Current estimates of the number of species on Earth range from four to forty million total species. Why are there so many species? The answer must include both ecology and evolution. Ecology looks at the interactions between coexisting species, while evolution tracks them through time. Both are required to understand aspects of environments which promote speciation, and which promote species pe...

W ithout bacteria, life on earth could not exist in its present form. Bacteria are key play­ ers in many geochemical processes, including the fundamental nitrogen, carbon and sulfur cycles, which are critical to the circulation of life's basic elements. If these processes were to grind to a halt, the planet's soils, wa­ ters and atmosphere would become inhospitable for life. Yet in spite of suc...

The ability of normal and Crohn's disease neutrophils to kill Candida albicans has been studied using neutrophils isolated from peripheral blood and suspended in phosphate buffered saline at 5x 106 cells per ml. C albicans was grown to a stationary phase in broth culture and suspended in phosphate buffered saline at 107 organisms/ml. Neutrophils and Candida were then incubated together at 37°C ...

Using a bit string model, we show that asexual reproduction for diploids is more efficient than for haploids: it improves genetic material producing new individuals with less deleterious mutations. We also see that in a system where competition is present, diploids dominate, even though we consider some dominant loci.

This article introduces an interdisciplinary subject of bioelectrodynamics in living organisms and its related research challenges and opportunities. Bioelectrodynamics in living organisms is aimed to reveal critical roles of electromagnetism and mechanics in biology, to correlate biophysical functions of living organisms with biochemical processes at the cellular level, and to introduce theore...

Populations of artificial organisms live in an environment in which light is cyclically present (day) or absent (night). Since being active during night is non-adaptive (activity consumes energy which is not compensated by the food found at night) the organisms evolve a sleep/wake behavioral pattern of being active during daytime and sleeping during nighttime. When the population moves to a dif...

all the humdrum of mental undressing, dressing, shaving, etc., there is the chance reward of being confidential ear to what may never be so well expressed or thought of again. The contributors of the "relatively brief" presentations are six in number. Alex Bavelas talks on "Communication patterns in problem-solving groups"; Ivor A. Richards, on "Communication between men: Meaning and language";...

As the earth faces a warming climate, the rock record reminds us that comparable climatic scenarios have occurred before. In the Late Cretaceous, Arctic marine organisms were not subject to frigid temperatures but still contended with seasonal extremes in photoperiod. Here, we describe an unusual fossil assemblage from Devon Island, Arctic Canada, that offers a snapshot of a ca 75 Myr ago marin...

Most organisms have complex life cycles, and in marine taxa, larval life-history stages tend to be more sensitive to environmental stress than adult (reproductive) life-history stages. While there are several models of stage-specific adaptation across the life history, the extent to which differential sensitivity to environmental stress (defined here as reductions in absolute fitness across the...

1Department of Radiology, Sloan Kettering Institute for Cancer Research, New York, New York; 2Cancer Biology and Genetics, Sloan Kettering Institute for Cancer Research, New York, New York; 3Department of Medical Physics, Sloan Kettering Institute for Cancer Research, New York, New York; 4Cyclotron and Radiochemistry Core, Sloan Kettering Institute for Cancer Research, New York, New York; 5Smal...