scholarly journals Life-history dynamics: damping time, demographic dispersion and generation time

2020 ◽  
Author(s):  
Sha Jiang ◽  
Harman Jaggi ◽  
Wenyun Zuo ◽  
Madan K. Oli ◽  
Jean-Michel Gaillard ◽  
...  
Keyword(s):  
Life History ◽  
Generation Time ◽  
Life Histories ◽  
Allometric Scaling ◽  
Theoretical Work ◽  
Metabolic Theory ◽  
External Disturbances ◽  
Late Maturity ◽  
Reproductive Events ◽  
The Relationship

AbstractTransient dynamics are crucial for understanding ecological and life-history dynamics. In this study, we analyze damping time, the time taken by a population to converge to a stable (st)age structure following a perturbation, for over 600 species of animals and plants. We expected damping time to be associated with both generation time Tc and demographic dispersion σ based on previous theoretical work. Surprisingly, we find that damping time (calculated from the population projection matrix) is approximately proportional to Tc across taxa on the log-log scale, regardless of σ. The result suggests that species at the slow end of fast-slow continuum (characterized with long generation time, late maturity, low fecundity) are more vulnerable to external disturbances as they take more time to recover compared to species with fast life-histories. The finding on damping time led us to next examine the relationship between generation time and demographic dispersion. Our result reveals that the two life-history variables are positively correlated on a log-log scale across taxa, implying long generation time promotes demographic dispersion in reproductive events. Finally, we discuss our results in the context of metabolic theory and contribute to existing allometric scaling relationships.

The Relationship of Form and Function of Minute Characters of Lepidopterous Larvae, and its Importance in Life-History Studies

1964 ◽  
Vol 96 (7) ◽  
pp. 991-1004 ◽  
Author(s):  
Margaret Rae MacKay
Keyword(s):  
Life History ◽  
Chemical Control ◽  
Life Histories ◽  
The Other ◽  
Taxonomic Study ◽  
Form And Function ◽  
Morphological Studies ◽  
And Function ◽  
Relationship Of ◽  
The Relationship

AbstractThe information to be obtained from thorough life-history studies is an extremely useful tool, perhaps especially so when ecology is being emphasized, as it is to-day, by the life-table and other mathematical approaches to the study of population processes. This information is desired by workers in many fields of entomology – by the biological and chemical control experts, the biomathematicians, the theorists and even the taxonomists. However, much of the knowledge that these workers require, for instance the fine distinctions of behaviour and environment, has been overlooked in most life-history studies, and I strongly suspect that one of the weaknesses of studies of this nature has been the failure to analyse the mode of living of an insect (or, in the case of Lepidoptera, of the immature forms) in relation to the anatomy on one hand and environmental circumstances on the other. To look for these relationships, I believe that one requires (a) the ability and perseverance to perceive detail as minute as that required for a taxonomic study, and (b) a considerable knowledge of the taxonomic detail that is to be obtained from basic morphological studies. Therefore, in this paper, attention is drawn to pertinent structural characters of lepidopterous larvae and their probable connection with the behaviour and microhabitats of the larvae, in the hope that some guidance may be offered to future students of life-histories, at least in Lepidoptera.

scholarly journals Generation time, life history and the substitution rate of neutral mutations

2014 ◽  
Vol 10 (11) ◽  
pp. 20140801 ◽  
Author(s):  
Jussi Lehtonen ◽  
Robert Lanfear
Keyword(s):  
Life History ◽  
Generation Time ◽  
Life Histories ◽  
Life History Traits ◽  
Theoretical Understanding ◽  
Substitution Rates ◽  
Demographic Theory ◽  
Full Life ◽  
Iteroparous Species ◽  
Neutral Mutations

Our understanding of molecular evolution is hampered by a lack of quantitative predictions about how life-history (LH) traits should correlate with substitution rates. Comparative studies have shown that neutral substitution rates vary substantially between species, and evidence shows that much of this diversity is associated with variation in LH traits. However, while these studies often agree, some unexplained and contradictory results have emerged. Explaining these results is difficult without a clear theoretical understanding of the problem. In this study, we derive predictions for the relationships between LH traits and substitution rates in iteroparous species by using demographic theory to relate commonly measured life-history traits to genetic generation time, and by implication to neutral substitution rates. This provides some surprisingly simple explanations for otherwise confusing patterns, such as the association between fecundity and substitution rates. The same framework can be applied to more complex life histories if full life-tables are available.

