Microevolution in an Electronic Microcosm
... Some experiments have yielded results that seem inconsistent with the paradigm (see Dykhuizen 1990). For example, Adams et al. (1985) found that the turnover in chemostat populations of yeast (about one substitution every 40 generations) seemed too rapid to be consistent with the assumption that the ...
... Some experiments have yielded results that seem inconsistent with the paradigm (see Dykhuizen 1990). For example, Adams et al. (1985) found that the turnover in chemostat populations of yeast (about one substitution every 40 generations) seemed too rapid to be consistent with the assumption that the ...
The Living World - McGraw Hill Higher Education
... There to Here Natural selection, the process that leads to evolution, occurs in steps 1. Gene variation exists among individuals in a population 2. This variation is often passed to offspring 3. All populations overproduce offspring 4. Individuals with traits that aid survival and reproduction have ...
... There to Here Natural selection, the process that leads to evolution, occurs in steps 1. Gene variation exists among individuals in a population 2. This variation is often passed to offspring 3. All populations overproduce offspring 4. Individuals with traits that aid survival and reproduction have ...
The Living World
... There to Here Natural selection, the process that leads to evolution, occurs in steps 1. Gene variation exists among individuals in a population 2. This variation is often passed to offspring 3. All populations overproduce offspring 4. Individuals with traits that aid survival and reproduction have ...
... There to Here Natural selection, the process that leads to evolution, occurs in steps 1. Gene variation exists among individuals in a population 2. This variation is often passed to offspring 3. All populations overproduce offspring 4. Individuals with traits that aid survival and reproduction have ...
Chapter 13
... There to Here Natural selection, the process that leads to evolution, occurs in steps 1. Gene variation exists among individuals in a population 2. This variation is often passed to offspring 3. All populations overproduce offspring 4. Individuals with traits that aid survival and reproduction have ...
... There to Here Natural selection, the process that leads to evolution, occurs in steps 1. Gene variation exists among individuals in a population 2. This variation is often passed to offspring 3. All populations overproduce offspring 4. Individuals with traits that aid survival and reproduction have ...
The Effect of Variation in the Effective Population Size on the Rate of
... evolution than D. melanogaster, even though it is thought to have a larger Ne (Andolfatto et al. 2011). However, the correlation between a and Ne might be misleading because a depends on the rate of effectively neutral and advantageous substitution, variation in either of which could be caused by Ne ...
... evolution than D. melanogaster, even though it is thought to have a larger Ne (Andolfatto et al. 2011). However, the correlation between a and Ne might be misleading because a depends on the rate of effectively neutral and advantageous substitution, variation in either of which could be caused by Ne ...
The role of hermaphrodites in the experimental evolution of
... http://www.biomedcentral.com/1471-2148/14/116 ...
... http://www.biomedcentral.com/1471-2148/14/116 ...
Oviparity or viviparity? That is the question…
... fertilized eggs’’ and viviparity is defined as ‘‘any mechanism for live-bearing or maintenance of development, by either maternal or paternal parent in or on any part of the body’’, while ovoviviparity straddles both modes [15]. In fact, this classification of different modes of reproduction into th ...
... fertilized eggs’’ and viviparity is defined as ‘‘any mechanism for live-bearing or maintenance of development, by either maternal or paternal parent in or on any part of the body’’, while ovoviviparity straddles both modes [15]. In fact, this classification of different modes of reproduction into th ...
Rajon, E. and Masel, J. (2013)
... Here we explore an abstract model of cryptic sequences, their attenuation, accumulation and eventual potential co-option. Our model is inspired by the concrete example of cryptic DNA sequences that are only rarely translated into proteins. These underexpressed sequences can be whole genes or parts ...
... Here we explore an abstract model of cryptic sequences, their attenuation, accumulation and eventual potential co-option. Our model is inspired by the concrete example of cryptic DNA sequences that are only rarely translated into proteins. These underexpressed sequences can be whole genes or parts ...
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... another marker that was embedded in the experimental design itself, which allowed us to exclude crosscontamination among the replicate populations. This same marker allowed us to put evolutionarily derived genotypes in competition with the ancestral strain of the opposite marker state and thereby di ...
... another marker that was embedded in the experimental design itself, which allowed us to exclude crosscontamination among the replicate populations. This same marker allowed us to put evolutionarily derived genotypes in competition with the ancestral strain of the opposite marker state and thereby di ...
The quantitative genetic basis of sex ratio variation in Nasonia
... male (sex ratio), the underlying trade-off is simply the production of either sons or daughters. As a result, patterns of sex ratios have been successfully predicted across an extremely broad range of organisms, from single-celled organisms such as Plasmodium, through to many plants and animals, lar ...
