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The rationale for this work is to make some sort of sense of the seeming myriad of adaptive explanations for why vertebrate brains vary in size. The role that natural selection has played in brain size has been addressed using the comparative method, which allows identification of evolutionary patterns across species. One starting assumption is that brain size is a useful proxy for intelligence and therefore that large-brained animals are more intelligent than smaller-brained animals. Five classes of selection pressure form the majority of explanations: ecology, technology, innovation, sex, and sociality. After chapters in which I describe the difficulties of measuring both brain size and intelligence (cognition), I address the evidence for each of the five factors in turn, reaching the conclusion that although ecology provides the best explanations for variation in the size of brain regions, none of the factors yet offers a robust and compelling explanation for variation in whole brain size. I end by providing the steps I consider necessary to reach such an explanation, steps that I suggest are feasible, if challenging.

The central question addressed in this book is this: How is the process of adaptation different if the members of a population live clustered in small groups instead of being homogenously distributed like grass on a lawn? The field is called ‘evolution in subdivided populations’ or ‘adaptation in metapopulations.’ The book covers a diverse array of topics, including group selection, family selection, kin selection and sexual selection, as well as speciation genetics, maternal and paternal genetic effects, and host-symbiont co-evolution. These topics are addressed using a combination of conceptual, theoretical, field and laboratory studies and a diversity of living systems ranging from the laboratory model of flour beetles in the genus, Tribolium, to willow leaf beetles, to other animals, plants and microbes.

This book aims to present different voices and perspectives on the adaptive landscape, its past, present, and future position in evolutionary biology. Chapters have been written by scientists in different fields, including ecology, evolution, developmental biology, genetics, history of science and philosophy. The idea for this book came a few years ago, as the 80-year anniversary of Sewall Wright's classic paper was approaching rapidly (2012). This seemed to be an excellent opportunity to summarize the state of the art of the adaptive landscape. The hope is that this volume won't mark the end of the scientific discussions about the adaptive landscape, but rather a new beginning. And finally, it is hoped that if the adaptive landscape will not survive another 80 years, it will hopefully be replaced by an even better concept or metaphor that will push evolutionary biology forward and increase knowledge about adaptation, speciation, and the origins and preservation of biodiversity on this fragile planet.

Aging has long since been ascribed to the gradual accumulation of DNA mutations in the genome of somatic cells. However, it is only recently that the necessary sophisticated technology has been developed to begin testing this theory and its consequences. This book critically reviews the concept of genomic instability as a possible universal cause of aging in the context of a new, holistic understanding of genome functioning in complex organisms resulting from recent advances in functional genomics and systems biology. It provides a synthesis of current research, as well as a look ahead to the design of strategies to retard or reverse the deleterious effects of aging. This is particularly important in a time when we are urgently trying to unravel the genetic component of aging-related diseases. Moreover, there is a growing public recognition of the imperative of understanding more about the underlying biology of aging, driven by continuing demographic change.

Ancestral sequence reconstruction is a technique of growing importance in molecular evolutionary biology and comparative genomics. As a powerful tool for testing evolutionary and ecological hypotheses, as well as uncovering the link between sequence and molecular phenotype, there are potential applications in almost all fields of applied molecular biology. This book starts with a historical overview of the field, before discussing the potential applications in drug discovery and the pharmaceutical industry. This is followed by a section on computational methodology, which provides a detailed discussion of the available methods for reconstructing ancestral sequences (including their advantages, disadvantages, and potential pitfalls). Purely computational applications of the technique are then covered, including whole proteome reconstruction. Further chapters provide a detailed discussion on taking computationally reconstructed sequences and synthesizing them in the laboratory. The book concludes with a description of the scientific questions where experimental ancestral sequence reconstruction has been utilized to provide insights and inform future research.

