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High schoolers co-author paleobiology study with Stanford researchers

A cohort of the Stanford Earth Young Investigators program helped advance our understanding of the relationship between the body size and circulatory systems of marine animals over a vast time frame.

Mussels like the ones pictured above have open circulatory systems, meaning blood is not contained entirely within enclosed blood vessels. New research shows over the history of marine animals from 541 million years ago until today, marine animals with op

Beginning of a summer high school internship: Learn to measure illustrations of marine animals using a caliper. Mid-summer: Process the data using a statistical programming language. Two years later: Publish the results in a peer-reviewed journal.

While most high schoolers learn science, a paleontology lab at Stanford has actually helped them to advance it. After participating in research through the Stanford Earth Young Investigators program at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth), 10 high school students became co-authors on a peer-reviewed academic study – an accomplishment few young researchers share, even by the time they finish a bachelor’s degree.

The research, published in Paleobiology May 12, shows that animals with closed circulatory systems – including marine animals, reptiles and fish – diversified rapidly in order to reach a much larger body size than those with open circulatory systems – such as clams, snails, crabs and lobsters. The work included analyses of the whole history of marine animals, from 541 million years ago until today.

“Our previous studies on body size have either looked at a very narrow interval of time or a very narrow group of animals,” said lead author Noel Heim, who ran the Biodiversity track of the Stanford Earth Young Investigators program from 2012 to 2019 that included the 10 interns who are co-authors. “Having this large data collection from the high school students has allowed us to look at a wide group of animals over a very long interval of time.”

Early in the history of animal evolution, having a closed versus an open circulatory system was not associated with any meaningful difference in average body size, according to senior author Jonathan Payne, the Dorrell William Kirby Professor in the Department of Geological Sciences at Stanford Earth. The new analyses show that over time, marine animals with open circulatory systems were less prone toward evolving larger body sizes and are now, on average, substantially smaller than marine animals with closed circulatory systems.

The study is the first to present statistical evidence of the relationship between marine animal body size and their circulatory systems by incorporating measurements from nearly 14,000 genera, or groups of animals – more than 10 times as much data than had been previously analyzed. The findings may be contrary to previous assumptions that large body size is inherently advantageous, according to Heim, who is now a lecturer with the Department of Earth and Ocean Sciences at Tufts University. It was also surprising to find that in the Cambrian time period – about 541 million years ago to 486 million years ago – the size differences didn’t exist between marine animals with closed and open circulatory systems, Payne said.

“What we see is that as the selective pressures on animals become stronger and more diverse, some lineages are driven toward larger sizes – and if you have a closed circulatory system, you can achieve that outcome more easily, without encountering as many tradeoffs in function,” Payne said.

A prolific summer

The paper is the result of work from the 2018 cohort of Stanford Earth Young Investigators who participated in the Biodiversity track of the program. Heim had been running the Biodiversity section since he started at Stanford in 2012, with about 20 students conducting research projects of their choice in small groups and producing posters that would be presented at the annual fall meeting of the American Geophysical Union (AGU). But that year, he and Payne decided to limit the group to 10 high school applicants and focus on writing and conducting in-depth scientific analyses.

Students working in lab
High school participants in the 2018 Biodiversity cohort of the Stanford Earth Young Investigators program analyze data in a paleontology lab on campus. (Photo credit: Noel Heim)

“For this kind of paper where we’re asking a fairly basic question about how anatomy relates to body size, the high school students are perfectly capable of helping to collect the data and make the graphs that help us figure out the answers,” said Payne. “They really did participate in the analysis and interpretation of the data – and that warrants co-authorship.”

In previous summers, the students were divided into groups to focus on different ecological characteristics and variations in body size over the course of the eight-week program. They spent mornings recording the size of marine animals in the literature using a caliper, an instrument for measuring dimensions, and afternoons reading technical literature or popular articles on paleontology or evolution topics, followed by another two hours of data collection.

In 2018, the students learned the statistical programing language R and conducted their own analyses of the previously collected data.

“When they made a plot showing the body size of some marine invertebrates over time, for example, nobody else in the world had made that plot before,” Heim said. “And when you explained that, many of their eyes lit up.”

Finally, the high schoolers wrote introductions on why each characteristic might be important for body size evolution, as well a section on their analytical methods, which Heim compiled into a single manuscript.

A win-win situation

“The high school interns are actually doing analyses that nobody has ever done before,” Heim said. “They see both the struggles and the tediousness of data collection, but also the reward of discovering something new.”