... male (sex ratio), the underlying trade-off is simply the production of either sons or daughters. As a result, patterns of sex ratios have been successfully predicted across an extremely broad range of organisms, from single-celled organisms such as Plasmodium, through to many plants and animals, lar ...
Article Reduced Representation Genome
... (Charlesworth et al. 1993) or selective sweep effects (Maynard Smith and Haigh 1974) due to proximity to genes. These effects are not apparent on the X, either due to the distinct nature of molecular evolution and adaptation on this chromosome, or (more probably) due to the considerably smaller data ...
... (Charlesworth et al. 1993) or selective sweep effects (Maynard Smith and Haigh 1974) due to proximity to genes. These effects are not apparent on the X, either due to the distinct nature of molecular evolution and adaptation on this chromosome, or (more probably) due to the considerably smaller data ...
Weighing the evidence for adaptation at the molecular level
... ranging from yeast to humans is often weak or absent. Although evidence for positive selection could be obscured in some species, there is also reason to believe that the frequency of adaptive substitutions could be overestimated as a result of epistatic fitness effects or hitchhiking of deleterious ...
... ranging from yeast to humans is often weak or absent. Although evidence for positive selection could be obscured in some species, there is also reason to believe that the frequency of adaptive substitutions could be overestimated as a result of epistatic fitness effects or hitchhiking of deleterious ...
Introduction to Genetic Algorithms
... Step 1: Represent the problem variable domain as a chromosome of a fixed length, choose the size of a chromosome population N, the crossover probability pc, and the mutation probability pm. Step 2: Define a fitness function to measure the performance (i.e., fitness) of an individual chromosome in th ...
... Step 1: Represent the problem variable domain as a chromosome of a fixed length, choose the size of a chromosome population N, the crossover probability pc, and the mutation probability pm. Step 2: Define a fitness function to measure the performance (i.e., fitness) of an individual chromosome in th ...
PowerPoint Presentation - I. Introduction to class
... Can exist as both multicellular fungi (molds) and yeasts. ...
... Can exist as both multicellular fungi (molds) and yeasts. ...
processes shaping diversity
... other species that reproduce sexually and do not self-fertilize. However, models require us to make assumptions that may not be true of all species. This problem drives mathematical models of evolution to become ever more sophisticated, abandoning simplifying assumptions one by one, and introducing ...
... other species that reproduce sexually and do not self-fertilize. However, models require us to make assumptions that may not be true of all species. This problem drives mathematical models of evolution to become ever more sophisticated, abandoning simplifying assumptions one by one, and introducing ...
in evolution - University of California, Berkeley
... inaccurate. Well-known examples are the prediction that most genes in natural populations must be monomorphic [34], and the calculation that a species could evolve at a maximum rate of the order of one allele substitution per 300 generations [13]. It is now known that a large proportion of gene loci ...
... inaccurate. Well-known examples are the prediction that most genes in natural populations must be monomorphic [34], and the calculation that a species could evolve at a maximum rate of the order of one allele substitution per 300 generations [13]. It is now known that a large proportion of gene loci ...
EVOLUTION EXPERIMENTS WITH MICROORGANISMS: THE DYNAMICS AND GENETIC BASES OF ADAPTATION
... size32 in E. coli) change with a step-like dynamic. Each step probably corresponds to the spread of a beneficial mutation13,33. The step-like aspect occurs because any new beneficial mutation must increase from a low initial frequency; during its ascendancy, it has little effect on mean fitness unti ...
... size32 in E. coli) change with a step-like dynamic. Each step probably corresponds to the spread of a beneficial mutation13,33. The step-like aspect occurs because any new beneficial mutation must increase from a low initial frequency; during its ascendancy, it has little effect on mean fitness unti ...
IV. PROKARYOTES – EUBACTERIA, cont
... o Changes in the gene pool due to chance. More often seen in small population sizes. Usually reduces genetic variability. There are two situations that can drastically reduce population size: The Bottleneck Effect: type of genetic drift resulting from a reduction in population (natural disaster) s ...
... o Changes in the gene pool due to chance. More often seen in small population sizes. Usually reduces genetic variability. There are two situations that can drastically reduce population size: The Bottleneck Effect: type of genetic drift resulting from a reduction in population (natural disaster) s ...
Senescence as an Adaptation to Limit the Spread of
... The genetics and phenomenology of senescence suggest the hallmarks of an adaptation; but the effect of senescence on individual fitness is negative, so theorists have preferred to regard it as a non-adaptive byproduct of selection. We ask whether the possibility that senescence is an adaptation in i ...
