Comparative Population Dynamics of Daphnia rosea and Holopedium gibberum in Four Oligotrophic Lakes

1990 ◽  
Vol 47 (2) ◽  
pp. 401-409 ◽  
Author(s):  
Carl J. Walters ◽  
Donald C. E. Robinson ◽  
Thomas G. Northcote
Keyword(s):  
Environmental Factors ◽  
Life Histories ◽  
Mortality Rates ◽  
Adult Mortality ◽  
Seasonal Abundance ◽  
Population Increase ◽  
Abundance Patterns ◽  
History Of ◽  
Daphnia Rosea ◽  
Comparative Population

Seasonal abundance patterns of Daphnia rosea and Holopedium gibberum showed great variability over the period 1974–83 in four coastal montane lakes of British Columbia. Though the lakes differed considerably in size, depth, and history of experimental disturbance (fish introductions, fertilization, plankton harvesting}, these differences apparently had much less influence on seasonal abundance patterns than did interannual variation in environmental factors shared by all the lakes. Spring rates of population increase differed strongly among years and were positively correlated between the two species. The timing and magnitude of summer population maxima also differed significantly among years, but were not correlated between the species. Adult mortality rates tended to increase through each season for both species, but showed no clear correlations either between the species or between years. Annual differences in growth and mortality rates and peak abundances were not associated with any obvious differences in environmental factors (insolation, rainfall, water temperature). There was no evidence of direct competition between the species, in terms of negative correlations in abundance. This is surprising in view of their similar life histories and feeding ecologies.

Can commercial fishing cause evolution? Answers from guppies (Poecilia reticulata)

2005 ◽  
Vol 62 (4) ◽  
pp. 791-801 ◽  
Author(s):  
David N Reznick ◽  
Cameron K Ghalambor
Keyword(s):  
Life History ◽  
Body Size ◽  
Life Histories ◽  
Life History Theory ◽  
Poecilia Reticulata ◽  
Mortality Rates ◽  
Adult Mortality ◽  
Commercial Fisheries ◽  
Commercial Fishing ◽  
Rate Of Evolution

Life history theory predicts that high adult mortality rates select for earlier maturity and increased reproduction. If such evolution occurs in response to the commercial exploitation of natural fish populations, then the correlated reduction in body size would reduce the yield of the fishery. Earlier maturity and reduced body size are seen in commercially exploited populations. Here, we compare the life histories of natural populations of guppies (Poecilia reticulata) from Trinidad that live in either high- or low-predation environments, which serve as surrogates for the presence or absence of commercial fishing. We can quantify mortality rate and life history variables, including age and size at maturity, in the laboratory and in nature. We have manipulated mortality rates in nature and measured the rate of evolution. High mortality selects for earlier maturity at a smaller size, as observed in commercial fisheries and as predicted by theory. Furthermore, the nature and magnitude of predator-induced mortality are comparable to those caused by commercial fishing. The rate of evolution in guppies predicts similar evolution in commercial fisheries on a time scale of decades. These attributes support arguments that humans, like predators, have acted as an agent of selection when exploiting populations of fish.

Microtine population dynamics in a predictable environment

1986 ◽  
Vol 64 (3) ◽  
pp. 785-792 ◽  
Author(s):  
Norman C. Negus ◽  
Patricia J. Berger ◽  
Bruce W. Brown
Keyword(s):  
Population Dynamics ◽  
Life Histories ◽  
Large Scale ◽  
Food Resource ◽  
Population Increase ◽  
Strongly Correlated ◽  
Environmental Regimes ◽  
History Of ◽  
Overwintering Survival ◽  
Fluctuating Populations

A noncycling population of Microtus montanus was studied for 8 years in a marsh community in Utah. Seasonal climatic and vegetational regimes were very similar each year. The food resource for voles in this habitat was almost solely salt grass (Distichlis stricta). Each year, salt grass began sprouting in late February and, several weeks later, most of the females were pregnant with their first litters. By August of each year, the salt grass had flowered, fruited, and was senescing; likewise, breeding had ceased by the end of August. Each year, four cohorts of young were produced between April and late August. Analysis of cohort life histories revealed that cohorts I and II matured rapidly and reproduced later in the same season. Cohort III animals grew very slowly, overwintered as subadults, and formed the primary breeding stock the following spring. Overwintering survival of cohort III animals was much higher than that of cohorts I and II. By the end of the breeding season each year, densities ranged between 150 and 225 animals/acre (1 acre = 0.405 ha). Densities at the end of winter varied between 50 and 120 animals/acre. The rate of population increase from April to August each year was virtually identical. Thus, the August densities were very strongly correlated with each preceding April density. The predictable seasonal phenology and uniform timing of cohort production each year seems to explain the yearly attainment of high density. Comparison of these data with studies of fluctuating populations of M. montanus in montane environments leads to the conclusion that the unique life history of each microtine cohort coupled with unpredictable environmental regimes may generate large-scale density oscillations. If this concept is valid, then microtine population dynamics are not cyclic at all, but rather pseudoperiodic.

