New Evolutionary Understanding of Horseshoe Crabs

A Critical Appraisal of the Placement of Xiphosura (Chelicerata) with Account of Known Sources of Phylogenetic Error
Jesús A. Ballesteros and Prashant P. Sharma
Summarized by Maggie Limbeck

What data were used? Data were collected from whole genome sequence projects and RNA sequence libraries for all 53 organisms included in this study. Because there are four living species of horseshoe crabs and many living representatives of arachnids (spiders, scorpions, ticks) genetic data was able to be used as opposed to morphologic (shape and form) data. Organisms from Pancrustacea (crabs, lobsters, etc.) and Myriapoda (centipedes and millipedes) were used as outgroup organisms, organisms that are included in the analysis because they are part of the larger group that all of these animals fit into (Arthropoda) but have been determined to not be closely related to the organisms that they cared about in this study.

Methods: Several different methods were used in this study to estimate the evolutionary relationships between horseshoe crabs and arachnids. By using multiple different phylogenetic methods (different calculations and models to estimate relationships between organisms) these researchers had several different results to compare and determine what relationships always showed up in the analyses. In addition to all of these different methods that were used, two different scenarios were tested in each method. The researchers wanted to be able to run their data and see what results they got, but also test the existing hypothesis that horseshoe crabs are sister taxa to land-based arachnids.

One of the trees that was reported from one of the many phylogenetic analyses that were completed using this data set. The orange color represents the horseshoe crabs in this study and you can see that the orange is surrounded by green branches which represent arachnids. The boxes that are present on the branches of the trees are representative of different analyses and data sets that were used to return this particular tree and support that these relationships have in other analyses that were run. The stars on the tree show relationships that were well supported in all analyses.
Results: The vast majority of the phylogenetic trees that were produced in these different analyses showed that horseshoe crabs are “nested” or included in the group Arachnida and are sister taxa to Ricinulei (hooded tick spiders). The only analyses that returned results different from this, were those that were forced to keep horseshoe crabs as sister taxa to the land-based arachnids, but those trees had very low statistical support of being accurate.

Why is this study important? This study is particularly cool because it highlights interesting problems associated with using genetic data versus morphologic data and problems with understanding evolution in groups that diversified quickly. Chelicerates (the group of Arthropods that have pincers like spiders, scorpions, horseshoe crabs) diversified quickly, live in both aquatic and terrestrial settings, and have many features like venom, that all appeared in a short time frame geologically. By gaining a better understanding of the relationships between the members of Chelicerata and Arachnida researchers can start to look at the rates at which these features developed and the timing of becoming a largely land-based group. This is also an important study because it has demonstrated that relationships we thought were true for horseshoe crabs and arachnids for a long time may not actually be the case.

The big picture: The research done in this study really highlights the major differences in relationships that can be demonstrated depending on whether you are using morphological data or genetic data. This study found that by using genetic data for 53 different, but related organisms, that horseshoe crabs belong within the group Arachnida rather than a sister taxa to the group. It’s also really cool that this study was able to demonstrate evolutionary relationships that are contrary to what have long been believed to be true.

Citation:
Jesús A Ballesteros, Prashant P Sharma; A Critical Appraisal of the Placement of Xiphosura (Chelicerata) with Account of Known Sources of Phylogenetic Error, Systematic Biology, syz011, https://doi.org/10.1093/sysbio/syz011

A Rare and Exciting Fossil Deposit Causes Excitement and Contention in the Paleontological Community

A seismically induced onshore surge deposit at the KPg boundary, North Dakota

Robert A. DePalma, Jan Smit, David A. Burnham, Klaudia Kuiper, Phillip L. Manning, Anton Oleinik, Peter Larson, Florentin J. Maurrasse, Johan Vellekoop, Mark A. Richards, Loren Gurche, and Walter Alvarez

Summarized by Jen Bauer, Maggie Limbeck, and Adriane Lam, who also comment on the controversy below

What data were used?

Data used in this study were identified from a new site, which the authors call Tanis (named after the ancient Egyptian city in the Nile River Delta), in the layers of rocks called the Hell Creek Formation. This formation is famous amongst paleontologists because it contains lots of dinosaur fossils from the late Cretaceous (about 66 million years ago). In this study, scientists found a new layer of fossils within the Hell Creek Formation that is unlike anything paleontologists have seen before. Those who found the site examined the rock’s features and fossils, which includes densely packed fish fossils and ejecta from the Chicxulub meteoric impact. The Chicxulub impact is what caused the dinosaurs to go extinct, and finding a layer of rock that was deposited minutes to hours after the impactor struck Earth is a very rare and exciting find.

Methods

This study included a variety of approaches. The rock features (called sedimentology) and fossil features of the Tanis area and event deposit are described to determine what caused this deposit in the first place. The authors also identified other pieces of evidence to aid in better understanding the situation at hand. Ejecta deposits were described as well, in comparison to ejecta deposits that are found closer to the impact site in the Yucatan Peninsula, Mexico.

Results

Figure 1. The extremely well preserved fossils from the Tanis site. (A) Shows a partially prepared plaster jacket with partially prepared fossil freshwater fish. Next to an ammonite shell with mother of pearl preservation (that’s the pretty iridescent part that is enlarged). (B) Shows how the large amount of specimens were oriented in the rock and the inferred direction of flow estimated from the rock and fossils at the site. (C) Photograph taken in the field showing the tightly packed fish, fossilized in a clear orientation. This is figure 7 in the paper, click here to see the other figures.

Much of the sedimentology can be related to other aspects of the Hell Creek Formation in southwestern North Dakota that is an ancient river deposit that has some marine influence. In the Cretaceous period, central North America’s topography was very low which allowed for a seaway to form. This was called the Western Interior Seaway, and was home to a diverse number of animals such as plesiosaurs, mososaurs, large sharks, and ammonites. Several rivers likely drained into the Western Interior Seaway, much like the Mississippi River drains into the Gulf of Mexico today.

