Reflections On Evolution

By Frederick Sproull

Evolution is a scientific theory asserting that species of organisms are capable of changing through time into different species. Present day species are thought to share common ancestors and genetic continuity with species that lived in the past. Evolution replaced an ancient view that species are basically static over time, not capable of significant change. Although Darwin was not the first to propose evolutionary views, he initiated a rapid paradigm shift. Within twelve years after publication of his On Origin of the Species in 1859, evolution became the predominant explanation by most mainstream Western intellectuals for how living organisms got here. Many scholars believe that evolution, in any recognizable form, only emerged in the eighteenth century associated with a broader philosophy of progress, and it continued to be strongly associated with that philosophy and ideology until the middle of the twentieth century. Even today, remnants of that association still survive. Evolution has always been culturally and ideologically linked. This linkage is so strong that evolution has been used in this work as a model to make a point that science is a social enterprise directly influenced by its cultural milieu. Such analysis rejects the more popular view that science is, or can be, merely a dispassionate search for the truth, detached from any cultural norm or ideology. Evolution has always had wide-ranging implications; it is an idea that reverberates far beyond science. One reason for this is that it removes humans and other living organisms from the status of being directly and specially created by God. Increasingly since Darwin, evolution explains the history of life in a materialistic way, freeing biology from theological constraints on the important question of how species got here. By detaching biology from the supernatural, evolution allowed biology to become modern science. Evolution also acts as one of the few unifying concepts in biology, bringing biology’s many desperate areas together into a cohesive scientific discipline. Recent developments in science and technology, many in the area of molecular biology, have resulted in the emergence of a new understanding of evolutionary mechanisms and they are providing deeper insight into the unity of living organisms and how biological novelty emerges. As incredible as these advances are, they have not silenced the religious debates that have historically been associated with evolution. These debates have continued into the twenty-first century. However, evolution is not necessarily at odds with religion. At least since Darwin, mainstream religions in the West have accommodated at least some form of it. This work attempts to place twenty-first century evolution into a historical and ideological context. New scientific ideas and discoveries that have shaped, and are shaping, evolution are discussed within this framework. Also discussed are how these discoveries are transforming, contradicting, and reshaping traditional Darwinism and new synthesis evolutionary thought.

• Language: English
• Publisher: Page Publishing, Inc.
• Release date: Jul 7, 2017
• ISBN: 9781635686029

Book preview

cover.jpg

Reflections on

Evolution

Frederick Sproull

Copyright © 2017 Frederick Sproull

All rights reserved

First Edition

PAGE PUBLISHING, INC.

New York, NY

First originally published by Page Publishing, Inc. 2017

ISBN 978-1-63568-601-2 (Paperback)

ISBN 978-1-63568-602-9 (Digital)

Printed in the United States of America

Introduction: Initial Reflections What Is Evolution?

Basic Definitions

Evolution is the idea that species of living organisms can change into different species over time. In essence, species alive today are believed to be derived from preexisting ones and to have genetic continuity with them. Evolution is change; it views the history of life as characterized by change. It rejects ancient views of nature, which see species as static, unchanging entities. However, the implications of evolution go far beyond the scope of these basic definitions. This work explores certain scientific and nonscientific factors that contributed to the development of evolutionary theory from the Enlightenment to present. Emphasis is placed on how new synthesis evolution is being revised, extended, and in some ways refuted by recent scientific advances and by developing views on how change occurs in nature.

Evolution as a Unifying Concept

Evolution is important to biology as one of a few unifying concepts. The following are just a few of the many seemingly disparate phenomena linked together by evolution. Evolution explains why there are so many different life-forms on earth (biodiversity). They branch through time from previously existing species! It explains why species are adapted to their environments. Darwin gave us this insight with his evolutionary mechanism of natural selection. It explains why the types of organisms found in the fossil record are different from organisms living today. Why deoxyribonucleic acid (DNA) is the primary genetic material in all living organisms. Why all organisms are composed of cells. Why genetic disorders such as sickle cell anemia emerge and are perpetuated in certain populations. Why bacteria are becoming antibiotic resistant and insects more pesticide resistant. Why species as different as humans and bacteria share similar or identical biochemical and metabolic pathways. Without evolution, these topics are unrelated. With evolution, all are explained within a common intellectual and scientific framework.

