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Biology

Whole Foods Confer a Greater Metabolic Advantage Than Processed Foods: Implications for the Growing Trend of Obesity in Response to the Western Diet

Sadie Barr ('09); Jonathan Wright

Rising obesity rates are associated with increased processed food consumption in America, and differences in postprandial thermogenic responses to whole verses processed foods may be a key factor in explaining this trend. The goal of this study was to determine if processed foods are more thermodynamically efficient than whole foods, i.e. they require less energy for digestion and thus a higher percentage of meal energy is likely to be stored within the body as mass. It was found that average energy expenditure for the whole food meal (137 kcal, 19.9% of meal energy) was larger than for the processed food meal (73 kcal, 10.7% of meal energy) (P < .01). Thus, intake of a diet composed predominantly of processed foods will decrease postprandial energy expenditure by nearly 50 percent compared with a whole food diet. This reduction in daily energy expenditure could lead to a significant annual weight gain.
Funding provided by: Howard Hughes Medical Institute

Murrelets on the Move: Seasonal Densities of Xantus's Murrelets Near Santa Barbara Island

Kristen Boysen ('10); Augie Lagemann ('10); Nina Karnovsky

Xantus’s Murrelet, a threatened seabird, nests on Santa Barbara Island, one of the Channel Islands west of Los Angeles. On ocean cruises in April and May, 2009, I collected oceanographic data and recorded bird densities around the island. Using these data, I was able to analyze the movement of the birds in relation to changing water temperatures. I hypothesized that the birds, due to their prey preference, would favor cooler waters, and thus the birds would be more dense in areas of colder sea temperatures. Indeed, in both April and May, more murrelets were found in colder water. As sea temperatures rise with climate change, xantus’s murrelets and their prey could be directly affected.
Funding provided by: Pomona College SURP (KB)

The Influence of Diet on the Distribution of Birds in a Riparian Area

Amy Briggs ('10); Charlotte Chang ('10); Sabrina McNew ('09); Nina Karnovsky; John Carlson*
*Bureau of Land Management, Glasgow, MT

Birds use different foraging habitats based on their dietary preferences. At a Monitoring Avian Productivity and Survivorship (MAPS) station in northeastern Montana, mist nets were placed in two distinct habitat types: an Ash woodland and a Cottonwood woodland. Birds captured in these nets were classified according to diet type as generalists, insectivores, or granivores. The number of birds of each dietary class caught in either Ash or Cottonwood nets in 2009 and 2007 were compared using a chi square. Granivores and generalists appeared to have no preference for either habitat because the number of birds in these classes did not differ significantly between Ash and Cottonwood (chi square, df = 1, p>0.05). Insectivores in both years had a preference for the Ash habitat (chi square, df =1, p<0.05). This was unexpected because the Cottonwood habitat has a stream running through it, which may increase the number of insect prey available.
Funding provided by: Rose Hills Foundation (CC); Bureau of Land Management, Glasgow, MN

The Effects of Patch Size on Sapphire Woolystar Pollination

Sally Carter ('10); Sharon Moore ('10); Sarah Woods ('10); Fran Hanzawa

We examined the effects of habitat fragmentation on pollination of the native annual Eriastrum sapphirinium at the Bernard Field Station. Habitat fragmentation can have detrimental effects, reducing populations of plants and their insect pollinators. We hypothesized that small patches of Eriastrum would receive fewer pollinator visits per flower and would attract different species of pollinators than large patches. We observed 20 pairs of sites, one “small” and one “large,” for three twenty minute periods, recording the identity and the number of flowers visited for each pollinator. Unexpectedly, we found that large patches did not receive more pollinator visits per flower. We did find that large patches attracted a higher proportion of bees, while small patches attracted a higher proportion of flies. Since bees have been shown to be more effective pollinators than flies, this may imply some advantage to plants in large patches.
Funding provided by: Pomona College SURP (SC); The Paul K. Richter and Evalyn E. Cook Richter Award (SC); The Schenck Fund (SM)

Using Cassin's Aukets as Indicators of Environmental Change: A Study of Foraging Behavior on Southeast Farallon Island

Eleanor Caves ('11); Nina Karnovsky; Russell W. Bradley*; Pete Warzybok*
*PRBO Conservation Science, Petaluma, CA

This study examined the foraging behavior of Cassin’s Auklets (Psychorampus aleuticus), small diving seabirds. Cassin’s Auklets act as a bioindicator species because they (1) react quickly to environmental changes; (2) exist in large numbers; (3) are accessible at their nest sites. I hypothesized that shifts in ocean temperatures and prey distribution will cause Cassin’s Auklets to expend more energy foraging, evidenced by increased dive depth and time underwater. To test these hypotheses, I attached Time-Depth Recorders to twenty Cassin’s Auklets breeding on Southeast Farallon Island. I retrieved 18 TDRs, obtaining data for 1,260 hours and 13,000 dives. Preliminary analysis of one bird’s behavior showed dive bouts of up to 28 minutes, reaching depths of 26 meters. These data are useful for establishing linkages between ocean conditions, prey abundance, and foraging behavior. Future analyses will include comparison of these data to those collected last year, when ocean temperatures were generally cooler.
Funding provided by: Howard Hughes Medical Institute (EC)

