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The Warrior Zero Body Weight Challenge Summary


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Of all books related to the topic, I love reading this e-book because of its well-planned flow of content. Even a beginner like me can easily gain huge amount of knowledge in a short period.

All the modules inside this book are very detailed and explanatory, there is nothing as comprehensive as this guide.

What Is The Relation Of Physical Fitness To Future Cardiovascular Events Or Total Mortality

This question was addressed by the Lipid Research Clinics' prevalence survey in the study of4276 individuals age 30 to 69 years who were followed for an average of 8.5 years (39,40). Baseline assessment of individuals in this study included an analysis of the conventional coronary risk factors and treadmill exercise testing. The performance during maximal exercise was used as a measure of physical fitness. Men who had clinical evidence of CVD at baseline (n 649) had their records analyzed separately. Among the remaining 3106 men, 45 deaths occurred from cardiovascular causes. After adjustment for age and known cardiovascular risk factors, a lower level of physical fitness was found to be associated with overall CVD, a higher coronary mortality, and death rate from all causes. The relative risk for cardiovascular mortality for the least-fit apparently healthy men was compared with the most fit healthy men according to their exercise capacity. The relative risk for overall...

Higher Levels Of Physical Fitness Delay Allcause Mortality And Cardiovascular Mortality In Particular

The relation of maximal oxygen uptake (measured during maximal exercise on a stationary bicycle) to cardiovascular mortality was studied in 2014 Norwegian men 40 to 59 years of age at the beginning of the study, with a follow-up period of 16 years (9). The relative risk of death from any cause in men in the fourth (highest) fitness quartile was compared with that in men in the first (lowest) quartile. The relative risk for total mortality in the highest fitness quartile was 0.54 after adjustment for age, smoking, serum lipid levels, blood pressure, resting heart rate, vital capacity, BMI, and glucose tolerance. Total mortality was similar among subjects in the three lowest quartiles. The adjusted relative risk of death from cardiovascular events in the highest quartile compared to the lowest was 0.41 (p - 0.013). The relative risks for the third and second quartiles (compared with the lowest) were 0.45 (p - 0.026) and 0.59 ip 0.15), respectively (9). The least fit and the least active...

Measuring fitness differences

For the most part, we can measure the differential fitness of different genotypes most easily when the genotypes differ at many loci. In very few cases, such as laboratory mutants, horticultural varieties, and major metabolic disorders, does an allelic substitution at a single locus make enough difference to the phenotype to measurably alter fitness. Figure 19-9 shows the probability of survival from egg to adult that is, the viability at three different temperatures of a number of different lines made homozygous for the second chromosomes of D. pseudoobscura. These chromosomes were sampled from a natural population and carried a variety of different alleles at different loci, as we expect from the very large amount of nucleotide variation present in nature (see pages 619-620). As is generally the case, the fitness (in this case, a component of the total fitness, viability) is different in different environments. The homozygous state is lethal or nearly so in a few cases at all three...

Fitness evaluation

Once a population of trees has been created, they can be evaluated for fitness in a similar way to a GA. There is a significant difference, however, in that whereas a GA chromosome is evaluated simply by viewing the gene values, a tree must be executed to give a result. This result can be a single value, or it can consist of a set of values created by executing the tree on a variety of different variable (terminal) settings. The result or results from the tree are compared with the required result by the user-defined objective function. The objective function therefore uses this comparison function and returns a fitness for the solution. Once the evaluation process has been completed, the genetic operators are used to create new

The genomics revolution invading ecology

Realizing the importance of Mendel's papers, William Bateson announced that genetics was to become the most promising research area of the life sciences. One hundred years later one cannot avoid the conclusion that the progress in understanding the role of genes in living systems indeed has been astonishing. The genomics revolution has now expanded beyond genetics, its impact being felt in many other areas of the life sciences, including ecology. In the ecological arena, the interaction between genomics and ecology has led to a new field of research, evolutionary and ecological functional genomics. Feder and Mitchell-Olds (2003) indicated that this new multidiscipline 'focuses on the genes that affect evolutionary fitness in natural environments and populations'.

The Heart Rate Changes from Minute to Minute Depending on What We Are Doing or Thinking about

Use of a person's age-predicted maximal heart rate. It is useful to know a person's maximal age-predicted heart rate. First, it helps them know if they are exercising close to their maximum (therefore they are doing useful exercise that is good for them and will improve their fitness). Second, we use the maximal heart rate to tell us if a patient has exercised enough or has been sufficiently stressed during an exercise test.

Evolutionary Voting Kernel Machines

In EVKMs, selection, crossover, and mutation operations are the same as in GKTSESs. The difference is in fitness evaluation. In each GKTs(cj) evaluation, the training data set S (x1 y1), , (xi,y ) is first separated into k mutually In Eq. (3.17), cv is a cost factor which is either the accuracy of the positive class of the vth SVMs if dv(x) is positive, or the accuracy of the negative class of if dv(x) is negative. Data set S is then predicted by d(x), and the accuracies (i+ and t ) of two classes are calculated, respectively. The prediction accuracy is chosen as fitness. Evaluate SVMs on using d(x) and calculate fitness For End

Resource Acceptability

Resource acceptability represents the willingness of the insect to feed, given the probability of finding more suitable resources or in view of other tradeoffs. Most insects have relatively limited time and energy resources to spend searching for food. Hence, marginally suitable resources may become sufficiently profitable when the probability of finding more suitable resources is low, such as in diverse communities composed primarily of nonhosts. Courtney (1985, 1986) reported that oviposition by a pierid butterfly, Anthocharis car-damines, among several potential host plant species was inversely related to the suitability of those plant species for larval development and survival (Fig. 3.10). The more suitable host plant species were relatively rare and inconspicuous compared to the less suitable host species. Hence, butterfly fitness was maximized by laying eggs on the most conspicuous (apparent) plants, thereby ensuring reproduction, rather than by risking reproductive failure...

Nesting and Brood Care

Development of altruistic behaviors such as social cooperation can be explained largely as a consequence of kin selection and reciprocal cooperation (Axelrod and Hamilton 1981, Haldane 1932, Hamilton 1964, Trivers 1971, E. Wilson 1973, Wynne-Edwards 1963,1965, see also Chapter 15). Self-sacrifice that increases reproduction by closely related individuals increases inclusive fitness (i.e., the individual's own fitness plus the fitness accruing to the individual through its contribution to reproduction of relatives). In the case of the eusocial Hymenoptera, because of haploid males, relatedness among siblings is greater than that between parent and offspring, making cooperation among colony members highly adaptive. The epitome of altruism among insects may be the development of the barbed sting in the worker honey bee, Apis mellifera, that ensures its death in defense of the colony (Haldane 1932, Hamilton 1964). Termites do not share the Hymenopteran model for sibling relatedness....

Competitive Defensive and Mutualistic Behavior

Competitive Behavior Competition occurs among individuals using the same limiting resources at the same site. Energy expended, or injury suffered, defending resources or searching for uncontested resources affects fitness. Competition often is mediated by mechanisms that determine a dominance hierarchy. Establishment of dominant and subordinate status among individuals limits the need for physical combat to determine access to resources and ensures that dominant individuals get more resources than do subordinate individuals.

Conclusions and Further Perspectives

Genome analysis indicates how the Listeria genomes may have evolved by multiple insertions and deletions of small islets rarely by site-specific recombination mediated by integrases or IS elements. Even the proposed pathogenicity islands LIPI1 and LIPI2 are devoid of integrase genes. Furthermore the genome comparisons highlight the functional diversity between the major lineages present not only within the species L. monocytogenes but also within each lineage. These multiple islets constitute the flexible gene pool of the species L. monocy-togenes. It includes a large proportion of genes encoding functions involved in the adaptation to various environments like permeases, carbon source catabolism enzymes, and surface proteins, and should thus contribute to the fitness of the strains in specific environments. However, we still do not know the complete size of the flexible gene pool and the relative role of vertical transmission and horizontal gene transfer. Further genome sequencing...

Demography and Population Regulation

Darwin's theory of natural selection depends Because not all individuals are identical, some will have greater fitness than others. Those with superior fitness will reproduce in greater numbers and therefore will contribute more genes to successive generations. In nature, many species consist of populations occupying more than a single habitat. This constitutes a buffer against extinction If one habitat is destroyed, the species will not become extinct, because it exists in other habitats.

