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Archive for July 2011

CAL:BLAST at Bodega Bay, June 28-29, 2011

Despite a fluke June rainstorm, grad students managed to keep spirits high during two days of field work at Bodega Bay. Just as the rain began to fall, each of the graduate students — Jenny Jacobs, Misha Leong, Joey Pakes, and Rosemary Romero — welcomed 37 elementary school teachers and took them in groups of ~10 on a preliminary tour of the Bodega Marine Reserve (BMR). This would serve as an initial orientation to the buildings and the different coastal habitats that would be their focus area for the next two days.

The name of the project is CAL:BLAST — a fun acronym for a complex title — Collaborative Approach to Learning: Bridging Language And Science Teaching — and an extraordinary project focusing on professional development for 3rd, 4th, and 5th grade teachers from Oakland Unified School District (OUSD). Our goals were to increase teachers' science content knowledge as well as their interest and confidence in science, so that in turn they would increase the amount of time spent on science in their classrooms! So when we saw the predictions for rain during our stay at Bodega, we were somewhat concerned that field science might become a "tough sell," but we soon realized that this was an amazing group of teachers, and it would take more than rain to dampen their spirits!

The teachers were presented with an overarching question: what lives in the many habitats of the Bodega reserve and how do these organisms interact with one another and their environments? — clearly a question beyond the scope of a two-day field investigation, so the focus was to have the teachers become familiar with the variety of habitats and then find smaller questions that actually could be answered within that time frame and that would help to inform the larger question.

Teachers were assigned by school and geographic region to one of four "research groups" led by a graduate student and joined by at least one additional CAL:BLAST project partner from either the Lawrence Hall of Science, the Bay Area Writing Project, OUSD, or the Berkeley Natural History Museums. Each group participated in roughly the same activities, but in different habitats of the BMR.

1. Site assessments – observing habitats at different levels
Teachers used words and/or sketches to record initial habitat observations in their field notebooks. Each team then headed in a different direction, taking note of any changes that they noticed as they moved across the landscape. Once in their new location, they discussed changes noticed and then began to observe the new habitat, often making comparisons to the first.

2. Field Research: Learning field techniques – Exploring, discovering, asking questions
Depending upon the environment, teachers learned how to use a variety of tools (bug nets, beating sticks, quadrats, etc.) with which to make collections and to learn about the biodiversity of that habitat. Returning to the lab facility, teachers were asked to reflect on all that they had explored and discovered and to list a minimum of 19 questions in their notebooks that related to their field experiences. The next challenge was to determine which of these questions were testable and which they might actually be able to investigate the next morning, given the constraints of both time and resources. By the end of the afternoon, each group had identified ~ the top 10 questions of interest to them, which they presented to the whole group.

3. Evening activities
Once checked into their rooms and with dinner consumed, there was time for whole group reflection and then meetings with grad students. Teachers identified which questions would be the focus of their explorations in the morning and with whom they would be working. For those who still had some energy left, there was a night hike or time for sketching and quiet conversation, before lights out.

A summary of Day Two
Despite the early hour for a low tide, about dozen CalBlasters enjoyed some early morning tide-pooling. Then, following breakfast, it was off to the lab and a team meeting to prepare for the investigations — strategies for gathering and recording data, equipment needed, identifying study areas, etc. With rain still falling, the teachers headed to their field sites and began their investigations. Each grad student assisted their teacher teams. All data was recorded in their notebooks, and as each team completed data collection, they headed back inside for data analysis. With a short lunch break, the final task was to prepare for the upcoming symposium in which they would be sharing their findings with their colleagues.

The 2011 CAL:BLAST Bodega Biodiversity Symposium
Each research team presented their findings to the whole group, taking ~ 5-10 minutes to share their original question/hypothesis/prediction, challenges and modifications, procedures, findings, and new questions generated. They also responded to questions from their colleagues. See a PDF summary of the poster presentations.

After a celebration of watermelon and chocolate, teachers reflected on the different parts of their scientific journeys and identified strategies for incorporating the same kinds of experiences into their classrooms. A final circle of sharing took place just as the sun came out and then teachers headed back home.

Overall summary
The CAL:BLAST project team (which included the graduate students) was more than impressed by the positive energies and the depth of science that took place. Basically within less than twelve "working" hours, the teachers (novices to biological field research) arrived, became familiar with multiple habitats, learned collecting techniques, identified a testable question of interest, prepared for the investigation, gathered and analyzed their data, and presented their findings to their peers. Not bad, not bad at all!!

