The Use of Behavioral Ecotypes in the Study of Evolutionary Processes

1999 ◽  
Author(s):  
Susan E. Riechert
Keyword(s):  
Selection Process ◽  
Optimal Solution ◽  
Population Variation ◽  
Phenotypic Traits ◽  
Local Conditions ◽  
Ecotypic Variation ◽  
Mechanism Optimization ◽  
Species Population ◽  
Phenotypic Variant ◽  
History Of

Ecotypic variation refers to differences in traits between populations that reflect adaptation to different selection pressures. The origin of the term lies in Turesson’s (1922) observation that population differences in plant growth forms often breed true in a controlled environment. From experiments, Turesson (1922) concluded that much between-population variation in phenotypic traits reflects genotypic adaptation to local conditions. He described the phenomenon as ecotypic variation and the species population exhibiting a particular variant as an ecotype. The meaning of adaptation must be examined if the phenomenon of ecotypic variation is to be understood. Readers should refer to Reeve and Sherman (1993) for an in-depth analysis of the problems surrounding various definitions of this term. Briefly, Antonovics (1987) divided evolutionary studies into two distinct classes: those that consider the influences of past events (phylogenies) and those that consider why certain traits predominate over others in an ongoing selection process. Tinbergen (1963) proposed a similar subdivision. Most definitions of adaptation incorporate these two elements in that they require a history of selective modification of a trait. For instance, Harvey and Pagel (1991) express adaptations in terms of traits derived in their phylogenetic group that have current utilitarian function. However, ecotypic variation refers to trait differences that reflect adaptations to local conditions at one point in time. Phylogenetic constraints need not be examined except in terms of how they might limit adaptation. Therefore, when I refer to adaptation in this chapter, I will be limiting it to “a phenotypic variant that results in the highest fitness among a specified set of variants in a given environment” (Reeve and Sherman 1993). This definition is history-free. It is based on extant competing phenotypes, and thus fitness is of significance only in reference to current alternatives. Although the definition I borrow from Reeve and Sherman (1993) for adaptation does not specify that there be an underlying genetic mechanism, optimization models assume that there is (Charlesworth 1977). Minimally, we wish to know whether sufficient genetic complexity (variability) exists for a predicted optimal solution to be reached.

scholarly journals Climate-driven divergent selection in a foundation tree species: QST-FST evidence from multiple common gardens

2021 ◽  
Author(s):  
Hillary Cooper ◽  
Gerard Allan ◽  
Lela Andrews ◽  
Rebecca Best ◽  
Kevin Grady ◽  
...  
Keyword(s):  
Local Adaptation ◽  
Tree Species ◽  
Divergent Selection ◽  
Population Variation ◽  
Population Divergence ◽  
Phenotypic Traits ◽  
Local Conditions ◽  
Basal Diameter ◽  
Common Gardens ◽  
Fremont Cottonwood

Widespread tree species span large climatic gradients that often lead to high levels of local adaptation and phenotypic divergence across their range. To evaluate the relative roles of selection and drift in driving divergence in phenotypic traits, we compared molecular and quantitative genetic variation in Populus fremontii (Fremont cottonwood), using data from > 9000 SNPs and genotypes from 16 populations reciprocally planted in three common gardens that span the species’ climatic range. We present three major findings: 1) There is significant within- and among-population variation in functional traits expressed in each of the common gardens. 2) There is evidence from all three gardens that population divergence in leaf phenology and specific leaf area has been driven by divergent selection (QST > FST). In contrast, QST-FST comparisons for performance traits like height and basal diameter were highly dependent on growing environment, indicating divergent, stabilizing, or no selection across the three gardens. We show this is likely due to local adaptation of source populations to contrasting growing environments. 3) Climate is a primary selective force driving trait divergence, where the traits showing the strongest correlations with a genotype’s provenance climate also had the highest QST values. We conclude that climatic gradients have contributed to significant phenotypic differences and local adaptation in Fremont cottonwood. These results are important because as climate is changing much more rapidly, traits such as phenology that are finely tuned to local conditions may now be subject to intense selection or quickly become maladaptive.

scholarly journals Contributions of source population and incubation temperature to phenotypic variation of hatchling Chinese skinks

2020 ◽  
Author(s):  
Hong-Liang Lu ◽  
Yan-Fu Qu ◽  
Hong Li ◽  
Xiang Ji
Keyword(s):  
Body Mass ◽  
Phenotypic Variation ◽  
Incubation Temperature ◽  
Tail Length ◽  
Population Variation ◽  
Phenotypic Traits ◽  
Source Population ◽  
Relative Importance ◽  
The Difference ◽  
Hatchling Size

