Cathy Lundmark

Undergraduate Mentoring Program Targets Hard-to-Find Students

I its program announcement for Undergraduate Mentoring in Environmental Biology (UMEB), the National Science Foundation clearly spells out whom the program is meant to attract: “members of those racial and ethnic groups underrepresented in science, mathematics, and engineering: Native Americans (American Indians and Alaskan Natives), Blacks (African Americans), Native Pacific Islanders (Polynesians or Micronesians), and Hispanics (Latinos).” “There is a recognized underrepresentation of certain groups in many fields of science. This is especially true in the area of field biology,” says Sally O’Connor, UMEB program director from NSF’s Division of Biological Infrastructure. “People of color have not traditionally looked at environmental biology as a career option. Field biology can offer many exciting possibilities, and students need to know they can make a very rewarding life doing this kind of science.” “The UMEB program, active since 1999, hasn’t hit its goal,” O’Connor admits. “We are looking for creative ways to attract students who normally would not consider this field.” “We didn’t know how to get students involved at first,” says Michael Hadfield, lead investigator of a unique UMEB program for Pacific Islanders and director of Kewalo Marine Laboratory, University of Hawaii–Manoa. “We put up posters and waited, but they didn’t flock to us. We needed to go to them.” The first year, just four students joined the Pacific Island program for the summer internship. A young woman from Yap, an island in the Federated States of Micronesia, chose to work with Hadfield in Hawaii; the other three went to the University of Guam to work with coral reef biologist Robert Richmond. The following academic year, Richmond, Hadfield, and then coinvestigator Rosemary Gillespie, now at the University of California– Berkeley, traveled to Guam, Pohnpei, and Palau to give presentations. “We met with faculty at the schools there as well as scientists working for the government and NGOs. That turned the tide,” Hadfield says,“and our first large cohort got going. Those students generated more interest in the program after that.” In its first four years, 29 students participated in the program. They are from territories conferring the rights of US citizenship: Guam, the Commonwealth of the Northern Mariana Islands, the Republic of Palau, the Federated States of Micronesia, and the Republic of the Marshall Islands. Most of them come from places with their own languages or dialects; they don’t speak English on a regular basis. When they come to Honolulu, it is often for the first time. “It’s the classic situation of a country kid seeing the city for the first time,” Hadfield says. “They lose track of where they’re walking because they can’t stop looking up.” Although attuned to their natural surroundings, students initially have a minimal background in biology. Many participate for only one summer, but eight have worked for two or more summers. They enter the program at one of several institutions: the University of Guam, the University of Hawaii– Manoa, the University of Hawaii–Hilo, and the University of California– Berkeley. Program leaders found that students work better as part of a cohort, so Berkeley will no longer be part of the program. Students who come to UH–Manoa spend the first 3 weeks of the 10-week summer session doing rotations with graduate students and postdoctoral fellows in Hadfield’s marine lab, looking at marine invertebrate life histories and ecology, and at his inland study site, studying endangered tree snails. Vanessa Fread, the student from Yap, has finished her third year of internship and is now working on her bachelor’s degree at the University of Queensland, in Brisbane, Australia. Her studies on the ecology of an invasive barnacle, which came to Hawaii from the Caribbean, will be published within a year. Students who come to UMEB are familiar with environmental problems. They have seen the effect of bleaching on coral reefs in Palau and know firsthand the impact that dead corals have on fisheries and tourism. One UMEB intern from the Marshall Islands, Melba White, is now a spokesperson for coral reef preservation. “Great people work in natural resources,” Hadfield says, “and having an undergraduate or master’s degree from University of Guam guarantees students a position. We want to train people to do this work.” “We want [students] to know they can make a difference in how we manage our environment,” says O’Connor. “We need scientists who come from all perspectives and backgrounds. Problems dealing with the environment are complex, and we need all members of our society to help solve them. “The UMEB program has changed— we needed to refocus on our goal. People need to know that the previous restriction that an institution must have three current grants [to apply for UMEB] has been removed for the first time this year. It has opened up the field to more schools and is better targeting the intended audience.... We are excited because we are better able to reach the target group than ever before.”