Sports Injuries

During the past decade, the importance of regular exercise in the maintenance of good health has been well established. Consequently, with increasing attention now focused on personal fitness, the incidence of sports-related injuries has increased significantly. Both primary care physicians and specialists can expect to see a variety of athletic injuries. All clinicians should be able to recognize these conditions and administer appropriate care. A thorough history, physical examination, musculoskeletal imaging, and laboratory testing are all important in arriving at the proper diagnosis. A treatment plan is then developed for the injured athlete based on these objective findings.

Market for medical devices

In addition to medical devices being valued as commodities, the medical device industry appears to be resistant to economic slowdown. This may be because the Baby Boomers (those born after World War II, between 1946 and 1964) are more concerned about staying fit than previous generations, and are also more receptive to high-technology solutions, e.g. having a stent implanted rather than life-long pharmaceutical use. There will also be more alternative treatment sites as patient treatment and care is moved out of the traditional hospital setting to the home, assisted living facilities, and regional treatment centers. While this has become common for some medical devices (e.g. diagnostic devices at regional laboratories and remote reading of radiological images), as technology develops, the types of alternative treatment locations will grow even more.

Water balance physiology

The physiological mechanisms involved in water balance and osmoregulation of individual insects were thoroughly reviewed in Edney's (1977) monograph and its successor by Hadley (1994a), and also by Wharton (1985) with a rather different emphasis, on the kinetics of water exchange. In the standard approach to water balance physiology, the overall flux of water through an insect is partitioned into different avenues of water loss and recovery, which vary greatly in both absolute and relative terms. A recent study on water-stressed caterpillars (Woods and Harrison 2001) illustrates this hierarchical nature of organismal physiology fitness-related performance traits represent the aggregate outcome of numerous, more mechanistic physiological traits. The performance trait in question is the growth rate of the caterpillars, which is depressed during water shortage, and the dominant mechanistic traits in this particular case involve modulation of faecal and evaporative water losses.

Resistance to extinction despite accumulation of mutations upon serial bottleneck passages of FMDV

Efficient extinction of FMDV by combinations of mutagens and inhibitors establishes an interesting contrast with resistance to extinction of FMDV clones subjected to repeated bottleneck events, experimentally achieved with serial plaque-to-plaque transfers 11, 29, 36, 37, 77, 78 . Fitness loss associated with serial bottleneck passages constitutes experimental evidence for the operation of Muller's ratchet 56 , a theoretical concept predicting that asexual populations of organisms tend to accumulate deleterious mutations unless compensatory mechanisms such as sex or recombination intervene. The experiments with FMDV have documented that, indeed, fitness loss occurs as a result of plaque-to-plaque transfers but that the decrease, rather than being uniform, follows a complex pattern 38,48,49 . During the first 20 to 40 transfers, relative fitness fluctuated around an average value that decreased in a nearly exponential manner. In the following transfers, the amplitude of the...

Mutations for survival or for extinction

A comparison of the features of FMDV populations on their way to extinction by enhanced mutagenesis, and populations subjected to plaque transfers and which elude extinction (Table 1), provides new insights into viral population dynamics. Mutagenesis-driven extinction of FMDV appears to be favored when the size of the viral population is small, the fitness of the virus low, and the mutational input does not allow for selection of compensatory mutations. In contrast, the tolerance of FMDV to accept mutations while remaining functional after repeated bottleneck passages appears to be based on occurrence of advantageous mutations which

Imaging of Stress Fractures in Runners

Running is an extremely popular form of exercise. The emphasis today on the importance of exercise and weight loss and the convenience and low cost of running as a form of exercise have undoubtedly led to this popularity. Running-related injuries are common, however, and the current focus on the importance of health, diet, and fitness as well as competitive athletics has resulted in many individuals undertaking new or increasing levels of physical activity. This results in increasing levels of stress on the musculoskeletal system. Stress fractures in runners are a common problem, but the diagnosis and treatment is often challenging. Health care providers caring for recreational and professional athletes must be knowledgeable of the signs and symptoms of these injuries and maintain a high suspicion when seeing active patients seeking care for lower extremity and axial skeletal pain, because the signs and symptoms are often vague and overlap with other diagnoses.

Butter Eggs and Cheese 3121 General Information

(3) Fitness for human consumption is still required on any local purchase food items not delivered by the SPV. d. Fitness for human consumption inspections must be conducted by the PMA both ashore and afloat. These inspections will be conducted only on locally purchased food items that were not obtained from an SPV and were not inspected by U.S. Army veterinary service personnel.

End of Replication and Exit

An alternative way of exiting infected Acanthamoeba has been reported by Berk et al. (1998). Live L. pneumophila can be released within vesicles, likely as a consequence of the amoebae trying to get rid of their food vacuoles before encysta-tion. In this process, vesicles containing hundreds of legionellae are produced, in contrast to the free legionellae released by the lytic process. Because these vesicles are of respirable-size, it has been argued that they could act as complex infectious units in the transmission of Legionnaires' disease. Furthermore, legionellae inside vesicles seem more resistant to some environmental challenges (Berk et al. 1998), suggesting that this mode of exit is associated with additional fitness advantages. Interestingly, numerous legionellae-laden vesicles are also produced by the ciliate Tetrahymena (McNealy et al. 2002), as discussed below.

Intentionality and the Self

As the self is known to be embodied, it was inevitable that the origins of the self would be examined in the context of the evolution of the brain. One would then ask what is the function of the self and how does consciousness of the self enhance the individual's fitness. Among the first to propose an evolutionary theory of the self was Gerald Edelman in The Remembered Present (1989). He linked the self to a more evolved and complex consciousness. In Edelman's view, the evolution of a self requires a neural apparatus capable of providing the individual with a schema of past, present, and future. Such a schema would enable internal reflection, a consciousness of consciousness. This in turn would free the individual of the necessity of an immediate response to environmental inputs it would in effect enable one to go offline. Such a self-reflective capacity requires what Edel-man called higher-order consciousness, in contrast to primary consciousness, which we share with many other...

Single use Gloves used for one Purpose and Discarded

Hazardous food items are products which would certainly or possibly cause, or suspected to have already caused, harm when consumed. Such items may be unfit for human consumption, suspected of being unfit for human consumption, or suspected to be the source of a food borne disease outbreak. Determination of fitness for human consumption is the responsibility of the PMA.

Treatment Of Stress Injuries

Successful treatment of stress injuries requires identification of the predisposing factor. A prolonged period of rest may result in resolution of pain, only for the symptoms to recur when the patient resumes running activities. A thorough review of training schedule, footwear, running surfaces, and other predisposing factors such as dietary and hormonal status should be performed. Most stress fractures can be managed with cessation of running and other lower extremity impact-type sports, with weight bearing only during normal daily activities. Cardiovascular fitness can be maintained with non-impact type sports such as cycling and swimming. Most stress fractures will heal in 6 to 8 weeks if compliance with protected weight bearing is followed 14 .

Pecking Orders in Domestic Fowl

Among common barnyard chickens, social behavior is a relatively simple system based on the dominance hierarchy. A power struggle begins soon after a new flock is established. The chickens quickly form a hierarchy that is quite literally a pecking order. The chickens establish their status by pecking or by threatening actions toward an opponent with the obvious intention of attacking in this manner. Superior genetic fitness is attained by the high-ranking birds. They enjoy more freedom of movement, and they have priority of access to food, better nesting sites, and favored roosting places. While the dominant males mate far more frequently than the subordinates, the dominant females actually mate less, because the subordinate females more readily display submissive and receptive postures to the males. The fitness of the dominant females is still enhanced due to the advantages gained in access to food and nesting sites. Males establish a separate hierarchy above that of the females. The...

Why Make Linkage Maps

Marker loci can be treated little differently from the co-segregation of alleles at pairs of marker loci, assuming the gene of interest does not have a substantial impact on the fitness of homozygotes or heterozygotes for the mutation. In these straightforward cases, linkage analysis packages, like CRIMAP (Green et a ., 1990), can be used to map the gene of interest. In human genetic studies, where small families are the rule, homozy-gosity mapping (Lander and Botstein, 1987) is an effective way of quickly locating a gene to a chromosome interval where positional candidate loci can then be investigated. This approach has also been successfully applied to the mapping of domestic animal mutations.