... The genetics and phenomenology of senescence suggest the hallmarks of an adaptation; but the effect of senescence on individual fitness is negative, so theorists have preferred to regard it as a non-adaptive byproduct of selection. We ask whether the possibility that senescence is an adaptation in i ...
Lesson Overview - Southgate Schools
... Animals’ care of their offspring varies from no care at all to years of nurturing. Most aquatic invertebrates and many fishes and amphibians release large numbers of eggs that they completely ignore. This reproductive strategy succeeds in circumstances favoring populations that disperse and grow rap ...
... Animals’ care of their offspring varies from no care at all to years of nurturing. Most aquatic invertebrates and many fishes and amphibians release large numbers of eggs that they completely ignore. This reproductive strategy succeeds in circumstances favoring populations that disperse and grow rap ...
Biology Cumulative Final Exam Review Sheet The
... 6. Describe how natural variation is used in artificial selection. 7. Explain how natural selection is related to species’ fitness. 8. Identify evidence Darwin used to present his case for evolution. 9. State Darwin’s theory of evolution by natural selection. Evolution of Population 1. Explain what ...
... 6. Describe how natural variation is used in artificial selection. 7. Explain how natural selection is related to species’ fitness. 8. Identify evidence Darwin used to present his case for evolution. 9. State Darwin’s theory of evolution by natural selection. Evolution of Population 1. Explain what ...
Adaptive Behavior - Psychology Today
... that even “perfect” assortative mating by attractiveness rank does not imply perfect assortative mating by signal investment, much less by actual condition or genetic quality. Each mated pair produces the same number of offspring, by default set to 4. The standardized death rate means that, on avera ...
... that even “perfect” assortative mating by attractiveness rank does not imply perfect assortative mating by signal investment, much less by actual condition or genetic quality. Each mated pair produces the same number of offspring, by default set to 4. The standardized death rate means that, on avera ...
Author`s personal copy
... These and other recent examples illustrate that assumptions of consistent directional, stabilising or disruptive selection on a particular sexual trait are biologically unrealistic. We predict that with increasing data on reproductive success in natural populations, spatial and temporal selection mo ...
... These and other recent examples illustrate that assumptions of consistent directional, stabilising or disruptive selection on a particular sexual trait are biologically unrealistic. We predict that with increasing data on reproductive success in natural populations, spatial and temporal selection mo ...
4 Natural Selection and Variation
... survive, because any other number would be unsustainable over the long term. It takes a pair of individuals to reproduce. If an average pair in a population produce less than two offspring, the population will soon go extinct; if they produce more than two, on average, the population will rapidly re ...
... survive, because any other number would be unsustainable over the long term. It takes a pair of individuals to reproduce. If an average pair in a population produce less than two offspring, the population will soon go extinct; if they produce more than two, on average, the population will rapidly re ...
Evolution of sexual reproduction
The evolution of sexual reproduction describes how sexually reproducing animals, plants, fungi and protists evolved from a common ancestor that was a single celled eukaryotic species. There are a few species which have secondarily lost the ability to reproduce sexually, such as Bdelloidea and some parthenocarpic plants. The evolution of sex contains two related, yet distinct, themes: its origin and its maintenance. The maintenance of sexual reproduction in a highly competitive world has long been one of the major mysteries of biology given that asexual reproduction can reproduce much more quickly as 50% of offspring are not males, unable to produce offspring themselves. However, research published in 2015 indicates that sexual selection can explain the persistence of sexual reproduction.Since hypotheses for the origins of sex are difficult to test experimentally (outside of Evolutionary computation), most current work has focused on the maintenance of sexual reproduction. Sexual reproduction must offer significant fitness advantages to a species because despite the two-fold cost of sex, it dominates among multicellular forms of life, implying that the fitness of offspring produced outweighs the costs. Sexual reproduction derives from recombination, where parent genotypes are reorganized and shared with the offspring. This stands in contrast to single-parent asexual replication, where the offspring is identical to the parents. Recombination supplies two fault-tolerance mechanisms at the molecular level: recombinational DNA repair (promoted during meiosis because homologous chromosomes pair at that time) and complementation (also known as heterosis, hybrid vigor or masking of mutations). Sexual reproduction has probably contributed to the evolution of sexual dimorphism, where organisms within a species adopted different strategies of parental investment. Males adopt strategies with lower investment in individual gametes and may present a higher mutation rate, while females may invest more resources and serve to conserve better-adapted solutions.