All images courtesy of Caleb Cheung and Jenny Jacobs

How mammals got their horns (and other headgear)

UCMP's Katherine Brakora and UCMP alums Edward Davis (now at University of Oregon) and Andrew Lee (now at Midwestern University) reviewed the evolution of mammal headgear in the latest edition of Proceedings of the Royal Society B. They examined phylogeny, development and fossil histology to establish a clearer picture of the evolution of these cranial appendages. This work has biomedical implications as well — understanding fast-growing antler bone may help with treating burns, bone cancer, osteoporosis and more.

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Elk photo by Gerald and Buff Corsi © California Academy of Sciences

Student Spotlight: Emily Lindsey and the late Pleistocene megafauna in South America

This post's text is also available in Spanish.

Emily Lindsey fossil hunting at her site in Ecuador.

Congratulations to graduate student Emily Lindsey, this year's recipient of the George D. Louderback Award! Emily has been hard at work the past few years investigating the timing, dynamics, and key players behind the late Pleistocene extinction of megafauna in South America.

Like the famous La Brea Tar Pits in Los Angeles, California, Emily's excavation site on the Santa Elena Peninsula in Ecuador is an asphalt seep preserving the remains of a wide array of organisms. However, unlike the Tar Pits in California, the Ecuador site doesn't appear to be a tableau depicting the tragic demise of animals stuck in tar. Instead, it is likely the final resting place of remains transported by running water and then covered by nearby asphalt.

A. Setting up camp at Emily's site on the Santa Elena Peninsula. B. Close up of one of the excavated walls. C. Panoramic view of the entire site during the fossil dig.

So what mysterious late Pleistocene megafauna did she uncover in the seep? Mainly giant ground sloths (Eremotherium laurillardi) ranging from juveniles to adults, along with gomphotheres (elephant-like relatives of mastodons), giant armadillos and prehistoric horse. In general, Emily’s site had rather reduced biodiversity compared to other notable tar seeps. In fact only herbivores were found, unlike La Brea, which included the infamous and carnivorous sabertoothed cat and dire wolf.

All photos demonstrate the excavation process in the field by Emily's many international collaborators. B. Close up of bones being exposed.

Emily couldn’t do all this work without some help. For the excavation, she brought together a slew of collaborators from across continents to uncover (zing!) and understand the mysteries surrounding the late Pleistocene megafaunal extinctions. The Universidad Estatal Peninsula de Santa Elena (UPSE) sponsored the excavation and kept the fossil finds at the Museo Paleontologico Megaterio (MPM). Members of the Page Museum in California also flew down to Ecuador, bringing their expertise on the La Brea Tar Pits and asphalt seeps. And, several U.C. Berkeley students and alumni have volunteered their time on the dig. Several international articles were written about Emily’s exciting work, including one from the Natural History Museum in Los Angeles and the Universidad Nacional de Piura (UNP).

A. An area of deposited bones after they've been excavated. B. and C. The exposed fossils are plastered to protect them for transport to the museum.

Emily’s collaboration with UNP members in Peru was part of her goal to compare asphalt seeps from different locales. “I think the Talara tar seeps in Peru are pretty similar to La Brea, geologically & taxonomically, just my site in Ecuador is distinct from them,” says Emily. “This isn’t necessarily true of other asphalt sites here on the Santa Elena Peninsula, which may represent more traditional “tar pit” scenarios.”  Emily presented her results in a lecture at UNP last year.

Another large focus of Emily's work has been to tease apart the roles of climate change and habitat degradation from the arrival of humans on the disappearance of large mammals.  Several of the fossils uncovered at her site in Ecuador were found with cut marks. Though this might suggest that humans played a hand in overharvesting and subsequently pushing these mammals to extinction, there is no further evidence of human activity at her site. “It is also possible that the marks are ‘taphonomic’ features, caused when the bones were swept down a river or rubbed against other bones and rocks in the tar pit,” says Emily. Likely both climate change and human activities led to the downfall of these South American megafauna. The question is, how much did each factor contribute.

Other important tasks to do at the site include A. mapping out the location of the bones, B. measuring the stratigraphic layers, and C. sifting for microfauna.

With a much deserved award under her belt, we look forward to hearing more about Emily’s discoveries in the future!

A display of a giant ground sloth at the Museo Paleontologico Megaterio (MPM).