Theodosius Dobzhansky, an important mid-twentieth-century evolutionist, recognized evolution’s unifying nature over fifty years ago. He stated, Nothing in biology makes sense except in light of evolution.¹ Without evolution, biology is only a catalog by interesting, but unrelated facts that describe the living world. Evolution acts as an explanatory and organizing framework which allowed biology to emerge as modern science.

Evolution as Myth

Evolution is a story about the origins of living organisms, including the origin of humans. No scientific theory has as much to say about who humans are and where we come from as evolution. Historically, evolution has often been interpreted as contradicting a literal interpretation of the Genesis stories of human origins. The beginning chapters of Genesis, the first book in the Jewish and Christian scriptures, describe how the Israelite God created the world and sequentially made all living creatures, including humans, in apparently their present form. The conflict between beliefs of this type and evolutionary views are a reason why evolutionary ideas have generated more controversy and passion over the last couple of hundred years than any other type of scientific theory.

Every culture or society has origin stories of one type or another. Western society has many, reflecting its diverse nature. Whatever their source, origin stories often have some common characteristics. Many are documented in religious books, folk tales, or oral traditions of a particular group. Most rely on intervention of supernatural entities or forces. Almost always, they reflect the values, beliefs, or history of the group. Stories of this type are commonly called myths.² A relevant example of this type of story is found in Genesis.

Evolution competes with such origin stories, and it is distinguishable from them in one fundamental way. At least since Darwin’s On Origin of the Species in 1859, evolution has relied on Western scientific methodology for its support and justification. It is tied to the scientific method.³,⁴

The scientific method is not easy to define and some of its characteristics have changed over time. However, increasingly by the second half of the nineteenth century and early twentieth century, it excluded supernatural explanations. The scientific method relies on repeatable observation and/or controlled experiments to gain information; often, this takes the form of hypothesis testing. There is also a tentative nature to its conclusions as it awaits further observations and testing that may change prevailing views. Evolution is the only origin story characterized by this approach. It is the only origin story that is science.

Notwithstanding this, evolution shares an important characteristic with other origin stories. It has always reflected the changing values and beliefs of our culture. Evolution was often linked in eighteenth century Western Europe to a more general philosophy of change (progressivism). It was often bound to progressive philosophy and its early acceptance was often attached to it.⁵,⁸ Although evolution began to dissociate itself from progressivism in the middle of the twentieth century, it has continued to reflect the values and beliefs of Western culture.

Evolution Explains Two Seemingly Contradictory Characteristics of Life

Modern evolution provides a relevant naturalistic explanation for the origin of species. It does this by explaining two seemingly contradictory characteristics of life on earth that have engaged naturalists and observers of nature for thousands of years; life’s underlying unity and its incredible diversity.

There are millions of different life-forms that inhabit this planet. Consider the vast array of different species of organisms that live in the various and diverse ecosystems of earth. Consider, also, the almost limitless species of microscopic organisms that exist. Life on earth is diverse!

Evolution explains this diversity by asserting that over time species branch and multiply into an almost endless array of new species. Another way of saying this is that species are not fixed entities; new species emerge through time with different characters from pre-existing ones.

Yet, biologists know that this diversity of life thinly veils an underlying unity that all living organisms possess. Living organisms share many fundamental characteristics with one another. This unity can be observed on at least three biologically levels; the level of the organism, the level of the cell, and the level of the molecule. For example, it has been observed for thousands of years that different species share characteristics with one another on an organismic level; structural and functional similarities abound among even diverse organisms. Five digits, segmentation, and bilateral symmetry are just a few similarities commonly found in various kinds of organisms. There are many others as well.

However, over the last couple of hundred years even greater unity has also been discovered at the cellular level. Cells were first discovered at the very end of the sixteenth with the invention of the microscope. Observations over hundreds of years allowed naturalists in the nineteenth century to inductively reason that all living organisms are composed of structural similar cells. This conclusion was codified in that century into the modern cell theory. The cell theory holds that all living organisms are composed of cells, and that the basic structural unit of all life is the cell; whether the life-form is bacteria, human, or anything else. There has never been a living organism discovered that is not composed of one or more cells.

