Biology Commons^™

Exploring The Biogeography Of South American Rainforest Understory Birds Using Morphological Variation In The Wedge-Billed Woodcreeper ( Glyphorynchus Spirurus ), Gregory Tito

Theses and Dissertations

Tropical rainforests in the Amazon Basin show an extraordinarily high degree of biodiversity, the reasons for which are poorly understood. A number of biogeographical models have been proposed to account for the variation present within and among species, including birds. This study tests the predictive ability of six major historical vicariant biogeographical models (Andean uplift, marine incursion, Amazonian lake, river barrier, refuge, and river refuge) using a large data set of morphological characters in the Wedge-billed Woodcreeper (Glyphorynchus spirurus), a small understory songbird found mostly in terra firme tropical rain forest. It also characterizes variation in key morphological characters and …

Identification Of Novel Nuclear Proteins Required For Meiotic Silencing By Unpaired Dna In Neurospora Crassa, Dilini Ralalage

Theses and Dissertations

A fundamental step that occurs during sexual reproduction is meiosis, which is a specialized type of cell division. During meiosis, pairs of chromosomes exchange genetic information via recombination. At this point, the genome is particularly susceptible to viruses and other foreign genetic invasions. Therefore, it is important to protect the genome to prevent the transmission of foreign genetic materials to the offspring. There are several mechanisms work together to protect host genome from foreign genetic materials. These are known as “genome defense mechanisms”.

The fungus Neurospora crassa is one of the best organisms for genome defense studies due to the …

Altered Na, K- Atpase Isoform Expression In Artemia Franciscana In Response To Hypersaline Environments, Jessica Drenth

Theses and Dissertations

The Na,K-ATPase (NKA) is an essential membrane pump that helps to establish cell ion gradients, and regulate intracellular salt in many organisms. One such species, Artemia franciscana (brine shrimp), extreme halophiles which live in hypersaline environments, expresses 2 distinct α-catalytic subunits of the NKA. One of these subunits, α2-(KK), has two key lysine substitutions located within the cation binding sites. Prior work has demonstrated this specific subunit may be directly involved in brine shrimp adaptation to their extreme environments. However, the precise molecular and physiological effects of α2-(KK) have not been entirely elucidated. I determined through immunohistochemistry that my initial …