Life Sciences Commons^™

Estimation Of Phytomass For Ungrazed Crested Wheatgrass Plants Using Allometric Equations, Neil West, Patricia Johnson, Craig Johnson

Patricia Johnson

No abstract provided.

Nonfish Prey Of Wintering Bald Eagles In Lilinois, Given Harper, D. Scott Hopkins, Thomas C. Dunston

Given Harper

Influence Of Wind And Windbreaks On Local Dispersal Of Insects, Judith Pasek

Judith E Pasek

Insect dispersal is affected by the wind and as a result, influenced by the presence of windbreaks. Wind reductions, microclimate modifications and vegetative diversity, influence insect distribution in sheltered areas.

Wingless insects and very small insects generally depend on air currents to carry them to new sites, but they tend to settle in areas with low windspeeds. It is often more advantageous for a flying insect to remain within its boundary layer where windspeeds are lower than the insect's flight speed. Flying insects tend to accumulate in areas of reduced windspeed where they have greater control of flight; however, distribution …

Neuromuscular Junction Development In The Cutaneous Pectoris Muscle Of Rana Catesbeiana, Diana Linden, Susan Jerian, Michael Letinsky

Diana Linden

Synaptic specializations were studied in the developing cutaneous pectoris muscle of Rana catesbeiana tadpoles and froglets to correlate nerve terminal morphology (by light and electron microscopy), accumulation of acetylcholine receptors, and the ability of the muscle to contract following nerve stimulation. This correlated approach was used to determine the developmental timing and possible causal relationship of events in nerve and muscle maturation at the neuromuscular junction. Initially, the cutaneous pectoris nerve trunk was present in the undifferentiated presumptive cutaneous pectoris mesenchyme, prior to muscle maturation. At stage XII when the muscle was first able to contract weakly in response to …

Correlated Muscle And Nerve Development In The Bullfrog Cutaneous Pectoris, Diana Linden, Michael Letinsky

Diana Linden

The development of the cutaneous pectoris muscle was studied and compared with the differentiation of its peripheral nerve in bullfrog (Rana catesbeiana) tadpoles and frogs by light and electron microscopic techniques. This muscle preparation was chosen for this study because it possesses a number of advantages for (and has become a model system for) the study of correlated nerve-muscle development. At the earliest stage examined (stage XI) the presumptive muscle did not contain any contractile or morphologically distinguishable myotubes, but was contacted by the well-defined cutaneous pectoris nerve trunk. Myotubes were present at stage XII, the same time that nerve-associated …

Entropy, Information, And Evolution: New Perspectives On Physical And Biological Evolution, David Depew, Bruce Weber

David J Depew

Can recent developments in thermodynamics and information theory offer a way out of the current crisis in evolutionary theory? One of the most exciting and controversial areas of scientific research in recent years has been the application of the principles of nonequilibrium thermodynamics to the problems of the physical evolution of the universe, the origins of life, the structure and succession of ecological systems, and biological evolution. These sixteen original essays by evolutionists, ecologists, molecular biologists, physical chemists, physicists, and philosophers of science provide the best current summary of this developing research program.Chapters in the book's first part - by …

Reproductive Success And Inflorescence Size Of Calopogon Tuberosus (Orchidaceae), David Firmage, F Cole

F. Russell Cole

Reproductive success of Calopogon tuberosus, which produces no nectar, was investigated in relation to inflorescence size and dispersion pattern. Mean inflorescence size was 2.56 (range 1-10). A bagging experiment showed that insects are required for pollen transfer and that fruits are produced from self-, geitonogamous, and cross-pollinations; fruit set was not 100%. Fruit set of nonmanipulated plants was limited by the number of pollinator visits. Reproductive success increased with increasing inflorescence size, although not above theoretical predictions. However, the probability of producing no fruit or contributing no pollinia decreased with increasing inflorescence size since sequential flowering increased the probability of …

Stressors In The Learned Helplessness Paradigm: Effects On Body Weight And Conditioned Taste Aversion In Rats., Clinton Chapman, Nancy Dess, John Garcia, Jeffrey Raizer

Clinton D Chapman

In Exp 1, 44 male rats drank saccharin or a control solution, followed by 100 inescapable shocks or simple restraint. Ss were weighed daily and were tested for saccharin aversion 2 days after the stress session. Shocked Ss gained less weight than restrained controls. Saccharin aversion was apparent only among Ss that had consumed saccharin before the stress session. In Exp 2, 72 Ss drank saccharin solution, followed by shock, restraint, or no treatment. Half of each group was injected with saline; the other half was injected with lithium chloride. Shock reduced body weight relative to restraint or no treatment …

Point Mutations Cause The Somatic Diversification Of Igm And Igg2a Antiphosphorylcholine Antibodies, Nadine Chien, Roberta Pollock, Catherine Desaymard, Matthew Scharff

Roberta Pollock

No abstract provided.