Abstract Phenotypic plasticity and local adaptation are viewed as the main factors that result in between-population variation in phenotypic traits, but contributions of these factors to phenotypic variation vary between traits and between species and have only been explored in a few species of reptiles. Here, we incubated eggs of the Chinese skink (Plestiodon chinensis) from 7 geographically separated populations in Southeast China at 3 constant temperatures (24, 28, and 32 °C) to evaluate the combined effects of clutch origin, source population, and incubation temperature on hatchling traits. The relative importance of these factors varied between traits. Nearly all examined hatchling traits, including body mass, snout–vent length (SVL), tail length, head size, limb length, tympanum diameter, and locomotor speed, varied among populations and were affected by incubation temperature. Measures for hatchling size (body mass and SVL) varied considerably among clutches. Source population explained much of the variation in hatchling body mass, whereas incubation temperature explained much of the variation in other examined traits. Our results indicate that between-population variation in hatchling traits of P. chinensis likely reflects the difference in natural incubation conditions and genetic divergence.

Late-glacial and Post-glacial history of the Chalk escarpment near Brook, Kent

1964 ◽  
Vol 248 (745) ◽  
pp. 135-204 ◽  
Keyword(s):  
Bronze Age ◽  
Iron Age ◽  
Late Glacial ◽  
Climatic Conditions ◽  
Valley Floor ◽  
Glacial Period ◽  
Late Neolithic ◽  
Local Conditions ◽  
Arable Farming ◽  
History Of

This paper describes the morphology of a small piece of the Chalk escarpment near Brook in east Kent, and reconstructs its history since the end of the Last Glaciation. The escarpment contains a number of steep-sided valleys, or coombes, with which are associated deposits of chalk debris, filling their bottoms and extending as fans over the Gault Clay plain beyond. Here the fans overlie radiocarbon-dated marsh deposits of zone II (10 000 to 8800 B.C.) of the Late-glacial Period. The debris fans were formed and the coombes were cut very largely during the succeeding zone III (8800 to 8300 B.C.). The fans are the products of frost-shattering, probably transported by a combination of niveo-fluvial action and the release of spring waters; intercalated seams of loess also occur. The molluscs and plants preserved in the Late-glacial deposits give a fairly detailed picture of local conditions. The later history of one of the coombes, the Devil’s Kneadingtrough, is reconstructed. The springs have effected virtually no erosion and have probably always emerged more or less in their present position. In the floor of the coombe the periglacial chalk rubbles of zone III are covered by Postglacial deposits, mainly hillwashes. They are oxidized and yield no pollen, but contain rich faunas of land Mollusca, which are presented in the form of histograms revealing changing local ecological and climatic conditions. During most of the Post-glacial Period, from the end of zone III until about the beginning of zone VIII, very little accumulation took place on the coombe floor. But below the springs there are marsh deposits which span much of this interval. They yield faunas of considerable zoogeographical interest. The approximate beginning of zone VII a (Atlantic Period) is reflected by a calcareous tufa, which overlies a weathering horizon, and represents an increase in spring flow. Two clearance phases are deduced from the molluscan record. The first may have taken place at least as early as the Beaker Period (Late Neolithic/earliest Bronze Age); the second is probably of Iron Age ‘A’ date. In Iron Age times the subsoil was mobilized and a phase of rapid hillwashing began. As a result the valley floor became buried by humic chalk muds. The prime cause of this process was probably the beginning of intensive arable farming on the slopes above the coombe; a possible subsidiary factor may have been the Sub-Atlantic worsening of climate. The muds yield pottery ranging in date from Iron Age ‘Kentish first A’ ( ca . 500 to ca . 300 B.C.) to Romano-British ware of the first or second centuries A.D. Evidence is put forward for a possible climatic oscillation from dry to wet taking place at about the time of Christ. In the later stages of cultivation, possibly in the Roman Era, the valley floor was ploughed and given its present-day form.

scholarly journals The ‘naturalistic’ fallacy: Leveraging the power of media to drive cognition

2021 ◽  
Author(s):  
Clare Grall ◽  
Emily S. Finn
Keyword(s):  
Practical Knowledge ◽  
Selection Process ◽  
Stimulus Selection ◽  
Brain Sciences ◽  
Affective Psychology ◽  
History Of ◽  
Media Research ◽  
The Rich ◽  
And Behavior ◽  
Rich History