Effect of Environmental Factors on the Frequency of Fatigued Pigs and Mortality Rates at a Commercial Abattoir

2008 ◽  
Author(s):  
Robert Fitzgerald ◽  
Kenneth J. Stalder ◽  
Neal Matthews ◽  
Collette Schultz-Kaster ◽  
Anna K. Johnson
Keyword(s):  
Environmental Factors ◽  
Mortality Rates

scholarly journals Correlation of Circular RNA hsa_circ_0001946, hsa_circ_0125589, and Environmental Factors With Hypertension

2020 ◽  
Vol 33 (11) ◽  
pp. 1047-1047
Author(s):  
Wan-yue Liu ◽  
Yi Sun ◽  
Shu-na Huang ◽  
Yu-zhen Lin ◽  
Hong-yan Guo ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Peripheral Blood ◽  
Circular Rna ◽  
Peripheral Blood Lymphocytes ◽  
Normal Weight ◽  
Circular Rnas ◽  
Blood Leukocytes ◽  
Crossover Analysis ◽  
History Of ◽  
The Relationship

Abstract Background To investigate the main environmental factors of hypertension and the relationship between hypertension and circular RNAs in peripheral blood lymphocytes. Methods This was a case–control study. A total of 681 hypertension patients and 485 subjects without hypertension were recruited between April 2017 and October 2018. All participations completed the questionnaire investigation, physical examination, and laboratory detection. Quantitative real-time polymerase chain reaction was used to analyze circRNAs (hsa_circ_0001946 and hsa_circ_0125589) in peripheral blood leukocytes in 84 hypertensives and 84 controls. Multivariate logistic regression and crossover analysis were used to analyze the interaction and association between environmental factors and circRNAs in hypertension. Results After adjusted by gender, age and marital status, overweight/obesity (odds ratio (OR) = 1.66, 95% confidence interval (CI) 1.24–2.22), abdominal obesity (OR = 2.17, 95% CI 1.54–3.04), anxiety (OR = 2.15, 95% CI 1.41–3.28), family history of hypertension (OR = 4.26, 95% CI 3.18–5.70), and higher levels of hsa_circ_0001946 (OR = 4.13, 95% CI 1.85–9.21) were risk factors for hypertension, while levels of hsa_circ_0125589 were not associated with hypertension. Crossover analysis showed that the risk of hypertension was 13.12 times higher (95% CI 3.89–44.23) in overweight subjects with high hsa_circ_0001946 levels compared with normal weight subjects with low hsa_circ_0001946 levels. Further, the risk of hypertension was 17.78 times higher (95% CI 1.88–168.61) in subjects with anxiety and high hsa_circ_0001946 levels. Conclusions Hypertension is the result of both environmental factors and genetic factors. Higher hsa_circ_0001946 levels, overweight and anxiety may increase the risk of hypertension, while hsa_circ_0125589 levels are not related to hypertension.

A comparative study of the life histories of Nematodirus battus and N. filicollis, nematode parasites of sheep

Parasitology ◽  
1959 ◽  
Vol 49 (3-4) ◽  
pp. 374-386 ◽  
Author(s):  
R. J. Thomas
Keyword(s):  
Life History ◽  
Intestinal Mucosa ◽  
Related Species ◽  
Life Histories ◽  
Basic Pattern ◽  
Culture Methods ◽  
Closely Related Species ◽  
Nematode Parasites ◽  
History Of ◽  
Comparative Description

1. The life history of N. battus is described, and a comparative description of the life history of N. filicollis is given.2. The life histories of these two species are compared with those of N. spathiger and N. helvetianus, two closely related species, and are shown to follow the same basic pattern, with minor variations in timing which appear to be specific in nature, and not related to differences in culture methods or host species.3. The pathogenesis of Nematodirus species is discussed and related to the migration of larvae into the intestinal mucosa during development.

III.—The Life-history and Cytology of Didymium nigripes Fr.

1932 ◽  
Vol 57 (1) ◽  
pp. 93-142 ◽  
Author(s):  
Elsie J. Cadman
Keyword(s):  
Life History ◽  
Life Histories ◽  
Important Research ◽  
Great Work ◽  
Animal Kingdom ◽  
History Of ◽  
Natural Groups

Since 1860, in which year De Bary published his great work Die Mycetozoen, the investigation of the life-history of members of the Mycetozoa has aroused a considerable amount of interest, and a great deal of important research has been carried out in this connection. The group of organisms is particularly interesting, because it lies on the borderline between plant and animal kingdoms, and it is very possible that a detailed investigation of several species of the Mycetozoa might be of considerable assistance in elucidating certain obscure points in the life-histories of higher members of both the great natural groups. The term “Mycetozoa,” which we owe to De Bary, will be used throughout in preference to the older term “Myxogastres” invented by Fries (32, p. 2), and that of “Myxomycetes” first employed by Link (32, p. 2). “Mycetozoon,” or “fungus-like animal,” is a very appropriate description of a member of the group, since during part of its life-history it exhibits distinctly animal-like characters, and the individuals move rapidly by means of flagella, whilst later, during the development of the sporangium, a plant-like form is assumed. The combination of plant and animal characters has given rise to much discussion as to the position of the Mycetozoa in plant or animal kingdom, and the group has been claimed by both zoologists and botanists.