Oedipal mating as a factor in sex allocation in haplodiploids

1993 ◽  
Vol 341 (1296) ◽  
pp. 195-202 ◽  
Keyword(s):  
Mathematical Model ◽  
Life History ◽  
Life Histories ◽  
Sex Allocation ◽  
Theoretical Work ◽  
Immature Stages ◽  
Sex Ratio Bias ◽  
Colonization Density ◽  
Female Bias ◽  
High Penalty

Most theoretical work on brood sex ratio bias is based on life histories involving potential sibmating, where inseminated females colonize a habitat producing progeny that mate randomly among themselves. However, another type of life history can favour female biased broods; it involves motherson matings and is uniquely accessible to haplodiploids. Colonization is accomplished by immature stages (mating is postdispersal) and female bias is favoured at low colonization densities by the fact that, unlike isolated males, isolated females are not lost to the gene pool because they can mate with their parthenogenetically produced sons. We present a mathematical model of the life history including parameters describing colonization density, degree of aggregation, the penalty incurred when a female must wait to mate with her parthenogenetically produced son, and inbreeding. Low colonization density favours female bias as does increased aggregation; a high penalty associated with waiting for maturation of a son with which to mate means that some proportion of males among progeny will be favoured even at very low colonization densities. Life histories that fit the model are known in nematodes and mites.

scholarly journals Toward a metabolic theory of life history

2019 ◽  
Author(s):  
Joseph Robert Burger ◽  
Chen Hou ◽  
James H. Brown
Keyword(s):  
Life History ◽  
Energy Balance ◽  
Life Histories ◽  
Biomass Energy ◽  
Metabolic Energy ◽  
Mass Energy ◽  
Metabolic Theory ◽  
Body Sizes ◽  
Growth Evolution ◽  
Growth And Reproduction

SignificanceData and theory reveal how organisms allocate metabolic energy to components of the life history that determine fitness. In each generation animals take up biomass energy from the environment and expended it on survival, growth, and reproduction. Life histories of animals exhibit enormous diversity – from large fish and invertebrates that produce literally millions of tiny eggs and suffer enormous mortality, to mammals and birds that produce a few large offspring with much lower mortality. Yet, underlying this enormous diversity, are general life history rules and tradeoffs due to universal biophysical constraints on the channels of selection. These rules are characterized by general equations that underscore the unity of life.Abstract The life histories of animals reflect the allocation of metabolic energy to traits that determine fitness and the pace of living. Here we extend metabolic theories to address how demography and mass-energy balance constrain allocation of biomass to survival, growth, and reproduction over a life cycle of one generation. We first present data for diverse kinds of animals showing empirical patterns of variation in life history traits. These patterns are predicted by new theory that highlights the effects of two fundamental biophysical constraints: demography on number and mortality of offspring; and mass-energy balance on allocation of energy to growth and reproduction. These constraints impose two fundamental tradeoffs on allocation of assimilated biomass energy to production: between number and size of offspring, and between parental investment and offspring growth. Evolution has generated enormous diversity of body sizes, morphologies, physiologies, ecologies, and life histories across the millions of animal, plant and microbe species, yet simple rules specified by general equations highlight the underlying unity of life.

scholarly journals Lower emotional awareness is associated with greater early adversity and faster life history strategy

2021 ◽  
Author(s):  
Ryan Smith ◽  
Horst Dieter Steklis ◽  
Netzin Steklis ◽  
Karen Weihs ◽  
John JB Allen ◽  
...  
Keyword(s):  
Life History ◽  
Short Form ◽  
Life History Strategy ◽  
Theoretical Work ◽  
Emotional Awareness ◽  
Early Adversity ◽  
Recent Theoretical Work ◽  
Two Measures ◽  
Reflective Cognition ◽  
The Relationship

Recent theoretical work suggests that emotional awareness (EA) depends on the harshness/predictability of early social interactions – and that low EA may actually be adaptive in harsh environments that lack predictable interpersonal interactions. In evolutionary psychology, this process of psychological “calibration” to early environments corresponds to life history strategy (LHS). In this paper, we tested the relationship between EA and LHS in 177 (40 male) individuals who completed the levels of emotional awareness scale (LEAS), Arizona Life History Battery (short form: K-SF-42), and two measures of early abuse/neglect. Significantly lower EA was observed in those with faster LHS and who had experienced greater early adversity. Notably, LEAS was associated with differences in 1) general reflective cognition, and 2) emotional support from parents during childhood. This suggests that EA may be learned during development based on the benefits of cognitive reflection in environments with different levels of harshness and social predictability.