From studying the characteristics of the rocks within the Tanis site, the authors of the study concluded that this site was part of one of the rivers that drained into the Western Interior Seaway long ago. When the impactor struck Earth in the Yucatan Peninsula, it send huge waves (tsunamis) into the Western Interior Seaway and into the rivers that drained into the seaway. These huge waves pushed fish, ammonites, and other creatures into the seaway and into the rivers. The Tanis site is one such place where these animals that were pushed into the rivers were deposited and preserved. But not only were marine animals preserved at the site, but also land plants, such as tree limbs and flowers.

The fossils found in the Tanis deposits are all oriented in the same direction, indicating that they have been aligned by flowing water. The abundance and remarkable preservation of these fossil fishes and tree limbs suggest a very rapid burial event (the best preserved fossils are often the ones that experience very quick burial after death). The orientation of the fossils at the site along with the mix of marine and terrestrial life further supports that these fossils were deposited from very large waves from the asteroid impact disturbed this region.

Within the Tanis deposit there are also ejecta spherules, microkrystites, shocked minerals, and unaltered impact-melt glass. These are features that are commonly associated with the Chicxulub Impactor. When the impactor struck Earth, it was so hot it melted the underlying rock, sending tiny bits of molten rock into the atmosphere. These bits of molten rock quickly cooled and eventually fell back down to Earth, where today they are found all over the world. Today, these ejecta spherules and impact melt-glass all mark the huge end-Cretaceous mass extinction event that occurred 66 million years ago.

Why is this study important?

The Cretaceous-Paleogene (K/Pg) extinction event is one of the ‘Big Five’ mass extinction events (click here to read more about extinction). Like many extinction events, it is often difficult to determine the specific causes of mass destruction. However, the K/Pg extinction event is unique because scientists have many lines of evidence that a huge impactor struck Earth, sending clouds of ash and gas into Earth’s atmosphere. The new Tanis site that the authors uncovered preserves a snapshot into this catastrophic event.

This finding is very important because scientists know better understand what happened directly after the impactor hit Earth. In addition, several new species of fish have been discovered at the Tanis site, which will be important for additional studies about fish evolution through time.

Citation:

DePalma, R.A., Smit, J., Burnham, D.A., Kuiper, K., Manning, P.L., Oleinik, A., Larson, P., Maurrasse, F.J., Vellekoop, J., Richards, M.A., Gurche, L., and Alvarez, W. 2019. A seismically induced onshore surge deposit at the KPg boundary, North Dakota. Proceedings of the National Academy of Sciences (PNAS), doi: 10.1073/pnas.1817407116

What’s all the commotion about?

It’s not every day that paleontologists make the national news, but this paper and the article written about it in the New Yorker (click here) caused a lot of commotion within the paleontological world. This is a great and potentially groundbreaking find, however, what caused the commotion was the sensationalist attitude of the New Yorker piece that left a lot of paleontologists uncomfortable. So what’s the big deal here? We break down a few (not all) of the issues with this article:

1. Breaking of Embargo

Although the published study is very exciting and will add greatly to our knowledge about the end-Cretaceous mass extinction event, the media hype around the study was handled very poorly for several reasons. All published studies go through peer review. This is when a paper is sent out to multiple other scientists who read the article and make sure that it is scientifically sound and is a good piece of science based upon other good science. During this waiting period while the paper is going through peer review or being finalized with publishers, the authors should avoid talking with popular media or publicizing their paper. When publishing in academia there is a period of time (embargo) where access to the findings of a paper is not allowed to the public. This is for a variety of reasons, having to do with copyright transfer, finances to support the journal or publisher, and more.

The New Yorker press article was released almost an entire week before being available for the community to examine. This means that the embargo was violated.

The reason embargos exist is to give journalists and the researchers they talk to some time to look at fresh findings and determine what the story is, whether it’s worth telling, and if there’s anything suspicious about what’s presented. – Riley Black (Slate article)

2. Paleontologists as Rough-and-Tough Dudes (and Unusual Folks)

The New Yorker article was also controversial because it framed paleontologists as belonging to a narrow demographic (read: white men who love the outdoors). Not all of us in paleontology are men, not all of us are white, and not all of us came into geology loving the outdoors (see the great diversity of folks working in paleontology on our ‘Meet the Scientist’ blog). Paleontologists have had to work very hard to break through the stereotypical conception of what we do and who we are, and this article did not help to address the great diversity of scientists working in the field of paleontology.

In addition, the New Yorker article only quoted and interviewed other male scientists, many of whom have been working in the field for decades. The article left out the voices of women and early-career researchers who have made valuable contributions to the field of paleontology. For more on this, read the Slate article by science writer, Riley Black “It’s Time for the Heroic Male Paleontologist Trope to Go Extinct”.

This article also reinforces the “lone-wolf” stereotype of geologists and paleontologists-a man going out west, few to no other people around, and spending his days looking for paleontological treasure. This image is perpetuated through the article because the author chose to continually highlight the privacy and secrecy asked by the De Palma. While this is certainly an attitude held by some paleontologists, the reality is that the majority of us work in teams. Time Scavengers is run by a large team of people and so is our research! Like working in any field, we all have our strengths and better science happens when we invite people to work with us who have different strengths and can help us.

Lastly, the article frames paleontologists in a not-so-flattering light. In one paragraph, the article states “…I thought that he was likely exaggerating, or that he might even be crazy. (Paleontology has more than its share of unusual people).” Firstly, what does unusual even mean? The STEM (Science, Technology, Engineering, Maths) fields are full of intelligent, diverse, and colorful folks from all walks of life. To imply that any one branch of science has ‘its share of unusual people’ is unfair and regressive.

3. Dinosaurs as the Star of the Show

Paleontology is not just diverse in terms of the people who work in the field, but also in terms of the different types of life that we work with. For example, our Time Scavengers team, we have folks who work with fossil plankton and echinoderms. In fact, most paleontologists work with invertebrates- animals that do not have backbones, or any bones at all. Some of the most foundational findings in paleontology are based on the fossil record of invertebrates and early vertebrates. Regardless, most of the public’s fascination lies with dinosaurs (we understand, they were gigantic, ferocious, and unlike anything that’s alive today).

