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Virtually all nonequilibrium electron transfers on Earth are driven by a set of nanobiological machines composed largely of multimeric protein complexes associated with a small number of prosthetic groups. These machines evolved exclusively in microbes early in our planet's history yet, despite their antiquity, are highly conserved. Hence, although there is(More)
The quantitative uptake of latex beads of different sizes and of live cells by 14 species of ciliates was studied. The functional response (uptake rate as function of food particle concentration) can be fitted to a hyperbolic function and this can be explained in terms of the function of the mouth apparatus. Each species shows a distinct size spectrum of(More)
57, 58 (1992). 23. M. L. Sutter and D. Margoliash, J. Neurophysiol. 72, 2105 (1994). 24. M. A. Wilson and B. L. McNaughton, Science 265, 676 (1994); W. E. Skaggs and B. L. McNaughton, ibid. 271, 1870 (1996). 25. A. C. Yu and D. Margoliash, ibid. 273, 1871 (1996). 26. J. S. McCasland, J. Neurosci. 7, 23 (1987); A. C. Yu and D. Margoliash, unpublished data.(More)
The relationship between previously published values of “the intrinsic rate of natural increase” (r m ) and body weight is studied. When organisms covering a wide range of body weights are compared, a correlation is found which can be described by the equation r m =aW n where r m is the intrinsic rate of natural increase per day and W is the average body(More)
The quantitative uptake of suspended particles has been studied in 14 species of ciliated protozoa in terms of the maximum rate of water cleared at low particle concentrations and of the maximum ingestion rate at high particle concentrations. The results, supported by data from the literature, show that ciliates which feed on larger particles (> 1–5μm)(More)
Published estimates of protozoan respiratory rates are reviewed with the object of clarifying their value in ecological studies. The data show a surprisingly large variance when similarly sized cells or individual species are compared. This is attributed to the range of physiological states in the cells concerned. The concept of basal metabolism has little(More)
The distribution patterns of four species of mud snails (Hydrobiidae) in a complex, estuarine environment are described. The species show habitat selection with respect to salinity but the tolerance ranges of the species overlap and it is shown that this factor alone cannot predict the distribution in the field. The found patterns show that the species are(More)
Metapopulations of macroscopic organisms tend to be geographically restricted, but free-living protists and other microbial eukaryotes present a different picture. Here we show that most organisms smaller than 1 mm occur worldwide wherever their required habitats are realised. This is a consequence of ubiquitous dispersal driven by huge population sizes,(More)
Most microorganisms are motile during at least part of their life cycle, because they need to find optimal conditions in a patchy world. The sheer volume of microorganisms in the biosphere means that their motile sensory behavior also contributes to the global transformation and cycling of matter. How microorganisms move and how they orient themselves using(More)