and two members of his team, setting up the reciprocal transplant experiment in Scandinavia.

Part I: Doug wanted to study how Arabidopsis is able to survive in such a range of climates. Depending on where they live, each population faces its own challenges. For example, there are some populations of this species growing in very cold habitats, and some populations growing in very warm habitats. He thought that each of these populations would adapt to their local environments. An Arabidopsis population growing in cold temperatures for many generations may evolve traits that increase survival and reproduction in cold temperatures. However, a population that lives in warm temperatures would not normally be exposed to cold temperatures, so the plants from that population would not be able to adapt to cold temperatures. The idea that populations of the same species have evolved as a result of certain aspects of their environment is called local adaptation.

To test whether Arabidopsis is locally adapted to its environment, Doug established a reciprocal transplant experiment. In this type of experiment, scientists collect seeds from plants in two different locations and then plant them back into the same location (home) and the other location (away). For example, seeds from population A would be planted back into location A (home), but also planted into location B (away). Seeds from population B would be planted back into location B (home), but also planted at location A (away). If populations A and B are locally adapted, this means that A will survive better than B in location A, and B will survive better than A in location B. Because each population would be adapted to the conditions from their original location, they would outperform the plants from away when they are at home (“home team advantage”).

In this experiment, Doug collected many seeds from warm Mediterranean locations at low latitudes, and cold Scandinavian locations at high latitudes. He used these seeds to grow thousands of seedlings. Once these young plants were big enough, they were planted into a reciprocal transplant experiment. Seedlings from the Mediterranean location were planted alongside Scandinavian seedlings in a field plot in Scandinavia. Similarly, seedlings from the Scandinavian locations were planted alongside Mediterranean seedlings in a field plot in the Mediterranean. By planting both Mediterranean and Scandinavian seedlings in each field plot, Doug can compare the relative survival of each population in each location. Doug made two local adaptation predictions:

Scandinavian seedlings would survive better than Mediterranean seedlings at the Scandinavian field plot.
Mediterranean seedlings would survive better than Scandinavian seedlings planted at the Mediterranean field plot.

Doug’s team in the Mediterranean prepped and ready to set up the experiment.

Part II: The data from Doug’s reciprocal transplant experiment show that the Arabidopsis populations are locally adapted to their home locations. Now that Doug confirmed that populations were locally adapted, he wanted to know how it happened. What is different about the two habitats? What traits of Arabidopsis are different between these two populations? Doug now wanted to figure out the mechanism causing the patterns he observed.

Doug originally chose Arabidopsis populations in Scandinavia and the Mediterranean for his research on local adaptation because those two locations have very different climates. The populations may have adapted to have the highest survival and reproduction based on the climate of their home location. To deal with sudden freezes and cold winters in Scandinavia, plants may have adaptations to help them cope. Some plants are able to protect themselves from freezing temperatures by producing chemicals that act like antifreeze. These chemicals accumulate in their tissues to keep the water from turning into ice and forming crystals. Doug thought that the Scandinavian population might have evolved traits that would allow the plants to survive the colder conditions. However, the plants from the Mediterranean aren’t normally exposed to cold temperatures, so they wouldn’t have necessarily evolved freeze tolerance traits.

To see whether freeze tolerance was driving local adaptation, he set up an experiment to identify which plants survived after freezing. Doug again collected seeds from several different populations across Scandinavia and across the Mediterranean. He chose locations that had different latitudes because latitude affects how cold an area gets over the year. High latitudes (closer to the poles) are generally colder and low latitudes (closer to the equator) are generally warmer. Doug grew more seedlings for this experiment, and then, when they were a few days old, he put them in a freezer. Doug counted how many seedlings froze to death, and how many survived, and he used these numbers to calculate the percent survival for each population. To gain confidence in his results, he did this experiment with three replicate genotypes per population.

Doug predicted that if freeze tolerance was a trait driving local adaptation, the seedlings originally from colder latitudes (Scandinavia) would have increased survival after the freeze. Seedlings originally from lower latitudes would have decreased survival after the freeze because the populations would not have evolved tolerance to such cold temperatures.

Featured scientist: Doug Schemske from Michigan State University (MSU). Written by Christopher Oakley from MSU and Purdue University, and Marty Buehler (RET) from Hastings High School.

Flesch–Kincaid Reading Grade Level = 12.0

There is one scientific paper associated with the data in this Data Nugget. The citation and PDF of the paper is below.

