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Biomedical subjects

W A Calder

Publications and source records attributed to W A Calder.

At least 19 recordsLinked to original sources
PubMed1985

The comparative biology of longevity and lifetime energetics.

The relationships between longevity and cumulative energy metabolism in homeothermic vertebrates are explored interspecifically as allometric functions, and intraspecifically in terms of metabolic extension, through restriction of energy intake, hibernation, and torpor. A new equation for marsupial longevity is presented. The first evidence of age-dependent mortality in a population of hummingbirds is shown. Hummingbirds are seen to be model subjects for the study of longevity in nature.

Animals↗
PubMed1983

Body size, mortality, and longevity.

The body-size dependent relationships of mortality and longevity are examined for birds and eutherian mammals. Differences between mass exponents for maximum recorded longevity and survival times for fractions of original adult populations confirm the age-dependence of mortality in both classes and a size-dependency of population-age distribution. The potential number of offspring produced by a surviving fraction of a mammalian population appears to be a size-independent ecological constant. Social structure would be more likely in larger animals since greater continuity would be provided when a higher proportion of the population consisted of senior, experienced animals, as described by the ratio of time for survival of 1 in 1000 to maximum potential lifespan: t0.001/tmax = 0.91 m0.32/2.94 m0.20 = 0.31 m0.12, that is, the expected lifespan approaches the maximum as size increases.

Animals↗
PubMed1983

Scaling of osmotic regulation in mammals and birds.

Allometric equations provide a means of summarizing and relating the components of renal structure and function in water balance and osmotic regulation. These summary equations also serve as base lines for evaluating adaptations to stressful environments and for comparisons of kidney designs and osmotic strategies of ureotelic mammals and uricotelic birds. Many of the functions can be quantitatively related to the M3/4 scaling of metabolic rates.

Animals↗