scholarly journals Toward a metabolic theory of life history

2019 ◽  
Vol 116 (52) ◽  
pp. 26653-26661 ◽  
Author(s):  
Joseph Robert Burger ◽  
Chen Hou ◽  
James H. Brown
Keyword(s):  
Life History ◽  
Energy Balance ◽  
Life Histories ◽  
Biomass Energy ◽  
Metabolic Energy ◽  
Mass Energy ◽  
Metabolic Theory ◽  
Trade Offs ◽  
Body Sizes ◽  
Growth And Reproduction

The life histories of animals reflect the allocation of metabolic energy to traits that determine fitness and the pace of living. Here, we extend metabolic theories to address how demography and mass–energy balance constrain allocation of biomass to survival, growth, and reproduction over a life cycle of one generation. We first present data for diverse kinds of animals showing empirical patterns of variation in life-history traits. These patterns are predicted by theory that highlights the effects of 2 fundamental biophysical constraints: demography on number and mortality of offspring; and mass–energy balance on allocation of energy to growth and reproduction. These constraints impose 2 fundamental trade-offs on allocation of assimilated biomass energy to production: between number and size of offspring, and between parental investment and offspring growth. Evolution has generated enormous diversity of body sizes, morphologies, physiologies, ecologies, and life histories across the millions of animal, plant, and microbe species, yet simple rules specified by general equations highlight the underlying unity of life.

scholarly journals Life histories of 9,488 bird and 4,865 mammal species

2021 ◽  
Author(s):  
Lars Witting
Keyword(s):  
Life History ◽  
Population Density ◽  
Generation Time ◽  
Life Histories ◽  
Individual Growth ◽  
Parameter Estimates ◽  
Mammal Species ◽  
Taxonomic Level ◽  
Life History Data ◽  
Existing Data

I use 56,214 life history data to estimate equilibrium life history models for birds and mammals with body mass estimates. Missing parameters were estimated by allometric correlations at the lowest taxonomic level (genus, family, order, class) with data. The estimation is optimised to predict the existing data, with precision estimated separately for the different taxonomic levels of the estimator. This provides complete life history models for 9,488 species of birds, and 4,865 species of mammals. Each model includes estimates of metabolism, net assimilated energy, individual growth, mortality, fecundity, age of reproductive maturity, generation time, life span, home range, population density, biomass, population consumption, and a relative measure of intra-specific interactive competition, providing 387,531 parameter estimates in total.

scholarly journals Universal Ontogenetic Growth without Fitting Parameters: Implications for Life History Invariants & Population Growth

2021 ◽  
Author(s):  
Andres Escala
Keyword(s):  
Life History ◽  
Population Growth ◽  
Metabolic Rate ◽  
Generation Time ◽  
Allometric Scaling ◽  
Growth Models ◽  
Growth Equation ◽  
Universal Curve ◽  
Heart Frequency ◽  
Fitting Parameters

Since the work of Von Bertalanffy (1957), several models have been proposed that relate the ontogenetic scaling of energy assimilation and metabolism to growth, being able to describe ontogenetic growth trajectories for living organisms and collapse them onto a single universal curve (West et al. 2001; Barnavar et al. 2002). Nevertheless, all these ontogenetic growth models critically depends on fitting parameters and on the allometric scaling of the metabolic rate. Using a new metabolic rate relation (Escala 2019) applied to a Bertalanffy-type ontogenetic growth equation, we find that ontogenetic growth can also be described by an universal growth curve for all studied species, but without the aid of any fitting parameters. We find that the inverse of the heart frequency fH, rescaled by the ratio of the specific energies for biomass creation and metabolism, defines the characteristic timescale for ontogenetic growth. Moreover, our model also predicts a generation time and lifespan that explains the origin of several 'Life History Invariants' (Charnov 1993) and predicts that the Mathusian Parameter should be inversely proportional to both the generation time and lifespan, in agreement with the data in the literature (Duncan et al. 1997; Dillingham et. al 2016; Hatton et al 2019). In our formalism, several critical timescales and rates (lifespan, generation time & intrinsic population growth rate) are all proportional to the heart frequency fH, thus their allometric scaling relations comes directly from the allometry of the heart frequency, which is typically fH ∝ M-0.25 under basal conditions.

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