Tree life history strategies: the role of defenses

1988 ◽  
Vol 18 (2) ◽  
pp. 209-222 ◽  
Author(s):  
Craig Loehle
Keyword(s):  
Growth Rate ◽  
Woody Plants ◽  
Heat Content ◽  
Wood Decay ◽  
Life History Strategies ◽  
Rapid Decline ◽  
Energy Investment ◽  
Protective Measures ◽  
Trade Offs

Analysis of energy partitioning between defensive investments and growth in woody plants indicates that increasing a tree's life-span should require increased energy investment in protective measures such as thick bark and defensive chemicals. Increased investment in such defenses, however, logically must slow down the growth rate, thereby raising the mortality rate for juveniles in competition for height growth. Early reproduction should also reduce the growth rate. It is hypothesized that rapid growth can substitute for these defenses, but the consequence is rapid decline upon reaching maturity. These predictions are tested with data compiled from the literature for 159 species of North American trees. Data analysis supports predictions. Longevity of angiosperms, but not of gymnosperms was correlated with increased investment in defenses as measured by volumetric heat content of the wood. Wood density was not as good a measure. Longevity of gymnosperms was predicted by resistance to wood decay. For both taxa there was a negative correlation between growth rate and longevity, supporting the hypothesis of growth trade-offs. Age of sexual maturity was closely predicted by longevity in angiosperms. There was no such relationship for conifers as a whole, though there was for pines. The lack of relationship for all conifers might be explained by (i) variation in reproductive opportunities for young trees of different species, or (ii) variation in growth rates of young trees in certain adverse habitats occupied by conifers.

scholarly journals Redox physiology in animal function: The struggle of living in an oxidant environment

2010 ◽  
Vol 56 (6) ◽  
pp. 687-702 ◽  
Author(s):  
David Costantini
Keyword(s):  
Oxidative Stress ◽  
Life Histories ◽  
Evolutionary Ecology ◽  
Life History Strategies ◽  
Ecological Studies ◽  
Oxidative Balance ◽  
Fitness Traits ◽  
Trade Offs ◽  
Strong Focus

Abstract A strong focus of ecological research for several decades has been to understand the factors underlying the variation in animal life-histories. In recent times, ecological studies have begun to show that oxidative stress may represent another important modulator of competitive trade-offs among fitness traits or of positively integrated patterns of traits. Therefore, incorporating mechanisms underlying oxidative physiology into evolutionary ecology has the potential to help understand variation in life-history strategies. In this review, I provide a general overview of oxidative stress physiology, and subsequently focus on topics that have been neglected in previous ecological reviews on oxidative stress. Specifically, I introduce and discuss the adaptations that animals have evolved to cope with oxidative stress; the environmental stressors that can generate changes in oxidative balance; the role of reactive species in transduction of environmental stimuli and cell signaling; and the range of hormetic responses to oxidative stress.

scholarly journals A Theory of the Spring Persistence Barrier on ENSO. Part III: The role of Tropical Pacific Ocean Heat Content

2021 ◽  
pp. 1-36
Author(s):  
Yishuai Jin ◽  
Zhengyu Liu ◽  
Michael J. McPhaden
Keyword(s):  
Growth Rate ◽  
Lead Time ◽  
Southern Oscillation ◽  
Heat Content ◽  
Ocean Heat Content ◽  
Upper Ocean Heat Content ◽  
Correlation Relationship ◽  
The Relationship ◽  
Sst Anomalies

AbstractIn this paper, we investigate the relationship between upper ocean heat content (OHC) and El Niño-Southern Oscillation (ENSO) sea surface temperature (SST) anomalies mainly using the neutral recharge oscillator (NRO) model both analytically and numerically. Previous studies showed that spring OHC, which leads SST by 6-12 months, represents a major source of predictability for ENSO. It is suggested that this seasonality is caused by the seasonally varying growth rate in SST anomalies. Moreover, a shortened ENSO period will lead to a reduced SST predictability from OHC, with the most significant decrease occurring in the latter half of the calendar year. The cross-correlation relationship between OHC and ENSO SST anomalies is further identified in damped and self-excited version of the recharge oscillator model. Finally, we suggest that the seasonal growth rate of ENSO anomalies is the cause of the seasonality in the effectiveness of OHC as a predictor in ENSO forecasting. We also explain the shorter lead time between spring OHC and ENSO SST anomalies after the turn of the 21st century in terms of the apparent higher frequency of the ENSO period.

scholarly journals Temperature affects the repeatability of evolution in the microbial eukaryote Tetrahymena thermophila

2020 ◽  
Author(s):  
Jason A Tarkington ◽  
Rebecca Zufall
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Tetrahymena Thermophila ◽  
Correlated Responses ◽  
Trade Offs ◽  
Evolutionary Trajectories ◽  
Two Temperatures ◽  
Higher Temperature ◽  
Lower Temperature

AbstractEvolutionary biologists have long sought to understand what factors affect the repeatability of adaptive outcomes. To better understand the role of temperature in determining the repeatability of adaptive trajectories, we evolved populations of different genotypes of the ciliate Tetrahymena thermophila at low and high temperatures and followed changes in growth rate over 4,000 generations. As expected, growth rate increased with a decelerating rate for all populations; however, there were differences in the patterns of evolution at the two temperatures. The growth rates of the different genotypes converged as evolution proceeded at both temperatures, but this convergence was quicker at the higher temperature. Likewise, we found greater repeatability of evolution, in terms of change in growth rate, among replicates of the same genotype at the higher temperature. Finally, we found no evidence of trade-offs in fitness between temperatures, but did observe asymmetry in the correlated responses, whereby evolution in a high temperature increases growth rate at the lower temperature significantly more than the reverse. These results demonstrate the importance of temperature in determining the repeatability of evolutionary trajectories.