Agren, J. and D.W. Schemske (2012). Reciprocal transplants demonstrate strong adaptive differentiation of the model organism Arabidopsis thaliana in its native range. New Phytologist 194:1112–1122.

10.12.16

Lobsters out of water: Scientists at film camp in Maine

This post is by MSU graduate student Carina Baskett. See the original article on the BEACON webpage (reproduced below):

Carina and her fellow science communicator Klara Scharnagl making a stop at Niagara Falls on the way back from a film workshop in Maine.

My colleague Klara Scharnagl had a great idea. “Let’s shoot it from the perspective of a vegetable!” As a scientist, I don’t usually go to work expecting to hear a sentence like that! But yes, we did end up shooting a short video at a farmer’s market from the perspective of a love-struck melon, all in the name of science education.

Klara and I were at a weeklong film workshop in Maine the first week of September to improve our filmmaking skills. We are working on a BEACON-funded project with Melissa Kjelvik, Liz Schultheis, Travis Hagey, and Anna Groves to make videos for classrooms about scientists. The videos will accompany Data Nuggets (DNs), which are exercises for K-12 and undergraduate students to practice working with data from real, current research. DNs were co-developed by MSU graduate students and K-12 teachers.

The goals of the videos are two-fold. First, we aim to redefine how students see science and scientists by featuring researchers from diverse backgrounds, giving students more face time with the scientists than they can get from a photo in a DN. Second, we aim to enhance evolution education by showing how data is collected and presenting information in an alternative media to the standard written descriptions.

A Maine lobster dinner was the cherry on top of the film workshop sundae!

On top of those goals, there is the overriding need for the videos to be engaging, and the first, somewhat invisible step toward that goal is to be technically proficient. Klara and I each have experience with science outreach and a smattering of the requisite technical skills for filmmaking, but we needed more training and experience with videos. So we found a workshop, “Documentary Camera” at a school called Maine Media.

Klara and I were the only scientists out of the 11 students in the class. In fact, some of the students said that we were the only scientists they had ever met. Being in a classroom where I was clueless and surrounded by people more expert than me was a lot like being a first-year graduate student again! But it was fun to learn so much.

To practice the techniques that we would be using for the DN videos, Klara and I made a “pilot.” We decided that it had to be about plants or lichens (the organisms that we study), not humans or animals, because a major challenge of the DN videos will be to tell engaging stories about organisms and questions that aren’t inherently exciting to most of the population. Personally, I find plants and lichens to be a lot more exciting than, say, sports, but I realize I’m in the minority with that view.

The closest we could come to interviewing a plant expert was to go to an “herbal apothecary,” a pharmacy where all the medicines and remedies come from plants. The message of the video was to get viewers excited about the chemicals that plants make, by pointing out that traditional and many modern medicines come from plants, and then slip in some biology by asking why plants make these chemicals (generally to defend themselves from pests and disease).

We visited the apothecary on short notice, and were able to snag a quick interview with a gardener. When asked, “Plants don’t make these chemicals for human use. Why do they?” she said, “How do we know they don’t make them for humans? Hmm, I’ll have to think about that.” This was an informative moment for us in a couple ways.

First, it was a good reminder that a lot of the scientific knowledge we take for granted, and even the questions that scientists think to ask, are not common sense. Even someone whose job it is to work with plants and the chemicals they manufacture was not considering the evolutionary explanation for why plants have these adaptations that we are co-opting. Yet it would be helpful for someone working with plant medicine to have an understanding that related plants might manufacture similar compounds and that the environmental context (such as an outbreak of caterpillars on a plant) might affect the drugs that they are harvesting. That’s why evolution education and outreach are so important!

Second, the interview was good practice for the DN videos because we aren’t always going to get a nice, video-ready sound bite from everyone we talk to. Some of the scientists we interview might use too much jargon and be unable to make their research approachable. But that’s why we will include narration and drawings to guide the narrative. We ended up using the gardener’s quote about why she thinks plants are amazing and exciting, and we provided the explanation of why plants make chemicals that we use for medicine.

