How Life Increases Biodiversity

An Autocatalytic Hypothesis

David Seaborg

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9780429802102
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Zoology
• Index: Biological Sciences

This book argues that organisms and their interactions create and maximize biodiversity. The evidence for this autocatalytic hypothesis has been collated and integrated into this provocative argument. Natural selection favors the increase of biodiversity. Organisms can be causative agents contributing to major macroevolutionary transitions. Species tend to have a net positive effect on biodiversity. All species are ecosystem engineers. Mutualism and commensalism are common and fundamental, and these coevolved interspecific interactions frequently generate enormous increases in biodiversity. Competition generally does not decrease biodiversity, and often leads to evolutionary innovation. Plants are ecosystem engineers that have made Earth more favorable to life and increased diversity in many ways. Herbivores and predators increase the diversity of the species they consume, and are necessary for ecosystem stability. Decomposers are essential to ecosystem health. All these examples illustrate the focus of this book – that organisms and their interactions stimulate biodiversity, and ecosystems maximize it.

Key Features

• Describes a hypothesis that life itself generates higher biodiversity

• Suggests a highly modified version of the established paradigm in population biology and evolution

• Asserts that all species are ecosystem engineers with a net positive effect on biodiversity and their ecosystems

• Suggests that mutualism and commensalism are the rule

• Presents a novel view likely to elicit deeper discussions of biodiversity

Related Titles

Dewdney, A. K. Stochastic Communities: A Mathematical Theory of Biodiversity (ISBN

978-1-138-19702-2)

Curry, G. B. and C. J. Humphries, eds. Biodiversity Databases: Techniques, Politics, and

Applications (ISBN 978-0-367-38916-1)

Pullaiah, T, ed. Global Biodiversity. 4 Volume Set (ISBN 978-1-77188-751-9)

1 Introduction

Evolution, ecology, and population biology have given us tremendous understanding and insights, but have for the most part missed one of the most important, interesting, exciting, explanatory, and unifying aspects of evolution, ecology, and how ecosystems function. This is that organisms, species, and life itself generate the vast majority of the biodiversity on Earth, much more than would be present from physical and chemical factors alone. The subject and thesis of this book, the Autocatalytic Biodiversity Hypothesis (ABH), proposes that organisms create most of the biodiversity on Earth, and that ecosystems maximize biodiversity. It proposes that the number of species on Earth is far greater because of the presence, actions, and interactions of its organisms. The hypothesis has autocatalytic in its name because it proposes that life itself and organisms themselves create more life, more species, and more biodiversity. Life causes far greater biodiversity than can be explained solely by physical and chemical processes. This is accomplished by two or three mechanisms. The first underlying mechanism uniting all the seemingly unrelated mechanisms is that every species is an ecosystem engineer that has a net beneficial impact on other species, its ecosystem, and biodiversity in a natural ecosystem over a sufficient time. Oxygenic photosynthesis caused a great loss of diversity because oxygen was toxic to many prokaryotes when it first became abundant in the atmosphere. It also caused the Earth to become very cold. Sulfate-reducing microbes produced toxic hydrogen sulfide that decreased diversity for a long time. But these phenomena were in time changed by life, making them not very harmful to life. In time, they both were essentially permanently converted to being factors that increase diversity. This is why the words “over a sufficient time” are in the above statement that every species is beneficial to biodiversity. This is discussed in more detail in Chapter 15. This statement is also the major underlying mechanism uniting most of the seemingly unrelated mechanisms by which organisms cause biodiversity to increase. Crucial to this theory is the assertion that mutualism is much more important than commonly thought, fundamental, an organizer of ecosystems, and a great promoter of biodiversity. The ABH and its mechanisms are entirely scientific, naturalistic, and mechanistic, and any attempt to interpret this hypothesis in teleological, pseudoscientific, or “Aquarian Age” terms, as some incorrectly did with the Gaia Hypothesis, is simply wrong. The presentation of this theory and the evidence for it are the theme and subject of this book.

The second mechanism by which organisms increase biodiversity is the behavior of the genome. Sexual recombination, transposable elements, viral transduction, repurposing of viruses as genetic material by the host, polyploidy, hybridization, epistasis and changes in regulatory genes, and other such mechanisms cause macroevolutionary innovations and great increases in biodiversity. This can be considered a form of ecosystem engineering in the sense that viral transduction, transposable elements, sexual recombination, and so on are molding (engineering) the genome, and the genome is part of the ecosystem. If one accepts this, there is no need for this additional unifying mechanism for the ABH, since all species are ecosystem engineers that tend to have a positive effect on diversity in natural systems over time covers genomic behavior. Genomic behavior can be incorporated in the ecosystem engineering mechanism of the ABH. I think this is legitimate. But some might differ. If one thinks calling the behavior of the genome a form of ecosystem engineering to be too much of a stretch, then a second unifying mechanism of the ABH can be added. That mechanism is the behavior of the genome, examples of which are listed in the second sentence of this paragraph. This mechanism is not discussed in this volume of book because of space limitations. However, I will discuss it in a second volume of this book that will be published next year or sooner.

The other mechanism by which the ABH works and organisms generate biodiversity is natural selection.