A Cultural History of Education in the Modern Age

2020 ◽  
Keyword(s):  
Cultural History ◽  
Life Histories ◽  
History Of Education ◽  
Political Transformation ◽  
Modern Age ◽  
History Of ◽  
Children And Childhood ◽  
Essential Resource ◽  
Literature Culture ◽  
The Many

The twentieth century brought profound and far-reaching changes to education systems globally in response to significant social, economic, and political transformation. This volume draws together work from leading historians of education to present a tapestry of seminal and enduring themes that characterize the many educational developments since 1920. An essential resource for researchers, scholars, and students in history, literature, culture, and education, A Cultural History of Education in the Modern Age presents essays that examine the following key themes of the period: church, religion and morality; knowledge, media and communications; children and childhood; family, community and sociability; learners and learning; teachers and teaching; literacies; and life histories.

Combined Effects of Lung Disease History, Environmental Exposures, and Family History of Lung Cancer to Susceptibility of Lung Cancer in Chinese Non-smokers

2021 ◽  
Author(s):  
Fanglin Yu ◽  
Rendong Xiao ◽  
Xu Li ◽  
Zhijian Hu ◽  
Lin Cai ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Family History ◽  
Environmental Factors ◽  
Lung Disease ◽  
Environmental Exposures ◽  
Collective Effects ◽  
Combined Effects ◽  
Cancer History ◽  
Increased Risk ◽  
History Of

Abstract Background: Although cigarette smoking is a major risk factor for lung cancer, the incidence rate of lung cancer among non-smokers is notable. The etiology and potential mechanism of non-smoker lung cancer are worthy of further research. This study was designed to explore the collective effects of environmental factors and the relationship between environmental exposure index (EEI) and lung cancer among non-smokers by evaluating the joint effects among lung disease history, environmental factors, and family history of lung cancer without smoking confounders.Methods: A total of 767 never-smoked lung cancer cases and 767 sex- and age-matched controls were selected from the department of Thoracic Surgery and Respiratory Medicine of three hospitals in Fujian, China. We used two methods to develop the EEI according to 12 statistically significant environmental risk factors. Restricted cubic spline (RCS) was applied to analyze the non-linear relationship between EEI and lung cancer in non-smokers. Combined effects, additive interaction, and multiplicative interaction were assessed among lung disease history, EEI, and family history of lung cancer to estimate susceptibility to develop lung cancer.Results: Lung disease history, especially asthma, was significantly associated with an increased risk of lung cancer with an odds ratio (OR) for asthma history of 14.720 (95% CI: 1.877–115.449). Family history of lung cancer was related to susceptibility of lung cancer (OR = 3.347, 95% CI: 1.930–5.806). According to type of relatives and cancer, a parental or children’s history and a sibling’s history of lung cancer were significantly associated with an increased risk of lung cancer. The positive association between EEI and lung cancer was apparently stronger in those with lung disease history or family lung cancer history. Furthermore, there was a addictive interaction between EEI and lung disease history, and a possibly addictive interaction between EEI and family lung cancer history on development of lung cancer.Conclusions: There were combined effects among lung disease history, environmental exposures, and family history of lung cancer toward susceptibility to lung cancer in Chinese non-smokers. Non-smokers who had a family history of lung cancer were at higher risk of lung cancer than non-smokers who had lung disease history. Non-smokers with family cancer history may obtain benefits from removal of environmental exposures and active treatment of lung disease.

scholarly journals The application of life history information to the conservation management of Chrysoritis butterflies (Lepidoptera: Lycaenidae) in South Africa

Koedoe ◽  
2004 ◽  
Vol 47 (1) ◽  
Author(s):  
R.F. Terblanche ◽  
H. Van Hamburg
Keyword(s):  
South Africa ◽  
Life History ◽  
Life Histories ◽  
Host Plants ◽  
Conservation Management ◽  
Aesthetic Value ◽  
Wing Patterns ◽  
In The Wild ◽  
History Of ◽  
Voucher Specimens

Due to their intricate life histories and the unique wing patterns and colouring the butterflies of the genus Chrysoritis are of significant conservation and aesthetic value. Thisoverview probes into practical examples of butterfly life history research applicable to environmental management of this relatively well-known invertebrate group in South Africa. Despite the pioneer work on life histories of Chrysoritis in the past, more should be done to understand the life history of the butterflies in the wild, especially their natural host plants and the behaviour of adults and larvae. A system of voucher specimens of host plants should be introduced in South Africa. Although various host plant species in nature are used by the members of Chrysoritis, including the Chrysoritis chrysaor group, the choice of these in nature by each species is significant for conservation management and in the case of Chrysoritis aureus perhaps even as a specific characteristic.A revision of the ant genus Crematogaster will benefit the conservation management of Chrysoritis species since some of these ant species may consist of a number of specieswith much more restricted distributions than previously thought. Rigorous quantified tudies of population dynamics of Chrysoritis butterflies are absent and the introductionof such studies will benefit conservation management of these localised butterflies extensively.

Sign in / Sign up

Export Citation Format

Share Document