So was our science communication effective? On the last day of the workshop, participants from several classes ate an amazing dinner of Maine lobster, and then watched each other’s projects. It was funny to see our educational video mixed in with a beautifully shot piece showing a nearby harbor as the catch was being brought in; with a portrait of a pair of local artists whose house is covered in drawings; and with some dramatic fictional pieces from another class. When I asked everyone afterward, “So why do plants make chemicals that we use for medicine?” almost all of them answered correctly. If we can reach a group of filmmakers who didn’t even know there would be a quiz, hopefully we can have an impact on students, by helping to make Data Nuggets just a little more delicious.

You can watch our 5-minute video below! And if you have an extra few minutes and wouldn’t mind giving us some feedback, please click here.

10.6.16

Gene expression in stem cells

Adam working in the lab at Colorado State University.

The activities are as follows:

Every cell in your body contains the same DNA. How is it that genetically identical skin, brain, and muscle cells can look very different and perform very different functions from each other? Cells differentiate, or become different from one another, by turning certain genes on and off. This process is called gene expression. For example, when you spend time in the sun your skin cells turn on the gene for pigment, which protects your cells from bright sunlight. In the winter when there is less sunlight, your cells turn off this gene. This process your body uses to turn genes on and off is the same one it uses to develop from one cell into the many different cell types that make up your body. Stem cells have the ability to turn into any other type of cell in the body, an ability known as pluripotency. Your body retains some stem cells for your entire life.

Some genes are only turned on in specific types of cells because they have specialized jobs for those cell types, like muscle or brain cells. Other genes are more like managers, controlling which genes are turned on and off. The activity of these manager genes may be more common in stem cells because they could control which type of cell the stem cell will become. In recent years, scientists discovered they could reprogram specialized cells back into non-specialized stem cells, simply by turning on several manager genes. They call these reprogrammed cells induced pluripotent, or iPS.

Adam working under the hood, reprogramming specialized cells into induced pluripotent stem cells for his experiments.

Adam was working as a biologist in Colorado when he learned that many cool medical advances in regenerative and personalized medicine will happen when we figure out which genes are turned on, and which are turned off, in pluripotent stem cells. In his research, Adam wanted to look at gene expression for two genetically identical cell lines, those that have specialized and those that have been reprogrammed to be iPS stem cells. He was interested to see which genes are expressed by both types of cells and which genes are only expressed in one type of cell.

He decided to work with fibroblast cells because they are easy to grow in the lab. Fibroblasts cells are mainly responsible for production and maintenance of the extracellular matrix (including joints, ligaments, tendons and connective tissues), which is critical in holding the body’s tissues together. From reading the work of other scientists, Adam learned how to transform fibroblast cells into iPS stem cells. This knowledge lead him to two genetically identical types of cells – (1) specialized fibroblast cells and (2) unspecialized iPS cells. When fibroblast cells are transformed into unspecialized iPS cells, their function changes and they become responsible for wound healing and generating new tissues, acting like a reserve set of cells. Because fibroblast and iPS cells perform very different functions, Adam thinks it is likely that each cell line will expresses genes that are specific to its individual function.

Adam looked at expression in 10 different genes that are thought to have important functions for fibroblast or iPS cells. Adam measured the expression for each gene by looking at RNA abundance of each gene in the different cell types. RNA is the intermediate between DNA (the genetic blueprint) and protein (the functional worker of the cell). Adam chose to look at RNA, because it is often representative of how much protein is present in a cell, which is very difficult to measure directly. Adam analyzed three replicates for each cell type. He replicated in order to get a more accurate representation for each cell type. This is important in case the samples were in slightly different conditions, like warmer or cooler temperatures, which could alter gene expression. This experiment allowed Adam to figure out which genes are turned on in iPS cells, allowing him to better understand how stem cells work.

iPS cells display different gene expression and physical appearance than HFF cells: Figures A and B are low magnification images of two different iPS cell colonies. iPS cells are usually small, round, and like to grow in circular-like colonies. Figures C is a low magnification image of HFF cells. HFF cells tend to appear long and slender almost like trees. Generally, HFF cells like to grow near each other, but not in colonies. Figure D is a higher magnification image of the black box in figure C, showing a group of HFF cells growing in close proximity with each other.

Featured scientist: Adam Heck from Colorado State University. Written with Sandra Weeks from the Poudre Valley School District.

Flesch–Kincaid Reading Grade Level = 10.6

The gene expression data found in this activity was gathered from the following paper – citation and link below:

Neff, A. T., Lee, J. Y., Wilusz, J., Tian, B., & Wilusz, C. J. (2012). Global analysis reveals multiple pathways for unique regulation of mRNA decay in induced pluripotent stem cells. Genome Research, 22(8), 1457–1467.