Regulation of Listeria monocytogenes Virulence Genes

Abstract Listeria monocytogenes is a gram-positive bacterium that lives within soil and decaying plant material but is also capable of transitioning into a deadly pathogen following ingestion by mammals. The bacterium makes the transition from outside environment to host via the coordinate regulation of virulence gene products that enable bacterial replication within host cells. PrfA is a transcriptional activator that is required for the expression of nearly all identified L. monocytogenes virulence gene products. The expression of the prfA gene and the activity of the PrfA protein are carefully regulated by multiple mechanisms within L. monocytogenes. Two promoters function to provide the initial levels of PrfA that direct bacterial escape from host cell vacuoles, whereas a third promoter contributes to high level expression ofprfA to promote spread of intracellular bacteria to adjacent host cells. The synthesis of PrfA protein is temperature-regulated such that prfA mRNA secondary...

Flowering time in Arabidopsis

The developmental patterns of plants show considerably more flexibility than those of animals. Most of the development process in plants occurs post-embryonically through the action of shoot and root apical meristems. Consequently, there is ample opportunity for plants to adapt their morphology to specific environmental conditions, whereas the body plan of animals is more or less fixed and only certain aspects of it may depend on the environment. One of the major developmental transitions in the life of a plant is the switch from vegetative growth to reproductive development. The timing of this switch in relation to environmental conditions is of crucial adaptive value fitness will be lost if reproduction and seed set fall in an unfavourable season or are not synchronized with other members of a population in out-crossing species. This implies that flowering time, also called bolting time, and especially the way in which it is modulated by environmental cues, is an important...

Carbon Storage Regulatory Csr System

Although specific mRNA targets of CsrA have not been identified, the CsrA-repressed transmission traits of cytotoxicity, lysosomal evasion, and motility all depend on the efficient transcription of the flagellar sigma factor, FliA (Fettes et al. 2001 Hammer et al. 2002 Molofsky and Swanson 2003). Furthermore, over-expression of csrA leads to a reduction in fliA and flaA transcript levels (Fettes et al. 2001). By analogy to other prokaryotic CsrA CsrB regulatory systems, it is predicted that L. pneumophila CsrA inhibits the stability or translation of fliA mRNA, thus affecting transcription of flaA and the expression of motility and transmission phenotypes (Romeo 1998). While data suggest that several copies of csrA are present in L. pnuemophila, the significance of multiple csrA homologs is unclear (Brassinga et al. 2003). Additional research will provide insight into how CsrA regulates its mRNA targets to enhance the fitness of L. pneumophila and control its differentiation.

Genomic Methods of Studying Differentiation

When confronted with environmental fluctuations, L. pneumophila must coordi-nately regulate its gene expression profile to enhance its fitness and adaptability. Since a large number of genes are dedicated to controlling differentiation, and a diverse repertoire of genes are expressed during the different phenotypic states, modern techniques have been applied to allow a comprehensive analysis of L. pneumophila biology. Recently, the complete genome sequences of L. pneumophila strains Lens, Paris, and Philadelphia 1 were published and many genes predicted to promote microbial adaptation were identified, including six sigma factors, 13 histidine kinases, 14 response regulators, and 23 members of the GGDEF-EAL family of regulators (Cazalet et al. 2004 Chien et al. 2004). A comparison of the genome sequences of Lens, Paris, and Philadelphia 1 revealed a remarkable plasticity and diversity of L. pneumophila, two characteristics thought to enhance the versatility of the microbe. In addition,...

Generational vs steady state

The steady-state genetic algorithm shown in Figure 8.6 selects a number of individuals from the population, applies the reproduction, crossover and mutation operators to them and then reinserts them into the population using a variety of criteria. These replacement criteria usually take the form of replacing the weaker (or weakest) solutions in the population and therefore increasing the fitness of the population in this way.

Application guidelines Introduction

2 An objective function should be constructed which relates the decision variables of the problem and assigns a 'fitness' to the solution that determines how good that solution is. Ideally this function will be as monotonic as possible (i.e. it will vary consistently with decision variable values), functions which vary wildly with respect to the decision variables are very difficult to optimize by using a GA. 3 The number and severity of constraints on the solutions should be small. A number of problems require that only a small number of the possible solutions can be considered as feasible. When this occurs, there are methods to implement constraints in genetic algorithms, but on the whole, soft constraints which penalize the fitness of solutions if they are outside the required bounds are generally preferable. If there are soft constraints on a number of variables in the fitness function, then a multi-objective approach should be considered as an alternative.

Evolutionary approaches to the reverse engineering problem

A succession of papers (Ando and Iba, 2001a, 2001b) have described methods of using GAs to extract the gene regulatory networks from gene expression data. Mostly, they used the approach detailed above by Weaver, et al. (1999) as the model for forward activation and reverse engineering their gene regulatory networks. The GA is applied to the problem in a number of ways, in adding noise to the reverse engineering process for example, but the results most often reported refer to the following representation of the network to the GA. The chromosome of the GA is encoded as a matrix of floating point values which correspond to the weight matrix between gene timesteps (as in Figure 8.9). The fitness function for the GA is calculated as the sum, over all timesteps, of the difference between the predicted and actual level of activation for the gene expression. The GA is then allowed to optimize this matrix of weights for these criteria. Another objective which is factored into the fitness...

The Process of Natural Selection

Natural selection occurs through the interaction of three factors variation among individuals in a population in some trait, fitness differences among individuals as a result of that trait, and heritable variation in that trait. If those three conditions are met, then the characteristics of the population with respect to that trait will change from one generation to the next until equilibrium with other processes is reached. An example that demonstrates this process involves the peppered moth. It has two forms in the United Kingdom, a light-colored form and a dark-colored form there is variation in color among individuals. Genetic analysis has shown that this difference in color is caused by a single gene the variation has a heritable basis. The moth is eaten by birds that find their food by sight. The light-colored form cannot be seen when sitting on lichen-covered trees, while the dark-colored form can be seen easily. Air pollution kills the lichen, however, and turns the trees dark...

Measuring Natural Selection

Direct methods involve two kinds of observation. First, there is observation of changes in a population following some change in the environment. There are many types of environmental changes, including man-made changes, natural disasters, seasonal changes, and introductions of species into new environments. For example, from the changes in the peppered moth following a change in pollution levels, one can measure the effects of natural selection. The second type of observation is the direct measurement of fitness differences among individuals with trait differences. For example, individual animals are tagged at an early age and survival and reproduction are monitored. Then, statistical techniques are used to find a relationship between fitness and variation among individuals in some trait. Alternatively, comparisons of traits are made between groups of individuals, such as breeding and nonbreeding, adults and juveniles, or live and dead individuals, again using statistical techniques....

Selection Versus Chance

Are too high to be attributable to selection, but instead, most variability at the molecular level is attributable to chance. The result, they say, has been a large amount of enzyme and DNA variability that is selectively neutral. They are neutral in the sense that their contributions to an organism's fitness are so small that their occurrence is attributable more to chance than to natural selection. Neutralists do not believe that most molecular mutations are neutral they assume that most are harmful and are eliminated by natural selection. Rather, they believe that those that currently exist are adaptively equivalent. Proponents of the neutrality theory believe that changes in DNA and amino acid sequences are for the most part neutral, consisting primarily of the gradual random replacement of functionally equivalent alleles.

Introduction and background

(2) they are an artifact or byproduct of evolutionary forces acting to maximize reproductive success and inclusive fitness in sexually reproducing organisms (Rose 1991). The next chapter will examine evolutionary models of senescence and the molecular and genetic bases of senescence while exploring how these fundamental concepts relate to human senescence and life span. Researchers and disciplines often define senescence and aging differently (Crews 1993a Harper and Crews 2000). For example, Comfort (1979) defined senescence as a deteriorating process, with an increasing probability of death with increasing age (p. 8). Fifteen years later, Finch (1994) refined this definition to include . . . age-related changes in an organism that adversely affect its vitality and function . . . (Associated with an) increase in mortality rate as a function of time (p. 5). Rose (1991) faulted earlier definitions for not including any aspect of reproduction, an essential component for an evolutionary...

