A DYNAMICAL THEORY OF HETEROCHRONY: TIME-SEQUENCING CHANGES IN ECOLOGY, DEVELOPMENT AND EVOLUTION

1993 ◽  
Vol 01 (04) ◽  
pp. 451-487 ◽  
Author(s):  
P. ANTONELLI ◽  
R. BRADBURY ◽  
V. KŘIVAN ◽  
H. SHIMADA
Keyword(s):  
Growth And Development ◽  
Present Theory ◽  
Dynamical Theory ◽  
Ecological Interactions ◽  
Projective Differential Geometry ◽  
Population Densities ◽  
Invertebrate Animals ◽  
Induced Changes ◽  
Natural Description ◽  
Development And Evolution

This work provides a foundation for a quantitative dynamical theory of heterochronic processes in the evolution of colonial invertebrate animals including Bryozoans, Siphonophores and Ants. These processes are environmentally induced changes in the time-sequencing of growth and development which can produce alterations in the morphotypes or castes within an individual colony. Motivation comes from Křivan’s theory of environmentally induced constraints on population densities for ecological interactions, but the present theory is second order with allometric production variables xi and population densities for morphotypes, Ni. We are able to unite ecological theory and the allometric form of the Wilson Ergonomic Theory via projective differential geometry and Wagner spaces which provide a natural description of environmentally induced time-sequencing changes altering the allometric curve of a species. Such changes define a model of heterochronic processes important in paleontology.

Glucocorticoid-induced changes in glucocorticoid receptor mRNA and protein expression in the human placenta as a potential factor for altering fetal growth and development

2017 ◽  
Vol 29 (5) ◽  
pp. 845 ◽  
Author(s):  
Svetlana Bivol ◽  
Suzzanne J. Owen ◽  
Roselyn B. Rose'Meyer
Keyword(s):  
Fetal Growth ◽  
Growth And Development ◽  
Glucocorticoid Receptors ◽  
Low Birthweight ◽  
Experimental Studies ◽  
Vital Role ◽  
The Body ◽  
Protein Levels ◽  
Organ Systems ◽  
Induced Changes

Glucocorticoids (GCs) control essential metabolic processes in virtually every cell in the body and play a vital role in the development of fetal tissues and organ systems. The biological actions of GCs are mediated via glucocorticoid receptors (GRs), the cytoplasmic transcription factors that regulate the transcription of genes involved in placental and fetal growth and development. Several experimental studies have demonstrated that fetal exposure to high maternal GC levels early in gestation is associated with adverse fetal outcomes, including low birthweight, intrauterine growth restriction and anatomical and structural abnormalities that may increase the risk of cardiovascular, metabolic and neuroendocrine disorders in adulthood. The response of the fetus to GCs is dependent on gender, with female fetuses becoming hypersensitive to changes in GC levels whereas male fetuses develop GC resistance in the environment of high maternal GCs. In this paper we review GR function and the physiological and pathological effects of GCs on fetal development. We propose that GC-induced changes in the placental structure and function, including alterations in the expression of GR mRNA and protein levels, may play role in inhibiting in utero fetal growth.

scholarly journals Behavioural mechanisms underlying parasite-mediated competition for refuges in a coral reef fish

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Graham E. Forrester ◽  
Erin Chille ◽  
Katie Nickles ◽  
Kiran Reed
Keyword(s):  
Coral Reef ◽  
Parasitic Copepod ◽  
Interactive Effects ◽  
Predatory Fish ◽  
Ecological Interactions ◽  
Host Manipulation ◽  
Predator Prey ◽  
Prey Interaction ◽  
Induced Changes ◽  
Host Behaviour

Abstract Parasites have been increasingly recognized as participants in indirect ecological interactions, including those mediated by parasite-induced changes to host behaviour (trait-mediated indirect interactions or TMIIs). In most documented examples, host behaviours altered by parasites increase susceptibility to predation because the predator is also a host (host-manipulation). Here, we test for a TMII in which a parasitic copepod modifies the predator-prey interaction between a small goby host and several larger predatory fish. Gobies compete for crevices in the reef to avoid predation and goby mortality increases more rapidly with increasing refuge shortage for parasitized gobies than for those free of parasites. We found interactive effects of refuge shortage and parasitism on two behaviours we predicted might be associated with parasite-mediated competition for refuges. First, as refuge-shortage increases, the rate of aggression among gobies increases and parasitism intensifies this interaction. Second, goby proximity to refuges increases as refuges become scarce, but parasitism nullifies this increase. In combination, these parasite-induced changes in behaviour may explain why parasitized gobies are poor competitors for refuges. Because the parasite is not trophically transmitted via host manipulation, these altered behaviours in parasitized gobies are likely coincidental to infection.