10.5.16

Raising Nemo: Parental care in the clown anemonefish

Clown anemonefish caring for their eggs.

The activities are as follows:

When animals are born, some offspring are able to survive on their own, while others rely on parental care. Parental care can take many forms. One or both parents might help raise the young, or in some species other members of the group help them out. The more time and energy the parents invest, the more likely it is that their offspring will survive. However, parental care is costly for the parents. When a parent invests time, energy, and resources in their young, they are unable to invest as much in other activities, like finding food for themselves. This results in a tradeoff, or a situation where there are costs and benefits to the decisions that must be made. Parents must balance their time between caring for their offspring and other activities.

The severity of the tradeoff between parental care and other activities may depend on environmental conditions. For example, if there is a lot of food available, parents may spend more time tending to their young because finding food for themselves takes less time and energy. Scientists wonder if parents are able to adjust their parental care strategies in response to environmental changes.

Photo of Tina (left) with other members of her lab. The glowing blue tanks around them all contain anemonefish!

Tina is a scientist studying the clown anemonefish. She is interested in how parental care in this species changes in response to the environment. She chose to study anemonefish because they use an interesting system to take care of their young, and because the environment is always changing in the coral reefs where they live.

Anemonefish form monogamous pairs and live in groups of up to six individuals. The largest female is in charge of the group. Only the largest male and female get to mate and take care of the young. Both parents care for eggs by tending them, mouthing the eggs to clean the nest and remove dead eggs, and fanning eggs with their fins to oxygenate them. A single pair may breed together tens or even hundreds of times over their lifetimes. But here is the cool part – anemonefish can change their sex! If the largest female dies, the largest male changes to female, and the next largest fish in line becomes the new breeding male. That means that a single parent may have the opportunity to be a mother and a father during its lifetime.

Parents will fan the eggs to increase oxygen by the nest, or mouth them to remove dead eggs and clean the nest.

On the reef, anemonefish groups also experience shifts in how much food is available. In years with lots of food, the breeding pair has lots of young, and in years with little food they do not breed as often. Tina presumed that food availability determines how much time and energy the parents invest in parental care behaviors. She collected data from 20 breeding pairs of fish, 10 of which she gave half rations of food, and 10 of which she gave full rations. The experiment ran for six lunar months. Every time a pair laid a clutch of eggs, Tina waited 7 days and then took a 15-minute video of the parents and their nest. She watched the videos and measured three parental care behaviors: mouthing, fanning, and total time spent tending for both males and females. Some pairs laid eggs more than once, so she averaged these behaviors across the six months of the experiment. Tina predicted that parents fed a full ration would perform more parental care behaviors, and for a longer amount of time, than parents fed a half ration.

Watch video of the experimental trials, demonstrating the mouthing and fanning behaviors:

Featured scientist: Tina Barbasch from Boston University

Flesch–Kincaid Reading Grade Level = 9.4

About Tina: I first became interested in science catching frogs and snakes in my backyard in Ithaca, NY. This inspired me to major in Biology at Cornell University, located in my hometown. As an undergraduate, I studied male competition and sperm allocation in the local spotted salamander, Ambystoma maculatum. After graduating, I joined the Peace Corps and spent 2 years in Morocco teaching environmental education and 6 months in Liberia teaching high school chemistry. As a PhD student in the Buston Lab, I study how parents negotiate over parental care in my study system the clownfish, Amphiprion percula, otherwise known as Nemo. More here!

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9.19.16

Collaborations with K-12 teachers first inspired Data Nuggets, and continue to today

This post is by MSU postdocs Liz Schultheis and Melissa Kjelvik. See the original article on the BEACON webpage (reproduced below):

Liz modeling the process of science within a Data Nugget.

Back when we were biology graduate students, the GK-12 program at the Kellogg Biological Station (KBS) exposed us to science education for the first time. When we signed up to work with K-12 teachers and go into schools as the “classroom scientist” we knew there would be benefits, such as time to hone our science communication skills, a venue to share our research with broad audiences, and of course saving us the hour and a half drive to MSU’s main campus to TA. However, we had no idea what we had really gotten ourselves into.

