Microbial Drivers Of Sociality From Multicellularity To Animal Societies

Beginning with the germ theory of disease in the 19th century and extending through most of the 20th century, microbes were believed to live their lives as solitary, unicellular, disease-causing organisms . This perception stemmed from the focus of most investigators on organisms that could be grown in the laboratory as cellular monocultures, often dispersed in liquid, and under ambient conditions of temperature, lighting, and humidity. Most such inquiries were designed to identify microbial pathogens by satisfying Koch's postulates.3 This pathogen-centric approach to the study of microorganisms produced a metaphorical "war" against these microbial invaders waged with antibiotic therapies, while simultaneously obscuring the dynamic relationships that exist among and between host organisms and their associated microorganisms-only a tiny fraction of which act as pathogens. Despite their obvious importance, very little is actually known about the processes and factors that influence the assembly, function, and stability of microbial communities. Gaining this knowledge will require a seismic shift away from the study of individual microbes in isolation to inquiries into the nature of diverse and often complex microbial communities, the forces that shape them, and their relationships with other communities and organisms, including their multicellular hosts. On March 6 and 7, 2012, the Institute of Medicine's (IOM's) Forum on Microbial Threats hosted a public workshop to explore the emerging science of the "social biology" of microbial communities. Workshop presentations and discussions embraced a wide spectrum of topics, experimental systems, and theoretical perspectives representative of the current, multifaceted exploration of the microbial frontier. Participants discussed ecological, evolutionary, and genetic factors contributing to the assembly, function, and stability of microbial communities; how microbial communities adapt and respond to environmental stimuli; theoretical and experimental approaches to advance this nascent field; and potential applications of knowledge gained from the study of microbial communities for the improvement of human, animal, plant, and ecosystem health and toward a deeper understanding of microbial diversity and evolution. The Social Biology of Microbial Communities: Workshop Summary further explains the happenings of the workshop.

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.

Groundbreaking research over the last 10 years has given rise to the hologenome concept of evolution. This concept posits that the holobiont (host plus all of its associated microorganisms) and its hologenome (sum of the genetic information of the host and its symbiotic microorganisms), acting in concert, function as a unique biological entity and therefore as a level of selection in evolution. All animals and plants harbor abundant and diverse microbiota, including viruses. Often the amount of symbiotic microorganisms and their combined genetic information far exceed that of their host. The microbiota with its microbiome, together with the host genome, can be transmitted from one generation to the next and thus propagate the unique properties of the holobiont. The microbial symbionts and the host interact in a cooperative way that affects the health of the holobiont within its environment. Beneficial microbiota protects against pathogens, provides essential nutrients, catabolizes complex polysaccharides, renders harmful chemicals inert, and contributes to the performance of the immune system. In humans and animals, the microbiota also plays a role in behavior. The sum of these cooperative interactions characterizes the holobiont as a unique biological entity. Genetic variation in the hologenome can be brought about by changes in either the host genome or the microbial population genomes (microbiome). Evolution by cooperation can occur by amplifying existing microbes, gaining novel microbiota and by acquiring microbial and viral genes. Under environmental stress, the microbiome can change more rapidly and in response to more processes than the host organism alone and thus influences the evolution of the holobiont. Prebiotics, probiotics, synbiotics and phage therapy are discussed as applied aspects of the hologenome concept.

First book to outline the fundamental principles of social evolution underlying the stunning diversity of social systems and behaviours.

This book is a treatise on microbial ecology that covers traditional and cutting-edge issues in the ecology of microbes in the biosphere. It emphasizes on study tools, microbial taxonomy and the fundamentals of microbial activities and interactions within their communities and environment as well as on the related food web dynamics and biogeochemical cycling. The work exceeds the traditional domain of microbial ecology by revisiting the evolution of cellular prokaryotes and eukaryotes and stressing the general principles of ecology. The overview of the topics, authored by more than 80 specialists, is one of the broadest in the field of environmental microbiology. The overview of the topics, authored by more than 80 specialists, is one of the broadest in the field of environmental microbiology.

Among the most important innovations in the history of life is the transition from single-celled organisms to more complex, multicellular organisms. Multicellularity has evolved repeatedly across the tree of life, resulting in the evolution of new kinds of organisms that collectively constitute a significant portion of Earth’s biodiversity and have transformed the biosphere. This volume examines the origins and subsequent evolution of multicellularity, reviewing the types of multicellular groups that exist, their evolutionary relationships, the processes that led to their evolution, and the conceptual frameworks in which their evolution is understood. This important volume is intended to serve as a jumping-off point, stimulating further research by summarizing the topics that students and researchers of the evolution of multicellularity should be familiar with, and highlighting future research directions for the field.