En Español:

Felicitaciones a la estudiante de doctorado Emily Lindsey, ganadora este año del Premio George D. Lauderback. Emily ha estado trabajando los últimos años investigando la cronología, los patrones y los actores principales en la extinción de la megafauna sudamericana al fin del Pleistoceno.

Tal como el famoso sitio Rancho La Brea en Los Ángeles, California, USA, el sitio que Emily está excavando en la Península de Santa Elena en Ecuador es un charco de asfalto que preserva los restos de una gran variedad de organismos. Sin embargo, a diferencia de los charcos de brea en Los Ángeles, el sitio en Ecuador no parece que fue una trampa donde varios animales murieron atrapados en brea, sino la ultima morada de restos trasladados por agua corriente y luego enterrados en el asfalto.

¿Y cual megafauna misteriosa ha encontrado Emily en los charcos de Santa Elena? Principalmente perezosos gigantes (Eremotherium laurillardi), desde críos hasta adultos, junto con gonfoterios (un pariente de los mastodontes parecidos a elefantes), armadillos gigantes, y caballos prehistóricos. En total, el sitio tiene menos biodiversidad en comparación con otros conocidos fosilíferos charcos de brea. De hecho, hasta ahora solo han encontrado herbívoros, a diferencia de Rancho La Brea, donde los fósiles más encontrados incluyen los famosos – y carnívoros – tigres dientes de sable y Canis dirus.

¡Emily no podría hacer todo este trabajo sin ayuda! Para las excavaciones, unió a un grupo de colaboradores de distintos continentes a des-cubrir (:)) y entender los misterios sobre la extinción de la megafauna Pleistocena sudamericana. La Universidad Estatal Península de Santa Elena (UPSE) apoyó la excavación y guardó los fósiles excavados en el Museo Paleontológico Megaterio (MPM). Personal del Museo de Historia Natural en Los Ángeles, California, también vino a ayudar con las excavaciones, contribuyendo con su alta experiencia y conocimiento sobre los charcos de brea. Además, varios alumnos y exalumnos de la Universidad de California en Berkeley han llegado como voluntarios a ayudar con los excavaciones. Algunos artículos internacionales han sido escritos sobre el trabajo emocionante de Emily, incluyendo uno del Museo de Historia Natural en Los Ángeles, y otro del Universidad Nacional de Piura (UNP) en Perú.

La colaboración de Emily con el personal del UNP fue en conexión con su proyecto de comparar charcos de brea de distintos lugares. "Yo creo que los charcos de brea en Talara, Peru son bien parecidos, geológicamente y taxonómicamente, con los de Rancho La Brea en Los Ángeles; solo el sitio que yo tengo es distinto," dijo Emily. "Esto no necesariamente es el caso con los otros sitios de asfalto que encontramos aquí en la Península de Santa Elena, los cuales podrían representar escenarios mas tradicionales de "trampas de brea."

Otro gran enfoque del trabajo de Emily ha sido diferenciar las contribuciones de cambios climáticos y degradación de hábitats y la llegada de los primeros humanos a Sudamérica, como causantes de la desaparición de mamíferos gigantes del continente. Algunos de los fósiles descubiertos en su sitio en Ecuador fueron encontrados con marcas parecidos a las hechas con cuchillos. Aunque esto podría sugerir que los humanos tenían un papel en la sobrecaza de estos animales y su eventual extinción, no hay mas evidencia de acciones humanos en el sitio. "También es posible que las marcas sean características 'tafonómicas,' producidas cuando los huesos fueron arrastrado por un río o cuando se frotaban unos contra otros o contra piedras en el charco de brea," dice Emily. Probablemente, ambos procesos – cambios climáticos y acciones de humanos – contribuyeron a la extinción de la megafauna Sudamericana. La pregunta es, ¿cuánto contribuyó cada factor?

Ya con un premio bien merecido, ¡esperaremos escuchar mas sobre los descubrimientos de Emily en el futuro!

Gray whales are survivors

UCMP's David Lindberg and the Smithsonian's Nicholas Pyenson determined how many gray whales could be supported by the ocean through periods of global cooling and warming. Their results, published in the latest edition of PLoS ONE, show that in the past 120,000 years gray whales survived periods when their feeding grounds were greatly-reduced due to glaciation. The authors propose that gray whales were able to survive the lean times by diversifying their feeding habits, a behavior that has been observed in modern gray whale populations.

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