Self Protection and Resistance

Inferior to most men and thus could not effectively defend themselves. Women are socialized to focus on beauty first, and more recently, on physical fitness (i.e., aerobic endurance), but not on physical strength. Like the women of the early twentieth century, modern women believe in their natural physical weakness and do little to change it. These beliefs persist in spite of evidence that shows women are four times more likely to escape a would-be rapist than they are to be raped by him (Riger & Gordon, 1989).

Variation at the phosphoglucose isomerase locus

Phosphoglucose isomerase (PGI) (see also Section 5.2.2) is involved in fuel supply to the flight muscles, catalysing an intervening step in glycolysis. Genetic variation at the PGI locus of Colias butterflies has been exploited as a model system for examining the fitness implications of different phenotypes (for review see Watt 1991). There are four major PGI alleles, and in vitro study shows that their thermal stability is inversely related to kinetic effectiveness. This trade-off between kinetics and stability of the enzyme should maintain the polymorphism in a thermally fluctuating environment. Among genotypes in the wild, thermally stable allozymes are favoured under warm conditions as predicted, while the most kinetically effective genotypes fly over a wider temperature range and survive better in low-to-moderate temperature habitats than their relatives with the thermally more stable genotypes (Watt et al. 1983). Much of the selection on the PGI locus appears to operate at more...

Herbivory and microbial infection

Not only abiotic conditions, but also biotic factors may limit the ecological niche and can elicit specific stress responses in plants and animals. Such biotic factors can be other organisms that decrease the fitness of plants or animals by consumptive action. Ecologists distinguish herbivores (animals consuming plants or parts of them), predators (animals consuming other animals after catching and killing them), parasites (organisms living inside or on the surface of plants or animals, diverting resources from the host to themselves), and parasitoids (animals living inside other animals but killing the host to complete the life cycle). The initial contact between the two players in such interactions is invariably accompanied by stress and specific defence responses, especially in the victim being preyed upon, being consumed, or acting as a host. In this section we will review studies dealing with stress responses associated with attack by herbivores and pathogenic

Reproduction and Survivial

The characterization of an organism's reproductive strategy involves more than an understanding of reproductive traits. There is a successful process by which offspring are produced, and reproductive success is one of the two principal measures of fitness the other is survival. Because a successful reproductive strategy ultimately results in high fitness, any discussion of these strategies bears directly on issues of natural selection and evolution.

Types And Patterns Of Seed Predation And Dispersal

The fate of seeds is critical to plant reproduction. A variety of animals feed exclusively or facultatively on fruits or seeds, limiting potential germination and seedling recruitment. Many animals, especially frugivores, facilitate seed dispersal. Dispersal of seeds is necessary for colonization of new habitats and for escape from high mortality near parent plants, but relatively few studies have measured the advantages of seed dispersal to plant fitness (Howe and Smallwood 1982). In contrast to pollination, effective seed dispersal relies less on disperser specialization than on movement to suitable habitat (Wheelwright and Orians 1982). These mechanisms confer varying degrees of dispersal efficiency and advantages for seedling growth, depending on ecosystem conditions.

Two forms of selection

Because the differences in reproduction and survival between genotypes depend on the environment in which the genotypes live and develop and because organisms may alter their own environments, there are two fundamentally different forms of selection. In the simple case, the fitness of an individual does not depend on the composition of the population rather it is a fixed property of the individual's phenotype and the external physical environment. For example, the relative ability of two plants that live at the edge of the desert to get sufficient water will depend on how deep their roots grow and how much water they lose through their leaf surfaces. These characteristics are a consequence of their developmental patterns and are not sensitive to the composition of the population in which they live. The fitness of a genotype in such a case does not depend on how rare or how frequent it is in the population. Fitness is then frequency-independent. will affect their relative fitnesses. An...

Rate of change in gene frequency

The general expression for the change in allele frequency derived in Box 19-5 is particularly illuminating. It says that Ap will be positive (A will increase) if the mean fitness of A alleles is greater than the mean fitness of a alleles, as we saw before. But it also shows that the speed of the change depends not only on the difference in fitness between the alleles, but also on the factor pq, which is proportional to the frequency of heterozygotes (2pq). For a given difference in fitness of alleles, their frequency will change most rapidly when the alleles A and a are in intermediate frequency, so pq is large. If p is near 0 or 1 (that is, if A or a is nearly fixed at frequency 0 or 1), then pq is nearly 0 and selection will proceed very slowly. When alternative alleles are not rare, selection can cause quite rapid changes in allelic frequency. Figure 19-12 shows the course of elimination of a malic dehy-drogenase allele that had an initial frequency of 0.5 in a laboratory...

Balance between mutation and selection

The general equation for this equilibrium is given in detail in Box 19-6. It shows that the frequency of the deleterious allele at equilibrium depends on the ratio s, where is the probability of a mutation's occurring in a newly formed gamete (mutation rate) and s is the intensity of selection against the deleterious genotype. For a completely recessive deleterious allele whose fitness in homozygous state is 1 - s, the equilibrium frequency is So, for example, a recessive lethal (s 1) mutating at the rate of 10-6 will have an equilibrium frequency of 10-3. Indeed, if we knew that an allele was a recessive lethal and had no heterozygous effects, we could estimate its mutation rate as the square of its frequency. But the biological basis for the assumptions behind such calculations must be firm. Sickle-cell anemia was once thought to be a recessive lethal with no heterozygous effects, which led to an estimated mutation rate in Africa of 0.1 for this locus, but now we know that its...

Reproductive isolation due to Wolbachia infection with different Wolbachia

Wolbachia may have a role in speciation of arthropods by generating reproductive isolation (Rokas 2000), although some argue that Wolbachia's role(s) remain unproved (Hurst and Schilthuizen 1998). Typically, Wolbachia cause unidirectional cytoplasmic incompatibility when a Wolbachia-infected male mates with an uninfected female (Figure 4.2A). The eggs or embryos of such matings die, resulting in a fitness cost to uninfected females, which over time results in the infected cytotype becoming fixed in the population. A problem with this speciation hypothesis is that Wolbachia are not transmitted 100 of the time from a female to her progeny, so that some progeny will be produced that are compatible. Secondly, incompatibility is not completely expressed (incomplete penetrance of the trait) when infected males and uninfected females mate in natural populations (perhaps due to differences in the titer of the Wolbachia within individuals). Furthermore, selection on both the host and Wolbachia...

Decoupling of upper and lower lethal limits

In marine species it has long been known that performance at high and low temperatures is often inversely correlated among populations or species. That is, an improvement in high temperature tolerance leads to a decline in low temperature tolerance and vice versa (Prosser 1986 Cossins and Bowler 1987). Building on previous work (Ushakov 1964 Prosser 1986), Portner and his colleagues (Portner 2001, 2002 Portner et al. 1998, 2000) have provided the most extensive exploration of this relationship. In essence, they have argued that in complex metazoans, critical temperatures that affect fitness (i.e. survival and reproduction) are not set by cellular level responses (such as the stress protein response), but are rather set by a transition to anaerobic metabolism. These pejus ( deleterious) temperatures, which are less extreme than traditionally measured critical limits, result from insufficient aerobic capacity of mitochondria at low temperatures, and a mismatch between excessive oxygen...

Focus on natural variation

The use of natural variation is also important because it allows ecological genomics to get away from the present focus on laboratory mutants (see the work presented in Chapter 5). Knocking-out genes to analyse their function is a crucial tool in mechanistic studies, but the relevance of the results for understanding functions in the environment is limited. The point is, we need to know the fitness consequences of gene mutations under ecologically relevant conditions. Where nature is already providing this variation, it is best to make optimal use of it.

Rate of moIecu Iar evoIution

There is no simple relation between the number of mutations in DNA or substitutions of amino acids in proteins and the amount of functional change in those proteins. Although it is possible that only one or a few mutations can lead to a major change in the function of a protein, the more usual situation is that DNA accumulates substitutions over long periods of evolution without any qualitative change to the functional properties of the encoded proteins. Some of the substitutions may, however, have smaller effects, influencing the kinetic properties, timing of production, or quantities of the encoded proteins that, in turn, will affect the fitness of the organism that carries them. Mutations of DNA can have three effects on fitness. First, they may be deleterious, reducing the probability of survival and reproduction of their carriers. All of the laboratory mutants used by the experimental geneticist have some deleterious effect on fitness. Second, they may increase fitness by...

