Growth Model of Daphnia

1982 ◽  
Vol 39 (4) ◽  
pp. 598-606 ◽  
Author(s):  
J. E. Paloheimo ◽  
S. J. Crabtree ◽  
W. D. Taylor
Keyword(s):  
Growth Model ◽  
Aquatic Ecosystems ◽  
Cell Concentration ◽  
Daphnia Pulex ◽  
Assimilation Efficiency ◽  
Somatic Growth ◽  
Individual Growth ◽  
Nutrient Level ◽  
Model Predictions ◽  
Growth And Reproduction

Data from experiments on feeding, assimilation, and reproduction of Daphnia pulex grown in different cell concentrations of Chlamydomonas reinhardtii formed the basis for an individual growth model for D. pulex. The model predictions of both the somatic growth and reproduction agree with subsequent experimental results. Contrary to many higher organisms, the assimilation efficiency increases with increasing body size. This may be, at least in part, the reason why larger body-sized zooplankton tend to dominate in aquatic ecosystems when not controlled by predators. The uptake rate per body weight as a function of cell concentration can be described by Michaelis–Menten type equations, but not the assimilation rate. Contrast between the feeding and assimilation rates suggest that as the nutrient level increases, a higher proportion of uptake is channeled by Daphnia into the detritus/bacterial compartment.Key words: Daphnia pulex, feeding, energetics, assimilation, growth model, nutrient level

Individual Growth and Reproduction

2019 ◽  
pp. 38-56
Author(s):  
Ken H. Andersen
Keyword(s):  
Life History ◽  
Growth Model ◽  
Life Histories ◽  
Maximum Size ◽  
Individual Growth ◽  
Energy Budgets ◽  
Asymptotic Size ◽  
The Individual ◽  
Growth And Reproduction

This chapter develops descriptions of how individuals grow and reproduce. More specifically, the chapter seeks to determine the growth and reproduction rates from the consumption rate, by developing an energy budget of the individual as a function of size. To that end, the chapter addresses the question of how an individual makes use of the energy acquired from consumption. It sets up the energy budgets of individuals by formulating the growth model using so-called life-history invariants, which are parameters that do not vary systematically between species. While the formulation of the growth model in terms of life-history invariants is largely successful, there is in particular one parameter that is not invariant between life histories: the asymptotic size (maximum size) of individuals in the population. This parameter plays the role of a master trait that characterizes most of the variation between life histories.

Ontogeny of energetic relationships and potential effects of tissue turnover: a comparative modeling study on lake trout

1998 ◽  
Vol 55 (11) ◽  
pp. 2518-2532 ◽  
Author(s):  
Jixiang He ◽  
Donald J Stewart
Keyword(s):  
Growth Model ◽  
Lake Trout ◽  
Somatic Growth ◽  
Complex Model ◽  
Individual Growth ◽  
Metabolic System ◽  
New Model ◽  
Gonadal Growth ◽  
Tissue Turnover ◽  
Energy Assimilation

Tissue turnover is endogenous energy flow and may play a regulatory role in the metabolic system of an organism. We developed a general growth model addressing potential effect of tissue turnover on energy acquisition and partitioning. We applied the model to estimate energy assimilation of lake trout (Salvelinus namaycush) in Lake Michigan and compared the model with a commonly used complex model. Both models are expansions of the Pütter - von Bertalanffy growth model. The new model suggested a consistent decreasing trend in energy net conversion efficiency (NCE) for somatic growth versus body energy. The complex model suggested that NCE is relatively stable in early ages and decreases slowly in comparison with the pattern suggested by the new model. The new model estimated higher specific assimilation rate and NCE for gonadal growth than for somatic growth of mature fish. The complex model did not distinguish gonadal growth from somatic growth. For a lake trout growing from the start of age-1 to the end of age-10, our new model suggested a total energy assimilation 25% higher than the complex model. The above comparisons support the inference that tissue turnover is an important bioenergetic component. Inclusion of tissue turnover in bioenergetic modeling analyses may be critical for studying the linkages among individual growth, reproduction, and population dynamics.

scholarly journals Comparison of growth models to describe growth from birth to 6 years in a Beninese cohort of children with repeated measurements

BMJ Open ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. e035785
Author(s):  
Shukrullah Ahmadi ◽  
Florence Bodeau-Livinec ◽  
Roméo Zoumenou ◽  
André Garcia ◽  
David Courtin ◽  
...  
Keyword(s):  
Growth Model ◽  
Goodness Of Fit ◽  
Growth Models ◽  
Information Criterion ◽  
Height Growth ◽  
Sub Saharan Africa ◽  
Individual Growth ◽  
Secondary Outcome ◽  
Growth Trajectories ◽  
Best Fitting

ObjectiveTo select a growth model that best describes individual growth trajectories of children and to present some growth characteristics of this population.SettingsParticipants were selected from a prospective cohort conducted in three health centres (Allada, Sekou and Attogon) in a semirural region of Benin, sub-Saharan Africa.ParticipantsChildren aged 0 to 6 years were recruited in a cohort study with at least two valid height and weight measurements included (n=961).Primary and secondary outcome measuresThis study compared the goodness-of-fit of three structural growth models (Jenss-Bayley, Reed and a newly adapted version of the Gompertz growth model) on longitudinal weight and height growth data of boys and girls. The goodness-of-fit of the models was assessed using residual distribution over age and compared with the Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC). The best-fitting model allowed estimating mean weight and height growth trajectories, individual growth and growth velocities. Underweight, stunting and wasting were also estimated at age 6 years.ResultsThe three models were able to fit well both weight and height data. The Jenss-Bayley model presented the best fit for weight and height, both in boys and girls. Mean height growth trajectories were identical in shape and direction for boys and girls while the mean weight growth curve of girls fell slightly below the curve of boys after neonatal life. Finally, 35%, 27.7% and 8% of boys; and 34%, 38.4% and 4% of girls were estimated to be underweight, wasted and stunted at age 6 years, respectively.ConclusionThe growth parameters of the best-fitting Jenss-Bayley model can be used to describe growth trajectories and study their determinants.