We were each assigned a partner teacher whose classroom we would visit a few times a week, and who would mentor us as we attempted to share our research with students for the first time. The experience of standing up in front of 30 sixth graders was intimidating at first. Yet, it was necessary to realize how hard it was to simplify and explain a topic, while also making it engaging for an audience who may never have thought about these ideas before. The teachers’ infectious enthusiasm boosted the passion we had for our research. They pushed us to describe why the things we were doing day-to-day mattered for the big picture. They were willing to stand in the back of the classroom and wave their arms when students checked out because we’d used too much jargon or started to nerd-out. These teachers had such a clear passion for improving student learning; they constantly stepped out of their comfort zone to try new ways to improve their teaching and integrate the latest effective science teaching strategies into their classrooms. Working with these teachers and their students quickly became our favorite time of the week.

These same teachers originally inspired Data Nuggets; they shared that their students were struggling to make sense of data in most applications, but especially data from classroom inquiry projects that turned out messy or did not follow predictions. Students should not feel they have failed when their data has variation around the mean or does not support their hypothesis. Typically, students are only exposed to research and data published in textbooks, leading to the misconception that all science is a completed product with well established ideas and clear results. To get students to think like scientists, they need to be exposed to the process of science itself and how scientists work to develop, test, and refine their ideas. As early-career scientists, we knew that along the way, experiments often fail or yield unexpected results.

Melissa running a professional development workshop for high school math and science teachers.

For continued support, we turned to BEACON, whose education objectives align with the Data Nuggets vision. Using these seed funds, we were able to work with Louise Mead and other BEACON scientists to develop Data Nuggets that connect students to real data and the motivation and passion of the scientists behind the research. Today we have 46 Data Nuggets (and counting) up on our website, freely available to teachers and students, many written by women and early career scientists.

As we wrapped up as graduate students, we realized there was so much more we wanted to do to improve and expand Data Nuggets. The support from BEACON allowed us time to fully develop our ideas and submit an NSF DRK-12 grant with Louise. As BEACON postdocs we are excited to have time to integrate all these great ideas into Data Nuggets. The main objective of the collaborative NSF DRK-12 grant, between MSU and Biological Science Curriculum Study (BSCS), is to assess whether Data Nuggets increase students’ quantitative reasoning abilities, along with their understanding of, and engagement with, science. In preparation for this efficacy study, we are currently revising each Data Nugget and integrating new ideas and feedback from our collaboration.

High school math and science teachers working to complete a Data Nugget during a professional development workshop.

This summer we worked with 4 teachers – Marcia Angle, Cheryl Hach, Ellie Hodges, and Kristy Campbell. Marcia and Cheryl have been with us since the beginning, and were among those who first helped us develop Data Nuggets. They were thrilled to see that we continued to develop Data Nuggets and were happy with how far they’d come since the original inception. This summer we had many insightful conversations about students’ struggles with certain scientific practices, including data interpretation and constructing explanations. The teachers shared their different teaching strategies, and researched new ones, in order to write guides to help other teachers cover these difficult topics. As a group we read through student responses to Data Nuggets piloted in the spring. This was a powerful way to think deeply about the areas students could improve, and ways for us to provide more context in our teacher guides to encourage rich classroom discussions. Along with BEACON postdoc Alexa Warwick, the teachers developed a grading rubric to help teachers score Data Nuggets and identify areas where their students need more practice. While reading student responses, the teachers collectively noticed that students had a difficult time using evidence to support their claims, so they worked on a new tool to ease students into this process. They presented this tool, along with other strategies, at professional development workshops for the KBS K-12 partnership teachers and all Kalamazoo Public Schools high school science teachers.

This year we are finalizing preparations for our Data Nugget efficacy study, taking place in 2017. Preliminary observations in classrooms, and feedback from teachers, indicate Data Nuggets effectively increase students’ quantitative and scientific literacy while engaging them with the story behind the research and building a connection to scientists. However, as scientists, we are of course not satisfied with anecdotal evidence and want data to support our claims! We are excited for the upcoming study to determine the ways in which Data Nuggets might contribute to a strong science education curriculum!

8.29.16

How do brain chemicals influence who wins a fight?

The activities are as follows:

In nature, animals compete for resources. These resources include space, food, and mates. Animals use aggression as a way to capture or defend these resources, which can improve their chances of survival and mating. Aggression is a forceful behavior meant to overpower opponents that are competing for the same resource. The outcome (victory or defeat) depends on several factors. In insects, the bigger individuals often win. However, if two opponents are the same size, other factors can influence outcomes. For example, an individual with more experience may defeat an individual with less experience. Also individuals that are fighting to gain something necessary for their survival have a strong drive, or motivation, to defeat other individuals.