What Will The End Result Be After Many Generations Of Mating Of Each Type

In population 10, it is discovered that the A a mutation rate is 5 X 10 6 and that reverse mutation is negligible. What must be the fitness of the a a phenotype d. In population 6, the a allele is deleterious furthermore, the A allele is incompletely dominant, so that A A is perfectly fit, A a has a fitness of 0.8, and a a has a fitness of 0.6. If there is no mutation, what will p and q be in the next generation 21. If we define the total selection cost to a population of deleterious recessive genes as the loss of fitness per individual affected (s) multiplied by the frequency of affected individuals (q2), then

Medical Terminology Case Studies - Skin


K.B., a 32-year-old fitness instructor, had noticed a tiny hard lump at the base of her left nostril while cleansing her face. The lesion had been present for about 2 months when she consulted a dermatologist. She had recently moved north from Florida, where she had worked as a lifeguard. She thought the lump might have been triggered by the regular tanning salon sessions she had used to retain her tan because it did not resemble the acne pustules, blackheads, or resulting scars of her adolescent years. Although dermabrasion had removed the obvious acne scars and left several areas of dense skin, this lump was brown-pigmented and different. K.B. was afraid it might be a malignant melanoma. On examination, the dermatologist noted a small pearly-white nodule at the lower portion of the left ala (outer flared portion of the nostril). There were no other lesions on her face or neck.

Density Independent Factors

Trees Surviving Direct Lightning Hit

Many environmental changes occur relatively slowly and cause gradual changes in insect populations as a result of subtle shifts in genetic structure and individual fitness. Other environmental changes occur more abruptly and may trigger rapid change in population size because of sudden changes in natality, mortality, or dispersal.

Frequencydependent selection maintains genetic variation within populations

Perissodus Microlepis Mouth

Natural selection often preserves variation as a polymorphism the coexistence within a population, at frequencies greater than mutations can produce, of two or more alleles at a locus. A polymorphism may be maintained when the fitness of a genotype (or phenotype) varies with its frequency relative to that of other genotypes (or phenotypes) in a population. This phenomenon is known as frequency-dependent selection.

Phages and Pathogenicity

Ikeda Tomizawa Transduction

A phenomenon called lysogenic conversion is often involved in the modulation of host pathogenesis by phage. After incorporation of a temperate phage genome into the host chromosome, most prophage genes are silenced, especially those involved in virus morphogenesis and host cell lysis. In contrast, the genes needed to maintain the lysogenic state are normally expressed during lysogeny. However, bioinformatic analyses have demonstrated that many phage-encoded genes have unknown functions, and it is generally assumed that temperate phages can serve as vectors to introduce novel genetic information into their host that may enhance their fitness in certain environments. These coding sequences may themselves directly specify new properties or act by influencing the expression of existing genes. If this new environment happens to be the human body, the results can be dramatic. Table 13.1. shows several examples of pathogens, their prophages, and the toxins or virulence factors that are...

Error catastrophe of FMDV

Extinction of FMDV by enhanced mutagenesis has been studied in cell culture using the mutagenic agents FU, AZC and ribavirin, alone or in combination with the antiviral inhibitors guanidine, heparin and mycophenolic acid (Fig. 2). During cytolytic infections in cell culture, low viral load and low viral fitness favoured extinction of FMDV by FU and AZC 59, 65 . The effect of fitness can be interpreted as a lower value of the superiority of the master sequence (ao in Eq. (1)) and, therefore, a decrease in vmax. FMDV populations in their way towards extinction showed no mutations in the consensus sequence, but displayed increases in the complexity of the mutant spectra, as quantified by the mutation frequency and Shannon entropy 43a, 59, 66 Gonzalez-Lopez et al., submitted for publication . Remarkably, the maximum increases of complexity were quantified for the FMDV RNA-dependent RNA polymerase (3D) which is very conserved in FMDV. This probably reflects an uncontrollable accumulation...

Tauxe Campylobacter Jejuni Current Status And Future Trends.

Sanitation and disinfection', J Food Prot 55, 808-14. brandl m t and mandrell r w (2000), 'Use of confocal microscopy and the green fluorescent protein in ecological studies of Salmonella on plant surfaces', J Scanning Microsc 22, 83-9. brandl m t and mandrell r e (2002), 'Fitness of Salmonella enterica serovar

Environmental contamination

In the case of grasshoppers treated with deltamethrin, one day after treatment, numbers were significantly reduced. There was no local loss of species, although population levels, especially of flightless bushhoppers, were reduced, even after summer rain (Stewart, 1998). Nevertheless, caution is required. Not only may insecticides be adversely synergistic with other impacts but, as demonstrated by Cilgi and Jepson (1995), they can have subtle effects such as reduced fitness on larval and adult butterflies when deltamethrin is applied at only 1 640th of the field dose rate.

Development Of The Concept

Group selection theory was advanced during the early 1960s by Wynne-Edwards (1963,1965), who proposed that social behavior arose as individuals evolved to curtail their own individual fitnesses to enhance survival of the group. Populations that do not restrain combat among their members or that overex-ploit their resources have a higher probability of extinction than do populations that regulate combat or resource use. Selection thus should favor demes with traits to regulate their densities (i.e., maintain homeostasis in group size). Behaviors such as territoriality, restraint in conflict, and suppressed reproduction by subordinate individuals (including workers in social insect colonies) thereby reflect selection (feedback) for traits that prevent destructive interactions or oscillations in group size. This hypothesis was challenged for lack of explicit evolutionary models or experimental tests that could explain the progressive evolution of homeostasis at the group level (i.e.,...

Regulation of Type I Ifn Gene Expression

Type Ifn Dependent Genes

Two nucleic acid-editing enzymes, adenosine deaminase acting on RNA (ADAR) and APOBEC3G, have also been shown to be ISG. ADAR-mediated transition of nucleotides from A to I disrupts base pairing and the AU base pair is replaced by the less stable IU pair, which destabilizes dsRNA. This A-I editing has been found in multiple viral RNA sites of negative-strand RNA viruses, and it has been associated with persistent infection (Murphy et al. 1991). APOBEC3G is a cytosine deaminase that converts cytidine to uridine in single-stranded proviral DNA, which results in hypermutation of the HIV-1 genome. Expression of APOBEC3G has been shown to be upregulated by IFNa (Chen et al. 2006 Yu et al. 2003). Thus both APOBEC3G and ADAR are IFN-induced antiviral proteins that can induce hypermutation of the viral genome and decrease viral fitness.

Roulette wheel selector

This selector works by adding all the fitness values of chromosomes in the population together to create a 'virtual roulette wheel'. This wheel is then spun to see which of the individuals is chosen for selection into the next generation. As can be seen by Figure 8.2, if the wheel is 'spun' there is a much greater chance of solution with higher fitness being selected over the other solutions in the 'roulette wheel'. This affords filter solutions a better chance of being kept in the next generation than the others. However, an important point is that there is still a chance that any of the solutions can be selected, as the selection procedure depends on a random number. This method allows the selection to be biased towards Figure 8.2 Roulette wheel selection the total fitness of a population of chromosomes can be represented as a wheel, where the fitness of an individual chromosome is represented an appropriate 'slice' of the wheel the higher the fitness value, the larger the portion...

Quasispecies dynamics

Populations of RNA viruses are not defined genetic entities but are distributions of related, non-identical genomes termed viral quasispecies 22, 24, 27, 32-34, 40 . Because of high mutation rates, viral mutants are produced continuously during virus replication, and in such a way that any individual genomic sequence has a very fleeting existence. Thus the system is a highly dynamic mutant cloud whose fine composition is constantly modelled by the environment. A distinctive feature of RNA genetics is that the rapid response to an environmental change is directed by ensembles of genomes rather than by individual genomes whose behavior cannot be understood except as part of an ensemble 24, 33, 34 . The quasispecies theory was formulated as a general theory of molecular evolution 30, 31 but has been extended to describe the dynamics of finite populations of replicons subjected to environmental (fitness) variations 34, 74 . Because of its

Endangered Species on the Cloning List

A broader question involves the potential role of cloning in maintaining species and genetic diversity. It has been argued that the selective cloning of individual members of a species will lead to a reduction in genetic diversity due to a streamlined gene pool. This may ultimately affect the survival and adaptability of a species. Moreover, cloning does not impact directly the conditions that led to the loss of species fitness, which are reflected in reproduction and survival rates. In many instances, species become endangered due to a loss of habitat thus, survival of the species may require long-term existence in captivity. In certain cases, attempts have been made to return animals bred in captivity to their natural habitat however, it is not clear that these efforts will be successful in general. The reproductive technologies and long-term effects of captivity may have serious consequences on the survival of the species once reintroduced to the wild. Some successes have been...