Lovelock [1] and Lovelock and Margulis [2] proposed the Gaia Hypothesis followed by Lovelock’s [3] popularizing, seminal book, Gaia: A New Look at Life on Earth [3]. The hypothesis proposed that organisms interact with their inorganic surroundings to form a cybernetic and self-regulating system that helps maintain and perpetuate the conditions for life. The hypothesis sees the Earth as analogous to an organism because it is homeostatic due to its life. Specifically, the hypothesis states that life regulates Earth’s atmospheric composition, and makes it favorable to life, largely by negative feedback. They both provided evidence for this. They are responsible for this insightful idea. Margulis presented evidence that mitochondria and chloroplasts originated from bacteria that were ingested by prokaryotic cells, but this was never incorporated as part of the hypothesis. They rejected uninformed, pseudoscientific interpretations of the hypothesis that claimed Earth is literally an organism with consciousness. My ABH was partly inspired by the Gaia Hypothesis, and I owe a debt to Lovelock and Margulis. The Gaia and Autocatalytic Biodiversity Hypotheses are in agreement on the point that life created an atmosphere favorable to life.

It is important to note that the ABH is not the same as the Gaia Hypothesis. There are three major differences between them. The first is that the Gaia Hypothesis is a subset of the ABH. The ABH is more general and broad than the Gaia Hypothesis. The Gaia Hypothesis is limited to life’s interaction with nonbiological aspects of the Earth system, focusing mainly on the atmosphere. It does address other factors than the atmosphere, such as oceanic salinity. The Gaia Hypothesis can be summarized as follows: Life made the Earth, mainly the atmosphere, more favorable to life, and this helped life thrive. It does recognize a coevolution between life and the nonbiological environment. It does not include interactions between species. Margulis did emphasize the importance of mutualism, especially with respect to the origin of the mitochondrion and chloroplast (see, for example, Margulis [4]), but mutualism was never incorporated into the Gaia Hypothesis. The Autocatalytic Hypothesis includes life’s coevolution with the nonbiological environment, and expands on the idea. For example, one way the ABH expands on this idea is that it includes life’s coevolution with and formation of the soil, which the Gaia Hypothesis does not include. But it also addresses interactions between species, such as predators and their prey, competition, and symbiosis; altruistic behavior between organisms of the same species; behavior of genomes; effects of viruses on the biosphere; and other diversity-enhancing actions of organisms.

Second, the only mechanism proposed by Gaia is negative feedback. The ABH accepts the importance of negative feedback in some cases, but proposes many other mechanisms that life employs to maintain and increase biodiversity, including the unifying concept that all species are ecosystem engineers. These mechanisms are summarized a few paragraphs below this one.

Finally, the Gaia Hypothesis does not propose that any variable in particular in an ecosystem is maximized by life. The ABH claims that life’s activities maximize an important variable of the ecosystem: biodiversity. Thus, the ABH can be briefly stated as follows: Organisms create and increase biodiversity, all species are ecosystem engineers that maintain or increase biodiversity under natural conditions over sufficient time and ecosystems maximize biodiversity. I hope to demonstrate these claims in this book.

The ABH may also be called the Pachamama Hypothesis, following the lead established by Lovelock [3], who named his idea the Gaia Hypothesis after the Greek primal Mother Earth goddess. Ward’s [5] Medea Hypothesis, named after the destructive Greek goddess, Medea, proposes that life is self-destructive, claiming that life has the opposite effect of the Gaia Hypothesis. Ward thus continued the idea of naming hypotheses about life’s effect on life after Greek goddesses. Pachamama is the ever-present Earth and time mother goddess who has her own self-sufficient and creative power to sustain life on Earth. She is also the prime origin of her four cosmological Quechua principles—Water, Earth, Sun, and Moon. She is revered by indigenous peoples of the Andes, such as the Quechua and Aymara. Pachamama is usually translated as Mother Earth, but a more literal translation is World Mother in Quechua and Aymara. This departs from the use of Greek goddesses, but continues the use of goddesses that are appropriate, powerful metaphors for these hypotheses. And like Gaia, Pachamama is an Earth goddess. Thus, I consider the name appropriate to the ABH.

A summary this volume and the various mechanisms by which life creates and increases biodiversity follows.