Since the middle of the twentieth century, technological advances have allowed an even deeper and more fundamental unity to be recognized by scientists at the molecular level. For example, we now know that all organisms discovered so far use DNA as the primary genetic material and that they all have a nearly identical genetic code. In addition, living organisms use ribonucleic acid (RNA) in protein synthesis and share remarkably similar biochemical processes for making proteins. All living organisms share many similar or nearly identical metabolic pathways and processes. There is close biochemical and molecular similarity among living organisms on earth. Organisms as diverse as bacteria and humans show an incredible unity at this level.

This molecular unity has been exploited over the last couple of decades with new techniques and technologies. For example, human insulin genes and human growth hormone genes are routinely genetically engineered into bacteria cells where they are expressed by the host bacteria with protein products harvested for medical use. Who would have believed, even a few decades ago, that the biochemical machinery of bacteria is so similar to that found in human cells that bacteria can express certain human genes and actually make functional human proteins?

In summary, the three levels of unity discussed, and life’s great diversity, are explained through evolution. The unity is the result of all life being genetically related and derived from common ancestors. The diversity is the result of branching and divergence from common ancestors over time.

Evolution and Adaptation

Evolution also explains another fundamental characteristic of life that has intrigued naturalists for ages, the adaptation of organisms to their particular environments. Naturalists and philosophers have noticed for thousands of years that living organisms generally fit well into the particular environments in which they live; that is, they are adapted to their environment. The fin of the fish or the flipper of the whale for swimming, the wing of the bat or bird for flying, and the paw of the cat for running, climbing, and predation are all examples of adaptation. Over the centuries adaptation was often explained in supernatural terms. One common idea from the seventeenth century to Darwin’s time was that adaptation was a manifestation of God’s wisdom and goodness. This is called natural theology. Darwin turned this idea 180 degrees by explaining adaptation in evolutionary terms. Adaptation, to Darwin, was the result of materialistic mechanisms driving evolutionary change of populations, rather than the result of supernatural forces. ⁵,⁶

Evolution Not Obvious

Despite the importance of evolution to modern biology, it has not always been an important part of natural history. Evolution is not intuitively obvious, and it cannot generally be observed directly. It was rather late in Western history before evolutionary thinking was explored by philosophers and naturalists in any consistent manner. Static belief systems were not seriously questioned by significant numbers of Western intellectuals until the eighteenth century. Static views of nature have ancient roots. They were supported by Plato and Aristotle’s philosophies, and often Judean-Christian theology. The Genesis creation story, interpreted in a hyper-literal manner, represents a Judean-Christian example of a static view, describing how God created modern species in their present form. Static views prevailed until Charles Darwin published his book, On the Origin of Species in 1859. In Origin, Darwin presented an enormous amount of circumstantial evidence supporting biological evolution; or as he called it, descent with modification . He also presented a material mechanism for evolution which he called natural selection.⁵, ⁹

Evolution as an Intellectual Paradigm

Prior to Origin of the Species, most intellectuals did not have an evolutionary view of nature. However, within twelve years after its publication, evolution became a dominant intellectual paradigm in the West.⁵, ¹⁰, ⁹, ¹¹ This change in thinking has enormous significance that goes far beyond biology. Freud believed that evolution represents one of two great intellectual revolutions of Western thought. It was only equaled, he believed, by the replacement of a geocentric model of the universe with a Copernican heliocentric one in the sixteenth and seventeen centuries. Freud felt that evolution was revolutionary because it removed humans from their status as specially created by God. Humans became merely one branch of the animal kingdom. Freud suggested that evolution’s impact on how humans see themselves is qualitatively different than that of any other intellectual idea.¹¹ It is this aspect of evolution that has generated so much religious and intellectual conflict over the last couple of hundred years.

In the last half of the twentieth century, Richard Lewontin also discussed evolution’s broader importance. Lewontin stated that "[T]here have been only two real revolutions in biology since the Renaissance. The first was the introduction of mechanical biology by William Harvey and René Descartes…The second biological revolution, to which we attach the name of Darwin, is still being consolidated. Although its manifesto, On Origin of Species, appeared in 1859, it was not until the 1940s that Darwinism really established a hegemonic hold on such branches of biology as classification, physiology, anatomy, and genetics. It is still under siege by the restorationist armies of creationism, while at the same time it is undergoing a severe internal struggle to define its own orthodoxy and to resolve its own contradictions".¹², ¹¹

The importance of evolutionary theory was also explored by biologist Ernst Mayr. Mayr lived a long life, dying in 2005 at the age of one hundred, intellectually active to the end. He was one of the twentieth century’s outstanding evolutionary biologists and one of the intellectual parents of the new synthesis of evolutionary biology. Mayr pointed out that evolutionary theory is so intellectually pervasive that almost every component of modern Western belief systems is somehow affected by Darwinian principles.¹³, ¹¹ His point was that ever since Darwin, evolution thinking has increasingly integrating itself into almost every part of Western intellectual life.

