Life Sciences Commons^™

A Review Of Shellfish Restoration As A Tool For Coastal Water Quality Management., Michael A. Rice

Michael A Rice

In many areas, coastal residents and others oppose establishment of bivalve molluscan aquaculture projects on the basis of perceived negative environmental impacts. Often overlooked are positive environmental impacts of shellfish aquaculture that can potentially mitigate the impacts of other anthropogenic activities. Filter feeding by populations of bivalve mollusks is reviewed with respect to their ability to act as an estuarine filter, increase clarity of coastal waters and facilitate the removal of nitrogen and other nutrients from eutrophic coastal waters. Most species of cultured bivalve mollusks clear particles from waters at rates of 1 to 4 L/h, and populations of shellfish …

Precise, Highly Female-Biased Sex Ratios In A Social Spider, Leticia Avilés, John Mccormack, Asher Cutter, Todd Bukowski

John E. McCormack

It has been recognized for some time that the risk of producing maleless clutches should select for a lower than binomial variance in the sex ratio of organisms with female–biased sex ratios, small clutches and breeding groups containing the clutch of a single female. However, to date, precise sex ratios have only been reported for organisms with haplodiploid sex determination, a system which allows direct control of the sex of individual offspring. In contrast, under heterogametic sex determination chance is expected to play a crucial role in determining the sex composition of any one family, in particular when males are …

An Outline Of A Theory Of The Constructional Constraints Governing Early Organismic Evolution, Winfried S. Peters, Bernd Herkner

Winfried S. Peters

This paper has no abstract; this is the first paragraph. The origin of life is one of the most fascinating biological enigmas (Dyson 1985, de Duve 1991). A multitude of hypotheses is available, ranging from the classical "primordial broth" (Haldane 1929) to the "genetic takeover" (Cairns-Smith 1982). Most of these models center on biochemical, metabolic, or genetic aspects. To our knowledge a comprehensive investigation into the mechanical constraints governing the early development of organismic constructions is not available to date. Attempting to close this gap, we here present an outline of a theory of the transformation of constructions in early …

The Baldwin Effect: An Archeology, David Depew

David J Depew

Abstract: “The Baldwin effect” stands for a wide variety of ways in which learn ing can be conceived as guiding adap tive evolution ary change. An analysis of the history of this notion reveals that it does not reliably refer either to a theory-neutral empirical phenomenon or to a single theoretical hypothesis. On the contrary, articulations of the general idea depend on distinctive, but in commensurable, theoretical backgrounds. In reconstructing the conceptual history of the Baldwin effect I hope to support contemporary explorations of idea by encouraging the articulation of new theoretical frameworks in which it might make sense. I …

Keeping And First Breeding Record Of Bourret’S Box Turtle Cuora Galbinifrons Bourreti, Obst And Reimann, 1994, With Comments On Its Conservation Status, Edgar Lehr, Joachim Fiebig

Edgar Lehr

A group of Bourret's box turtles were obtained from the animal trade in central Vietnam in 1993. Although eggs were recorded in captivity since 1994, successful breeding was first achieved in 1998. Three clutches each containing one egg were laid between March and June 1998 and one clutch of two eggs was laid in 1999. The eggs had an average length of 55.4 mm and an average width of 30.0 mm. At a temperature of 24-30 °C the eggs hatched after an incubation period of 85-117 days. One hatchling incubated constantly under 27.5 °C left the egg after 97 days …

The Tadpole Of The Central American Toad Bufo Luetkenii Boulenger, Edgar Lehr, Gunther Kohler, James Mccranie

Edgar Lehr

No abstract provided.

Use Of Thermal Water By The Andean Toad Bufo Spinulosus, Edgar Lehr, Emilio Fuentes, Gunther Kohler

Edgar Lehr

Tadpoles of the Andean toad Bufo spinulosus were found in warm water of a thermal spring in central Peru (Banos, 3460 m elev., Departamento Hmlnuco, Provincia Dos de Mayo). Adjacent water bodies of similar size but without connections to the thermal spring did not contain tadpoles. Water temperatures of the thermal and non-thermal water were measured and compared. 33,4 °C was the highest water temperature where a tadpole of Bufo spinulosus was observed.

A New Species Of Phrynopus From Peru (Amphibia, Anura, Leptodactylidae), Edgar Lehr, Gunther Kohler, Elias Ponce

Edgar Lehr

A new species of leptodactylid frog, Phrynopus horstpauli, is described from the eastern Andean slopes of central Peru (Departamento de Huanuco, Provincia de Ambo, Distrito de Conchamarca) between 3030 and 3430 m elevation. The new species is assigned to the Phrynopus Peruanus group. Phrynopus horstpauli occurs sympatrically with Gastrotheca Griswoldi and another undescribed species of Phrynopus.

Barriers To Genetic Exchange Between Bacterial Species: Streptococcus Pneumoniae Transformation, J. Majewski, P. Zawadzki, P. Pickerill, Frederick M. Cohan, C. W. Dowson

Frederick M. Cohan

No abstract provided.

Temperature-Dependent Parental Investment In The Giant Waterbug Belostoma Flumineum (Heteroptera: Belostomatidae), Scott Kight

Scott Kight