Ecological implicationsUVB and the structure of seaweed communities

Linking UV-effects on macroalgae with trophic interactions seems to be an interesting, but as yet not fully accounted venue for further exploiting the effects of climatic and ecological drivers on the performance and fitness of seaweeds and the species composition and productivity of seaweed communities. Presently, too few studies tested the interactive effects of UV-exposure and herbivory on alga-consumer interactions to draw general conclusions about the influence of UV-radiation on herbivory. It seems likely that UV-induced chemicals may indirectly change the susceptibility of algae to consumers by altering the function of existing chemicals, which could in- or decrease algal palatability. Alternatively, UV-induced compounds may have multiple functions. Schmitt et al. (1995) demonstrated that herbivore-deterrent chemicals displayed also anti-fouling activities. To our knowledge, only the study by Pavia et al. (1997) suggests multiple functions in UV-induced phlorotannins. The...

Dennis G Caralis md PhD mph faha facc and Stamatis Dimitropoulos md

Protection Physical Inactivity Is an Independent Risk Factor for the Development of Cardiovascular Disease, Coronary Disease, and Lower Extremity Arterial Disease What is the Relation of Physical Fitness to Future Cardiovascular Events or Total Mortality Higher Levels of Physical Fitness Delay All-Cause Mortality and Cardiovascular Mortality in Particular Does Moderate Daily Exercise Have an Impact on Secondary Prevention of Coronary Heart Disease Proposed Biological Mechanisms by Which Exercise May Contribute to the Primary and Secondary Prevention of Coronary Heart Disease References

Factors Affecting Expression of Defenses

Defensive compounds may be energetically expensive to produce, and their production competes with production of other necessary compounds and tissues (e.g., Baldwin 1998, Chapin et al. 1987, Herms and Mattson 1992, Kessler and Baldwin 2002, Strauss and Murch 2004). Some, such as the complex phenolics and terpenoids, are highly resistant to degradation and cannot be catabolized to retrieve constituent energy or nutrients for other needs. Others, such as alkaloids and nonprotein amino acids, can be catabolized and the nitrogen, in particular, can be retrieved for other uses, but such catabolism involves metabolic costs that reduce net gain in energy or nutrient budgets. Few studies have addressed the fitness costs of defense. Baldwin (1998) evaluated seed production by plants treated or not treated with jasmonate, a phytohomone that induces plant defenses. Induction of defense did not significantly increase seed production of plants that came under herbivore attack but significantly...

Growth Hormone And Abdominal Obesity

The relationship between regional fat distribution and GH secretion has only recently been considered. No significant correlation was found between the waist-to-hip ratio and 24-hour GH secretion rates in a study of 21 healthy men (74). However, in healthy non-obese men and women intra-abdominal fat mass had a strong negative exponential relationship with mean 24-hour serum GH concentrations which was independent of age, gender and physical fitness (75). This indicates that, for each increment in intra-abdominal fat mass, there is a more than linear reduction in mean 24hour GH concentration.

Clinical Content Adds Interest

Remember that Brenda experienced muscle pain and fatigue during her training, and that she had an episode where she experienced severe pain in her left pectoral region following an intense workout. Boxed Clinical and Fitness Applications Applications in clinical medicine general health, and physical fitness of basic physiological principles are found intermittently throughout the body of the text. Placement of these applications is precise they always relate to concepts that have been presented immediately preceding the application. As such, they provide immediate reinforcement for students learning the fundamental principles on which the applications are based. This is preferable to longer but fewer magazine-article-type applications that are separated from the text information. The immediate reinforcement allows students to see the practical importance of learning the material they have just studied.

Stress and the ecological niche

Ecological Niche Graph

Ecologists have invented the concept of an ecological niche to organize their thoughts about the ways in which organisms fit into their environment. The inception of this concept in the ecological literature is attributed to the American ornithologist Joseph Grinnell with his now classical paper on the California thrasher published in 1917, but the most widely used and influential elaboration of the niche concept is due to Hutchinson (1957). Hutchinson defined the niche in terms of any number of conditions and resources that limit the distribution of a species. The niche was pictured as an n-dimensional hypervolume that envelops those values of continuously varying environmental factors that allow long-term survival of the species. As an illustration of the Hutchinsonian niche concept we reproduce a two-dimensional picture of fitness in the collembolan Folsomia Candida as a function of zinc exposure and food density (Fig. 6.1 Noel et al. in press). Figure...

Plant Productivity Survival and Growth Form

Primary Production Limiting Factor

Plant condition is affected by developmental stage and environmental conditions and determines herbivore population dynamics (see Chapters 3 and 6) and plant capacity to compensate for herbivory. Low or moderate levels of herbivory often increase photosynthesis and stimulate plant productivity (e.g., Belovsky and Slade 2000, Carpenter and Kitchell 1984, Carpenter et al. 1985, C. Carroll and Hoffman 1980, Detling 1987, 1988, M. Dyer et al. 1993, Kolb et al. 1999, Lowman 1982, McNaughton 1979,1993a, Pedigo et al. 1986, Trumble et al. 1993, S. Williamson et al. 1989), whereas severe herbivory usually results in mortality or decreased fitness (Detling 1987,1988, Marquis 1984, S.Williamson et al. 1989). Healthy plants can replace lost foliage, resulting in higher annual primary production, although standing crop biomass of plants usually is reduced. McNaughton 1979). D. Inouye (1982) reported that herbivory by several insect and mammalian herbivores had a variety of positive and negative...

The Science Of Free Speech

In 1951, at the height of anticommunist repression in the United States, a military review board demanded that Pauling explain his political views. The board's aim was to determine his fitness to review the classified government documents that were sometimes involved in Caltech grant requests.

Post Transcriptional Control of Differentiation 71 LetALetS Two Component System

Similar to BvgA BvgS, the L. pneumophila LetA LetS two-component system likely utilizes a four-step phosphorelay to fine-tune its panel of transmission traits. A threonine-to-methionine substitution, four residues from the proposed autophosphorylation site in LetS, creates a L. pneumophila mutant locked in a Let-intermediate (let1) phase (Edwards and Swanson, unpublished). When compared with wild-type and letS null bacteria, let1 mutants are intermediate in their ability to enter and survive in macrophages and intermediately cytotoxic. In contrast, let1 mutants resemble either letS null bacteria or wild-type cells for each of the other known transmissive phase phenotypes (Edwards and Swanson, unpublished). Interestingly, while only 30-50 of let1 mutants are motile, promoter analysis of the flaA gene demonstrates that the entire population of cells express flaA, though later than wild-type, indicating that robust control of the flagellar regulon is required for flagellum assembly...

Transcriptional Control of Differentiation via Sigma Factors

Recent biochemical and genetic data indicate that the effector molecule of the stringent response, (p)ppGpp, controls sigma factor competition for the RNAP core enzyme (Nystrom 2004). In particular, (p)ppGpp not only regulates the ability of different alternative sigma factors to bind RNAP but also controls the production and activity of many sigma factors (Magnusson et al. 2005). Therefore, under nutrient-limiting conditions, the stringent response governs sigma factor competition and other aspects of gene transcription, thus altering the expression profile and enhancing the fitness of the microbe.

Natural selection results in adaptation

Structure Thrum Flower

The reproductive contribution of a phenotype to subsequent generations relative to the contributions of other phe-notypes is called its fitness. The word relative is critical The absolute number of offspring produced by an individual does not influence the genetic structure of a population. Changes in absolute numbers of offspring are responsible for increases and decreases in the size of a population, but only the relative success of different phenotypes within a population leads to changes in allele frequencies that is, to evolution. To contribute genes to subsequent generations, individuals must survive to reproductive age and produce offspring. The relative contribution of individuals of a particular phenotype is determined by the probability that those individuals survive multiplied by the average number of offspring they produce over their lifetimes. In other words, the fitness of a phenotype is determined by the average rates of survival and reproduction of individuals with...

