Fulltext PDF - Indian Academy of Sciences
... that came to participate in evolutionary processes in their own right (Maynard Smith and Szathmary 1995; Michod 1999; Okasha 2006). This involved a hierarchical shift in the level of selection and with it the emergence of new kinds of biological individuals – individuals whose success very often cur ...
... that came to participate in evolutionary processes in their own right (Maynard Smith and Szathmary 1995; Michod 1999; Okasha 2006). This involved a hierarchical shift in the level of selection and with it the emergence of new kinds of biological individuals – individuals whose success very often cur ...
Microbial endemism: does phosphorus limitation enhance speciation?
... between the populations that were isolated on different islands, he would probably have found only one or two finch species, not the remarkable number of species that he did. Genetic diversity and genetic novelty arise in all organisms by various forms of mutation. The role of recombination through ...
... between the populations that were isolated on different islands, he would probably have found only one or two finch species, not the remarkable number of species that he did. Genetic diversity and genetic novelty arise in all organisms by various forms of mutation. The role of recombination through ...
Biology EOC Study Guide - Volusia County Schools
... 28. Carrot sticks that are left in a dish of freshwater for several hours become stiff and hard. Similar sticks left in a saltwater solution become limp and soft. From this we can deduce that the freshwater is ______ and the saltwater is ________ to the cells of the carrot sticks. A. hypotonic, hype ...
... 28. Carrot sticks that are left in a dish of freshwater for several hours become stiff and hard. Similar sticks left in a saltwater solution become limp and soft. From this we can deduce that the freshwater is ______ and the saltwater is ________ to the cells of the carrot sticks. A. hypotonic, hype ...
genetics and the fitness of hybrids
... background. The results of this work indicate that hybrid sterility results from a large number of genetic interactions. Indeed, Palopoli & Wu (84) estimate that there are at least 40 loci that influence hybrid male sterility on the X chromosome alone, and Hollocher & Wu (57) found that the density ...
... background. The results of this work indicate that hybrid sterility results from a large number of genetic interactions. Indeed, Palopoli & Wu (84) estimate that there are at least 40 loci that influence hybrid male sterility on the X chromosome alone, and Hollocher & Wu (57) found that the density ...
Rapid evolution in crop-weed hybrids under artificial selection for
... in homoploid hybrid lineages in both plants (Hegarty and Hiscock 2005) and animals (Mallet 2007). In general, evidence for new lineages has been inferred from the geographic occurrence of hybrid zones. The use of experimental hybridization and artificial selection to speed up natural processes allow ...
... in homoploid hybrid lineages in both plants (Hegarty and Hiscock 2005) and animals (Mallet 2007). In general, evidence for new lineages has been inferred from the geographic occurrence of hybrid zones. The use of experimental hybridization and artificial selection to speed up natural processes allow ...
Darwin on Mind, Morals, and Emotions
... Malthus, he had formulated several theories to account for heritable modifications, the most prominent of which depended on the notions of use-inheritance and its result, instinct. Darwin assumed that in a changed environment, an animal might adopt habits that would accommodate it to the new conditi ...
... Malthus, he had formulated several theories to account for heritable modifications, the most prominent of which depended on the notions of use-inheritance and its result, instinct. Darwin assumed that in a changed environment, an animal might adopt habits that would accommodate it to the new conditi ...
How much do genetic covariances alter the rate of adaptation?
... variance in one or more directions can occur even when all genetic correlations are less than unity in magnitude when nO2. If one of these directions with no genetic variation matches the direction of selection (b), then there will be no evolution. In such a case, we can say that genetic correlation ...
... variance in one or more directions can occur even when all genetic correlations are less than unity in magnitude when nO2. If one of these directions with no genetic variation matches the direction of selection (b), then there will be no evolution. In such a case, we can say that genetic correlation ...
Wright`s adaptive landscape versus Fisher`s fundamental theorem
... which the colonies are exposed. Moreover, so long as it could be believed that large fluctuations in gene ratios occur only in small isolated colonies by reason of fluctuations of random survival, then it might have been true that such fluctuations themselves favoured evolutionary change in a way th ...
