Browsing Biology by Title
Now showing items 70-89 of 103
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The Paleobiology of South African Therocephalian Therapsids (Amniota, Synapsida) and the Effects of the End-Permian Extinction on Size, Growth, and Bone Microstructure
(2013-11-14)Despite their relative diversity in terrestrial Permian and Triassic rocks, the fossil record of therocephalian therapsids (Eutheriodontia) and their utility for understanding evolutionary patterns in the therapsid forerunners ... -
Pattern and process in primary succession in high elevation habitats on Mount St. Helens
(1987)The mechanistic basis of primary succession remains poorly known. The facilitation model, thought to describe primary succession, stresses the environmental modifications caused by early colonists as important in promoting ... -
Phenotypic plasticity in the red alga Porphyra abbottae: environmental factors influencing light harvesting ability
(1990)Gametophytes of the red intertidal macroalga Porphyra abbottae were grown in batch cultures in order to examine some of their plastic responses to key environmental factors. Conchospores from a conchocelis stock culture ... -
Phylogeography, population genetic structure, and reproductive biology of antelope ground squirrels
(2006)The genetic structure of populations over a wide geographic area should reflect the demographic and evolutionary processes that have shaped a species across its range. Similarly, variation in physiological traits should ... -
Physiological and behavioral responses to temperature and flow in the barnacle Balanus glandula Darwin (1854)
(2013-11-14)Given the scale and pace of anthropogenic change in marine environments, it is important to understand the manner in which organisms respond to environmental uncertainty. For many aquatic species, fundamental processes ... -
PIE-1, MEX-5, MEX-6, and soma/germline asymmetry in C. elegans embryos
(2000)The separation between soma and germline in C. elegans embryos occurs through a series of asymmetric cell divisions initiating with the 1-cell stage. Each of these divisions results in one daughter that will produce only ... -
Plants, pollinators and global change: the effects of invasion and flowering phenology on plant-pollinator interactions
(2013-11-14)Global environmental change is currently happening more rapidly than at any time known in Earth's previous history. The impacts of rapid biotic and abiotic change will affect multiple species interactions, including ... -
Polymorphism and replication of heterochromatic repeats in the DNA of Arabidopsis
(2006)The composition of the individual eukaryote's genome and its variation within a species remain poorly defined. Even for a sequenced genome such as that of the model plant Arabidopsis thaliana accession Col-0, the large ... -
Regulation of dendrite growth, placement, and patterning in Drosophila melanogaster class 4 dendrite arborization neurons
The directional flow of information in neurons depends on compartmentalization: dendrites receive inputs whereas axons transmit them. Axons and dendrites likewise contain structurally and functionally distinct subcompartments. ... -
Regulation of life history strategies with individuals in predictable and unpredictable environments
(1996)Animals must adjust their physiology and life histories to conform with changes in the environment. These changes can be fairly predictable, such as the changes in the season, or they can be unpredictable, such as an attack ... -
Restoration of native plant communities: an examination of seed limitation and microsite limitation in the Garry oak ecosystem.
The Garry oak ecosystem is one of the most highly degraded ecosystems in North America due to fragmentation, development, and conversion to incompatible uses, with less than three percent of the ecosystem dominated by ... -
The role of habitat quality in shaping evolutionary dynamics, population dynamics, and conservation planning
(2001)Understanding ecological and evolutionary consequences of variation in habitat quality is increasingly important as biologists seek to address human-mediated environmental change. I investigated effects of natural temperature ... -
The role of wing mechanosensory feedback in insect flight control
Flying insects rapidly stabilize after perturbations using multiple sensory modalities (e.g., vision mechanoreception, olfaction) for active control. Mechanoreceptors’ direct coupling of sensory structure to the environment, ... -
Roles for callose in plant development and intercellular communication
(2006)Cell-to-cell communication through plasmodesmata (PD) exists between most plant cells. The small fluorescent dye Lucifer Yellow CH (LYCH) has been used to determine that in the Arabidopsis root meristem there are tissues ... -
Roles of the Rho1 small GTPase during development in Drosophila melanogaster
(2004)Rho, Rac and Cdc42 are small GTPases in the Ras superfamily initially shown to regulate the actin cytoskeleton. Subsequent work linked them to many cellular processes. The diversity of functions exhibited by Rho suggests ... -
Shape matters: corolla curvature improves nectary discovery in the hawkmoth Manduca sexta
I measured the effects of variation in corolla curvature and nectary aperture radius on pollinator foraging ability using the hawkmoth Manduca sexta and 3D-printed artificial flowers whose shapes were mathematically ... -
Stem cells and fate control in plant stomatal development
(2013-07-25)The plant epidermis is a critical interface between the atmosphere and internal plant tissues, which allows plants to succeed on land by restricting their exposure to the environment. Stomata, closable pores on the plant ... -
Studies on the Mechanism of Phosphate Accumulation by Sea Urchin Embryos
(1954)The problem of phosphate entry into cells has been the subject of many studies with radioactive phosphorus during the past fifteen years. These studies, when compared with similar experiments with monovalent cations or ... -
The systematics and evolution of Lantaneae (Verbenaceae), a molecular phylogenetic approach
(2013-07-25)Lantaneae are a morphologically variable group of 300-400 species, representing the largest tribe within Verbenaceae. They are widespread and diverse in the new world tropics and subtropics; some members are native to ... -
Systematics of Ulvaceae (Ulvales, Ulvophyceae) and the genus Ulva L. based on nuclear and chloroplast sequence data
(2001)Systematic hypotheses for Ulvaceae were tested using sequences for the chloroplast gene encoding the large subunit of RUBISCO (rbc L) and nuclear small subunit ribosomal DNA (18S rDNA). Ulvaceae sensu Floyd and O'Kelly ...