However, this fascination with dinosaurs can lead to over exaggeration of studies and sensationalizing, which is exactly what happened with this article. The published study of the Tanis site only mentions one dinosaur bone out of all the fossils found. The real story here is about the wonderful assortment of fish, tree, and flower fossils, some of which are completely new to paleontologists.

Another article by Riley Black that gives more of a spotlight to the amazing fish found at the locality, “Fossil Site May Capture the Dinosaur-Killing Impact, but It’s Only the Beginning of the Story.”

Dr. Steve Bursatte, Paleontologist at University of Edinburgh commented on both the New Yorker article and the PNAS article on his Twitter account, click here to read more. He comments on the broken embargo and how the New Yorker article sensationalized the ‘dinosaur’ side of the story.

4. Proper Handling of Museum-Quality Specimens

The article that was published in the New Yorker raised a lot of concerns within the paleontology community regarding the handling and storage of the fossils that were found at the Tanis site. It is clear from the article that DePalma had a bad experience early on with fossils that he had loaned a museum not being returned to him, however, by maintaining control over the management of his specimens, it undermines those people working in museums who have degrees and years of experience handling fossil and other specimen collections. Anyone who has borrowed specimens from a museum knows the immense amount of paperwork that goes in on all ends to make sure the specimens leave a well documented trail.

Jess Miller-Camp, Paleontology Collections Manager and Digitization Project Coordinator at Indiana University commented on the New Yorker article and addressed her concerns as a museum professional, click here to read her Twitter thread. She comments on the process of loaning specimens to and from museums and proper ettiqute. Read her thread to learn more about this and why museums should be asked to comment.

In 1997, a T. rex nicknamed Sue was sold at a Sotheby’s auction, to the Field Museum of Natural History, in Chicago, for more than $8.3 million.

This quote is misleading. No museum would have adequate funds to secure Sue. The California State University system, Walt Disney Parks and Resorts, McDonald’s, Ronald McDonald House Charities, and other individual donors aided in purchasing Sue for the Field Museum. The Field Museum rallied resources to ensure this valuable specimen remained in a public institution.

In addition to proper storage and archiving of fossils, one of the key tenets of any kind of scientific research is reproducibility– how well can other scientists replicate the results that you got. In paleontology, being able to look at the exact same fossils that another scientists looked at is a key part to reproducibility, as well as allowing the science of paleontology to advance. Whenever a paleontologist finds something they think is “new” to science, or is a really important find (special preservation, currently undocumented here, etc.) if you want to publish a paper on that fossil, the fossil needs to be placed in a public institution like a museum or a similarly accredited fossil repository. This way, future scientists are able to track down that fossil you published on and continue working on understanding it, or using it in other studies. Keeping fossils that are published on in museums is also critical because it ensures that that fossil has a safe place to be stored after being worked on and is less likely to be lost in an office or lab space!

5. Respecting the Land and Indigenous People

In the field of paleontology, people, who are more often than not white, venture into another country or a part of the ‘wilderness’ to find fossils and sites that are completely new and never-before-discovered or seen. These lands that contain fossils were owned by indigenous people long before Europeans arrived in North America, and were likely known about centuries before. Often, when sensational popular science paleontology articles are published, the authors leave out the voices of indigenous people and respect for their land. In the New Yorker article, there was no mention of the indigenous people that lived in the Dakotas, or how their ancestors perceived the dinosaur and fish fossils in the area. To frame amazing paleontological finds as being in desolate wastelands is harmful and erases the narratives of people who have lived in these lands for centuries.

For a more thorough discussion on this topic, click here to read the Twitter thread by Dr. Katherine Crocker.

 

Click here to read a article written by Dr. Roy Plotnick in Medium that also summarizes the issues and causes of commotion surrounding this astounding find.

Learning New Methods

Maggie here-

One of my favorite parts of being a scientist is constantly learning about new ways to answer research questions that I have. I am a paleontologist, but in recent years, I have become very interested in how I can use geochemistry (looking at stable isotopes and trace elements) to address paleontological questions. Since this is a relatively new interest of mine, I have been taking classes in geochemistry, and this past semester I took an analytical geochemistry class to learn different methods that I can use to answer my own research questions. I want to share some of what that class was like because WOW, I’m still processing how awesome it was!

The Lab
Two years ago now, my department (Department of Earth and Planetary Sciences, University of Tennessee) moved into a new building that has not only lab space for faculty and graduate students, but has a research lab designated for undergraduate research. This lab has many different instruments (ion chromatograph, gas chromatograph, inductively-coupled plasma optical emission spectrometer) as well as equipment for bench experiments that is intended to provide undergraduates with research experience through classes and working with faculty members and graduate students. The class that I was a part of did consist of graduate students, but we got to be a part of the process of launching the use of this lab and continued to prepare this space for use by undergraduates. This lab space in and of itself is a unique space for undergraduates to explore the geosciences, but my experience using the lab and learning the methodology of the instrumentation available in the lab was very beneficial.

A gas chromotographer. These instruments are designed to separate and analyze compounds (substances with two or more elements).

Class Set Up
My favorite part of this class was how it was set up because it was so interactive. We spent the first half of the semester getting acquainted with the lab itself and learning the processes that are involved with setting up a lab like this and preparing for a safety inspection. We completed a chemical inventory, worked on developing a chemical hygiene plan, and discussed budgeting (everything from how much DI water costs to the basics of how much each standard is). While this seems pretty mundane, it was an interesting process to complete and to see how detailed the process of setting up a lab is.

Photo by Dr. Annette Engel.

The second half of the semester, each student in the class chose a method to research and teach the class to use. This was a two day lesson that we were each in charge of, the first day spent teaching the theory behind the method and how the equipment works, the second day was spent using that method to look at a quick in class experiment. This meant that not only did we each become the in-class expert on a method, but we had to be able to think about timing to stage each step of the process to using that method. Some of the methods we learned about include gas chromatography, ion chromatography, and inductively-coupled plasma optical emission spectrometry (ICP-OES).