... which the colonies are exposed. Moreover, so long as it could be believed that large fluctuations in gene ratios occur only in small isolated colonies by reason of fluctuations of random survival, then it might have been true that such fluctuations themselves favoured evolutionary change in a way th ...
4 Chapter
... They are similar to living organisms in having nucleic acids (DNA,RNA) They are similar to the non-living in existing in most cases in a crystalline form. The size ranges between 10-100 millimicrons They are Obligate parasites…………Why? Because they absolutely require living host cells in order ...
... They are similar to living organisms in having nucleic acids (DNA,RNA) They are similar to the non-living in existing in most cases in a crystalline form. The size ranges between 10-100 millimicrons They are Obligate parasites…………Why? Because they absolutely require living host cells in order ...
Selection experiments: an under-utilized tool in
... kinds of respiratory and locomotor mechanics that could potentially evolve in future turtles. Such constraints would, of course, reduce the likelihood that organisms could become optimally adapted. And this type of question is also related to the issue of multiple solutions. All constraints are ulti ...
... kinds of respiratory and locomotor mechanics that could potentially evolve in future turtles. Such constraints would, of course, reduce the likelihood that organisms could become optimally adapted. And this type of question is also related to the issue of multiple solutions. All constraints are ulti ...
Experimental evidence that source genetic variation drives
... particles; the probability of infection of an uninfected host cell when it encounters a phage; and the number of host cells likely to be encountered. A novel host could be a sink because any of these quantities are low. We specifically used serial passages combined with dilution to create sinks; a h ...
... particles; the probability of infection of an uninfected host cell when it encounters a phage; and the number of host cells likely to be encountered. A novel host could be a sink because any of these quantities are low. We specifically used serial passages combined with dilution to create sinks; a h ...
Perspectives Poulton, Wallace and Jordan: how discoveries
... and also certain recent ‘phylogenetic’ species concepts that depend on fixed, diagnostic differences. Poulton shows that diagnostic definitions have the problem that geographic races, as well as polymorphic forms of mimetic Papilio butterflies, would be split into separate species if diagnosis alone ...
... and also certain recent ‘phylogenetic’ species concepts that depend on fixed, diagnostic differences. Poulton shows that diagnostic definitions have the problem that geographic races, as well as polymorphic forms of mimetic Papilio butterflies, would be split into separate species if diagnosis alone ...
A Darwinist View of the Living Constitution
... Part I has introduced the metaphor of a "living" Constitution, posed some preliminary questions about the metaphor, and underscored why we ought to care about it. Part II frames the concept of the "living" Constitution as a powerful biological metaphor characterizing the Constitution as a living org ...
... Part I has introduced the metaphor of a "living" Constitution, posed some preliminary questions about the metaphor, and underscored why we ought to care about it. Part II frames the concept of the "living" Constitution as a powerful biological metaphor characterizing the Constitution as a living org ...
The fitness costs of adaptation via phenotypic plasticity and maternal
... The interplay between within- and transgenerational plasticity matters because the stage when an individual processes an environmental cue affects its biological response (Ricklefs & Wikelski 2002). Environmental change propagates through phenotypes to affect mean population fitness in theoretical (Gre ...
... The interplay between within- and transgenerational plasticity matters because the stage when an individual processes an environmental cue affects its biological response (Ricklefs & Wikelski 2002). Environmental change propagates through phenotypes to affect mean population fitness in theoretical (Gre ...
The evolution of non-ecological reproductive barriers
... speciation was due to the almost absence of clear examples and to the special conditions required for divergence to occur in sympatry (Ödeen & Florin, 2000; Via, 2001). Indeed as sympatric speciation occurs within a panmictic population, it requires strong natural and/or sexual disruptive selection ...
... speciation was due to the almost absence of clear examples and to the special conditions required for divergence to occur in sympatry (Ödeen & Florin, 2000; Via, 2001). Indeed as sympatric speciation occurs within a panmictic population, it requires strong natural and/or sexual disruptive selection ...
