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This study employs geometric morphometric methods to investigate the morphology and shape change of the frontal bone for Pan troglodytes and Pan paniscus. Unlike previous work on the topic, this research analyzed morphology and ontogenetic shape change in a single bone of the cranium, namely the frontal bone. Frontal bone shape was compared between juvenile Pan troglodytes and Pan paniscus and the ontogeny of the bone was assessed in Pan paniscus infants and juveniles. Analyses were performed on frontal bone morphology with and without the browridge in order to assess the morphology of the frontal apart from influences affecting the browridge. Results of ANCOVA with principal component shape variables indicate that the frontal bone shape differs between species (P=.000) and between infant and juvenile Pan paniscus for log centroid size (P=.109), but this shape change occurs largely in the browridge. Results for the frontal without the browridge do not significantly differ in shape between species for PC1 (P=.205) and PC3 (P=.113) and between Pan paniscus life stages for PC3 (P=.103). These results have implications for current and future work as they contribute to a growing body of knowledge aimed at understanding the complexities of cranial growth. Adviser: Daniel Osborne

Aged-related macular degeneration (AMD) is a common eye condition among people older than 65 years and is a leading cause of vision loss. It gradually destroys the macula, the part of the eye that provides sharp, central vision needed for seeing objects clearly. This study aims to test the hypothesis that the morphology of retina pigment epithelium, a key site of AMD pathology, can reflect the various stresses aging and AMD progression impose. We first identify and separate the young and old age group for mouse eyes. Then we classify, the mouse eyes using two genotypes (C57BL/6L, RD10), and two age group (young, old).We show that without dimensional reduction, the cell area and shape measures do not provide good classification of the mouse eyes. But with the dimension reduction at the eye level, the cell area and shape measures provide excellent classification for mouse genotype and age.

Mesoamerica, a region of cultural evolution in the world, is known as a cradle for plant domestication. Studies exploring the domestication origin and history of H. annuus, a globally significant crop plant, greatly benefit from genetic and morphological assessments of modern plant populations and archaeological remains in that region, particularly southern Mexico. Inclusion of Mexican representatives of sunflower, both wild and cultivated, in domestication studies of this plant is necessary to make a precise inference of the origin of sunflower. In this study, we morphologically evaluated sunflower achene populations from Mexico and the U.S. Anatomical characteristics of achenes including the shape (narrow or plump), seed coat (pericarp) color, pattern, and attachments were described and evaluated. High variation was recorded for achene shape and seed coat coloration within domesticated landraces as well as between wild and domesticated populations. Interestingly, achenes in one of the Mexican landraces, collected from the southern state of Guerrero, were the most morphologically similar to the wild sunflowers in that region. This set of observations coupled with the fact that archeological sites with pre-Columbian domesticated H. annuus remains in Mexico are located in southern regions of the country; imply that southern Mexico may represent a center for the diversity of domesticated H. annuus. The detailed description of achenes in each population, presented here, can serve as a database for future references to sunflower plants in Mexico. Also, we sought to test the utility of modern computer-assisted shape analysis techniques in distinguishing between wild and domesticated sunflower achenes. Computerized approaches offer faster and more reliable methods for identification and classification of seed populations. A comparative study was conducted to evaluate the efficiency of computer-assisted shape measurements compared to the conventional size measurements which are obtained manually. Four shape parameters (formfactor, convexity, roundness and curl), which have been shown to be informative in other seed populations, were measured on digital images of achenes using an image processing script (developed in a computational program called MATLAB). Our results showed that these shape measurements were not as efficient as size characteristics in separating wild achenes from domesticated types. In addition, we evaluated the achene size variation in the both modern and archaeological sunflowers. Significant increase in fruit (achene) size is the main consequence of cultivation in sunflower. When considering the differences in size of the achenes between the modern samples from Mexico and the U.S. we found that both wild and domesticated H. annuus plants in the U.S. produce significantly larger achenes compared to Mexican varieties. This trend is contradicted by the significantly larger archaeological specimens of ancient domesticated achenes discovered in Mexico compared to the earliest archaeological remains in eastern North America. Climatic variables and the wild sunflower genome contribute to wild achene size variation across North America. This pattern of achene size changes is suggestive of a longer or a more intense domestication practice for Mexican ancient sunflower to make the transition from small-seeded wild phenotype to the large domesticated phenotype observed in archaeological samples from pre-Columbian Mexico.

The choice of a classification scheme is based both on the variance within categories and the discontinuities between categories. This leads to difficulties in classifying biologic taxa that exhibit continuous morphological variation. But, although complete discontinuities in variation are rare, the morphologic distributions may be statistically heterogeneous and rich in information about evolution in time and space. Samples of Early to Middle Miocene Globorotalia from two Southwest Pacific DSDP sites were analyzed in multivariate morphometric space, beginning with a minimum of assumptions about the structure of the sample distributions. The distributions of the DSDP data were compared to morphologies of named species of Globorotalia. Species erected for fossil planktonic foraminifera may be an attempt to categorize complex variation by applying an inappropriate assumption of discrete variation. Morphologic change in chamber shape was measured from medial axis analysis of the chambers and variation in parameters of the coiling geometry were obtained from two point registration of landmarks taken on the test. Principal component analysis indicates that there are three major components of chamber shape variation for these forms. These components do not differ among the data sets examined. Decomposition of landmark transformation into uniform and nonuniform components allows identification of parameters of shape change, examination of variation in known parameters of abstract geometry, and evaluation of their relative importance. The major components of landmark variation incorporate several parameters of abstract spiral geometry, such as angle of increment and expansion rate, as well as other types of shape variation, such as chamber orientation and aperture shape. These components are the same for each data set examined. Within the morphologic spaces defined by these components, the distribution of sampled individuals is generally continuous, but the shape of the distributions and the areas of morphologic space occupied change both stratigraphically and geographically. The most variable and structured morphologic space is that of chamber shape. There is no evidence for the persistence of discrete clusters in morphologic space that could be presumed to be biologic entities at the level of species. If the nominal species are not biologic entities they cannot participate as lineages in evolutionary processes, but the pattern of variation among individuals can be useful for examining biologic questions.