Photo by Dr. Annette Engel.
In addition to learning the process of setting up a lab and learning all different methods, budgeting was also emphasized in this class. Our professor was very transparent with us about how much money was spent to set up the lab as well as how much our science cost to do. With every method, every student leader included a question for us to figure out how much it would cost to run a certain number of samples using that method. This really impressed upon all of us in the class that science does cost money and more importantly, time, and how that all needs to be thought about well before wanting to do any analyses.

The set up of this class ensured that not only did we learn how to use different methods, but that we learned how to run our own labs and understand the work that goes into the different analyses that we write about wanting to complete. Not only did I walk out of the lab this semester being able to complete many different geochemical analyses on my own, but with some idea of the complexities of running a lab!

Class Projects

Photo by Dr. Annette Engel.
I mentioned above that part of this class was to see the breadth of projects that could be completed using the equipment that already exists in the lab. The four other people who took this class with me and myself all have VERY different areas of research and our class projects reflected that. One person was looking at fluid inclusions in granites, someone else was looking at toxins in microbes, and I was looking at trace elements in different skeletal elements of sea urchins. Almost all of us used the ICP-OES because we were interested in trace elements, but for several of us, our samples required other methods that we discussed in class to prepare the samples to be run through the ICP-OES.

All of us in the class completed all of the prep work and ran our own samples regardless of the method that we chose. Yes, we had guidance from our professor and lab manager, but the project work was all very hands on and completed by us. This gave us each a chance to apply what we had learned in class, see just how long some of these methods take, and gave us an appreciation for juggling multiple people’s lab schedules! At the end of the day though, all of us walked out of the lab with useable data to complete our chosen research projects. And, for several of us, the work done for this class project either directly helps with the completion of analyses for our theses and dissertations or helped inform us if the method we used is useful for the question we want to address.

Personal Takeaways

This is the first time in Maggie’s science journey that she has had to wear a traditional white lab coat. Photo by Dr. Annette Engel.
I am going to be really honest here, at points this class was incredibly overwhelming to me-I don’t have a strong geochemistry background and I really didn’t know what I was expecting to see in the results of my research project. But I’m really glad that I took a chance on it because I did learn so much more than I thought I would. I feel more confident in my abilities to complete geochemical analyses on my own, I learned the capabilities of several different instruments and have ideas of how to use them in future research projects, and overcame some personal lab fears-using acid to break down solids into liquids is a little scary the first time you do it! But beyond the methods, this class really emphasized the process of setting up a lab for the first time and understanding how time and monetary budgets fit in to building labs and getting analyses run. I am glad that I challenged myself to learn new methods this semester and I encourage you all to step outside your comfort zone to see where you can stretch your research to!

Excursions with Tennessee’s Governor’s School

Maggie here-

This past June, I helped teach biology, with a focus on vertebrate evolution, with Tennessee’s Governor’s School, a program for high school students to come and experience college life for a month. Last year, Time Scavenger mastermind, Jen, wrote a post about what Governor’s School is, so I’m going to focus on the field trips that we went on!

Figure 1: Here we all are out in front of the entrance to the Gray Fossil Site! In addition to having a lot of information about the fossil site itself, there is a very hands-on science museum at the site.

Field trips are a really important part of learning about science, but can also be really valuable in showing young students what careers are available to scientists. Most students understand that scientists have all kinds of different research interests and biologists don’t spend their days rehashing high school biology curriculum, but it can be hard to imagine what else you would do with a degree in biology without seeing it in action. So, to show our students what all biology encompasses, we went on four field trips this year to the Gray Fossil Site, Oak Ridge National Lab, ProNova, and fossil collecting in east Tennessee!

Our first field trip was to the Gray Fossil Site, a Miocene (4.9-4.7 million years ago) fossil assemblage. This site is really cool because it is a lot younger than most fossil sites in east Tennessee and they have a plethora of vertebrate fossils preserved there. They have found everything from tapirs (similar in look to a pig) to alligators, mammoths, and even a new species of red panda! We unfortunately went on the paleontologist’s day off, so we didn’t see anyone actively working at the site, but we could see the pit that is being excavated this summer as well as peek into the preparation labs to see which fossils are currently being cleaned and put back together. After our tour we had some time to explore the museum that is a part of the Gray Fossil Site which does a good job of explaining what the preserved environment is like, how the site itself was discovered, and what the roles are of the scientists involved at this site.

Figure 2: An image from ProNova’s website showing how protons can more directly target a tumor when compared to radiation therapy. By more directly targeting a tumor, the patients risk of developing complications (including different cancer later on) from healthy tissue being exposed to high levels of radiation, decrease dramatically.

The second field trip that we went on was to Oak Ridge National Lab. We are super lucky living in Knoxville that we have a national lab ~40 minutes away that is welcoming to visiting groups! Since we were talking about biology, our main tour was in the biofuels (fuel derived from living matter) lab. There we discussed the major setbacks to biofuels (large land areas needed to grow plant matter to turn into biofuels, making sure that the carbon footprint of the growing and production of biofuels was also lessened, etc.) and how scientists at Oak Ridge are trying to solve these problems to make biofuels more readily accessible for large-scale use. In addition to biofuels, we met with other scientists and talked about big data and the computing power of the supercomputers housed at Oak Ridge. There’s nothing like talking about supercomputers and all that they can to do to get a bunch of science nerds buzzing!

Our third field trip was to ProNova, a facility that is using proton therapy to fight cancer. This field trip was particularly exciting to our students because many of them want to go into the medical fields, but was also a great learning experience for me! Using protons to treat cancers is a relatively new treatment, so none of us had any idea of what to expect, or what we were going to learn. At ProNova, they use large electromagnets to generate a beam of protons that can be directed to target tumors and that beam has more control than radiation, so only the tumor is being “attacked” by the protons, not the tumor + healthy tissue. The coolest part of this field trip was being able to go behind the scenes and see the magnets and resulting beamline that then is directed into treatment rooms and eventually into patients!

