Physiological and Biochemical Zoology 

About: Physiological and Biochemical Zoology is an academic journal published by University of Chicago Press. The journal publishes majorly in the area(s): Population & Basal metabolic rate. It has an ISSN identifier of 1522-2152. Over the lifetime, 4778 publications have been published receiving 182395 citations. The journal is also known as: PBZ.

Why Not to Do Two-Species Comparative Studies: Limitations on Inferring Adaptation

Abstract: Interspecific comparison is a common approach in physiological ecology, comparative physiology, and biochemistry, and in such related fields as ';,functional morphology and ethology (Hochachka and Somero 1984; Feder et al. 1987; Brooks and McLennan 1991; Harvey and Page1 1991). In their most basic form, comparisons are used simply to identify which characteristics differ among species. Sometimes the goal is to identify alternative physiological or biomechanical mechanisms (multiple solutions; see, e.g., Bartholomew 1987) that have achieved a similar functional endpoint (e.g., longer legs vs. faster muscles, either of which may cause higher maximal sprinting abilities), or perhaps to identify new "models" in which to study particular phenomena (see, e.g., Faraci, Kilgore, and Fedde 1984; Kellogg and Shaffer 1993). Interspecific comparisons are also used frequently to elucidate the endpoint and/or the process of evolutionary adaptation, that is, genetic changes in response to natural selection (reviews in Harvey and Page1 1991; Miles and Dunham 1993; Losos and Miles 1994). Specifically, interspecific correlations between some aspect(s) of the phenotype (e.g., low rates of evaporative water loss) and some aspect(s) of the environment (e.g., heat and aridity) are taken to indicate that past and/or present natural selection acting

Factors That Influence Assimilation Rates and Fractionation of Nitrogen and Carbon Stable Isotopes in Avian Blood and Feathers

Abstract: By switching great skuas Catharacta skua from one isotopically distinct diet to another, we measured diet-tissue discrimination factors and tested the assumption that dietary nitrogen and carbon isotope signatures are incorporated into blood and feathers at similar rates. We also examined the effects of metabolic rate and looked for evidence of isotopic routing. We found that blood delta(15)N and delta(13)C signatures altered after the diet switch at similar rates (14.4 d and 15.7 d, respectively). Qualitative analyses imply that the same was true with feathers. Mass balance calculations suggest that only a small amount of lipid is likely to be involved in the synthesis of blood and feathers. Differences in diet-tissue discrimination factors before and after the diet switch may mean that toward the end of the experiment, some of the nutrients for blood synthesis had been coming from stores. Repeated measures mixed models provided evidence that increases in metabolic rate might accelerate fractional turnover rates in blood. There is a need for more laboratory-based experimental isotope studies in order to address further questions that this study has raised.

Hibernation versus Daily Torpor in Mammals and Birds: Physiological Variables and Classification of Torpor Patterns

Abstract: Hibernation and daily torpor are usually considered to be two distinct patterns of heterothermia. In the present comparison we evaluated (1) whether physiological variables of torpor from 104 avian and mammalian species warrant the distinction between hibernation and daily torpor as two different states of torpor and (2), if so, whether this distinction is best based on maximum torpor bout duration, minimum body temperature ($T_{b}$), minimum metabolic rate during torpor, or the reduction of metabolic rate expressed as percentage of basal metabolism (BMR). Initially, animals were grouped into species displaying either daily torpor or prolonged torpor (hibernation) according to observations from original sources. Both cluster and discriminant analyses supported this division, and further analyses were therefore based on these two groups. Frequency distributions for all tvariables tested differed significantly (P < 0.001) between daily torpor and hibernation. The average maximum torpor bout duration was 355...

The Misuse of Ratios, Indices, and Percentages in Ecophysiological Research

Abstract: Ratios are used by many ecological physiologists to adjust (or scale) data that vary allometrically with body size. We use two sets of real data from our laboratory to illustrate in detail how investigators may be misled by statistical analyses performed on such ratios. The first example concerns the use of ratios to increase the precision of data gathered in planned experiments where body size varies within experimental groups but not among them. The second example concerns the use of ratios to remove confounding effects of body size from studies where animals in one group are larger than those in other groups, as a result either of the experimental manipulation itself or of the procedure for assigning animals to treatment groups. In both of these examples, statistical analyses of ratios lead to conclusions that are inconsistent with impressions gained from visual examinations of data displayed in bivariate plots. In comparison, analyses of covariance lead to conclusions that agree with impressions gaine...

Climatic Adaptation in Arctic and Tropical Poikilotherms

Abstract: in response to white and monochromatic lights following differential adaptation of the eyes to various light stimuli. 3. The ability of Drosophila to discriminate among wave lengths is lost with a reduction of intensity to a level previously shown to involve a photoreceptive mechanism different from that shown to operate in bright light. 4. The color-differentiating capacity appears, therefore, to be associated with a high-illumination receptive mechanism (photopic) in a manner paralleling that in the vertebrate eye. 5. The dim-light receptive mechanism (scotopic) lacks color-differentiating capacity. 6. The results indicate that there are