Word - Colorado Department of Education
... dark conditions, the only plants that grow well are small mosses and fungi. Animals on this planet include a type of mouse, a nocturnal hunting large cat, fish, and a variety of insects. Planet Nero: This planet is dry, hot, and flat. Water is found in underground streams but there is little surface ...
... dark conditions, the only plants that grow well are small mosses and fungi. Animals on this planet include a type of mouse, a nocturnal hunting large cat, fish, and a variety of insects. Planet Nero: This planet is dry, hot, and flat. Water is found in underground streams but there is little surface ...
LFS_208_Applied_Biology,_Nugent,_Gr._10,_13_pgs
... How do adaptations, mutations and recombinant DNA change a population of organisms? Concept: Describe the theory suggesting that life on Earth arose as a single, primitive prokaryote about 4 billion years ago and that for the next 2 billion years, a huge diversity of single-celled organisms evolved. ...
... How do adaptations, mutations and recombinant DNA change a population of organisms? Concept: Describe the theory suggesting that life on Earth arose as a single, primitive prokaryote about 4 billion years ago and that for the next 2 billion years, a huge diversity of single-celled organisms evolved. ...
Adaptations of Life Over Time - Colorado Department of Education
... Planet Toto: This planet is dark and cold most of the time. It is very mountainous, it rains almost all day, and because of the wet, dark conditions, the only plants that grow well are small mosses and fungi. Animals on this planet include a type of mouse, a nocturnal hunting large cat, fish, and a ...
... Planet Toto: This planet is dark and cold most of the time. It is very mountainous, it rains almost all day, and because of the wet, dark conditions, the only plants that grow well are small mosses and fungi. Animals on this planet include a type of mouse, a nocturnal hunting large cat, fish, and a ...
Understanding evolution as an emergent process: learning with
... for Connected Learning and Computer-Based Modeling (CCL) and were then reviewed for scientific accuracy and importance by university biologists. The curricular materials developed to accompany each model include conceptual scaffolding for students to interact with and explore models, to run experime ...
... for Connected Learning and Computer-Based Modeling (CCL) and were then reviewed for scientific accuracy and importance by university biologists. The curricular materials developed to accompany each model include conceptual scaffolding for students to interact with and explore models, to run experime ...
Darwin after Malthus
... In the Origin of Species (1859) natural selection is presented as an autonomous biological process which is, potentially, in continuous operation. No organism is perfect. There is always room for improvement. At any time or place a species, however well adapted it may seem to be, may give rise to st ...
... In the Origin of Species (1859) natural selection is presented as an autonomous biological process which is, potentially, in continuous operation. No organism is perfect. There is always room for improvement. At any time or place a species, however well adapted it may seem to be, may give rise to st ...
Darwinian metaphysics
... remained to advocate a limited processpluralism, gene-Darwinism reduces all evolutionary processes to the only truly Darwinian process of natural selection (process reductionism). For example, sexual selection from the perspective of single genes cannot be seen as a mechanism in its own right (refer ...
... remained to advocate a limited processpluralism, gene-Darwinism reduces all evolutionary processes to the only truly Darwinian process of natural selection (process reductionism). For example, sexual selection from the perspective of single genes cannot be seen as a mechanism in its own right (refer ...
Comparative Evolution of Duplicated Ddx3 Genes in Teleosts
... TGD-derived gene duplicates that evolved distinct physiological or developmental functions in various teleost lineages provide evidence, supporting a cause2effect relationship between gene copy number and species diversity (Braasch et al. 2006, 2009; Mulley et al. 2006; Hoegg and Meyer 2007; Siegel ...
... TGD-derived gene duplicates that evolved distinct physiological or developmental functions in various teleost lineages provide evidence, supporting a cause2effect relationship between gene copy number and species diversity (Braasch et al. 2006, 2009; Mulley et al. 2006; Hoegg and Meyer 2007; Siegel ...
Introduction
... Combinations of traits that are better adapted tend to increase representation in population Individuals are “units of selection” Variations occur through random changes yielding constant source of diversity, coupled with selection means that: Population is the “unit of evolution” Note the absence o ...