Figure 3: Left: One of the receptaculites specimens that was found while we were fossil collecting. You can see in the image on the right how similar they look to the center of a sunflower!

Our final field trip was to go fossil collecting in east Tennessee. While we weren’t collecting vertebrate fossils (east Tennessee is chock full of lovely invertebrate fossils-I might be a little biased in calling them lovely!), many of our students grew to appreciate paleontology over the month-long course and were excited to be able to collect their own fossils to bring home. Most everyone found crinoid stems, receptaculitids (an algae that looks a lot like the center of a sunflower), and bryozoans (small colonial organisms). We also stopped to look at a wall that was made almost entirely of trace fossils!

While we spent a lot of time in the classroom discussing vertebrate evolution and all of the different aspects of science that play a role in understanding how life and humans evolved, our field trips provided our students with real world applications for the science that they were learning. And from my perspective, the field trips were a way to get ideas of how to present this kind of material in my classroom, as well as to collect current research examples to help answer questions of why biology and vertebrate evolution are important to our understanding of the world! Governor’s school is a really intense month for both the students and the teachers, but the field trips gave us all a chance to connect and have candid conversations about science. It also gave me a chance to reflect on the field trips I took as a young scientist, and how they shaped my desire to become a scientist–so remember, field trips may appear on the surface to be just fun and games, but are incredibly important to the learning process!

Geoconclave

Maggie here-

The Geoconclave team from the University of Tennessee this year. We had a great mix of student experiences-several upperclassmen as well as several students who are new to the major. This was a great way for us all to get to know each other and get everyone excited about geology and our department!

A couple of weekends ago I was able to tag along to a very special geology event-Geoconclave. Geoconclave is a competition in Tennessee for undergraduate geology majors from schools in Tennessee and nearby in the surrounding states. Each school participating brings a team of students to compete in various events and camp out with other geology nerds. As a graduate student there, I was able to help out our team (cooking, cleaning up, making sure people got to their competition sites, etc.) as well as help out the faculty members in charge of the weekend as a whole and helped with specific competitions. Our first night there was very reminiscent of being at camp for the first night-we got to meet students from the other schools, eat dinner, and play card games all night. Most of us got to bed pretty early because we needed to be up early the next day to start the conclave fun!

One of our fearless students participating in the geode roll-you can see the geode in the bottom left corner of the picture.

The next morning all of the competitions started. The first half of the day was spent doing written competitions in hydrogeology, pace and compass, maps, rock identification, mineral identification, and fossil identification. These written competitions were set up as 30 minute tests, some were more hands-on than others, that one student from each school participated in. Every team was awarded points towards the overall competition based on how they placed in each individual event.

During the afternoon we had our fun field events-the rock hammer throw and the geode roll! These were separated by hammer throw for distance and accuracy, and geode roll for distance and accuracy. It was interesting to see the different techniques that everyone had for throwing hammers and rolling the geode. You wouldn’t think that there would be a strategy or technique for these things, but there certainly is! It was fun to sit with the team from University of Tennessee and hear them discuss and strategize how to throw each object for each event. These events were definitely some of the most fun and it was great to be able to cheer on other teams and laugh along with them as we threw hammers and geodes.

The waterfall at Fall Creek Falls State Park in Tennessee. The waterfall had much less water running than normal (so I hear) but it was still a stunning site! For a sense of scale, down at the pool that the water collects in, there is a person and their dog standing next to the pool of water.

After dinner, all of the teams competed in the rock bowl–a geology-based quiz game! We played bracket elimination style and the questions alternated between questions that would be fair game in any intro geology class all the way up to questions that are typical to ask senior geology students. This was the hardest event (in my opinion!) for students to sit through because the audience had to be silent, no matter how badly we wanted to answer questions! At the end of rock bowl, the winners of Geoconclave and rock bowl were announced, but, the best part was after cleaning up many students went and hung out around a campfire-the competition was fun but at the end of the day, we had more fun hanging out with other young geologists than competing with them.

By the time that we got up and started making breakfast on Sunday morning, most of the other teams had left already (they had much longer drives that we did!) and it was nice to have our quiet breakfast before the deep cleaning of the camp kitchen started. After camp was cleaned up, several of us went to go look at the waterfall in the state park in which we were camping. It was such a nice way to end the weekend!

Being able to experience Geoconclave as a grad student made me really appreciate the work that goes into hosting an event like this, but also made me really jealous that we didn’t have something like this where I did my undergrad. It is such a fun way for students who love geology to practice their skills, but also to meet other geologists around the state. I know I speak for many people on UT’s team when I say that I can’t wait for next year!

2017 Hurricane Season Changes Lizard Population in Turks and Caicos

Hurricane-induced selection on the morphology of an island lizard
Colin M. Donihue, Anthony Herrel, Anne-Claire Fabre, Ambika Kamath, Anthony J. Geneva, Thomas W. Schoener, Jason J. Kolbe & Jonathan B. Losos
Summarized by Maggie Limbeck

What data were used? Individuals of Anolis scriptus were captured and specific measurements (such as total length, length specific bones, longest toe on fore- and hindlimb, area of toepad) were taken of each lizard along with pictures. In the initial survey study, 71 lizards were captured and measured and in the post-hurricane study, 93 lizards were examined.

Five lizard individuals undergoing the wind behavior experiment. In the first frame for each lizard you can see that they all have the same perch tactic on the dowel as the leaf blower is turned on. By the second or third frame, it is observed that their hindlimbs are starting to have air flow under them and by the third or fourth frame their back legs have completely detached from the perch. These are the lizards that were captured after the hurricanes occurred and have larger toepads and decreased femur lengths.