Comparison of Otolith-Based Back-Calculation Methods to Determine Individual Growth Histories of Larval Striped Bass, Morone saxatilis

1992 ◽  
Vol 49 (7) ◽  
pp. 1439-1454 ◽  
Author(s):  
David H. Secor ◽  
John Mark Dean
Keyword(s):  
Striped Bass ◽  
Somatic Growth ◽  
Morone Saxatilis ◽  
Growth Effect ◽  
Individual Growth ◽  
Quadratic Model ◽  
Calculation Methods ◽  
Otolith Growth ◽  
Experimental Proof ◽  
Back Calculation

In rearing studies on 6- to 22-d-old larval striped bass, Morone saxatilis, we applied several back-calculation methods to known-growth larvae. A growth effect occurred on otolith diameter – standard length relationships, where slower growing larvae had relatively larger otoliths. Otolith growth was less affected by feeding regime than was somatic growth. Due to the conservative nature of otolith growth, proportional based (Biological Intercept Method) and simple linear regression methods linearized somatic growth transitions and did not estimate periods of negative growth. A quadratic regression method which used age as an additional predictor resulted in the accurate back-calculation of size at age in all groups of laboratory-reared larvae. However, when model coefficients were applied to a test population of pond-reared larvae, the quadratic model performed poorly. While differences in relative otolith size between pond- and laboratory-reared larvae could be ascribed to a temperature effect, the inability to apply the model also indicates a problem specific to regression-based methods. Theoretical rationale and experimental proof provided evidence for the inclusion of age in back-calculation models, but parameterization will have to occur for each field application.

Length-at-Age Analysis: Can You Get What You See?

1992 ◽  
Vol 49 (4) ◽  
pp. 632-643 ◽  
Author(s):  
T. J. Mulligan ◽  
B. M. Leaman
Keyword(s):  
Growth Model ◽  
Time Trend ◽  
Single Point ◽  
Mortality Rates ◽  
Individual Growth ◽  
Parameter Estimates ◽  
Von Bertalanffy ◽  
Model Ambiguity ◽  
Von Bertalanffy Growth Model ◽  
Single Set

Observations at a single point in time of length-at-age (LAA) for a long-lived rockfish (Sebastes alutus) show that old fish are shorter than intermediate-aged fish. Fitting of a von Bertalanffy growth model to these data produces a systematic trend in the residual of observed versus calculated LAA. We examined how such LAA data can lead to erroneous conclusions about individual growth, and whether asymptotic growth can give rise to such data. We considered two hypotheses: (i) that a time trend in growth rate resulted in larger fish in more recent years and (ii) that there are multiple growth types, where growth and mortality rates are directly related. Using a general growth model that incorporated both (i) and (ii), we show that both hypotheses can generate data identical to those for the rockfish. A single set of LAA data is inadequate for describing individual growth; however, if sufficient data are available, model ambiguity can be resolved and reasonable parameter estimates obtained. Analysis of the rockfish data indicates that (ii) is more likely to explain the observations than (i). We show how fisheries on such species may preclude our understanding these biological relationships.

scholarly journals Towards a general life-history model of the superorganism: predicting the survival, growth and reproduction of ant societies

2012 ◽  
Vol 8 (6) ◽  
pp. 1059-1062 ◽  
Author(s):  
Jonathan Z. Shik ◽  
Chen Hou ◽  
Adam Kay ◽  
Michael Kaspari ◽  
James F. Gillooly
Keyword(s):  
Life History ◽  
Terrestrial Ecosystems ◽  
The Body ◽  
Ant Colonies ◽  
Insect Societies ◽  
Model Predictions ◽  
Body Sizes ◽  
Survival And Reproduction ◽  
Growth And Reproduction ◽  
Colony Level

Social insect societies dominate many terrestrial ecosystems across the planet. Colony members cooperate to capture and use resources to maximize survival and reproduction. Yet, when compared with solitary organisms, we understand relatively little about the factors responsible for differences in the rates of survival, growth and reproduction among colonies. To explain these differences, we present a mathematical model that predicts these three rates for ant colonies based on the body sizes and metabolic rates of colony members. Specifically, the model predicts that smaller colonies tend to use more energy per gram of biomass, live faster and die younger. Model predictions are supported with data from whole colonies for a diversity of species, with much of the variation in colony-level life history explained based on physiological traits of individual ants. The theory and data presented here provide a first step towards a more general theory of colony life history that applies across species and environments.

scholarly journals Combined effects of food quality and temperature on somatic growth and reproduction of two freshwater cladocerans

2009 ◽  
Vol 54 (4) ◽  
pp. 1323-1332 ◽  
Author(s):  
HÉlène Masclaux ◽  
Alexandre Bec ◽  
Martin J. Kainz ◽  
Christian Desvilettes ◽  
Lionel Jouve ◽  
...  
Keyword(s):  
Food Quality ◽  
Somatic Growth ◽  
Combined Effects ◽  
Growth And Reproduction
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