Evolutionary Physiology

Aggression is a common behavioral trait shared in many animals, including both vertebrates and invertebrates. However, the type and intensity of agonistic encounters and displays can vary widely both across and within species, resulting in complicated or subjective interpretations that create difficulties in developing theoretical models that can be widely applied. The need to easily and objectively identify quantifiable behaviors and their associated morphologies becomes especially important when attempting to decipher the neurological mechanisms underlying this complex behavior. Monoamines, neuropeptides, and pheromones have been implicated as important neuromodulators for agonistic displays in both invertebrates and vertebrates. Additionally, recent breakthroughs in insect research have revealed exciting proximate mechanisms important in aggression that may be broadly relevant, due to the relatively high conservation of these neurochemical systems across animal taxa. In this review, we present the latest research demonstrating the importance of monoamines, neuropeptides, and pheromones as neuromodulators for aggression across a variety of insect species. Additionally, we describe the stalk-eyed fly as a model system for studying aggression, which integrates physiological, morphological, and neurochemical approaches in exploring detailed mechanisms responsible for this common yet complex behavior. We conclude with our perspective on the most promising lines of future research aimed at understanding the proximate and ultimate mechanisms underlying aggressive behaviors.

The extent of changes in basic physiological and
demographic traits associated with reproduction was investigated in the highly cultivated haploid–diploid red alga,
Gracilaria chilensis. Sixty individuals bearing vegetative and
reproductive fronds collected in the natural population of
Niebla (39°52′S, 73°23′W), in Chile, were cultivated under
controlled culture conditions. Our results demonstrated that
vegetative fronds have a higher survival rate and a better
growth rate than reproductive ones irrespective of the type of
individual analyzed (male gametophyte, female gametophyte,
and tetrasporophyte). Moreover, the reproductive fronds clearly
showed a decrease in photosynthetic activity compared to nonreproductive ones. In males and tetrasporophytes, the photosynthetic reduction in reproductive individuals could be
explained by a physical effect of reproductive structure development as well as spores release, disrupting the continuity of
the photosynthetic cortical tissues. Translocation of photoassimilates from nearby vegetative tissue or the previous accumulation of photosynthetic products seems to be a prerequisite for reproductive structure development in this species. Altogether, these results document for the first time in G.
chilensis that reproduction has a strong physiological effect
on male, female, and tetrasporophyte fronds. This trade-off
between reproduction, growth, and survival suggest the existence of reproductive costs in the life history of G. chilensis.

Rossier BC, Baker ME, Studer RA. Physiol Rev 95: 297– 340, 2015; doi:10.1152/physrev.00011.2014.
Transcription and translation require a high concentration of potassium across the entire tree of life. The conservation of a high intracellular potassium was an absolute requirement for the evolution of life on Earth. This was achieved by the interplay of P- and V-ATPases that can set up electrochemical gradients across the cell membrane, an energetically costly process requiring the synthesis of ATP by F-ATPases. In animals, the control of an extracellular compartment was achieved by the emergence of multicellular organisms able to produce tight epithelial barriers creating a stable extracellular milieu. Finally, the adaptation to a terrestrian environment was achieved by the evolution of distinct regulatory pathways allowing salt and water conservation. In this review we emphasize the critical and dual role of Na+-K+-ATPase in the control of the ionic composition of the extracellular fluid and the renin-angiotensin-aldosterone system (RAAS) in salt and water conservation in vertebrates. The action of aldosterone on transepithelial sodium transport by activation of the epithelial sodium channel (ENaC) at the apical membrane and that of Na+-K+ATPase at the basolateral membrane may have evolved in lungfish before the emergence of tetrapods. Finally, we discuss the implication of RAAS in the origin of the present pandemia of hypertension and its associated cardiovascular diseases.

Mudskippers are amphibious fishes that have developed morphological and physiological adaptations to match their unique lifestyles. Here we perform whole-genome sequencing of four representative mudskippers to elucidate the molecular mechanisms underlying these adaptations. We discover an expansion of innate immune system genes in the mudskippers that may provide defence against terrestrial pathogens. Several genes of the ammonia excretion pathway in the gills have experienced positive selection, suggesting their important roles in mudskippers’ tolerance to environmental ammonia. Some vision-related genes are differentially lost or mutated, illustrating genomic changes associated with aerial vision. Transcriptomic analyses of mudskippers exposed to air highlight regulatory pathways that are up- or down-regulated in response to hypoxia. The present study provides a valuable resource for understanding the molecular mechanisms underlying water-to-land transition of vertebrates.

The extent of changes in basic physiological and demographic traits associated with reproduction was investigated in the highly cultivated haploid-diploid red alga, Gracilaria chilensis. Sixty individuals bearing vegetative and reproductive fronds collected in the natural population of Niebla (39°52′S, 73°23′W), in Chile, were cultivated under controlled culture conditions. Our results demonstrated that vegetative fronds have a higher survival rate and a better growth rate than reproductive ones irrespective of the type of individual analyzed (male gametophyte, female gametophyte, and tetrasporophyte). Moreover, the reproductive fronds clearly showed a decrease in photosynthetic activity compared to nonreproductive ones. In males and tetrasporophytes, the photosynthetic reduction in reproductive individuals could be explained by a physical effect of reproductive structure development as well as spores release, disrupting the continuity of the photosynthetic cortical tissues. Translocation of photoassimilates from nearby vegetative tissue or the previous accumulation of photosynthetic products seems to be a prerequisite for reproductive structure development in this species. Altogether, these results document for the first time in G. chilensis that reproduction has a strong physiological effect on male, female, and tetrasporophyte fronds. This trade-off between reproduction, growth, and survival suggest the existence of reproductive costs in the life history of G. chilensis.

The history of comparative and evolutionary physiology since the early XIX century is given; 2) The methods of evolutionary physiology are described; 3) Principles of the evolution of function are discussed at every level of physiological organization (cellular, functional units of the organ, the organ itself, functional systems) as they apply to the kidney and to the regulation of salt and water balance; and 4) General questions of evolutionary physiology covering physico-chemical factors in evolution of functions, the development of the integrity of an organism, the origin of physiological adaptation, the development of interconnection of physiological systems are discussed. comp biochem physiol 118A;1:63-79, 1997.