scholarly journals Effects of Nocturnal Soil Temperatures and Meloidogyne incognita Densities on Cotton Seedling Growth and the Interaction with Thielaviopsis basicola

Plant Disease ◽  
2006 ◽  
Vol 90 (4) ◽  
pp. 519-522 ◽  
Author(s):  
W. S. Monfort ◽  
T. L. Kirkpatrick ◽  
C. S. Rothrock
Keyword(s):  
Plant Height ◽  
Meloidogyne Incognita ◽  
Growth And Development ◽  
Growing Season ◽  
Thielaviopsis Basicola ◽  
Plant Growth And Development ◽  
Population Densities ◽  
Pathogen Population ◽  
Growing Seasons ◽  
Soil Temperatures

Controlled studies were conducted to evaluate the effects of soil temperatures typical of field conditions during the first 6 weeks of the growing season in Arkansas and different population densities of Meloidogyne incognita on damage to cotton (Gossypium hirsutum) seedlings associated with the interaction between M. incognita and Thielaviopsis basicola. Treatments consisted of varying nocturnal temperatures that approximated the temperatures that occurred during the 2001, 2002, and 2003 growing seasons in southeastern Arkansas. Nocturnal temperatures in the study were as follows: high, the first week at 15°C, followed by 3 weeks at 17°C, 1 week at 21°C, and 1 week at 17°C (approximating the 2002 season); medium, 3 weeks at 15°C and 3 weeks at 19°C (approximating the 2003 season); and low, 1 week at 15°C, 1 week at 13°C, 2 weeks at 17°C, 1 week at 15°C, and 1 week at 17°C (approximating the 2001 season). Pathogen population densities were either 0 or 100 chlamydospores of T. basicola per gram of soil and 0, 2,000, 4,000, or 8,000 eggs of M. incognita per 500 cm3of soil. Plant height and fresh top weight increased with an increase in nocturnal temperature across treatments. There were significant reductions in plant growth and development with T. basicola, but not with M. incognita, at these nocturnal temperatures, but decreased plant height and weight were seen where both pathogens were present in comparison with either pathogen alone. Trends of increased disease associated with T. basicola were observed with increasing inoculum rates of M. incognita, indicating that the interaction between T. basicola and M. incognita occurs even at soil temperatures below the minimum temperature reported as necessary for damage from M. incognita.

scholarly journals The visual ecology of selective predation: Are unhealthy hosts less stealthy hosts?

2021 ◽  
Author(s):  
Nina Wale ◽  
Rebecca Fuller ◽  
Sonke Johnsen ◽  
McKenna Turrill ◽  
Meghan Duffy
Keyword(s):  
Disease Transmission ◽  
Ecological Interactions ◽  
Water Color ◽  
Selective Predation ◽  
Chromatic Contrast ◽  
Visual Models ◽  
Pasteuria Ramosa ◽  
Mechanistic Basis ◽  
Induced Changes ◽  
Infected Prey

Predators can strongly influence disease transmission and evolution, particularly when they prey selectively on infected hosts. Although selective predation has been observed in numerous systems, why predators select infected prey remains poorly understood. Here, we use a model of predator vision to test a longstanding hypothesis as to the mechanistic basis of selective predation in a Daphnia-microparasite system, which serves as a model for the ecology and evolution of infectious diseases. Bluegill sunfish feed selectively on Daphnia with a variety of parasites, particularly in water uncolored by dissolved organic carbon. The leading hypothesis for selective predation in this system is that infection-induced changes in the appearance of Daphnia render them more visible to bluegill. Rigorously evaluating this hypothesis requires that we quantify the effect of infection on the visibility of prey from the predator’s perspective, rather than our own. Using a model of the bluegill visual system, we show that the three common parasites, Metschnikowia bicuspidata, Pasteuria ramosa and Spirobacillus cienkowskii, increase the opacity of Daphnia, rendering infected Daphnia darker against the background of downwelling light. As a result of this increased brightness contrast, bluegill can see infected Daphnia at greater distances than uninfected Daphnia – between 19-33% further, depending on the parasite. Pasteuria and Spirobacillus also increase the chromatic contrast of Daphnia. Contrary to expectations, the visibility Daphnia was not strongly impacted by water color in our model. Our work generates hypotheses about which parasites are most likely affected by selective predation in this important model system and establishes visual models as a valuable tool for understanding ecological interactions that impact disease transmission.