To Breed or Not to Breed: The Effect of Diet on Breeding Status for Grassland-Associated Passerines

Charlotte Chang ('10); Amy L. Briggs ('10); Sabrina M. McNew ('09); Nina Karnovsky; John Carlson*
*Bureau of Land Management, Glasgow, MT

Different avian species employ different foraging strategies. Natural resources provided by a habitat affect reproductive decisions distinctly for each diet type. In particular, prey or forage availability impacts ability to attain enough energy to breed. Our study focused on a community of granivorous, insectivorous, and generalist passerines in a riparian corridor of a shortgrass prairie environment. We expected that this lowland creekbed riparian zone would have a large insect prey base and thus disproportionately support insectivorous breeding birds. However, our results indicate that this site provides ample support for all three diet types to reproduce. Future studies will focus on supplementing breeding status measurements with nesting success data.
Funding provided by: Rose Hills Foundation (CC); Bureau of Land Management, Glasgow, MT

Genes that control vesicular transport in Drosophila

Kimberly Chau ('10); Clarissa Cheney

Abstract removed upon request.

Genes that control vesicular transport in Drosophila

Benjamin Kozak ('10); Clarissa Cheney

Abstract removed upon request.

Changes in At-Sea Distribution of Xantus's Murrelets Since 1976

Augie Lagemann ('10); Kristen Boysen ('10); Nina Karnovsky

Xantus’s murrelets are small seabirds that breed on a few islands off the coast of California and Mexico. Their largest breeding colony is found on Santa Barbara Island. In 2004, California listed them as a threatened species. This study assesses the differences in the murrelet population between the late ‘70s, when the population was first surveyed, and 2009. Ship-board surveys of XAMU along the same transects that were used in the ‘70s were conducted in May and April of 2009. The data collected in 2009 was compared to that collected in 1976. Murrelet numbers were higher in 1976 than in 2009, with the highest densities of murrelets in western transects. These data will be useful for monitoring the health of the SBI XAMU population. Future surveys may reveal increases as murrelet nesting habitat is currently being restored to SBI and will help determine habitat critical to their foraging.
Funding provided by: Pomona College SURP (KB); Montrose Settlements Restoration Program

Characterization of Novel Homing Endonucleases I-CFRI and I-CPAII

Zachary Mirman ('11); Len Seligman

Homing Endonucleases (HEs) recognize 14-40 base pair sequences in DNA and induce double-stranded breaks. The HEs I-CfrI and I-CpaII were previously isolated by Erin Noble (’07) and Diana Koulechova (’08) from the chloroplast DNA of Chlamydomonas species and shown to have some activity in vivo in E. coli. In order to identify mutants with enhanced activity, we are adapting a bacterial selection system originally described by Doyon et al. for use with these HEs. We have successfully constructed the necessary plasmids containing the target sequences for I-CfrI and I-CpaII, and are currently establishing the parameters and controls for this selection system. We are also constructing libraries of HE variants by degenerative PCR.
Funding provided by: The Paul K. Richter and Evalyn E. Cook Richter Award

Getting Science Out of the Box: Somatic Markers and (Trans)Gender Identity

Kristin Raphel ('11); Jenny Franks (’12); Katie Cettie (’11); Ian Hannigan (’08); Rachel Levin

Abstract removed upon request.

Seed Bank Viability and Germination After Simulated Fire in Senescent Coastel Sage Scrub Habitat

Allison Rossman ('10); Connor Smith ('11 Duke University); Frances Hanzawa

Fire occurs in coastal sage scrub (CSS) habitats approximately every 30 years, removing older shrubs and increasing germination of some seeds. The Bernard Field Station contains mature CSS that hasn’t burned in 40 years, resulting in senescent shrubs and little new growth. Can CSS remain viable over the long term with fires absent? We investigated recruitment in areas near senescent shrubs in 34 1-m2 plots that were dominated by bare soil and dead branches. We examined whether seeds are in the soil and whether germination increases with simulated fire. By germinating soil samples in the lab, we determined that the soil around senescent shrubs contains many viable seeds of native species. Finally, we investigated if recruitment can be increased by applying smoke compounds and by removing dead branches, simulating the effects of fire. Monitoring will continue through next year to determine if this is a viable option for restoring senescent CSS.
Funding provided by: The Paul K. Richter and Evalyn E. Cook Richter Award (AR); The Schenck Fund (AR)

Research at Pomona