Conceptual Breakthroughs in Evolutionary Genetics

A Brief History of Shifting Paradigms

John C. Avise

• Publisher: Academic Press
• Year: 2014
• Print ISBN: 9780124201668
• eBook ISBN: 9780124202375
• Topic: Biological Sciences
• Subtopic: Ecology
• Index: Biological Sciences

Conceptual Breakthroughs in Evolutionary Genetics is a pithy, lively book occupying a special niche—the conceptual history of evolutionary genetics— not inhabited by any other available treatment. Written by a world-leading authority in evolutionary genetics, this work encapsulates and ranks 70 of the most significant paradigm shifts in evolutionary biology and genetics during the century-and-a-half since Darwin and Mendel. The science of evolutionary genetics is central to all of biology, but many students and other practitioners have little knowledge of its historical roots and conceptual developments. This book fills that knowledge gap in a thought-provoking and readable format. This fascinating chronological journey along the many conceptual pathways to our modern understanding of evolutionary and genetic principles is a wonderful springboard for discussions in undergraduate or graduate seminars in evolutionary biology and genetics. But more than that, anyone interested in the history and philosophy of science will find much of value between its covers. - Provides a relative ranking of 70 seminal breakthroughs and paradigm shifts in the field of evolutionary biology and genetics - Modular format permits ready access to each described subject - Historical overview of a field whose concepts are central to all of biology and relevant to a broad audience of biologists, science historians, and philosophers of science - Extensively cross-referenced with a guide to landmark papers and books for each topic

Part I

The First 50 Years (1859–1910): Laying the Foundations

Outline

Part I. The First 50 Years (1859–1910): Laying the Foundations

Chapter 1 1859 Whose Handiwork?

Chapter 2 1861 Spontaneous Generation

Chapter 3 1865 The Nature of Heredity

Chapter 4 1871 Pre-copulatory Sexual Selection

Chapter 5 1875 Nature versus Nurture

Chapter 6 1876 Biogeography

Chapter 7 1889 Germ Plasm

Chapter 8 1902 The Etiology of Disabilities

Chapter 9 1902 Autosomes

Chapter 10 1905 Epistasis

Chapter 11 1908 Hardy-Weinberg

Chapter 12 1909 Genotype versus Phenotype

Chapter 13 1909 Non-Mendelian Inheritance

Chapter 14 1910 Sex Chromosomes

Part I. The First 50 Years (1859–1910): Laying the Foundations

The breakthroughs in Part I begin with Charles Darwin’s treatises on natural selection (1859) and sexual selection (1871), and Gregor Mendel’s (1865) unanticipated documentation of particulate inheritance. They continue with several other highly notable accomplishments, including the births of biogeography (1876) and biochemical genetics (1902), and they conclude with Morgan’s (1910) key discoveries that linked the observed behaviors of chromosomes to Mendel’s inferred laws of genetic segregation and independent assortment. In these and in the dozen other discoveries included in Part I, biologists thereby began to lay the conceptual foundations for what later would become recognizable as the field of evolutionary genetics.

Chapter 1

1859 Whose Handiwork?

Life’s beauty and variety are prima facie evidence of God’s creative handiwork. Throughout most of human history, and including parts of classical Greek philosophy to 19th century theology, a standard sentiment was that supernatural agents (Gods) were directly responsible for the diversity and the exquisite functional features of life. The 17th century naturalist John Ray famously referred to this notion as “The Wisdom of God”. In 1802, this traditional paradigm – natural theology – was again epitomized in a powerful treatise by the Anglican minister William Paley, who paid homage to a beneficent Creator God for directly fashioning organic material into the myriad phenotypic features that enable organisms to survive and reproduce. In the modern era, natural theology has resurfaced in the guise of the “intelligent design” (ID) religious movement. Proponents of ID posit that complex biological outcomes, ranging from bacterial cells to human beings, were purposefully designed and directly crafted by a supreme intelligence (e.g., by a Creator God) rather than having arisen via non-sentient natural evolutionary forces.

Keywords

theology; evolutionary forces

The Standard Paradigm

Life’s beauty and variety are prima facie evidence of God’s creative handiwork. Throughout most of human history, and including parts of classical Greek philosophy to 19th century theology, a standard sentiment was that supernatural agents (Gods) were directly responsible for the diversity and the exquisite functional features of life. The 17th century naturalist John Ray famously referred to this notion as “The Wisdom of God”. In 1802, this traditional paradigm – natural theology – was again epitomized in a powerful treatise by the Anglican minister William Paley, who paid homage to a beneficent Creator God for directly fashioning organic material into the myriad phenotypic features that enable organisms to survive and reproduce. In the modern era, natural theology has resurfaced in the guise of the “intelligent design” (ID) religious movement. Proponents of ID posit that complex biological outcomes, ranging from bacterial cells to human beings, were purposefully designed and directly crafted by a supreme intelligence (e.g., by a Creator God) rather than having arisen via non-sentient natural evolutionary forces.