Evolution by natural selection is one several mechanisms by the ABH works. Life has extraordinary abilities to adapt to environmental challenges, resulting in extreme and incredible adaptations. Mutualism is far more important and common than commonly accepted; it is fundamental; it organizes ecosystems; and it has increased biodiversity tremendously, both directly and indirectly. Mutualism results from the coevolution of two species. It often creates a new adaptive zone with a multitude of new niches. When it does so, the mutualists radiate into a tremendous number of new mutualist species. Other species then evolve to exploit the many niches provided by the new species of mutualists, further increasing diversity. Commensalism is common, and maintains and increases diversity. Ecosystem engineers greatly increase biodiversity by creating habitat and niches for many species commensal and mutualistic with them. Examples are beavers and termites. Competition does not significantly reduce species richness because competing species partition niches and evolve divergently. Plants are ecosystem engineers that sequester carbon; produce oxygen; make and improve soil; liberate soil nutrients; aerate the soil; and provide food and a three-dimensional habitat for many animals, other plants, fungi, and prokaryotes. Rivers would not exist without plants stabilizing their banks. Phytoplankton are the basis of oceanic food webs, major climate regulators, and produce most of the planet’s oxygen. They often produce oxygen in great amounts by using nutrients provided by rainforests, the two ecosystems working together. Herbivores increase plant diversity, fertilize soil and marine and freshwater ecosystems, maintain mosaic habitats, and provide food to predators. They till and aerate the soil when they run from predators. Predators are mutualists with their prey if one considers prey at the levels of population and species. Predators regulate prey populations, increase prey diversity by consuming more of the prey that is the best competitor, prevent catastrophic trophic cascades, and select for novel adaptations in their prey. Parasites enhance the diversity of their hosts by similar mechanisms. Decomposers remove carcasses and feces, recycle nutrients, enrich soil, and can even reduce the amount of the powerful greenhouse gas methane (CH₄) in the atmosphere. This book proposes eight principles of ecology and evolution. The first states that in a natural ecosystem, situation, and conditions, over a time interval sufficiently long to accurately represent the effect of a species on its ecosystem, every species has a net positive effect on other species, its ecosystem, and biodiversity. The second states that all species are ecosystem engineers.

I am asking the reader to keep an open mind to my thesis that we need a fundamental paradigm shift. That is central to the ABH. The new paradigm states that biology is the major generator of biodiversity, and has an inherent tendency to do this. Ecosystems maximize biodiversity. Life is autocatalytic. Mutualism is a major source of ecosystem structure, a driver of high biodiversity, and a fundamental feature of evolution. All biological evolution is coevolution. No gene, organism, or species evolves in isolation. Genes, genomes, organisms, and species cannot be isolated from the network they evolve in. All of these entities evolve in an interconnected web. No species can be understood without understanding its connections, species it interacts with, and its environment. The relationships between species are as important in affecting ecosystems and evolution as the species themselves. Organisms do not exist as individuals, but are both chimeras and interconnected parts of systems. There is a tendency toward order when certain conditions are met that does not violate the Second Law of Thermodynamics.

This book attempts a comprehensive presentation of the evidence for the autocatalytic, coevolutionary, symbiotic generation of biodiversity by life called the ABH, drawing from a large number of disciplines. This presents the problem that the specialized scientist will be quite knowledgeable of one or perhaps two fields discussed in this book, while not being very familiar with the literature and terminology of the other fields. I have done my best to solve this dilemma with a compromise, whereby I use language less technical than in a scientific journal, but more rigorous than a popular science book for the educated layman. My hope is to make all chapters comprehensible to all readers, but not boring to the experts in the area being discussed at any given time.

I have resisted the temptation of setting up an easy-to-falsify straw man hypothesis that claims that the standard theory of evolution has no recognition of ideas similar to the ABH in the literature and that it opposes any suggestion that the actions of organisms can increase diversity. Also, I recognize that other authors have proposed similar ideas. Scientific integrity requires these two actions. There is the problem that many of the ideas in this volume are floating in the literature, and some may question the originality of some ideas in this book. I have done my best to credit previous authors and state when ideas presented are not novel, and when they are. I have been as diligent as I could about this. Sometimes this is obvious or implied.

Also, the reiteration of already existing concepts such as mutualism to support arguments being made could make my ideas appear unoriginal. It would be unfair and unscientific to judge the ABH unoriginal by taking it piecemeal; one must consider the whole picture, the entire gestalt. To describe the mutualism between angiosperms and their pollinators is not original; demonstrating how it fits contextually into a larger theory of how organisms generate diversity is.

I will state what I consider to be original in this book and concerning the ABH, to avoid any confusion on this issue. It is as follows.

First is the generality of the idea that organisms and life create biodiversity. The Gaia Hypothesis already pointed out that life regulates atmospheric gases, but the ABH adds many more mechanisms, including species interactions, sexual selection, and the behavior of DNA. This is the first compilation of the evidence supporting, logical arguments for, and mechanisms by which, life generates diversity and is autocatalytic in one book. The idea has certainly not yet achieved consensus or proof. The cen...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Acknowledgments
• Author
• Chapter 1 Introduction
• Chapter 2 Biodiversity: Organisms Create It, Ecosystems Maximize It
• Chapter 3 Natural Selection Is One Mechanism by Which the Autocatalytic Biodiversity Hypothesis Operates
• Chapter 4 Mutualism Is Fundamental and Greatly Increases Diversity
• Chapter 5 Commensalism Is Ubiquitous, and Maintains and Increases Diversity
• Chapter 6 Interspecific Competition Increases Species Richness
• Chapter 7 Plants Are Ecosystem Engineers That Aid Other Life and Are Linked to It
• Chapter 8 Herbivores Generate Biodiversity
• Chapter 9 Predators and Prey, Parasites and Hosts: Mutualistic Relationships That Create High Diversity
• Chapter 10 Decomposers Are Indispensable to Their Ecosystems
• Chapter 11 Eight New Proposed Principles of Ecology and Evolution
• Index