So-called “naturalistic” stimuli have risen in popularity in cognitive, social, and affective psychology and neuroscience over the last 15 years. However, a critical property of these stimuli is frequently overlooked: Media—like film, television, books, and podcasts—are fundamentally not natural. They are deliberately crafted products meant to elicit particular human thought, emotion, and behavior. Given the rich history of scholarship on media as an art and science, subsuming media stimuli under the term “naturalistic” in psychological and brain sciences is inaccurate and obfuscates the advantages that media stimuli offer because they are artificial. Here, we argue for a more informed approach to adopting media stimuli in naturalistic paradigms. We empirically review how researchers currently describe and justify their choice of stimuli for a given experiment and present strategies to improve rigor in the stimulus selection process. We assert that experiencing media should be considered a task akin to any other experimental task(s), and explain how this shift in perspective will compel more nuanced and generalizable research using these stimuli. Throughout, we offer theoretical and practical knowledge from multidisciplinary media research to raise the standard for the treatment of media stimuli in psychological and neuroscientific research.

Europe's Path To Mars: The European Space Agency's Mars Express Mission

2011 ◽  
Vol 41 (2) ◽  
pp. 123-178 ◽  
Author(s):  
Arturo Russo
Keyword(s):  
Selection Process ◽  
European Space Agency ◽  
Management Approach ◽  
Mars Exploration ◽  
Mars Express ◽  
The Public ◽  
Science Programme ◽  
Space Agency ◽  
History Of

Mars Express is the first planetary mission accomplished by the European Space Agency (ESA). Launched in early June 2003, the spacecraft entered Mars's orbit on Christmas day of that year, demonstrating the new European commitment to planetary exploration. Following a failed attempt in the mid-1980s, two valid proposals for a European mission to Mars were submitted to ESA's decision-making bodies in the early 1990s, in step with renewed international interest in Mars exploration. Both were rejected, however, in the competitive selection process for the agency's Science Programme. Eventually, the Mars Express proposal emerged during a severe budgetary crisis in the mid-1990s as an exemplar of a “flexible mission” that could reduce project costs and development time. Its successful maneuvering through financial difficulties and conflicting scientific interests was due to the new management approach as well as to the public appeal of Mars exploration. In addition to providing a case study in the functioning of the ESA's Science Programme, the story of Mars Express discussed in this paper provides a case study in the functioning of the European Space Agency's Science Programme and suggests some general considerations on the peculiar position of space research in the general field of the history of science and technology.

scholarly journals Applying Neural Networks to Find the Minimum Cost Coverage of a Boolean Function

VLSI Design ◽  
1995 ◽  
Vol 3 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Pong P. Chu
Keyword(s):  
Neural Network ◽  
Boolean Function ◽  
Input Data ◽  
Selection Process ◽  
Optimal Solution ◽  
Minimum Cost ◽  
Hopfield Network ◽  
Neural Network Approach ◽  
Complete Problem ◽  
Np Complete

To find a minimal expression of a boolean function includes a step to select the minimum cost cover from a set of implicants. Since the selection process is an NP-complete problem, to find an optimal solution is impractical for large input data size. Neural network approach is used to solve this problem. We first formalize the problem, and then define an “energy function” and map it to a modified Hopfield network, which will automatically search for the minima. Simulation of simple examples shows the proposed neural network can obtain good solutions most of the time.

The evaluation of the rate of major depression in those who use norplant at shiraz Hafez hospital

2011 ◽  
Vol 26 (S2) ◽  
pp. 641-641
Author(s):  
S.H. Kavari
Keyword(s):  
Family Planning ◽  
Major Depression ◽  
Research Study ◽  
Selection Process ◽  
Research Work ◽  
Minor Depression ◽  
Depression And Anxiety ◽  
Family Planning Clinic ◽  
The Family ◽  
History Of

IntroductionDepression is a serious condition that can impact every area of your life. Female depression and even the pattern of symptoms are often different.AimsThe aim of this research study is to investigate the rate of server depression in those who use propellant. In order to achieve this objective, 260 patients volunteered to participate in this investigation and they were referred to the family planning clinic at Hafez hospital, and were planted capsule of Norplant.MethodsIn order to further fulfill selection process of patients suitable for this project, 200 of the most suitable candidates who suffered from even minor depression but had no history of congenital and familial major depression were selected and considered fit for this research work.ResultsThe results drawn from this investigative study can be summarized as follows;1-The relationships between progesterone in anti pregnancy compound tablets, major depression and anxiety were recognized from many years ago. Norplant which is progestin itself can also be regarded as the cause of these conditions.2-This investigation concluded that, among those patients studied, only 0.5% started having major depression as a result of the plantation. Therefore, Norplant was removed from their body.ConclusionsA good consultation, awareness, correct guidance and efficient method of educating people before using Norplant, seeking prompt referral advice and future follow ups, will result in an effective way of preventing, diagnosis and treatment of these side effect conditions.

