Search results for "Evolutionary dynamic"
showing 10 items of 59 documents
Pulsed-Resource Dynamics Constrain the Evolution of Predator-Prey Interactions
2011
Although temporal variability in the physical environment plays a major role in population fluctuations, little is known about how it drives the ecological and evolutionary dynamics of species interactions. We studied experimentally how extrinsic resource pulses affect evolutionary and ecological dynamics between the prey bacterium Serratia marcescens and the predatory protozoan Tetrahymena thermophila. Predation increased the frequency of defensive, nonpigmented prey types, which bore competitive costs in terms of reduced maximum growth rate, most in a constant-resource environment. Furthermore, the predator densities of the pulsed-resource environment regularly fluctuated above and below …
Taxonomic flux as a measure of evolutionary turnover
2021
We introduce a new metric, "taxonomic flux", to quantify evolutionary trends both within and across taxonomic boundaries. This metric is normalized, which reduces the effect of sample size disparity between biologic groups and time intervals. Furthermore, this methodology considers stratigraphic range data as a whole, and measures relative growth or decline of diversity values as they deviate from system stability. Such trends may yield key information relating to evolutionary processes and forcing functions, especially if these trends are correlative within particular taxa or niche occupancy. Thus far, scientists and researchers have been stymied by absolute values derived from unequal dat…
Social transmission in the wild can reduce predation pressure on novel prey signals
2021
Funder: Suomen Kulttuurirahasto (Finnish Cultural Foundation); doi: https://doi.org/10.13039/501100003125
Increasing growth temperature alters the within-host competition of viral strains and influences virus genetic variation
2020
AbstractThe emergence of viral diseases in plant crops hamper the sustainability of food production, and this may be boosted by global warming. Concurrently, mixed viral infections are becoming common in plants, of which epidemiology are unpredictable due to within-host virus-virus interactions. However, the extent in which the combined effect of variations in the abiotic components of the plant ecological niche (e.g., temperature) and the prevalence of mixed infections (i.e., within-host interactions among viruses) affect the evolutionary dynamics of viral populations is not well understood. Here, we explore the interplay between ecological and evolutionary factors during viral infections,…
Time and energy constraints: reply to Nolet and Klaassen (2005)
2006
Jonathan M. Jeschke, (jonathan.jeschke@gmx.net), Laboratory of Ecological and Evolutionary Dynamics, Dept of Biological and Environmental Sciences, Univ. of Helsinki, P.O. Box 65, FI-00014 Helsinki, Finland; and Evolutionary Ecology Unit, Dept of Biological and Environmental Science, Univ. of Jyvaskyla, P.O. Box 35, FI-40014 Jyvaskyla, Finland. Michael Kopp, Dept Biologie II, Univ. of Munich, Grosshaderner Str. 2, DE-82152 Planegg-Martinsried, Germany. Ralph Tollrian, Biological Sciences, Ruhr-Universitat Bochum, Universitatsstr. 150, DE-44780 Bochum, Germany.
The Power of Weak Ties: Leveraging Weak Ties in the Evolution of Alliance Networks
2014
In today's knowledge-based economy, the sources of competitive advantage lie more and more in webs of relationships among a variety of firms that over time originate the emergence of interfirm strategic networks. The paper aims to shed light on the role of complex leadership exerted by network central firms in promoting and supporting network interactions and the ensuing processes of knowledge and resource transfer and diffusion. Processes on which the network-based sources of competitive advantage are rooted. In the attempt to make the proposed contribution, on the one hand, we underscore the emergent nature of network interactions stemming from the self-organizing behaviors that spontaneo…
Genomic conflicts and sexual antagonism in human health: Insights from oxytocin and testosterone
2015
We review the hypothesized and observed effects of two of the major forms of genomic conflicts, genomic imprinting and sexual antagonism, on human health. We focus on phenotypes mediated by peptide and steroid hormones (especially oxytocin and testosterone) because such hormones centrally mediate patterns of physical and behavioral resource allocation that underlie both forms of conflict. In early development, a suite of imprinted genes modulates the human oxytocinergic system as predicted from theory, with paternally inherited gene expression associated with higher oxytocin production, and increased solicitation to mothers by infants. This system is predicted to impact health through the i…
A universal definition of life: autonomy and open-ended evolution.
2004
Life is a complex phenomenon that not only requires individual self-producing and self- sustaining systems but also a historical-collective organization of those individual systems, which brings about characteristic evolutionary dynamics. On these lines, we propose to define univer- sally living beings as autonomous systems with open-ended evolution capacities, and we claim that all such systems must have a semi-permeable active boundary (membrane), an energy trans- duction apparatus (set of energy currencies) and, at least, two types of functionally interdependent macromolecular components (catalysts and records). The latter is required to articulate a 'phenotype- genotype' decoupling that…
Interactions among bacterial strains and fluke genotypes shape virulence of co-infection.
2015
Most studies of virulence of infection focus on pairwise host–parasite interactions. However, hosts are almost universally co-infected by several parasite strains and/or genotypes of the same or different species. While theory predicts that co-infection favours more virulent parasite genotypes through intensified competition for host resources, knowledge of the effects of genotype by genotype (G × G) interactions between unrelated parasite species on virulence of co-infection is limited. Here, we tested such a relationship by challenging rainbow trout with replicated bacterial strains and fluke genotypes both singly and in all possible pairwise combinations. We found that virulence (host mo…