This book re-examines the endosymbiotic theory, and presents various related theories and hypotheses since the first proposal in 1905 by a Russian biologist. It also demonstrates that Lynn Margulis’s contribution to the current endosymbiotic is less than sometimes thought, and presents a plausible idea on how the organelles were formed. Explaining that Margulis’s initial work did not intend to show the endosymbiotic origin of chloroplasts and mitochondria, the book discusses their endosymbiotic origin in the light of current biology with the help of clear visual images. Further, by including numerous historical facts and details of phylogenetic analyses using recent genomic data that are largely unknown to many in the field, it offers deep insights into the history of biology, phylogenetic analysis, and the new evolutionary thinking. 2017 was the 50-year anniversary of Margulis’s first paper in the Journal of Theoretical Biology, and 2020 will mark 50 years since the publication her famous work Origin of Eukaryotic Cells, and as such this book offers a timely reconsideration ofthe works of Lynn Margulis and the endosymbiotic origin of organelles.

This book re-examines the endosymbiotic theory, and presents various related theories and hypotheses since the first proposal in 1905 by a Russian biologist. It also demonstrates that Lynn Margulis’s contribution to the current endosymbiotic is less than sometimes thought, and presents a plausible idea on how the organelles were formed. Explaining that Margulis’s initial work did not intend to show the endosymbiotic origin of chloroplasts and mitochondria, the book discusses their endosymbiotic origin in the light of current biology with the help of clear visual images. Further, by including numerous historical facts and details of phylogenetic analyses using recent genomic data that are largely unknown to many in the field, it offers deep insights into the history of biology, phylogenetic analysis, and the new evolutionary thinking. 2017 was the 50-year anniversary of Margulis’s first paper in the Journal of Theoretical Biology, and 2020 will mark 50 years since the publication her famous work Origin of Eukaryotic Cells, and as such this book offers a timely reconsideration ofthe works of Lynn Margulis and the endosymbiotic origin of organelles.

In this comprehensive history of symbiosis theory--the first to be written--Jan Sapp masterfully traces its development from modest beginnings in the late nineteenth century to its current status as one of the key conceptual frameworks for the life sciences. The symbiotic perspective on evolution, which argues that "higher species" have evolved from a merger of two or more different kinds of organisms living together, is now clearly established with definitive molecular evidence demonstrating that mitochondria and chloroplasts have evolved from symbiotic bacteria. In telling the exciting story of an evolutionary biology tradition that has effectively challenged many key tenets of classical neo-Darwinism, Sapp sheds light on the phenomena, movements, doctrines, and controversies that have shaped attitudes about the scope and significance of symbiosis. Engaging and insightful, Evolution by Association will be avidly read by students and researchers across the life sciences.

Mitochondria are sometimes called the powerhouses of eukaryotic cells, because mitochondria are the site of ATP synthesis in the cell. ATP is the universal energy currency, it provides the power that runs all other life processes. Humans need oxygen to survive because of ATP synthesis in mitochondria. The sugars from our diet are converted to carbon dioxide in mitochondria in a process that requires oxygen. Just like a fire needs oxygen to burn, our mitochondria need oxygen to make ATP. From textbooks and popular literature one can easily get the impression that all mitochondria require oxygen. But that is not the case. There are many groups of organismsm known that make ATP in mitochondria without the help of oxygen. They have preserved biochemical relicts from the early evolution of eukaryotic cells, which took place during times in Earth history when there was hardly any oxygen avaiable, certainly not enough to breathe. How the anaerobic forms of mitochondria work, in which organisms they occur, and how the eukaryotic anaerobes that possess them fit into the larger picture of rising atmospheric oxygen during Earth history are the topic of this book.

Are humans a galactic oddity, or will complex life with human abilities develop on planets with environments that remain habitable for long enough? In a clear, jargon-free style, two leading researchers in the burgeoning field of astrobiology critically examine the major evolutionary steps that led us from the distant origins of life to the technologically advanced species we are today. Are the key events that took life from simple cells to astronauts unique occurrences that would be unlikely to occur on other planets? By focusing on what life does - it's functional abilities - rather than specific biochemistry or anatomy, the authors provide plausible answers to this question. Systematically exploring the various pathways that led to the complex biosphere we experience on planet Earth, they show that most of the steps along that path are likely to occur on any world hosting life, with only two exceptions: One is the origin of life itself – if this is a highly improbable event, then we live in a rather “empty universe”. However, if this isn’t the case, we inevitably live in a universe containing a myriad of planets hosting complex as well as microbial life - a “cosmic zoo”. The other unknown is the rise of technologically advanced beings, as exemplified on Earth by humans. Only one technological species has emerged in the roughly 4 billion years life has existed on Earth, and we don’t know of any other technological species elsewhere. If technological intelligence is a rare, almost unique feature of Earth's history, then there can be no visitors to the cosmic zoo other than ourselves. Schulze-Makuch and Bains take the reader through the history of life on Earth, laying out a consistent and straightforward framework for understanding why we should think that advanced, complex life exists on planets other than Earth. They provide a unique perspective on the question that puzzled the human species for centuries: are we alone?