Dynamical theory of electron diffraction for the electron microscopic image of crystal lattices II. Image of superposed crystals (moiré pattern)

1961 ◽  
Vol 253 (1033) ◽  
pp. 490-516 ◽  
Keyword(s):  
Electron Diffraction ◽  
Present Theory ◽  
Dynamical Theory ◽  
Bragg Angle ◽  
Electron Microscopic ◽  
Microscopic Images ◽  
Electron Microscopic Image ◽  
Moire Patterns ◽  
Lattice Images ◽  
Moiré Patterns

The dynamical theory of electron diffraction is applied to the interpretation of electron microscopic images of moire patterns. Two cases often observed are treated. One is the case where two plate-shaped crystals are superposed closely without a vacuum layer between them and another is the case where two crystals are superposed with a vacuum layer between them. Resolved lattice images of two superposed crystals are also interpreted. The intensity profiles of the images vary with the thicknesses of the crystals and vacuum layer and with the deviation from the Bragg angle. The shifts of the fringes and anomalies of the contrast which are expected from the present theory were observed in the electron microscopic images of moire patterns of cupric sulphide, palladiumgold and platinum-phthalocyanine. The relation between moiré patterns and crystal structure is also discussed.

Measuring Tourism Carrying Capacity

2019 ◽  
pp. 42-67
Author(s):  
Manju S. Raju ◽  
Nayana Udayashankar ◽  
Swathi Seshadri
Keyword(s):  
Economic Growth ◽  
Human Activity ◽  
Carrying Capacity ◽  
Growth And Development ◽  
Local Communities ◽  
Indian Context ◽  
Planning And Management ◽  
Employment Generation ◽  
Suitable Framework ◽  
Induced Changes

Tourism is used as an engine for economic growth and is considered a source of income and employment generation. However, like any other human activity, it causes changes to its surroundings. Planners often plan for growth and development of tourism, ignoring the rights of local communities, who are custodians of the resources and are dependent on them. Local communities are most harshly affected by tourism-induced changes. The concept of tourism carrying capacity tries to identify how much change is acceptable change, which would then guide planning and management of tourism in the area. In this chapter, the authors explore the different methodologies that have been developed for assessment of tourism carrying capacity and suggest a suitable framework for the Indian context.

scholarly journals CO<sub>2</sub> effects on diatoms: a synthesis of more than a decade of ocean acidification experiments with natural communities

Ocean Science ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 1159-1175 ◽  
Author(s):  
Lennart Thomas Bach ◽  
Jan Taucher
Keyword(s):  
Ocean Acidification ◽  
Size Structure ◽  
Ecological Interactions ◽  
High Co2 ◽  
Marine Food Web ◽  
Diatom Communities ◽  
Carbon Pump ◽  
Marine Food ◽  
Taxonomic Affiliation ◽  
Induced Changes

Abstract. Diatoms account for up to 50 % of marine primary production and are considered to be key players in the biological carbon pump. Ocean acidification (OA) is expected to affect diatoms primarily by changing the availability of CO2 as a substrate for photosynthesis or through altered ecological interactions within the marine food web. Yet, there is little consensus how entire diatom communities will respond to increasing CO2. To address this question, we synthesized the literature from over a decade of OA-experiments with natural diatom communities to uncover the following: (1) if and how bulk diatom communities respond to elevated CO2 with respect to abundance or biomass and (2) if shifts within the diatom communities could be expected and how they are expressed with respect to taxonomic affiliation and size structure. We found that bulk diatom communities responded to high CO2 in ∼60 % of the experiments and in this case more often positively (56 %) than negatively (32 %) (12 % did not report the direction of change). Shifts among different diatom species were observed in 65 % of the experiments. Our synthesis supports the hypothesis that high CO2 particularly favours larger species as 12 out of 13 experiments which investigated cell size found a shift towards larger species. Unravelling winners and losers with respect to taxonomic affiliation was difficult due to a limited database. The OA-induced changes in diatom competitiveness and assemblage structure may alter key ecosystem services due to the pivotal role diatoms play in trophic transfer and biogeochemical cycles.

Δ9-Tetrahydrocannabinol-induced changes in prenatal growth and development of mice

1975 ◽  
Vol 33 (2) ◽  
pp. 333-340 ◽  
Author(s):  
Bernardo Mantilla-Plata ◽  
Geralyn L. Clewe ◽  
Raymond D. Harbison
Keyword(s):  
Growth And Development ◽  
Prenatal Growth ◽  
Induced Changes
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