... Combinations of traits that are better adapted tend to increase representation in population Individuals are “units of selection” Variations occur through random changes yielding constant source of diversity, coupled with selection means that: Population is the “unit of evolution” Note the absence o ...
Problems for Natural Selection as a Mechanism
... information that prevents schema instantiation in the case of natural selection. Rather, it is variation that prevents it. This variation represents another point of substantial disanalogy with the case of gene selection. Consider several paradigmatic cases of natural selection: finches whose beak s ...
... information that prevents schema instantiation in the case of natural selection. Rather, it is variation that prevents it. This variation represents another point of substantial disanalogy with the case of gene selection. Consider several paradigmatic cases of natural selection: finches whose beak s ...
Force–velocity trade-off in Darwin`s finch jaw function: a
... associated with vocal performance in Darwin’s finches covary negatively with overall beak size (Podos 2001; Huber & Podos 2006). This co-variation presumably arises because high performance songs require rapid and broad jaw gape modulations that cannot be achieved by large-beaked birds with high bit ...
... associated with vocal performance in Darwin’s finches covary negatively with overall beak size (Podos 2001; Huber & Podos 2006). This co-variation presumably arises because high performance songs require rapid and broad jaw gape modulations that cannot be achieved by large-beaked birds with high bit ...
Introduction to evolution
Evolution is the process of change in all forms of life over generations, and evolutionary biology is the study of how evolution occurs. Biological populations evolve through genetic changes that correspond to changes in the organisms' observable traits. Genetic changes include mutations, which are caused by damage or replication errors in an organism's DNA. As the genetic variation of a population drifts randomly over generations, natural selection gradually leads traits to become more or less common based on the relative reproductive success of organisms with those traits.The age of the Earth is about 4.54 billion years old. The earliest undisputed evidence of life on Earth dates at least from 3.5 billion years ago, during the Eoarchean Era after a geological crust started to solidify following the earlier molten Hadean Eon. There are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. Other early physical evidence of a biogenic substance is graphite in 3.7 billion-year-old metasedimentary rocks discovered in western Greenland. More than 99 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described.Evolution does not attempt to explain the origin of life (covered instead by abiogenesis), but it does explain how the extremely simple early lifeforms evolved into the complex ecosystem that we see today. Based on the similarities between all present-day organisms, all life on Earth originated through common descent from a last universal ancestor from which all known species have diverged through the process of evolution. All individuals have hereditary material in the form of genes that are received from their parents, then passed on to any offspring. Among offspring there are variations of genes due to the introduction of new genes via random changes called mutations or via reshuffling of existing genes during sexual reproduction. The offspring differs from the parent in minor random ways. If those differences are helpful, the offspring is more likely to survive and reproduce. This means that more offspring in the next generation will have that helpful difference and individuals will not have equal chances of reproductive success. In this way, traits that result in organisms being better adapted to their living conditions become more common in descendant populations. These differences accumulate resulting in changes within the population. This process is responsible for the many diverse life forms in the world.The forces of evolution are most evident when populations become isolated, either through geographic distance or by other mechanisms that prevent genetic exchange. Over time, isolated populations can branch off into new species.The majority of genetic mutations neither assist, change the appearance of, nor bring harm to individuals. Through the process of genetic drift, these mutated genes are neutrally sorted among populations and survive across generations by chance alone. In contrast to genetic drift, natural selection is not a random process because it acts on traits that are necessary for survival and reproduction. Natural selection and random genetic drift are constant and dynamic parts of life and over time this has shaped the branching structure in the tree of life.The modern understanding of evolution began with the 1859 publication of Charles Darwin's On the Origin of Species. In addition, Gregor Mendel's work with plants helped to explain the hereditary patterns of genetics. Fossil discoveries in paleontology, advances in population genetics and a global network of scientific research have provided further details into the mechanisms of evolution. Scientists now have a good understanding of the origin of new species (speciation) and have observed the speciation process in the laboratory and in the wild. Evolution is the principal scientific theory that biologists use to understand life and is used in many disciplines, including medicine, psychology, conservation biology, anthropology, forensics, agriculture and other social-cultural applications.