Methods: After taking measurements of all lizards, a multivariate analysis of covariance was completed. This type of analysis is used when a question has many variables (in this case all of the different measurements) and you want to know if there is a significant difference between the measurements. So the researchers in this case wanted to know how different the measurements taken before Hurricanes Irma and Maria were from the measurements taken after. In addition to this statistical analysis, a behavioral study was completed to see how the observed changes in predominant body type were beneficial in withstanding hurricane force winds. This elegant study was comprised of placing a lizard on a wooden dowel surrounded by a net and padding to catch the lizard as it was blown off the dowel. A leaf blower was then turned on and “wind speed” gradually increased until the lizard could no longer hold on to the dowel.

Results: After completing the statistical analyses, it was found that the morphologies (shape) of A. scriptus on these two islands were significantly different from the morphologies of the individuals measured prior to the hurricanes. Two of the most notable changes was the increase in size of toepads on both the fore- and hindlimbs, and the decrease in femur (thigh bone) length. These changes in morphology are what led the researchers to predict that these surviving lizards had a better clinging ability. The results of the wind behavior test show that all lizards clung to the dowel in the same way with their femurs jutting out. As wind speeds increased the hindlimbs lost their grip on the dowel first, suggesting that their hindlimbs catch wind and ultimately pull them off of their perch.

Why is this study important? This study is important because Anolis lizards are known to be good examples of adaptive radiation (evolving to be better suited for many different ecological roles) and this is the first study where researchers were able to study two populations immediately preceding and shortly after two hurricanes devastated the islands they initially studied.

The big picture: Big picture, this study is important to understanding how small island populations react to severe weather events. The researchers were able to determine that this was a natural selection event because even though there was variation in morphologies, the trends all show this shift to being better suited to hold onto a perch in high winds. The next question that is addressed in this paper is whether or not this will be a permanent adaptation or if the previous level of morphological variation will be able to return. The answer to this question lies with the lizards just as much as it lies with climate change. As the Earth’s climate continues to warm and weather events continue to become more extreme and more frequent, researchers and inhabitants of these islands may see permanent shifts in the morphologies of the organisms on these islands as they adapt to be able to survive these weather extremes.

*All lizards were returned to their habitats unharmed after their capture and the following experiments*

Citation: Donihue, C. M., A. Herrel, A. Fabre, A. Kamath, A. J. Geneva, T. W. Schoener, J. J. Kolbe, J. B. Losos, 2018. Hurricane-induced selection on the morphology of an island lizard. Nature, 1-8. Data from study.

Resources for DACA & Undocumented Students

Maggie here-

I recently had the opportunity to work with high school students and like many high schoolers, everyone was nervously discussing AP (advanced placement) classes that they were taking, when the next ACT or SAT test day was, and of course, what colleges everyone was looking at. For several of those students, thinking about college brought up questions about their immigration status in this country and what resources were available to them to help finance their education. I felt honored that these students felt comfortable enough to ask me for help finding these resources and I wanted to share with others some of the resources that I have found.

FAFSA + State Aid + In-State Tuition:

Map of the states that currently give in-state tuition to undocumented students, in-state tuition + financial aid to undocumented students. From We are the Dream.

FAFSA (Free Application for Student Aid) is the most annoying and painful online form that ultimately results in loans from the Department of Education to help pay for school. If you have DACA (Deferred Action for Childhood Arrivals) status, you are eligible to apply for FAFSA. However, even if you don’t have DACA status and are an undocumented student, you may be eligible to apply for state aid in certain states. In at least six states (California, Minnesota, New Mexico, Oregon, Texas, and Washington) you are able to apply for state aid.

In-State tuition varies from state to state, but thankfully there are good graphics and readily available lists of the states that are currently allowing in-state tuition. This can be a big issue for students because if you aren’t getting in-state tuition, often the school then has you pay international tuition, which is significantly more expensive. Like applying for state aid, these in-state tuition states do require residency in those states, and some of those states have an application that needs to be filled out in order to be considered for in-state tuition.

Click here for more information about FAFSA + State Aid + In-State Tuition

Private Scholarships:

Privately funded scholarships are also an option and a quick Google search will bring up more than I have included here. Like with any scholarships though, there are applications (and sometimes other supplemental materials) with strict deadlines, so looking sooner rather than later is to your benefit! Some of these scholarships do require you to go to specific schools or be a resident of specific states, so make sure to look at the fine print and all eligibility requirements before applying!

Scholarships:

Golden Door Scholars
The Dream
Scholarships for DREAMers

Tennessee specific scholarships:
Equal Chance for Education

Other Resources:

Applying to and attending college as an undocumented student can come with a very different set of challenges placed on top of the usual nerves of going away to school. The website My Undocumented Life has blog posts and articles written by other undocumented students about all kinds of life situations that are different or challenging because of immigration status. I will also say that Twitter can be a very valuable resource to anyone looking for scholarships, financial aid, or any questions about college as an undocumented student. If you search hashtags like #undocumented, #DACA, #Dreamers, #UndocuSTEM, or if you tweet asking for help looking for resources using those hashtags, other students who have gone through similar situations already are likely to respond and help you out or provide advice!

From the perspective of a teacher, I will also say that if you have a teacher, guidance counselor, or another person that you trust to share this information with and ask for help, we want to help you. Every person who wants an education deserves access to that education and at least in my case, I will continue to help anyone and everyone who needs help finding a way to make that happen!

Are corals adapting to keep up with changes in ocean temperature?

Potential and limits for rapid genetic adaptation to warming in a Great Barrier Reef coral

Mikhail V. Matz, Eric A. Treml, Galina V. Aglyamova, Line K. Bay
Summarized by Maggie Limbeck

What data were used?

Researchers looked at genetic data for Acropora millepora (coral common in the Great Barrier Reef) to model (simulate) how corals will adapt to increasing temperatures, establish a direction of coral migration, and measure genetic diversity. These data were then used to predict the future survival of A. millepora in the Great Barrier Reef.

Methods

The corals used in this study were previously described in van Oppen et al. (2011) and several samples were collected from Orpheus and Keppel Islands. The coral samples were then genotyped (the genetic material was sequenced so that researchers could examine it) and that data was used to model all of the other experiments that were conducted. The coral genomes were used to look at divergence between populations (how genetically different are the populations that were sampled) and what are the demographics among populations. A biophysical model was used to examine the migration patterns between known coral habitats and the broader region surrounding the Great Barrier Reef. This model required data describing the seascape environment as well as coral-specific data relating to adult density (how many adults), reproductive output and larval spawning time, as well as how far do the larvae travel or disperse.