Galileo wrote that “nature cannot produce a horse as large as twenty ordinary horses or a giant ten times taller than an ordinary man unless by miracle or by greatly altering the proportions of his limbs and especially of his bones”—a statement that wonderfully captures a long-standing scientific fascination with body size. Why are organisms the size that they are? And what determines their optimum size? This volume explores animal body size from a macroecological perspective, examining species, populations, and other large groups of animals in order to uncover the patterns and causal mechanisms of body size throughout time and across the globe. The chapters represent diverse scientific perspectives and are divided into two sections. The first includes chapters on insects, snails, birds, bats, and terrestrial mammals and discusses the body size patterns of these various organisms. The second examines some of the factors behind, and consequences of, body size patterns and includes chapters on community assembly, body mass distribution, life history, and the influence of flight on body size.

Animal life, now and over the past half billion years, is incredibly diverse. Describing and understanding the evolution of this diversity of body plans — from vertebrates such as humans and fish to the numerous invertebrate groups including sponges, insects, molluscs, and the many groups of worms — is a major goal of evolutionary biology. This book adopts a modern, integrated approach to describe how current molecular genetic techniques and disciplines as diverse as palaeontology, embryology, and genomics have been combined, resulting in a dramatic renaissance in the study of animal evolution. The last decade has seen growing interest in evolutionary biology fuelled by a wealth of data from molecular biology. Modern phylogenies integrating evidence from molecules, embryological data, and morphology of living and fossil taxa provide a wide consensus of the major branching patterns of the tree of life; moreover, the links between phenotype and genotype are increasingly well understood. This has resulted in a reliable tree of relationships that has been widely accepted and has spawned numerous new and exciting questions that require a reassessment of the origins and radiation of animal life. The focus of this volume is at the level of major animal groups, the morphological innovations that define them, and the mechanisms of change to their embryology that have resulted in their evolution. Current research themes and future prospects are highlighted including phylogeny reconstruction, comparative developmental biology, the value of different sources of data and the importance of fossils, homology assessment, character evolution, phylogeny of major groups of animals, and genome evolution. These topics are integrated in the light of a 'new animal phylogeny', to provide fresh insights into the patterns and processes of animal evolution.

This book provides a comprehensive analysis of evolution in the animal kingdom. It reviews the classical, morphological information from structure and embryology, as well as the new data gained from studies using immune stainings of nerves and muscles and blastomere markings, which makes it possible to follow the fate of single blastomeres all the way to early organogenesis. Until recently, the information from analyses of gene sequences has tended to produce myriads of quite diverging trees. However, the latest generation of molecular methods, using many genes, expressed sequence tags, and even whole genomes, has brought a new stability to the field. The book brings together the information from these varied fields, and demonstrates that it is indeed now possible to build a phylogenetic tree from a combination of both morphology and gene sequences. This thoroughly revised third edition brings the subject fully up to date, especially in light of the latest advances in molecular techniques. The book is illustrated throughout with finely detailed line drawings and clear diagrams, many of them new.

The second volume in a series dedicated to fossil discoveries made in the Afar region of Ethiopia, this work contains description of the geological context and paleoenvironment of the early hominid Ardipithecus kadabba. This research, carried out by an international team, describes Middle Awash late Miocene faunal assemblages recovered from sediments firmly dated to between 5.2 and 5.8 million years ago. Compared to other assemblages of similar age, the Middle Awash record is unparalleled in taxonomic diversity, composed of 2,760 specimens representing at least sixty five mammalian genera. This evaluation of the vertebrates from the end of the Miocene in Africa provides detailed morphological and taxonomic descriptions of dozens of taxa, including species new to science. It also incorporates results from analyses of paleoenvironment, paleobiogeography, biochronology, and faunal turnover around the Pliocene-Miocene boundary, opening a new window on the evolution of mammals, African fauna, and its environments.