Researchers Andrew, Ken, and John study what role an animal’s brain plays in regulating behavior when motivation is present. They wanted to know if specific chemicals in the brain influenced the outcome of a physically aggressive competition. Andrew, Ken, and John read a lot papers written by other scientists and learned that there is a brain chemical that plays an important role in regulating aggressive behavior. This chemical is called serotonin and is found in the brains of all animals, including humans. Even a small amount of this chemical can make a big impact on aggressive behavior, and perhaps the outcome of competition.

The researchers decided to do an experiment to test what happens to aggression during competition as serotonin levels in the brain increase. They used stalk-eyed flies in their experiment. Stalk-eyed flies have eyes on the ends of stalks that stick out from the sides of their heads (Pictures 1 & 2). They reasoned that brain serotonin levels in stalk-eyed flies influence their aggressive behaviors in battle and therefore impact the outcome of competition. If their hypothesis is true, they predicted that increasing the brain serotonin in a stalk-eyed fly would make it more likely to use aggressive behaviors, and flies that used more aggressive behaviors would be more likely to win. Battling flies use high-intensity aggressive attacks like jumping on or striking an opponent. They also use less aggressive behaviors like flexing their front legs or rearing up on their hind legs.

Two stalk-eyed flies rearing/extending forearms in battle. Photo credit: Sam Cotton.

To test their hypothesis, the researchers set up a fair test. A fair test is a way to control an experiment by only changing one piece of the experiment at a time. By changing only one variable, scientists can determine if that change caused the differences they see. Since larger flies tend to win fights, the flies were all matched up with another fly that was the same size. This acted as an experimental control for size, and made it possible to look at only the impact of serotonin levels on aggression. The scientists also controlled for the age of the flies and made sure they had a similar environment since the time they were born. The experiment had 20 trials with a different pair of flies in each. In each trial, one fly received corn mixed with a dose of serotonin, while another fly received plain corn as a control. That way, both flies received corn to eat, but only one received serotonin.

Each pair of flies was placed in a fighting arena and starved for 12 hours to increase their motivation to fight over food. Next, food was placed in the center of the arena, but only enough for one fly! The researchers observed the flies, recording three types of behaviors for each opponent. High intensity behaviors were when the fighting flies touched one another. Low-intensity behaviors were when the flies did not touch each other, for example jump attacks, swipes, and lunges. The last behavior type was retreating from the fight. Flies that retreated fewer times than their opponent were declared the winners. After the battles, the researchers collected the brains of the flies and measured the concentration of serotonin in each fly’s brain.

Featured scientists: Andrew Bubak and John Swallow from the University of Colorado at Denver, and Kenneth Renner from the University of South Dakota

Flesch–Kincaid Reading Grade Level = 9.2

There is a scientific paper associated with the data in this Data Nugget. The citation and PDF for the paper is below.

Bubak, A.N., K.J. Renner, and J.G. Swallow. 2014. Heightened serotonin influences contest outcome and enhances expression of high-intensity aggressive behaviors. Behavioral Brain Research 259: 137-142.

An article written about the research in this Data Nugget: John Swallow: Co-authors study on insect aggression and neurochemistry

Video showing two stalk eyed flies battling in the fighting arena.

Video showing how the long eyestalks of males form!

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8.20.16

Beetle battles

Erin has always loved beetles! Here she is with a dung beetle in Tanzania, during a graduate school class trip.

The activities are as follows:

Male animals spend a lot of time and energy trying to attract females. In some species, males directly fight with other males to become socially dominant. They also fight to take over and control important territories. This process is known as male-male competition. The large antlers of male elk are an example of a trait that has been favored by male-male competition. In other species, males try to court females directly. This process is known as female choice. The flashy tails of male peacocks are a good example of a trait that has been favored by female choice. Lastly, in some species, both male-male competition AND female choice determine which males get to mate. In order to be successful, males have to be good at both fighting other males and making themselves attractive to females. Erin is a biologist interested in these different types of mating systems. She wondered if she could discover a single trait that was favored by both male-male competition and female choice.

Two dung beetle males fighting for ownership of the artificial tunnel. Why is the photo pink? Because beetles mate and fight in dark, underground tunnels, Erin carried out all of her experiments in a dark room under dim red-filtered light. Beetles can’t see the color red, so working under red-filtered light didn’t affect the beetles’ behavior, and allowed Erin to see what the beetles were doing.