The dilemma for natural theology had always been the fact that many biological phenomena seem inconsistent with a wise and benevolent Creator. Why, for example, do parasites and diseases exist, why are pain and suffering so prevalent, and, more generally, why are biological imperfections and the natural equivalent of “evil” apparently so common in the organic world? This perennial philosophical problem is known as theodicy (literally translated as “God’s justice”, from the Greek words theós for God and dik for justice). The word theodicy was coined in 1710 by the German Philosopher and mathematician Gottfried Leibniz in an essay entitled Theodicic Essays on the Benevolence of God, the Free Will of Man, and the Origin of Evil.

The Conceptual Revolution

Charles Darwin (and, independently, Alfred Russel Wallace) identified a non-sentient evolutionary process – natural selection – that can sculpt organic material (forge adaptations) without the need to invoke either conscious or direct supernatural causation. Darwin adduced that evolution is a necessary consequence of natural selection as the explanation of biological design because natural selection fosters the adaptation of organisms to their environmental milieu. Natural selection not only provided a powerful explanation for evolution, but thereby also offered a potential solution to the longstanding theodicic conundrum. Natural selection is a mindless process of nature, as unthinking and uncaring as gravity or lightning. No longer need rationalists directly blame a Creator God for life’s miseries (or directly credit Him for biological adaptations). Instead, the proximate driving force of evolution is an unconscious and non-omnipotent agent, which obviates the necessity to invoke supernatural agents to account for life’s flaws as well as beauties. The concept of biological evolution by natural selection – and ergo the influence of Darwinian evolutionary thought – has spread far beyond biology and well into the realms of the social sciences, philosophy, and religion.

PS-score: 10

This perfect score is merited by the fact that scientists ever since Darwin have universally accepted the reality of evolution by natural selection (among many other population genetic forces). In terms of epistemological significance, the Darwinian revolution of the 19th century – by unshackling science from untestable religious doctrines – did for biology what the Copernican revolution of the 16th century had done for the physical sciences. The Darwinian conceptual revolution has transformed and unified thought throughout the biological sciences. Indeed, it has been aptly stated that nothing in biology makes sense except in evolution’s light (Dobzhansky, 1973).

References and Further Reading

1. Ray J. The Wisdom of God Manifested in the Works of Creation London, UK: Smith; 1691.

2. Paley W. Natural Theology Oxford, UK: Reprinted by Oxford University Press; 1802; 2006.

3. Darwin C. On the Origin of Species London, UK: John Murray; 1859.

4. Dobzhansky T. Nothing in biology makes sense except in the light of evolution. Am Biol Teacher. 1973;35:125–129.

5. Dawkins R. The Blind Watchmaker New York, NY: Norton & Co.; 1987.

6. Ruse M. The Darwinian Revolution Chicago, IL: University of Chicago Press; 1999.

7. Ruse M. Darwin and Design Cambridge, MA: Harvard University Press; 2003.

8. Manning RE, ed. The Oxford Handbook of Natural Theology. Oxford, UK: Oxford University Press; 2013.

Chapter 2

1861 Spontaneous Generation

Life continually arises spontaneously. A widespread belief from the time of the ancient Romans through and beyond the Middle Ages was that organic life routinely generates from non-life, such as when rats emerge from a heap of trash, amphibians appear each spring from swampy mud, or maggots swarm from rotting meat. This standard folklore is known as abiogenesis, or the origin of life via spontaneous generation.

Keywords

abiogenesis; proliferation

The Standard Paradigm

Life continually arises spontaneously. A widespread belief from the time of the ancient Romans through and beyond the Middle Ages was that organic life routinely generates from non-life, such as when rats emerge from a heap of trash, amphibians appear each spring from swampy mud, or maggots swarm from rotting meat. This standard folklore is known as abiogenesis, or the origin of life via spontaneous generation.

The Conceptual Revolution

The revised worldview is that only life normally begets life. The “disproof” of spontaneous generation traditionally is ascribed to the French chemist and microbiologist Louis Pasteur, who in 1861 conducted a critical laboratory experiment showing that sterilized broth cultures do not regrow microorganisms unless exposed to suitable inocula containing other microbes. Apparently, the microbes were proliferating rather than arising spontaneously.

PS-score: 5

Pasteur’s experiments – important though they were – were not entirely novel in concept, because two centuries earlier the Italian physician Francesco Redi similarly had disproved the maggots-from-meat hypothesis simply by keeping adult flies (and thus their eggs) away from rotting meat. Thus, Pasteur merely extended doubts about spontaneous generation into the microbial realm. Also, Pasteur’s work gets only a modest PS-score because, by hard criteria, his experiments did not prove that life has never arisen from inorganic materials, but rather that any such spontaneous proces...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Acknowledgments
• Introduction
• Part I: The First 50 Years (1859–1910): Laying the Foundations
• Part II: The Next 50 Years (1910–1960): Expanding the Foundations
• Part III: The 1960s and 1970s: Dawn of the Molecular Era
• Part IV: Post-1980: Elaborating and Revisiting the Foundations
• Epilogue
• Glossary
• Index