scholarly journals A theory of Spring Persistence Barrier on ENSO. Part II: Persistence Barriers in SST and ocean heat content

2021 ◽  
pp. 1-30
Author(s):  
Yishuai Jin ◽  
Zhengyu Liu
Keyword(s):  
Growth Rate ◽  
Numerical Solutions ◽  
Southern Oscillation ◽  
Heat Content ◽  
Ocean Heat Content ◽  
Seasonal Growth ◽  
Approximate Analytical Solutions ◽  
Potential Factors ◽  
The Relationship

AbstractIn this paper, we investigate the potential factors that control the relationship between the El Niño-Southern Oscillation (ENSO) persistence barriers (PB) in sea surface temperature (SST) and ocean heat content (OHC) and apply it to explain observational ENSO PBs. With the addition of seasonal growth rate in SST in the neutral recharge oscillator (NRO) model, approximate analytical solutions of autocorrelation functions for SST and OHC suggest strictly that the timing of PB for OHC leads that of SST by half a year and the strength of the two PBs are the same. The numerical solutions of the NRO model also show a similar relationship. The role of ENSO growth rate to PBs in SST and OHC is then identified in the damped and unstable ENSO regime. Therefore, it is suggested that for the observational ENSO, the seasonally varying ENSO growth rate in SST controls PBs in SST and OHC simultaneously.

The intrinsic mechanism of life history trade-offs: The mediating role of control striving

2017 ◽  
Vol 49 (6) ◽  
pp. 783 ◽  
Author(s):  
Yan WANG ◽  
Zhenchao LIN ◽  
Bowen HOU ◽  
Shijin SUN
Keyword(s):  
Life History ◽  
Mediating Role ◽  
Trade Offs ◽  
Intrinsic Mechanism ◽  
Control Striving

Emerging Challenges and Opportunities of Mobile Commerce in India: A Study on Societal Perspective

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Utkarsh Kumar ◽  
Anil Kumar Gope ◽  
Shweta Singh
Keyword(s):  
Growth Rate ◽  
Societal Perspective ◽  
Mobile Applications ◽  
Mobile Application ◽  
Mobile Commerce ◽  
Mobile Banking ◽  
Black And White ◽  
The People ◽  
Challenges And Opportunities

In India, the position of mobile banking was in saga and this time, it is in pic position. The speedof reaching the people is going high and high. This is time of wireless world and sense of prestige; no doubt the mobile commerce is contributing to enhance the beauty of life and playing the role of metaphor and has become the part and parcel of our life. This growth has changed people to do business in mobile commerce (М- Commerce). Peoples are transferring to M-Commerce to attain good and fast transaction into market and saving their precious time. M-Commerce has become distinguished in Indian people, quickly during last few years. Due to large number of mobile application, growth rate in mobile penetration in India is increasing with the rapid speed. The mobile users has shifted to use the android phone from simple and black and white phone and taking the service of internet, the role of telecom companies is also important in the being popular of mobile commerce. Although many people have started E-Commerce but still a separate part of the society feel uncomfortable and hesitate to use M-Commerce because of security problems, payment issues and complexity of mobile applications. This paper identifies facts about the feasibility of MCommercein India today its growth and the Strength and opportunity, weakness and threats lying ahead.

Beyond Bias

2020 ◽  
pp. 736-753
Author(s):  
Chelsea Barabas
Keyword(s):  
Best Practices ◽  
Criminal Law ◽  
Criminal Justice Reform ◽  
Trade Offs ◽  
System P ◽  
Accuracy Measures ◽  
Criminal Legal System ◽  
And Function ◽  
Role And Function

This chapter discusses contemporary debates regarding the use of artificial intelligence as a vehicle for criminal justice reform. It closely examines two general approaches to what has been widely branded as “algorithmic fairness” in criminal law: the development of formal fairness criteria and accuracy measures that illustrate the trade-offs of different algorithmic interventions; and the development of “best practices” and managerialist standards for maintaining a baseline of accuracy, transparency, and validity in these systems. Attempts to render AI-branded tools more accurate by addressing narrow notions of bias miss the deeper methodological and epistemological issues regarding the fairness of these tools. The key question is whether predictive tools reflect and reinforce punitive practices that drive disparate outcomes, and how data regimes interact with the penal ideology to naturalize these practices. The chapter then calls for a radically different understanding of the role and function of the carceral state, as a starting place for re-imagining the role of “AI” as a transformative force in the criminal legal system.

Hormones and Behavior

2019 ◽  
pp. 11-26
Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Endocrine System ◽  
Phenotypic Traits ◽  
Social Environments ◽  
Trade Offs ◽  
And Behavior

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.

Energy Markets and Trading

2018 ◽  
Author(s):  
David Mares
Keyword(s):  
Fossil Fuels ◽  
Negative Impact ◽  
Adjustment Costs ◽  
Institutional Context ◽  
Energy Markets ◽  
Energy Resources ◽  
Trade Offs ◽  
The Social ◽  
Impact Risk

This chapter discusses the role of energy in economic development, the transformation of energy markets, trade in energy resources themselves, and the geopolitical dynamics that result. The transformation of energy markets and their expansion via trade can help or hinder development, depending on the processes behind them and how stakeholders interact. The availability of renewable, climate-friendly sources of energy, domestically and internationally, means that there is no inherent trade-off between economic growth and the use of fossil fuels. The existence of economic, political, social, and geopolitical adjustment costs means that the expansion of international energy markets to incorporate alternatives to oil and coal is a complex balance of environmental trade-offs with no solutions completely free of negative impact risk. An understanding of the supply of and demand for energy must incorporate the institutional context within which they occur, as well as the social and political dynamics of their setting.

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