Results

Figure 1. A. A map of the coast of Australia and the locations along the Great Barrier Reef that coral samples were taken from. A temperature gradient is also plotted on the map, with warmer colors indicating warmer temperatures and cooler colors indicating cooler temperatures. B. A plot of the different water conditions that were measured for each study site and where each study site plots in relation to those water conditions. C. A plot of how similar each coral population was to one another. The separation of the purple dots indicates that it is more genetically separated from the other coral populations that were sampled. D. This plot further shows that the population at Keppel is more genetically distinct from the other groups as the proportion of blue to yellow is drastically increased.

The results of this study indicate that the populations examined are demographically different from one another and that overall migration of these corals is moving in a southward direction (higher latitudes). The migration southwards is still largely driven by ocean currents, rather than preferential survival of warm-adapted corals migrating to cooler locations. It was also determined through the model that those corals that were pre-adapted to a warmer climate, were able to survive gradual warming for 20-50 generations which equates to 100-250 years. However, as the temperature increased, the overall fitness (the ability of a species to reproduce and survive) of these populations began to fluctuate with random thermal anomalies (e.g. El Nino Oscillations) and these fluctuations in fitness continue to increase as warming progressed, independent of the severity of the thermal anomalies. The good news in all of this is that much of the variation in the trait associated with the ability to adapt to warmer temperatures is due to the type of algal symbionts (algae that helps the coral to survive and reproduce) in the area. This means that coral larvae have very plastic (easily changed) phenotypes (genes that are visibly expressed) and can easily adapt to whatever algal symbionts are locally available.

Why is this study important?

This study is important because it has been projected that the global temperature is going to rise 0.1°C per decade for a total of 1°C in the next 100 years and as scientists we want to know how that global temperature change is going to affect organisms. Corals function as a “canary in the coal mine” because they and their algal symbionts are incredibly sensitive to temperature and light changes in the ocean. If we know how corals are going to respond to these changes in temperature, researchers and conservationists will have a better understanding of how to better protect the coral’s environment. This study has shown that corals are able to adapt to the changes in temperature and are migrating southward, but also demonstrated that the ability of mature corals to reproduce in rising temperatures is declining. To combat this, because of this study, conservationists know and may be able to release larval and juvenile corals that have been raised in labs into new environments to perpetuate the species.

The big picture

The big picture here is that climate change is very real and we can use evolution and models of evolution to understand how organisms are going to and are reacting to increasing temperatures. This research indicates that even with low levels of mutation, corals are able to adapt to warming oceans and can associate with different, local algal symbionts as they migrate. However, mature adult corals have increasingly less fitness as ocean temperatures rise which means that they are reproducing less, leading to overall decreased coral populations. There is hope for this particular coral though, if researchers and conservationists can find a way to successfully raise coral larvae and release them into their current and future habitats.

Citation:
Matz, M. V., E. A. Treml, G.V. Aglyamova, L. K. Bay, 2018. Potential and limits for rapid genetic adaptation to warming in a Great Barrier Reef coral. PLOS Genetics, 14:4:1-19, doi: 10.1371/journal.pgen.1007220

Applying to Graduate School

Maggie here-

I am finishing applying to grad schools for my Ph.D. and figured some of you might also be currently applying to graduate programs or starting to think about if you want to pursue a Master’s degree or a Ph.D. My main goals for this post are sort of two-fold: what is the process of applying to graduate programs and how do you stay sane while applying. So let’s get to it!

Key aspects of this post

  • Look for people and research that interests you, not just locations
  • Contact people at the school that you would want to work with-this is key! Look for people whose work interests you and start contacting them early-ask if they are taking students, what kind of research they do, what it would entail, etc.
  • Communicate with friends, professors, etc. if you need help with your statements or even just someone to say I know this sucks!
  • Make time for yourself-do things that aren’t related to applying to schools and have fun!
  • No matter how daunting and stressful this is, you are capable of doing this!

How to Apply for Grad School

Applying for grad school is very different from applying to undergraduate programs and unfortunately a lot less intuitive. When you were in high school (or shortly after) and applying to colleges there were a lot of people who were around to help you navigate applications and there may have only been one application you needed to fill out to send to many schools. You could also choose colleges based on what state or even which city you wanted to be in for the next four years.

Grad school is very different in that you are looking for specific research programs and people that you want to work with, rather than a location. The location can sometimes be a driver for your research, but in most cases that really is one of the last things that plays a role in your decision to apply there. Grad applications are also more short statement driven; you will be asked for statements of purpose (why do you want to come to this school), personal history statements, and the ever vague “additional statements.”

Statement of Purpose

This statement really is the meat of your application. What has made you decide to go to grad school, what do you want to study, why do you think this school and this advisor is the only place that you can learn what you want to learn. This statement can be totally daunting because often there are no directions or clarifying statements about what to include. I personally like to include a quick paragraph that is more of a narrative- what experience in science did I have that has stuck with me and made me want to be a scientist as an adult? Did you go to a cool summer camp or have an awesome science teacher? Something to show your background and make you a human can make your statement easier for you to write and easier for people to read. After that paragraph is your chance to wow them- what super cool research have you done, do you have a research question that you just have to know the answer to? How does this advisor and school help you reach your research and personal goals? This statement really is up to you to decide which direction you take it in, just make sure that if a school does want you to address something specific in this statement that you answer it!

Personal History Statement

The personal history statement is a place for you to go a little more in depth with personal experiences that you have had (positive or negative) that have led you to where you are today. It can be family or personal matters, or even research experiences that you feel have shaped your career trajectory. In this statement you can also address any “problems” in your transcripts or academic records. If you do choose to address something that was a challenge to you or something that impacted you negatively, try to keep positive language throughout. How did you overcome these challenges, what did you learn about yourself with this challenge, etc. Grad schools and advisors want to know who you are now, not who you were your first semester freshman year. If you have something in your transcript that you want to address and a personal history statement isn’t asked for, I have also asked a trusted letter writer to discuss that in my letter. The personal history statement is a chance for you to show how much you shine, even in the face of adverse conditions.

