Interannual Variability of Dinophysis acuminata and Protoceratium reticulatum in a Chilean Fjord: Insights from the Realized Niche Analysis

Here, we present the interannual distribution of Dinophysis acuminata and Protoceratium reticulatum over a 10-year period in the Reloncaví Fjord, a highly stratified fjord in southern Chile. A realized subniche approach based on the Within Outlying Mean Index (WitOMI) was used to decompose the species’ realized niche into realized subniches (found within subsets of environmental conditions). The interannual distribution of both D. acuminata and P. reticulatum summer blooms was strongly influenced by climatological regional events, i.e., El Niño Southern Oscillation (ENSO) and the Southern Annual Mode (SAM). The two species showed distinct niche preferences, with blooms of D. acuminata occurring under La Niña conditions (cold years) and low river streamflow whereas P. reticulatum blooms were observed in years of El Niño conditions and positive SAM phase. The biological constraint exerted on the species was further estimated based on the difference between the existing fundamental subniche and the realized subniche. The observed patterns suggested that D. acuminata was subject to strong biological constraint during the studied period, probably as a result of low cell densities of its putative prey (the mixotrophic ciliate Mesodinium cf. rubrum) usually observed in the studied area.

Seeking the Roots of Health and Action in Biological Autonomy

The roots of biological autonomy and health are the same. Goals make biology distinct as a science, for without goals, we cannot understand why a biological trait exists. Organisms are autonomous biological entities because they define what is inside and what is outside themselves. This boundary between inner and outer gives the organism a self-referential purpose. Claude Bernard made experimental physiology possible with his concept of the internal environment, but he was unable to explain how the organism established the boundary between itself and its environment. Hence, homeostasis portrays the organism as reactive not active. Autopoiesis is an alternative defining characteristic of living beings. It generates biological autonomy through additional biological constraint on chemical processes, not through a special vital force. Healthy organisms can construct their own environmental niche. For humans, this niche is social and is constructed with a social physiology. Both exercise and education increase health by increasing capacity for niche construction.

Hedonics and the “Selective Associations” Biological Constraint on Learning

Research concerned with visual dominance in appetitive and auditory dominance in aversive learning situations (selective associations) is reviewed. The present analysis stresses that the dominant sensory modality of stimulus control is determined by the relative affective valence acquired by a compound auditory-visual stimulus through reinforcement contingencies, rather than by whether the primary reinforcer is appetitive or aversive. For example, take two groups of rats or pigeons on exactly the same shock-avoidance contingency in a tone-light compound (TL), but with different contingencies when the compound is absent (TL). Responding came predominantly under (1) auditory control when conditions in TL were hedonically negative relative to those in (TL), and (2) visual control when conditions in (TL) made TL relatively positive. Selective associations here are a product of the relative hedonic state, positive or negative, established to the auditory-visual compound. Therefore, this constraint reflects a high level of functioning by a hedonic comparator -- with TL’s hedonic value contextually determined by the totality of the events encountered, and reinforcement contingencies, operating in its world. The physical particulars of the reinforcer in TL here, shock avoidance, clearly were not responsible for the hedonic psychological state TL produced. Weiss, Panlilio, and Schindler (1993a, 1993b) went on to show that these proclivities can be (1) reversed, and (2) overcome by a blocking design when the biologically-contingency-disadvantaged stimulus is first pretrained on its own. Relating the “hedonic model” to evolution is speculative. But, the hedonic model is scientifically integrative by relating this biological constraint to a variety of phenomena that involve incentive-motivational states. These include choice behavior, conditioned preference, behavioral contrast and appetitive-aversive interactions.

Biology is only part of the story …

The origins and development of human cognition constitute one of the most interesting questions to which archaeology can contribute today. In this paper, we do so by presenting an overview of the evolution of artefact technology from the maker's point of view, and linking that development to some hypotheses on the evolution of human cognitive capacity. Our main hypothesis is that these data indicate that, in the first part of the trajectory, biological limits to cognitive capacity were a major constraint that limited technology, whereas, in the second part, this biological constraint seems to have been lifted and others have come in its place. But these are modifiable by means of conceptual frameworks that facilitate concept innovation and therefore enable learning, thereby permitting acceleration in the pace of change in technology. In the last part of the paper, we elaborate on some of the consequences of that acceleration.

THE USE OF THE ABOAV-WEAIRE LAW TO ESTIMATE A BIOLOGICAL CONSTRAINT

Developmental processes may impose limitations and directionality in the mode of development of a particular structure. The main problem is to determine the nature and the respective effects of physical and biological constraints in the development of organisms. The Aboav-Weaire law is a semi-empirical law developed to explain the topological structure of physical materials. In the present paper, we make a formal analysis of the quantitative relationships between physical and biological constraints in biological structures by using the inflorescence of the Araceae as a case study. The Aboav-Weaire law permits to obtain a quantitative estimate of the biological constraint acting on the inflorescences of this family. In the case of the Araceae, the empirical curve presents a constant deviation with respect to the Aboav-Weaire law. This deviation is due to the presence of a biological constraint as opposed to a physical constraint. The biological constraint tends to decrease the variance of the number of sides while it is the inverse situation for the physical constraint. The results obtained using the Araceae model can be used to study the interrelationships between biological and physical constraints in any organism or biological structure.

Response to superovulation in Scottish Blackface ewes during seasonal anoestrus

A major limitation to the success of genetic improvement programmes using multiple ovulation and embryo transfer is the failure to generate sufficient viable embryos per donor ewe to maintain selection intensities and sustain a low generation interval. Seasonal anoestrus imposes a biological constraint on embryo production in many breeds of sheep. The objective of this study was to investigate the response to superovulation during seasonal anoestrus (April - May) in Scottish Blackface ewes.

Response to superovulation in Scottish Blackface ewes during seasonal anoestrus

A major limitation to the success of genetic improvement programmes using multiple ovulation and embryo transfer is the failure to generate sufficient viable embryos per donor ewe to maintain selection intensities and sustain a low generation interval. Seasonal anoestrus imposes a biological constraint on embryo production in many breeds of sheep. The objective of this study was to investigate the response to superovulation during seasonal anoestrus (April - May) in Scottish Blackface ewes.