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Undergraduate Research in Biology

Student Research in Biology

Click to watch Peter Pellitier '14 discuss his research project.

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Student-faculty research is an essential part of Pomona’s educational mission. In biology, the research process teaches students how to think like a scientist. Students engaged in research work closely with faculty to develop the skills needed to form a biological question and answer it in a rigorous way.

All biology majors either carry out an original experimental or field research project or develop an original research proposal for their senior capstone experience, but students are encouraged to engage in research before their senior year. Some students first become engaged with a research lab as an assistant — helping the faculty member and advanced students with their projects and carrying out lab support tasks. The department also encourages students to spend a summer or a semester involved in biological research, either working with a faculty member on campus or through one of many available research internship programs or biological field station programs.

Students interested in research or laboratory assistant positions in the biology department should contact the potential faculty mentor.

Recent Student Research in Biology

Effects of Soil Temperature and Moisture on Stomatal Density and Water Use Efficiency in Pseudotsuga macrocarpa

Daniel Mendes (2014); Student Collaborator(s): Peter Pellitier (2014); Mentor(s): Frances Hanzawa

Abstract: Pseudotsuga macrocarpa is a conifer endemic to mountain ranges in southern California. Our goal was to determine abiotic stresses such as hotter temperatures and decreased soil moisture being placed on P. macrocarpa trees at various elevations along Mount Baldy Road, near Claremont, California. Additionally, we wished to measure stomatal density and Delta C 13 of year old needles, and compare them with the abiotic factors. As a montane-tree, P. macrocarpa is more sensitive to climate changes, and more susceptible to range shifts across elevation. We found that Delta C 13 increased across elevation, indicating that trees at lower elevations have a higher water use efficiency, which suggests that they are faced with a more intense water deficit at the lower elevations. We also found that stomatal density decreased as soil temperature increased, suggesting that the trees at hotter sites have been selected for higher resource use efficiencies.
Funding Provided by: Schulz Fund for Environmental Studies (DM); Sherman Fairchild Foundation (PP); Pomona College Biology Department

Climate Linked Range Shift in Southern California Endemic Conifer

Peter Pellitier (2014); Student Collaborator(s): Danniel Mendes (2014); Mentor(s): Frances Hanzawa

Abstract: In response to continuing climatic warming, plant species worldwide have shifted in geographic 6 distribution to be in suitable growing conditions. Detailed measurement of population age structure and environmental conditions can reveal past events and disturbances affecting the population. We determined current numbers of Pseudotsuga macrocarpa seedlings, saplings, and adults in stands on Mt Baldy, with the long term goal of predicting the likelihood of a range shift or contraction as climate continues to change. This study examined the seedling, sapling, and adult distribution of P. macrocarpa, a large, long-lived conifer, endemic to the Southern California mountains. Diameter at breast height (DBH) and fire marks were recorded for each individual tree in 11 stands. Soil moisture, soil temperature, and ambient temperature were measured throughout the study at each stand. Hottest and driest soils were found at lowest elevations 595m-965m, producing low levels of seedling survival, 13.6% juveniles. At mid elevations 1190m-1760m, where soil and air temperatures were among the coolest, recruitment was highest, 28% juvenile. At the highest elevations >1950m, recruitment is occurring to maintain the current population, yet data remains inconclusive. These findings suggest that P. macrocarpa is experiencing an upwards range shift on Mt Baldy, with low elevation populations going locally extinct.
Funding Provided by: Sherman Fairchild Foundation (PP); Schulz Fund for Environmental Studies (DM)