Evolution of Mammalian Brains

992 BioScience • November 2001 / Vol. 51 No. 11 We know what distinguishes us from the rest of the animal kingdom: our brains. The increase in brain capacity throughout hominid evolution brought with it language, complex social structure, creativity, curiosity, and the capacity to reason, among other things. So it’s only human nature to wonder how we got where we are. As scientists continue to probe the dramatic transformations mammalian brains have undergone, the types of analyses they perform also evolve. A recent study by Sam Wang, Damon Clark, and Partha Mitra (Nature, 11 May 2001) is a thought-provoking reanalysis of 20year-old data that have been reanalyzed before. The original data are volumetric measurements of the five main parts of the brain (telencephalon, diencephalon, mesencephalon, medulla, cerebellum) for extant representatives of several groups—insectivores (28 species), tree shrews (three species), and primates (44 species). What emerges from the recent reanalysis is a comparison of relative changes in brain architecture, independent of a species’ absolute size. To compare the structure of brains from animals of disparate size, Wang and his colleagues used the total brain volume for each species as a reference, arguing that it is more appropriate than body size, which can be variably influenced by other factors such as diet and environment. Each brain component for a species was expressed as a volume fraction of that species’ total brain volume. Wang and company dubbed the set of volume fractions for each species its cerebrotype. The dominant structure in human brains is the telencephalon, which comprises the two cerebral hemispheres and is the locus of higher-order, informationprocessing functions. As might be expected, the volume fraction of telencephalon increases from 60% and 61% in insectivores and tree shrews, respectively, to 74% in primates, primarily at the expense of diencephalon, mesencephalon, and medulla. By contrast, the volume fraction of cerebellum, which was previously thought to vary with the telencephalon, remains relatively constant: 13.2%, 12.7%, and 12.4% in insectivores, tree shrews, and primates, respectively. Functionally, the cerebellum coordinates motor activity with sensory information. The authors expanded the study to members of 19 mammalian taxa (15 orders and four primate suborders) to test how consistent the cerebellar fraction is generally, and it held up. Interestingly, the two orders for which the cerebellar fraction is significantly higher than for other mammals are Microchiroptera (microbats) and Cetacea (whales and dolphins), whose members use echolocation to gather information about their surroundings. Those bats that do not echolocate (Megachiroptera) have cerebellar fractions resembling other mammals, indicating the enlarged cerebellar fraction of microbats is probably tied to their sophisticated sensory adaptation. The same whole-brain approach was used to study evolutionary changes within the telencephalon. Wang and coauthors normalized volume fractions of the seven subcomponents (neocortex, hippocampus, schizocortex, septum, piriform cortex, olfactory bulb, striatum) to the total volume fraction of telencephalon for each species. The volume fraction of neocortex climbs from 28% in insectivores to 55% in tree shrews to 81% in primates (95% in Homo sapiens). These increases were shown to come at the expense of the other subcomponents, except the striatum, which was relatively constant: 8%, 8%, and 6% in insectivores, tree shrews, and primates, respectively. The striatum functions in motor activity and forms extensive connections between parts of the brain, including much of the telencephalon, which may be why its relative size is maintained throughout mammalian evolution. Wang and coauthors map the relationships between cerebrotypes several ways, and from these analyses they conclude that mammals can be grouped taxonomically according to brain structure. Cerebrotypes are clumped within taxa, and they are clearly distinct between taxa. For example, cerebrotype comparisons show tree shrews to be distinct from primates and insectivores; at a finer scale, the taxonomic subgroups within the larger groupings of insectivores and primates have distinct cerebrotypes as well. The few overlaps that are found, between certain New World monkeys (four species) and Old World monkeys, for example, can be attributed to other similarities, such as social organization, between the groups. These findings suggest mammalian brains are scalable structures, meaning the relative proportions of brain components are constrained within taxonomic groups, even when absolute brain sizes vary considerably. They also indicate that major shifts in brain architecture accompany the appearance of new taxa. Of course, the next thing we’ll want to know is what underlying factors determine the cerebrotype, so we can understand more precisely how we came to be.

A Hitchhiker's Guide to…

beloved and consummate University citizen who contributed to the well being of the institution and his fellow faculty in innumerable ways. He spearheaded the creation of Hitchhiker, led its compilation and subsequent annual updates, and edited the first three editions. He will be missed. This guide was prepared by members of the Penn Association of Senior and Emeritus Faculty as a summary of issues that faculty members should review as they begin to consider retirement. It is not intended to be a detailed description of available benefits, nor is it intended to replace any of the official documents published by the University of Pennsylvania. The guide was not prepared by and is not published by the University of Pennsylvania, its Division of Human Resources, or any University benefits administrators. The University therefore makes no representations or assurances regarding its accuracy or completeness. Faculty are strongly encouraged to review in detail any summary plan description of benefits they consider to be important, as well as to speak to representatives from the Division of Human Resources before making any decision regarding retirement or benefits. The University offers many benefits to active and retired faculty, the terms of which are set forth in various plans and summary plan descriptions, which may be subject to change.