Interactions critical questions

Determining the likely abiotic thresholds for survival, development, or reproduction in the laboratory, or perhaps with limited caging experiments, is only the first step in explaining their relevance to population dynamics and ultimately to the abundance and distribution of a species (or suite of species) (Kingsolver 1989 Holt et al. 1997). Several critical questions remain, including which stage, gender, or age group is most likely to experience the critical population bottleneck (van der Have 2002), how physiological characteristics and fitness are actually related (Feder 1987 Kingsolver 1996), and how frequently environmental extremes might be encountered. In some cases, the immature stages might be most critical because development generally proceeds within a smaller range of environmental variables (e.g. temperature) than the adult organisms can survive (van der Have 2002). In consequence, both abundance and distribution might be determined by growth conditions faced by the...

LPXTG Proteins and Sortases

The biodiversity DNA array data revealed two genes encoding LPXTG proteins, ORF29 and ORF2568, present exclusively in serotypes 1 2b, 4a, 4b, and 4c (Doumith et al. 2004). Since L. monocytogenes serotype 4b strains are responsible for the majority of epidemic cases of listeriosis, these genes were investigated for their role in infection. Inactivation of these genes does not however alter either infection in vitro or virulence following oral infection of hEcad mice (Sabet et al. 2005). However, the bacterial load of the ORF2568 deletion mutant in organs, especially spleens, increases compared to the wild type 4b strain. Inactivation of ORF2568 may somehow affect expression or function of other virulence factors and enhance bacterial fitness in organs.

Assess Pattern of Results in Relation to Markers of Susceptibility to Selection Bias

In some instances, the mechanism thought to underlie selection bias may be directly amenable to empirical evaluation. A classic selection bias is the healthy worker effect in studies that compare health and mortality among industrial workers with health and mortality patterns in the community population. The demand for fitness at the time of hire and for sustained work in physically demanding jobs gives rise to an employed group that is at lower risk of mortality from a range of causes as compared to the general population (Checkoway et al., 1989), literally through selection for employment. Consistent with the approach suggested for examining selection bias, the more highly selected subgroups are in regard to the physical or other demands of their job that predict favorable health, such as education or talent, the more extreme the discrepancy tends to be (Check-oway et al., 1989). One might expect the magnitude of selection to be greater for a job requiring intense physical labor,...

The role of parasites in regulating host populations

Parasitism Effect Host Fecundity

Parasites can impact total host population size (N) through their effects on individual host fitness, including parasite-induced host mortality and reductions in host fertility. To illustrate this mathematically for the microparasite model shown in Box 4.1, the change in total host population size can be written as, Relative to microparasites, host regulation by macroparasites further depends on the degree to which parasites are aggregated among hosts (Anderson and May 1978 May and Anderson 1978 Tompkins et al. 2001). This effect arises because hosts that harbor high numbers of parasites are most likely to be removed from the population, whereas host with few parasites might experience little or no reductions in fitness. When a large proportion of a macroparasite population is aggregated in a small proportion of the hosts, stable regulation is more likely, although at the other extreme, parasites can be so aggregated that the host escapes regulation entirely. As most macroparasites...

Reproductive Strategies

The concept of reproductive strategies is closely related to that of natural selection. Natural selection results in the more fit individuals within a population, under a given set of environmental circumstances, being more likely to pass on their genes to future generations. By this process, the gene pool (genetic makeup) of the population is altered over time. An organism's fitness can be assessed by evaluating two key characteristics survival and reproductive success. The organism's reproductive strategy, then, is that blend of traits enabling it to have the highest overall reproductive success. Application of the term reproductive strategy has also been extended to describe patterns beyond individual organisms the population, species even entire groups of similar species, such as carnivorous mammals.

BOX 195 The Effect of Selection on Allele Frequencies

Further suppose that the three genotypes have the relative probabilities of survival to adulthood (viabilities) of WA A, WA a, and Wa a. For simplicity, let us also assume that all fitness differences are differences in survivorship between the fertilized egg and the adult stage. (Differences in fertility give rise to much more complex mathematical formulations.) Among the progeny, once they have reached adulthood, the frequencies will be So defined, W is called the mean fitness of the population because it is, indeed, the mean of the fitnesses of all individuals in the population. After this adjustment, we have

Neutral mutations accumulate within species

As we saw in Chapter 12, some mutations do not affect the functioning of the proteins encoded by the mutated genes. An allele that does not affect the fitness of an organism is called a neutral allele. Such alleles, untouched by natural selection, may be lost, or their frequencies may increase with time, purely by genetic drift. Therefore, neutral alleles often accumulate in a population over time, providing it with considerable genetic variation.

Fatty acids and cardiovascular risk clinical epidemiology

Abdominal obesity is linked to increased non-esterified fatty acid (NEFA) concentrations and turnover that are resistant to suppression by insulin (1,2). Similarly, physical activity and maximal oxygen consumption, a marker of physical fitness, are inversely associated with plasma NEFA concentrations measured as the area under-the-curve during a standard 2-h oral glucose tolerance test (3). Familial combined hyperlipidemia, a relatively common autosomal dominant trait, is associated with high plasma NEFAs as well as greater and more prolonged elevation of NEFAs following a fat load (4). Obesity, sedentary lifestyles, and familial combined hyperlipidemia are associated with high blood pressure, abnormal glucose and lipid metabolism, and more cardiovascular events including sudden death (5-7).

Overdominance and underdominance

First, the heterozygote might be more fit than either homozygote, a condition termed overdominance in fitness. When one of the alleles, say, A, is in low frequency, there are virtually no homozygotes A A and the allele occurs almost entirely in heterozygous condition. Since heterozygotes are more fit than homozygotes, A alleles are almost all carried by the most fit genotype, so A will increase in frequency, while a decreases in frequency. On the other hand when a is in very low frequency, it occurs almost entirely in heterozygous condition. In this case, a alleles are almost all carried by the most fit genotype, and they will increase in frequency at the expense of A alleles. The net effect of these two pressures, one increasing the frequency of A alleles when they are rare, and the other increasing a alleles when they are rare, is to bring the allele frequencies to a stable equilibrium that is intermediate between a composition consisting of all of one allele or all of the other....

Efficiency Of Resource

Fitness accrues to organisms to the extent that they survive and produce more offspring than do their competitors. Hence, the efficiency with which assimilated resources are allocated to growth and reproduction determines fitness. However, except for sessile organisms, much of the assimilated energy and material must be allocated to activities pursuant to food acquisition, dispersal, mating, competition, and defense. The amount of assimilated resources allocated to these activities reduces relative growth efficiency (Schultz 1983, Zera and Denno 1997). Clearly, the diversion of resources from growth and reproduction to these other pathways must represent a net benefit to the insect.

The Management Of Chronic Stress

Exercise and the maintenance of physical fitness also reduce the inappropriate arousal responses to stressful life events. The effects are reported immediately after exercise and following a regular exercise programme (Markoff, Ryan & Young, 1982 Ransford, 1982). Both basal and phasic physiological responses are reduced as a result of increased physical fitness. Once more motivation of the patient to maintain this programme is difficult even after the rationale is explained.

Individual Insects

THE INDIVIDUAL ORGANISM IS A FUNDAMENTAL unit of ecology. Organisms interact with their environment and affect ecosystem processes largely through their cumulative physiological and behavioral responses to environmental variation. Individual success in finding and using necessary habitats and resources to gain reproductive advantage determines fitness. Insects have a number of general attributes that have contributed to their ecological success (Romoser and Stoffolano 1998).


Table 3.1 shows the performances of four types of systems. CV-1, CV-2, and CV-3 are three evaluations. In the table, GAs-RBF-SVMs are SVMs with traditional RBF kernels and the systems' regularization parameter C and the RBFs' g are optimized with GAs. GAs-RBF-SVMs-1 uses the same fitness evaluation as that used by GKTSESs and GAs-RBF-SVMs-2 used the same voting scheme as that used by EVKMs. Table 3.2 shows four systems' average prediction accuracies and the standard deviations of testing accuracies.