Optimal harvesting for a single-species population governed by Gompertz law: Influence of environmental fluctuation and limited harvesting capacity

2019 ◽  
Vol 12 (02) ◽  
pp. 1950018
Author(s):  
P. D. N. Srinivasu ◽  
Simon D. Zawka
Keyword(s):  
Control Variable ◽  
Optimal Solution ◽  
Single Species ◽  
Optimal Harvesting ◽  
Environmental Fluctuation ◽  
Gompertz Equation ◽  
Species Population ◽  
Gompertz Law ◽  
Binding Constraints ◽  
Single Species Population

This work presents an optimal harvesting problem associated with a single-species population governed by Gompertz law in a seasonally fluctuating environment. The influence of environmental fluctuation is accommodated by choosing the coefficients in the differential equation to be periodic functions with the same period and restriction on the harvesting effort is accommodated by considering binding constraints on the control variable. Hence, a linear optimal control problem has been considered where the state dynamics is governed by Gompertz equation and the control variable is subject to the binding constraints. With the help of maximum principle and the concept of blocked intervals, an optimal periodic solution has been obtained which is followed by the construction of optimal solution using the theory of most rapid approach. Important results of the study are demonstrated through numerical simulations.

scholarly journals Parameter Identification of the Vortex-Induced Vertical Force Model Using a New Adaptive PSO

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Xiaoxia Tian ◽  
Jingwen Yan ◽  
Chi Xiao
Keyword(s):  
Optimal Solution ◽  
Time History ◽  
Vertical Displacement ◽  
Force Model ◽  
Vertical Force ◽  
Inertia Weight ◽  
Adaptive Pso ◽  
Short Run ◽  
History Of ◽  
Searching Ability

The paper proposes a new adaptive PSO (NAPSO) that adaptively adjust the inertial weight of every particle according to its own current fitness. In NAPSO, the searching ability of each particle is controlled by the inertial weight. In pursuit of the optimal solution, if a particle has a rather small value of normalized fitness, it has a small inertia weight so as to increase local searching ability; on the contrary, it has a large inertia weight to increase global searching ability. Simulation results include three parts: the NAPSO shows fast convergence and good stability compared with other PSOs; the NAPSO shows good fit and short run-time compared with GA and GALMA; according to the identified parameters, the time history of predicted vertical displacement is quite in accordance with the time history of measured displacement. As far as the nonlinear VIVF model is concerned, the NAPSO is a simple and effective identification method.

scholarly journals Morphological characteristics of local populations of European vendace Coregonus albula (L.) in some lakes of Latvia during 50 years

2009 ◽  
Vol 63 (6) ◽  
pp. 271-278 ◽  
Author(s):  
Jeļena Oreha ◽  
Nataļja Škute
Keyword(s):  
Cluster Analysis ◽  
Statistical Analysis ◽  
Morphological Characteristics ◽  
Specific Form ◽  
Living Conditions ◽  
Local Conditions ◽  
Coregonus Albula ◽  
Local Populations ◽  
History Of

Morphological characteristics of local populations of European vendace Coregonus albula (L.) in some lakes of Latvia during 50 years The vendace (Coregonus albula (L.)) is a widespread fish in the waters of the Holarctic and has been much studied in regard to history of spread and evolution. Statistical analysis of morphometric and meristic changes in Coregonus albula in some Latvian lakes for the last 50 years was conducted. Cluster analysis of meristic parameters showed that the vendace populations of lakes Stirnu - Alūksnes have become closer in meristic properties while the vendace populations of lakes Drīdzis - Sventes have become more dissimilar. The diversity and variation of morphological characteristics of vendace in the studied lakes are within the range of variations of the European vendace (Coregonus albula), although due to its flexibility it makes a lake-specific form depending on the local conditions of each reservoir. The discovered differences in the vendace populations from Lakes Nirzas, Rāznas, Stirnu, Alūksnes, Drīdzis, and Sventes seem to have resulted solely from/due to the adaptation of vendace to living conditions, which has changed during the previous 50 years.

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