In horned dung beetles, male-male competition and female choice are both important in determining which males get to mate. Females dig tunnels underneath fresh piles of dung where they mate and lay their eggs. Beetles only mate inside these underground tunnels, so males fight with other males to become the owner of a tunnel. Males that control the tunnels have a better chance to mate with the female that dug it. However, there is often more than one male inside a breeding tunnel. Small males will sneak inside a main tunnel by digging a connecting side tunnel. Additionally, the constant fights between large males means that the ownership of tunnels is constantly changing. As a result, females meet many different males inside their tunnels. It is up to them to choose the male they find the most attractive, and with whom they’ll mate. In this species of dung beetle, males try to persuade females to mate by quickly tapping on the females’ back with their forelegs and antennae. Previous research has found that females are more likely to mate with males that perform this courtship tapping at a fast rate. Because both fighting and courtship tapping take a lot of strength, Erin wondered if the trait of strength was what she was looking for. Would stronger male dung beetles be favored by both male-male competition and female choice?

To keep beetles alive in the lab, Erin set up a bucket with sand, and placed one pile of dung in the center. Female beetles dug tunnels below the dung.

To test her hypothesis, Erin conducted a series of experiments to measure the mating success, fighting success, and strength of male dung beetles. First, Erin measured the mating success of male beetles by placing one male and one female in an artificial tunnel (a piece of clear plastic tubing). She watched the pair for one hour, and measured how quickly the males courted, and whether or not the pair mated. Second, Erin measured the fighting success of males by staging fights between two males over ownership of an artificial tunnel. Beetle battles consist of a head-to-head pushing match that results in one male getting pushed out of the tunnel, and the other male remaining inside. To analyze the outcome of these fights, Erin randomly selected one male in each pair as the focal male, and scored the interaction as a “win” if the focal male remained inside the tunnel, and as a “loss” if the focal male got pushed out of the tunnel. In some cases, there was not a clear winner and loser because either both males left the tunnel, or both males remained inside. These interactions were scored as a “tie”. Finally, Erin determined each beetles’ strength. She measured strength as the amount of force it took to pull a male out of an artificial tunnel. To do this, she super-glued a piece of string to the back of the beetle, had it crawl into an artificial tunnel, attached the string to a spring scale, and then pulled on the scale until the beetle was pulled out of the tunnel.

Featured scientist: Erin McCullough from the University of Western Australia

Flesch–Kincaid Reading Grade Level = 8.8

Additional resources related to this Data Nugget:

There is one scientific paper associated with the data in this Data Nugget. McCullough, E.L. and L.W. Simmons (2016) Selection on male physical performance during male–male competition and female choice. Behavioral Ecology
Alignment of this activity to NGSS Standards can be found on the NSTA website here.

About Erin: I am fascinated by morphological diversity, and my research aims to understand the selective pressures that drive (and constrain) the evolution of animal form. Competition for mates is a particularly strong evolutionary force, and my research focuses on how sexual selection has contributed to the elaborate and diverse morphologies found throughout the animal kingdom. Using horned beetles as a model system, I am interested in how male-male competition has driven the evolution of diverse weapon morphologies, and how sexual selection has shaped the evolution of physical performance capabilities. I am first and foremost a behavioral ecologist, but my research integrates many disciplines, including functional morphology, physiology, biomechanics, ecology, and evolution.

8.18.16

Professional Development Workshop @ KBS Summer Institute 8/18/16

Advice on how to use the Claims-Evidence-Reasoning framework in your classroom intentionally. Session presented with two Michigan science teachers, Marcia Angle and Cheryl Hach.

Session Description: In our session we will talk about the transition of science education away from memorization of facts and more towards the application of applying critical thinking and quantitative reasoning. We will discuss the importance of scaffolding student learning centered on the scientific principles of investigation, student discourse, and will unveil our new graphic CER organizer that we designed to support student writing when it comes to Claim, Evidence and the oh so difficult Reasoning portions of science writing. We use Data Nuggets throughout the session to model how you can integrate our CER tool into the classroom and increase the amount of data analysis and interpretation done in your classroom. This session is for upper elementary, middle and high school teachers whose students struggle with quantitative skills and CER writing. Our little nuggets can do great things!