Inbreeding, the mating of close kin, and outbreeding, the mating of distant relatives or unrelated organisms, have long been important subjects to evolutionary biologists. Inbreeding reduces genetic diversity in a population, increasing the likelihood that genetic defects will become widespread and deprive a population of the diversity it may need to cope with its environment. Most plants and animals have evolved behavioral and morphological mechanisms to avoid inbreeding. However, today many endangered species exist only in small, very isolated populations where inbreeding is unavoidable, so it has become a concern for conservationists. In this volume, twenty-six experts in evolution, behavior, and genetics examine the causes and consequences of inbreeding. The authors ask whether inbreeding is as problematic as biologists have thought, under what ecological conditions inbreeding occurs, and whether organisms that inbreed have mechanisms to dampen the anticipated problems of reduced genetic variation. The studies, including theoretical and empirical work on wild and captive populations, demonstrate that many plants and animals inbreed to a greater extent than biologists have thought, with variable effects on individual fitness. Graduate students and researchers in evolutionary biology, animal behavior, ecology, and conservation biology will welcome this wide-ranging collection.

Inbreeding, the mating of close kin, and outbreeding, the mating of distant relatives or unrelated organisms, have long been important subjects to evolutionary biologists. Inbreeding reduces genetic diversity in a population, increasing the likelihood that genetic defects will become widespread and deprive a population of the diversity it may need to cope with its environment. Most plants and animals have evolved behavioral and morphological mechanisms to avoid inbreeding. However, today many endangered species exist only in small, very isolated populations where inbreeding is unavoidable, so it has become a concern for conservationists. In this volume, twenty-six experts in evolution, behavior, and genetics examine the causes and consequences of inbreeding. The authors ask whether inbreeding is as problematic as biologists have thought, under what ecological conditions inbreeding occurs, and whether organisms that inbreed have mechanisms to dampen the anticipated problems of reduced genetic variation. The studies, including theoretical and empirical work on wild and captive populations, demonstrate that many plants and animals inbreed to a greater extent than biologists have thought, with variable effects on individual fitness. Graduate students and researchers in evolutionary biology, animal behavior, ecology, and conservation biology will welcome this wide-ranging collection.

The 7-volume Encyclopedia of Biodiversity, Second Edition maintains the reputation of the highly regarded original, presenting the most current information available in this globally crucial area of research and study. It brings together the dimensions of biodiversity and examines both the services it provides and the measures to protect it. Major themes of the work include the evolution of biodiversity, systems for classifying and defining biodiversity, ecological patterns and theories of biodiversity, and an assessment of contemporary patterns and trends in biodiversity. The science of biodiversity has become the science of our future. It is an interdisciplinary field spanning areas of both physical and life sciences. Our awareness of the loss of biodiversity has brought a long overdue appreciation of the magnitude of this loss and a determination to develop the tools to protect our future. Second edition includes over 100 new articles and 226 updated articles covering this multidisciplinary field— from evolution to habits to economics, in 7 volumes The editors of this edition are all well respected, instantly recognizable academics operating at the top of their respective fields in biodiversity research; readers can be assured that they are reading material that has been meticulously checked and reviewed by experts Approximately 1,800 figures and 350 tables complement the text, and more than 3,000 glossary entries explain key terms

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A detailed introduction to the genetic and demographic issues relevant to the conservation of fragmented populations.

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1919 edition. Excerpt: ...starts off poorly, as shown in the accompanying illustration (Fig. 33), but soon catches up and passes the second generation. At maturity the second generation is shorter and less productive, although it has a much greater variability. The third generation from selfed plants of this particular cross has been grown, and there is still further loss of the stimulation which is at its maximum in the first generation. On continued inbreeding these families presumably would exhibit a continuation of the same course of reduction in size, vigor and variability shown in the original inbreeding experiment, until homozygosity was again 100 78 50 29 Sronth Curres of Two Inbred Strains ef Maize and Their Fj and F2 Hybrids. 30 40 50 Gf 7 8 Wumlaer of Days from Planting 9 33.--Qraphs showing growth curves of two inbred strains'of maiie and thier first and second generation hybrids. reached. The resulting inbred strains would have about the same amount of development as the original inbred strains, but would probably differ from them in appearance through the possession of different combinations of characters. The principal point is that the vigor and size lost by inbreeding are immediately restored by crossing, but lost again on further inbreeding. It is a transitory effect, for the most part, impossible of fixation. Increases in yield of grain are also frequently obtained when ordinary commercial varieties of maize are crossed. Earely are the increases greater than 10 per cent., however, and even this is more commonly to be expected when varieties of somewhat different type are used; for example, flint and dent. Most varieties of corn are now so widely crossed and furthermore are so near the limit of production that great advances are not...