The role of genes in governing behavior remains one of the most controversial topics in human biology. Early in this century, over-eager promotion of a genetic basis for behavior led to the excesses, and ultimately the horrors, of eugenics. Subsequent reactions to these excesses, both within the scientific community and society as a whole, led to a nearly complete dismissal of a role for genes in human behavior. Slowly we come back to a more balanced view. Detailed studies of the biological basis of behavior in animals, from the simplest single-celled creatures through the most complex mammals, show that genes play an important role in guiding behavior. Studies in humans, especially those involving twins reared together or apart, indicate clearly that humans are no exception. The variability we see around us in the way humans respond in a given situation is strongly influenced by the variability in their genetic makeup. So are we powerless creations of our genes? Not at all. Guided by differing genetic makeups, we respond to our environment in different ways. But these responses, and the actions of our genes, are in turn modified by the environment itself. Behavior is the result of a balancing act between genes and the environment; between what we inherit and what we learn. To understand ourselves fully, we must understand both.

The purpose of migration, regardless of the distance involved, is to exploit two or more environments suitable for survival or reproduction over time, usually on a seasonal basis. Yet individual organisms can practice the phenomenon differently, and birds deploy unique patterns of movement over particular segments of time. Incorporating the latest research on bird migration, this critical assessment offers a firm grasp of what defines an avian migrant, how the organism came to be, what is known about its behavior, and how we can resolve its enduring mysteries. The book clarifies key ecological, biological, physiological, navigational, and evolutionary concerns. It begins with the very first avian migrants, who traded a home environment of greater stability for one of greater seasonality, and uses the structure of the annual cycle to examine the difference between migratory birds and their resident counterparts. It ultimately connects these differences to evolutionary milestones that have shaped a migrant lifestyle through natural selection. Rather than catalogue and describe various aspects of bird migration, the book considers how the avian migrant fits within a larger ecological frame, enabling a richer understanding of the phenomenon and its critical role in sustaining a hospitable and productive environment. It concludes with a focus on population biology and conservation across time periods, considering the link between bird migration and the spread of disease among birds and humans, and the effects of global warming on migrant breeding ranges, reaction norms, and macroecology.

Avoiding Attack discusses the diversity of mechanisms by which prey avoid predator attacks and explores how such defensive mechanisms have evolved through natural selection. It considers how potential prey avoid detection, how they make themselves unprofitable to attack, how they communicate this status, and how other species have exploited these signals. Using carefully selected examples of camouflage, mimicry, and warning signals drawn from a wide range of species and ecosystems, the authors summarize the latest research into these fascinating adaptations, developing mathematical models where appropriate and making recommendations for future study.This second edition has been extensively rewritten, particularly in the application of modern genetic research techniques which have transformed our recent understanding of adaptations in evolutionary genomics and phylogenetics. The book also employs a more integrated and systematic approach, ensuring that each chapter has a broader focus on the evolutionary and ecological consequences of anti-predator adaptation. The field has grown and developed considerably over the last decade with an explosion of new research literature, making this new edition timely.

Cladistics, or phylogenetic systematics — an approach to discovering, unraveling, and testing hypotheses of evolutionary history — took hold during a turbulent and acrimonious time in the history of systematics. During this period — the 1960s and 1970s — much of the foundation of modern systematic methodology was established as cladistic approaches became widely accepted. Virtually complete by the end of the 1980s, the wide perception has been that little has changed. This volume vividly illustrates that cladistic methodologies have continued to be developed, improved upon, and effectively used in ever widening analytically imaginative ways.

This book chronicles the discovery and analysis of animal fossils found in one of the most important paleontological sites in the world: Porcupine Cave, located at an elevation of 9,500 feet in the Colorado Rocky Mountains. With tens of thousands of identified specimens, this site has become the key source of information on the fauna of North America's higher elevations between approximately 1 million and 600,000 years ago, a period that saw the advance and retreat of glaciers numerous times. Until now, little has been understood about how this dramatic climate change affected life during the middle Pleistocene. In addition to presenting data from Porcupine Cave, this study also presents analysis on what the data from the site show about the evolutionary and ecological adjustments that occurred in this period, shedding light on how one of the world's most pressing environmental concerns—global climate change—can influence life on earth.