"These are impactful experiences that are really helping students see themselves as scientists."

The students reviewed and commented on the study drafts and also participated in the post-submission stage, sending feedback for how to respond to questions and comments from reviewers.

“I learned a lot about understanding the formalities of writing your own research paper,” said Young Investigator and then-San Jose high school student Saket Bakshi, now a freshman at Pennsylvania State University.

In addition to expanding the high schoolers’ skillsets and advancing scientific knowledge, the program offers unique mentorship opportunities for graduate students and postdoctoral researchers at Stanford Earth.

“It’s good for the lab and for our research, but also good for the person who’s running it,” said Payne, adding that Pedro Monarrez, a new postdoctoral researcher in his lab, will be leading the Biodiversity cohort this summer in an online program. “Having the graduate students and postdocs interact with the high schoolers gives them a chance to mentor people who are in very different career stages. It is good for everybody involved.”

Serving local communities

The Stanford Earth Young Investigators program, which was organized into an eight-week internship by Stanford Earth Director of Outreach Education Jennifer Saltzman in 2005, aims to give high school students a taste of research, scientific career pathways and experiential learning in Earth and environmental sciences.

“It’s different than doing a research paper, which is usually the compilation of already existing knowledge,” Saltzman said. “This is contributing to creating new knowledge – and that’s what the scientific endeavor is.”

The nonresidential program is only open to students who live within 25 miles of the Stanford campus and attend high school in the Bay Area. Although she does minimal advertising, mainly attracting students through their teachers or past participants, Saltzman has had over 100 annual applicants for the past 10 years.

As part of the application process, the students rank their interest in different topics in addition to the Biodiversity track, such as energy or geology, depending on the research opportunities available in a given summer. Stanford provides a stipend for those who fall in the diversity category, which includes underrepresented and low-income students, as well as those who would be the first generation in their family to attend college.

“I choose students from as many high schools as I can – it’s a chance for young people who love science to get to know each other across school boundaries, across race, across socioeconomic status,” Saltzman said. “We’re creating a community, a culture of young people who have experienced scientific research and can discover for themselves whether it is something they’re interested in doing.”

Out of the lab

While the program mainly involves lab-based research, the high school interns also participate in weekly career talks from other scientists, lab tours and field trips as a group. The Biodiversity track has offered additional programming to expose students to local resources unique to that subject, from exploring fossils on a beach in Capitola and visiting the paleontology museum at the University of California, Berkeley, to research cruises on the San Francisco Bay and an overnight trip to Pinnacles National Park.

Getting out of the lab can trigger a shift in perception that reaches beyond a single experience and leads a student into the academic pipeline – and even increases diversity.

“One student on the camping trip loved it so much that she went to college and majored in environmental science, and then her first job after college was in Colorado taking Latino students on camping experiences for a nonprofit group that aimed to get students outside,” said Heim, noting that the student, Mayra Pelagio, is now pursuing a master’s degree in environmental studies at San Jose State University. “These are impactful experiences that are really helping students see themselves as scientists.”

Students on hike
 The 2018 Biodiversity interns hike to learn about the geology at the Pinnacles National Monument, where they camped that night. (Photo credit: Jennifer Saltzman)

Into the data

With Stanford’s operations being conducted remotely in 2020 due to COVID-19, this year’s internship program will likely involve four weeks of career talks and video lab tours for all its 160 applicants in lieu of the typical eight weeks of in-person lab research, according to Saltzman. The Biodiversity section will accept 12 students for a part-time program who will conduct body size measurements and data analysis at home to explore additional remaining questions about how and why animal body sizes have evolved over time.

The organizers hope to continue fostering their unique environment for exchanging ideas.

“It’s been fun to work with the students – they bring a new energy to the lab during the summers,” said Payne, who is also an affiliate with the Stanford Woods Institute for the Environment. “They’re also a little less conditioned that certain questions are OK and other questions are not right, and so you get more outside-the-box feedback.”

The program has been a boon for Payne’s lab, and he and Heim are continuing to write papers based the large amount of data the high school students have collected. He hopes the participants continue to see the benefits of their work into the future, as well.

“This gives them a chance to glimpse what being a scientist or majoring in science in college would look like,” Payne said. “My hope is that it increases their confidence about pursuing science as college students and that maybe for a few of them, it even inspires them to go on to a career in science.”

Applications for the 2020 Stanford Earth Young Investigators program are closed. The application for 2021 will be posted in late January and due in March. For more information, visit

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Danielle T. Tucker

Stanford Doerr School of Sustainability

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