Other Documents

This upload button can cause a lot of grief because it will literally say “other documents.” Don’t panic, this is not required and you don’t have to upload something if you don’t have something else you want to add. If you know you want to be a professor and you have already had some teaching experience so you have a teaching philosophy or want to learn how to teach more effectively, that could be a statement you might add. If you love doing outreach and you feel very strongly that you can bring something to the table with your outreach efforts, you can add a statement about that. I just submitted my first “other document” with my Ph.D. applications and I only submitted it because I feel very strongly about the importance of teaching and outreach and wanted to share that side of myself with the schools I was applying to. If you don’t feel like you need to share anything else with the schools, don’t. It’s not something to stress too much over, because this whole process is stressful enough!

How to stay sane while applying

As someone who is currently applying for grad schools, this is 100% the hardest part for me. Even though I have really supportive family and lab mates who read over every statement that I write, the process can still feel very overwhelming. You have worked so hard for so long and you just want these people you have talked to to see how great you are and be deemed worthy enough to work with them. The best advice I can offer is to surround yourself with friends. Some of them may have done this before or are in the process of doing this with you, take the time you need to talk about applications but don’t let it consume your life. Spend time with people away from computers, go do fun things, remind yourself that life isn’t just about school. Take walks during the day-I spend ~8 hours a day sitting at my desk and a lab bench and I have found that taking a walk with my friends during the day can be just what I need to feel refreshed and ready to keep working. Play with animals-my cat has been a very big help in this application process because he provides so much comic relief! Play music that boosts you up and makes you feel good-this past week my lab group had a jam session to the Moana soundtrack. If that isn’t love and support, I don’t know what is!

Darwin Day Celebrations 2018

Maggie here –

The Darwin Day events at the University of Tennessee, Knoxville have been running since 1997 and I was one of the leaders for the 2018 events. Darwin Day is all about celebrating the life and work of Charles Darwin, and sharing that information with members of the UT campus as well as the surrounding community in Knoxville. For this year’s celebration we hosted a birthday party in collaboration with a McClung Museum Family Fun Day and had a special keynote lecture by Dr. Nizar Ibrahim.

Darwin and Wallace puppets that are used to advertise our Darwin Day events. These puppets are ~10 feet tall and our very wonderful friends wear them and walk around or even dance in them!

The birthday party had cake (of course!), games, crafts, a scavenger hunt, and a larger-than-life puppet of Charles Darwin. This year, we wanted to make sure that our activities were designed to be able to really teach about evolution. One of the activities was to test out different “finch beaks” to see how easy it was to pick up “food”. Our finch beaks consisted of paper clips, binder clips, and wooden skewers that were used to pick up different objects. For our younger guests this activity concluded with a quick talk about which beak they thought was easier to use and how that might translate to real beaks on birds. For our older guests we were able to bring in the ideas of adaptations, natural selection, and speciation during the wrap up conversation. We were also lucky enough to have one of the McClung Museum docents come in for the birthday party to lead a couple of tours through the Human Origins exhibit. This was the first time that these tours had been led during Darwin’s Birthday party and helped us engage in evolution discussions with our older guests. As with any large scale event, each year is a little different and we continually try to come up with new activities and try to reach new areas of the Knoxville community. While this birthday party was incredibly successful (we had ~260 people come!) we are already looking forward to next year and making the birthday party even more successful!

Leslie Chang Jantz, Curator of Education; Callie Bennet, Asst. Museum Educator; Emily Nield, Earth and Planetary Sciences graduate student all work to pass out cake and snacks to birthday party guests.

The evening lecture with Dr. Ibrahim was a rewarding excursion through the past. He has done significant work reconstructing the ecosystems of the Cretaceous of Morocco. He has primarily worked on uncovering an ancient river system community that was dominated by many types of predatory animals, namely Spinosaurus. There was a special underlying story on a German paleontologist, Ernst Stromer, who originally discovered Spinosaurus, but the specimens were lost during World War II in the bombing of Munich. Dr. Ibrahim was able to find another specimen of Spinosaurus in Morocco -his “needle in the Sahara”. He worked with local fossil hunters as well as a museum in Italy and was able to find more bones that belonged to Spinosaurus. There is not yet a complete skeleton of Spinosaurus.  However, with new technology researchers were able to 3D print the skeleton of Spinosaurus that tours museums today. Dr. Ibrahim’s talk impressed upon the audience that paleontology is hard work, but that collaboration with other scientists and foundations can ease that burden and make discoveries that much more rewarding. He also gave great insight on the challenges that come with doing field work in the Sahara desert and how terrifying it can be when two of your three vehicles break down in the middle of the desert! I think I’ll stick to local field work and museums…

Artists rendition of Spinosaurus in the Cretaceous river system of Morocco. Painting by Davide Bonadonna.

Putting on a large scale event like Darwin Day during the last year of my Master’s degree was very challenging-I often felt that if my days weren’t planned well or if I wasn’t working a month ahead of schedule that I wouldn’t be able to pull off writing my thesis and planning a birthday party and speaker visit! It was incredibly difficult, but doing outreach events like this are what makes science rewarding in my eyes. I have spent several years cultivating my scientific knowledge, but my passion (outside of research!) is doing outreach and talking to the communities that I work and live in about science and sharing my excitement about research with them. Darwin Day at UT changes and morphs every year based on who is leading it, but it continues to grow and continues to reach more people as the focus becomes more centered on reaching the communities surrounding the university. I also have to thank Jen Bauer, Joy Buongiorno, and Audrey Martin, as well as all of the other volunteers, for their help and support with executing this year’s Darwin Day events-these events could not have happened without the help of other amazing scientists who want to share science with the public!

Click here for an interview that discussses the Darwin Day program at UT.