This book describes forty-two fossil taxa recovered during a study of the San Timoteo Badlands that used magnetobiostratigraphy to develop a temporal framework for addressing the tectonic evolution of southern California over the last six million years. For the Pliocene, small mammals are an effective means of correlating a magnetostratigraphy to the Geomagnetic Polarity Time Scale when radioisotopic dates are unobtainable.

The vertebrate fossil record extends back more than 500 million years, and bonebeds—localized concentrations of the skeletal remains of vertebrate animals—help unlock the secrets of this long history. Often spectacularly preserved, bonebeds—both modern and ancient—can reveal more about life histories, ecological associations, and preservation patterns than any single skeleton or bone. For this reason, they are frequently studied by paleobiologists, geologists, and archeologists seeking to piece together the vertebrate record. In this book, thirteen researchers combine their experiences to provide readers with workable definitions, theoretical frameworks, and a compendium of modern techniques in bonebed data collection and analysis. By addressing the historical, theoretical, and practical aspects of bonebed research, they provide the background and methods that students and professionals need to explore and understand these records of ancient life and death.

Much is conserved in vertebrate evolution, but significant changes in the nervous system occurred at the origin of vertebrates and in most of the major vertebrate lineages. This book examines these innovations and relates them to evolutionary changes in other organ systems, animal behavior, and ecological conditions at the time. The resulting perspective clarifies what makes the major vertebrate lineages unique and helps explain their varying degrees of ecological success. One of the book’s major conclusions is that vertebrate nervous systems are more diverse than commonly assumed, at least among neurobiologists. Examples of important innovations include not only the emergence of novel brain regions, such as the cerebellum and neocortex, but also major changes in neuronal circuitry and functional organization. A second major conclusion is that many of the apparent similarities in vertebrate nervous systems resulted from convergent evolution, rather than inheritance from a common ancestor. For example, brain size and complexity increased numerous times, in many vertebrate lineages. In conjunction with these changes, olfactory inputs to the telencephalic pallium were reduced in several different lineages, and this reduction was associated with the emergence of pallial regions that process non-olfactory sensory inputs. These conclusions cast doubt on the widely held assumption that all vertebrate nervous systems are built according to a single, common plan. Instead, the book encourages readers to view both species similarities and differences as fundamental to a comprehensive understanding of nervous systems.

This volume is a comprehensive review of the African mammalian fossil record over the past 65 million years. The book includes current taxonomic and systematic revisions of all African mammal taxa, detailed compilations of fossil site occurrences, and a wealth of information regarding paleobiology, phylogeny, and biogeography. Primates, including hominins, are particularly well covered. The discussion addresses the systematics of endemic African mammals, factors relating to species richness, and a summary of isotopic information. The work also provides contextual information about Cenozoic African tectonics, chronostratigraphy of sites, paleobotany, and global and regional climate change. Updating our understanding of this important material with the wealth of research from the past three decades, this volume is an essential resource for anyone interested in the evolutionary history of Africa and the diversification of its mammals.

This book begins the inquiry into the evolution of the collective sensitivities of life. Chapters trace the emergence and evolution of consciousness. Complex behaviors and the social imperatives of bacteria and other life forms during 3,000 million years of Earth history gave rise to mammalian cognition. Awareness and sensation led to astounding activities; millions of species incessantly interacted to form our planet’s complex conscious system. Our planetmates, all of them conscious to some degree, were joined only recently by us, the aggressive modern humans. From social bacteria to urban citizens, all living beings participate in community life. Nested inside families within communities inside ecosystems, each metabolizes, takes in matter, expends energy, and excretes. Each of the members of our own and other species, in groups with incessantly shifting alliances, receives and processes information. Mergers of radically different life forms with myriad purposes—the “chimeras” of the title—underlie dramatic metamorphosis and other positive evolutionary change. Since early bacteria avoided, produced, and eventually used oxygen, Earth’s sensory systems have expanded and complexified. The chapters in this book serve to put sensitive, sensible life in its cosmic context.