Variation And Evolution In Plants And Microorganisms

"The present book is intended as a progress report on [the] synthetic approach to evolution as it applies to the plant kingdom." With this simple statement, G. Ledyard Stebbins formulated the objectives of Variation and Evolution in Plants, published in 1950, setting forth for plants what became known as the "synthetic theory of evolution" or "the modern synthesis." The pervading conceit of the book was the molding of Darwin's evolution by natural selection within the framework of rapidly advancing genetic knowledge. At the time, Variation and Evolution in Plants significantly extended the scope of the science of plants. Plants, with their unique genetic, physiological, and evolutionary features, had all but been left completely out of the synthesis until that point. Fifty years later, the National Academy of Sciences convened a colloquium to update the advances made by Stebbins. This collection of 17 papers marks the 50th anniversary of the publication of Stebbins' classic. Organized into five sections, the book covers: early evolution and the origin of cells, virus and bacterial models, protoctist models, population variation, and trends and patterns in plant evolution.

Considers how the study of variation in plants has developed over the last 300 years.

"The present book is intended as a progress report on [the] synthetic approach to evolution as it applies to the plant kingdom." With this simple statement, G. Ledyard Stebbins formulated the objectives of Variation and Evolution in Plants, published in 1950, setting forth for plants what became known as the "synthetic theory of evolution" or "the modern synthesis." The pervading conceit of the book was the molding of Darwin's evolution by natural selection within the framework of rapidly advancing genetic knowledge. At the time, Variation and Evolution in Plants significantly extended the scope of the science of plants. Plants, with their unique genetic, physiological, and evolutionary features, had all but been left completely out of the synthesis until that point. Fifty years later, the National Academy of Sciences convened a colloquium to update the advances made by Stebbins. This collection of 17 papers marks the 50th anniversary of the publication of Stebbins' classic. Organized into five sections, the book covers: early evolution and the origin of cells, virus and bacterial models, protoctist models, population variation, and trends and patterns in plant evolution.

"The lack of discussion of the life histories of modular organisms is the weakness of this book that I most regret. . . . Modular organisms are different. " S. C. Steams: The Evolution of Life Histories (1992) Life-history theory endeavours to increase our understanding of the processe,s whereby the broad features of the life cycles of organisms, such as the timing and magnitude of reproduction, have evolved. Although reproductive traits have dominated as study objects due to their immediate importance for evolutionary success, much work has also been conducted on patterns of development, growth and senescence, as well as on the shifts in resource allocation related to these processes. The basic axiom of life-history theory is that patterns of life histories, such as reproductive traits, are subject to evolutionary explanation. This idea can be traced back at least as far as Darwin's Origin of Species (1859). In his discussion of plant domestication, Darwin wrote: "I cannot doubt that the continued selection of slight variations, either in the leaves, the flowers, or the fruit, will produce races differing from each other chiefly in these characters". Darwin was impressed by the success of plant breeders in moulding the growth and reproductive parameters of cultivated plants, and believed that natural selection could have a similar impact in natural populations.

Bacteria have been the dominant forms of life on Earth for the past 3.5 billion years. They rapidly evolve, constantly changing their genetic architecture through horizontal DNA transfer and other mechanisms. Consequently, it can be difficult to define individual species and determine how they are related. Written and edited by experts in the field, this collection from Cold Spring Harbor Perspectives in Biology examines how bacteria and other microbes evolve, focusing on insights from genomics-based studies. Contributors discuss the origins of new microbial populations, the evolutionary and ecological mechanisms that keep species separate once they have diverged, and the challenges of constructing phylogenetic trees that accurately reflect their relationships. They describe the organization of microbial genomes, the various mutations that occur, including the birth of new genes de novo and by duplication, and how natural selection acts on those changes. The role of horizontal gene transfer as a strong driver of microbial evolution is emphasized throughout. The authors also explore the geologic evidence for early microbial evolution and describe the use of microbial evolution experiments to examine phenomena like natural selection. This volume will thus be essential reading for all microbial ecologists, population geneticists, and evolutionary biologists.

Many of the characteristics that distinguish plants from other living organisms can be traced to their bacterial origin early in the history of life. These features-such as a multicellular haploid life stage, prevalent hermaphroditism, self-fertilization, and general dependence on biotic and abiotic vectors for reproduction-stem directly from the plant's ability to obtain energy from the sun. This novel mode of energy capture had far-ranging implications for plant evolution. It not only fueled the tremendous diversification of life on Earth that followed, but also had far-ranging implications for the evolution of photosynthetic microorganisms and eventually for land plants. Understanding the evolutionary processes for the proliferation and diversification of plants requires an appreciation of their unique biological features. While the processes of mutation, selection, genetic drift, and gene flow remain the same for both plants and animals, there are specific characteristics of plants that modify the way their evolution is implemented. Unique traits of plants affect everything from the fate of mutations, through exposure to selection in a haploid life phase, to the distribution of genetic variation within populations, and ultimately the rates and patterns of diversification. This book examines the origins of the unique evolutionary features of plants, as well as their implications for evolutionary processes. Author Mitchell B. Cruzan provides contemporary discussion of subjects including population genetics, phylogeography, phylogenetics, ecological genetics, and genomics. The book fills a need for modern coverage of these topics, all of which are essential to a wide range of advanced courses in plant biology.

We are in the midst of a biological revolution. Molecular tools are now providing new means of critically testing hypotheses and models of microevolution in populations of wild, cultivated, weedy and feral plants. They are also offering the opportunity for significant progress in the investigation of long-term evolution of flowering plants, as part of molecular phylogenetic studies of the Tree of Life. This long-awaited fourth edition, fully revised by David Briggs, reflects new insights provided by molecular investigations and advances in computer science. Briggs considers the implications of these for our understanding of the evolution of flowering plants, as well as the potential for future advances. Numerous new sections on important topics such as the evolutionary impact of human activities, taxonomic challenges, gene flow and distribution, hybridisation, speciation and extinction, conservation and the molecular genetic basis of breeding systems will ensure that this remains a classic text for both undergraduate and graduate students in the field.