Resource Budget

Larger animals travel more efficiently than do smaller animals, expending less energy for a given distance traversed. Hence, larger animals often cover larger areas in search of resources. Flight is more efficient than walking, and efficiency increases with flight speed (Heinrich 1979), enabling flying insects to cover large areas with relatively small energy reserves. Dispersal activity is an extension of foraging activity and also constitutes an energy drain. Most insects are shortlived, as well as energy-limited, and maximize fitness by accepting less suitable,

Oviposition Behavior

Insects deposit their eggs in a variety of ways. Most commonly, the female is solely responsible for selection of oviposition site(s). The behaviors leading to oviposition are as complex as those leading to mating because successful ovipo-sition contributes to individual fitness and is under strong selective pressure.


Potential role of selection is diminished. The inbred progenitor population is considered to be mutation-free and should be preserved in that state. The mean fitness of all MA lines is estimated at generation time t. Also, the mean fitness of the mutation-free population can be inferred. The first parameter of interest is the change in mean fitness per generation that is due to MA (DM). Secondly, we can estimate the increase in genetic variance in fitness among inbred lines per generation (Vm). If we assume that the average deleterious effects of mutation (s) are equal, then AM Uds, where Ud is the genomic rate for mutations affecting fitness per generation. Furthermore, Keightley and Eyre-Walker (1999) showed that Vm Uds2, so that Ud can be estimated from the formula Ud AM2 Vm. mutations per site per generation and a Ut value of approx. 2.1 mutations per genome per generation. Surprisingly, the direct estimates of Denver et al. (2004) are at least 10 times higher than previous...

Dyspnoea on effort

Brcathlessness on effort is physiological. It becomes a symptom of disease if it occurs at exercise levels below those expected for the patient's age and degree of previous fitness. Dyspnoea 011 exertion may be the only symptom of heart failure caused by left ventricular systolic dysfunction. Such patients frequently give a history consistent with previous myocardial infarction, Other common cardiac causes of exertional brealhlessness include hypertension, valvular heart disease, cardiomyopathies and arrhythmias such as atrial fibrillation.

Population Ecology

Population dynamics reflect the net effects of differences among individuals in their physiological and behavioral interactions with the environment. Changes in individual success in finding and exploiting resources, mating and reproducing, and avoiding mortality agents determine numbers of individuals, their spatial distribution, and genetic composition at any point in time. Population structure is a component of the environment for the members of the population and provides information that affects individual physiology and behavior, and hence fitness (see Section I). For example, population density affects competition for food and oviposition sites (as well as other resources), propensity of individuals to disperse, and the proximity of potential mates.

Behavioral Genetics

Sociobiology is another major area of modern ethology. Sociobiology examines animal social behavior within the framework of evolution. Animal species vary in the degree of social behavior they exhibit other variables include group size and the amount of coordination of activities occurring within the group. The sociobiologist is interested in a number of questions, but prominent among them are the reasons for grouping. Hypotheses such as defense against predators or facilitation of reproduction can be tested. The particular advantage or advantages gained by grouping varies among species. Two important concepts in sociobiology are kin selection and inclusive fitness. ness is the term used to recognize the concept that fitness includes the total genotype, including those genes that may lower the individual's survival as the price of leaving more genes in surviving kin. The concepts of kin selection and inclusive fitness help to address one problem raised by Darwin, the question of...

OH OH b5 Azacytidine

A classical approach based on administration of combinations of inhibitors alone, could be provided by the suppressive effect of a highly mutated spectrum of mutants on residual infectivity. Suppression of mutant spectra on higher fitness virus or on specific variant virus types was previously documented with VSV 20 , with poliovirus vaccines containing virulent forms as minority components 12 , with antigenic variants of FMDV 9 and with variants of LCMV with different potential to induce a growth hormone deficiency syndrome in mice 72 . RNA cotransfection experiments have shown that mutated, preextinction RNA is able to interfere with residual infectious RNA, resulting in a delayed viral production 43 . The interference was exerted specifically by high molar mass preextinction RNA, and was not the result of induction of interferon or other nonspecific antiviral responses. This type of interference is probably mediated by abnormal expression of normal and aberrant FMDV proteins that...

Social Insects

Genetic studies have challenged the traditional view of the role of genetic relatedness in the evolution and maintenance of eusociality. Eusociality in the social Hymenoptera has been explained by the high degree of genetic relatedness among siblings, which share 75 of their genes as a result of haploid father and diploid mother, compared to only 50 genes shared with their mother (Hamilton 1964, See Chapter 15). However, this model does not apply to termites. Husseneder et al. (1999) and Thorne (1997) suggested that developmental and ecological factors, such as slow development, iteroparity, overlap of generations, food-rich environment, high risk of dispersal, and group defense, may be more important than genetics in the maintenance of termite eusociality, regardless of the factors that may have favored its original development. Myles (1999) reviewed the frequency of neoteny (reproduction by immature stages) among termite species and concluded that neoteny is a primitive element of...

Background concepts

What factors explain variation in the diversity and types of parasites found in different primate species The reproductive fitness of any parasite depends on its ability to successfully infect and replicate within an individual host and to disperse to other hosts. We can therefore think about whether or not parasites occur in a given host as depending on two major factors encounter between hosts and parasites, and successful infection following encounter.


Over evolutionary time scales, genes on B chromosomes may be silenced, undergo heterochromatinization, and accumulate repetitive DNA and transposons. B-chromosome frequencies in populations result from a balance between their transmission rates and their effects on host fitness. The long-term survival of B chromosomes depends on their ability to survive efforts by their host to eliminate or suppress them because they are often considered to be parasites. Because B chromosomes can interact with standard chromosomes, they could play a positive role in genome evolution if they contribute useful genetic information.

Respiratory Symptoms

Dyspnea is defined as difficult or labored respiration or the unpleasant awareness of one's respiration. It has many causes. A clue to the etiology is obtained from the factors that precipitate or relieve it.1 Chronic dyspnea can be caused by heart failure, pulmonary disease, anxiety, obesity, poor physical fitness, pleural effusions, and asthma.2 Acute dyspnea may occur with acute pulmonary edema, hyperventilation, pneumothorax, pulmonary embolism, pneumonia, and airway obstruction.2


Mutations that decrease fitness greatly outnumber mutations that increase fitness. In a large population in which drift is weak, selection prevents most such mutations from becoming common. In very small populations, however, alleles that decrease fitness can drift to fixation, causing a decrease in average fitness. This is one manifestation of a phenomenon called inbreeding depression. In populations with very small Ne, this inbreeding depression can be significant enough to threaten the population with extinction. If a population remains small for many generations, mean fitness will continue to decline as new mutations become fixed by drift. When fitness declines to the point where offspring are no longer overproduced, population size will decrease further. Drift then becomes stronger, mutations are fixed faster, and the population

Creative Potential

By itself, drift cannot lead to adaptation. However, drift can enhance the ability of selection to do so. Because of diploidy and sexual recombination, some types of mutations, either singly or in combinations, will increase fitness when common but not when rare. Genetic drift can cause such genetic variants to become sufficiently common for selection to promote their fixation. A likely example is the fixation of new structural arrangements of chromosomes that occurred frequently during the diversification of flowering plants. New chromosome arrangements are usually selected against when they are rare because they disrupt meiosis and reduce fertility. The initial spread of such a mutation can therefore only be caused by strong genetic drift, either in an isolated population of small effective size or in a larger population divided into small neighborhoods.


To evaluate the chromosome, the objective function takes the chromosome (which is usually represented in some numerical or binary format), decodes it according to a problem specific decoding scheme and then computes the fitness of the solution which is then passed back to the algorithm. The most important skill in applying a GA to a problem is to be able to correctly map the problem to a set of integers or binary variables and accurately compute a fitness so that it reflects the problem at hand. Later in this chapter various methods for accomplishing this for bioinformatics problems will be discussed.


As with other search algorithms, the GA needs to remember good solutions and discard bad ones if it is to make progress towards the optimum. A very simple selector would be to select the top N chromosomes from each population for progression to the next population. This would work up to a point, but any solutions which have very high fitness will always make it through to the next population. This concept is known as elitism and will be covered later in this chapter. However, to make sure that the GA doesn't converge on a set of solutions too quickly, a random element is usually introduced into the selection procedure. The following section describes the roulette wheel selector, which is one of the most popular procedures along with the tournament selector.

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