Evolution and Political and Social Thought

As might be expected from an idea that has such broad implications, over the years evolution has often been used to support many diverse and sometimes exploitative political and economic ideologies. Proponents of social Darwinism (a philosophy that attempts to [mis]apply evolutionary principles to human behavior, usually equating the fittest or best with those rich or politically powerful) and other exploitative philosophies such as laissez-faire capitalism, eugenics, Nazism, racism, and imperialism have used evolutionary theories, of one type or another, for support or ratification.⁶, ⁷, ⁸

In Darwin’s time, biological evolution was used as a legitimating ideology supporting the bourgeois revolution. In this sense, it was used as scientific justification for the emerging mercantile capitalist class’ attempt to gain political and economic power at the expense of the hereditary, static establishment. ⁶, ⁷, ⁸

Evolution is still being used to justify various ideologies. For example, beginning in the middle of the 1970s, proponents of a new discipline, sociobiology, proposed that Darwinian natural selection can explain a variety of complex social behaviors in animals. The reason this idea is controversial is because it also includes human social behaviors. Human behaviors explained through selection have included greed, selfishness, exploitation, racism, sexism, aggression, spite, xenophobia, conformity, and even upward mobility. ¹⁴, ¹⁵, ¹⁶

Human sociobiology poses a number of scientific and ideological problems. For instance, if sociobiologists are correct, complex behavior in humans must be under the direct control of genes. The reason for this is because only heritable traits are generally subject to selection.

Opponents of sociobiology have taken issue with this view, asserting that there is little scientific evidence to support a direct genetic link for complex behaviors. Rather, they see human sociobiology as deterministic and "hyper-adaptationist" ideology which causes more scientifically legitimate non-adaptationist alternatives to be deemphasized.¹⁴, ¹⁵ Human sociobiology has also been opposed ideologically as an extension of capitalist libertarianism, and as a modern form of social Darwinism, providing justification and validation for a variety of exploitative social behaviors.¹⁶, ¹⁵, ¹⁴ These ideas will be explored later in this work.

Evolution and Ideology

There has always been a bidirectional link between evolution and ideology. Although, evolution has served as an ideological foundation for various political philosophies, many argue that evolution itself emerged as part of a larger progressive ideology (progressivism) during the Enlightenment, which held that change is natural and beneficial. Evolution did not begin to detach itself from progressive ideology until the middle of the twentieth century, with this trend continuing into the first part of the twenty-first century. ⁸, ⁵

Evolution as Science and Fact

However, changing ideologies cannot fully explain the emergence of evolutionary theory. Quite the contrary, modern evolution owes its emergence to a complex interplay of ideology and the accumulation of knowledge, and the development of scientific technologies and methodologies by naturalists, inventors, and explorers that began in earnest in the seventeenth century and continues to this day. Evolution is science.

Evolution as science is the reason it is often called fact by so many modern intellectuals. Evolution as fact is a well-settled principle in biology. Few biologists doubt that evolution happened, or that it is happening. Debates among most scientists are confined to which biological mechanisms are central to evolutionary change; that, is how evolution generally proceeds. To be sure, intense arguments over mechanisms have occurred and are occurring. ²⁰

The fact of evolution and these debates will be explored in this work within their scientific and ideological context. Discussions will include whether evolution’s mode (the way it proceeds) is most often gradual as Darwin and most new synthesis biologists believed. Why does evolution often appear punctuated in the fossil record? Is its tempo (rate) generally slow, or is it often rapid? Is genetic recombination and mutation the only, or main, sources of variation important in evolution?

Two great mergers or reconciliations that have shaped modern evolution will be discussed. The new synthesis of evolutionary biology, resulting from the merger of Darwinian evolution with Mendelian and population genetics in the first half of the twentieth century will be addressed. The new synthesis was the main evolutionary paradigm of