Using Place-Based Economically Relevant Organisms to Improve Student Understanding of the Roles of Carbon Dioxide, Sunlight, and Nutrients in Photosynthetic Organisms (2018)

Biology students require broad preparation for diverse careers including agriculture, natural resource management, and laboratory research. Concurrent with this need, employers are seeking applicants who have the scientific skills that allow them to solve problems related to locally relevant economic systems and develop ways to foster economic growth. To support these efforts, biology faculty from six different campuses in the University of Maine System collaborated to develop an economically relevant activity where students differentiate the roles light energy, carbon dioxide, and nutrients have in photosynthetic organisms

The basic nonuniformity of the cerebral cortex

Evolutionary changes in the size of the cerebral cortex, a columnar structure, often occur through the addition or subtraction of columnar modules with the same number of neurons underneath a unit area of cortical surface. This view is based on the work of Rockel et al. [Rockel AJ, Hiorns RW, Powell TP (1980) The basic uniformity in structure of the neocortex. Brain 103:221–244], who found a steady number of approximately 110 neurons underneath a surface area of 750 μm2 (147,000 underneath 1 mm2) of the cerebral cortex of five species from different mammalian orders. These results have since been either corroborated or disputed by different groups. Here, we show that the number of neurons underneath 1 mm2 of the cerebral cortical surface of nine primate species and the closely related Tupaia sp. is not constant and varies by three times across species. We found that cortical thickness is not inversely proportional to neuronal density across species and that total cortical surface area increases more slowly than, rather than linearly with, the number of neurons underneath it. The number of neurons beneath a unit area of cortical surface varies linearly with neuronal density, a parameter that is neither related to cortical size nor total number of neurons. Our finding of a variable number of neurons underneath a unit area of the cerebral cortex across primate species indicates that models of cortical organization cannot assume that cortical columns in different primates consist of invariant numbers of neurons