Wonderful life theory

Last updated

In biology, the wonderful life theory, also known as contingency theory, postulates that after hundreds of different phyla evolved during the Cambrian period, many of them subsequently became extinct, leaving the relatively few phyla that exist today. [1] The theory was first suggested in 1989 by Stephen Jay Gould in his book Wonderful Life . [2]

Contents

Evolutionary iconography

In Wonderful Life , Stephen Jay Gould discusses the iconography of evolution in popular culture and the damaging effects of the march of progress on public understanding of the theory.

The march of progress, Gould argues, has led to the popular interpretation that the evolution of increased mental powers, ultimately culminating in the development of man's complex brain, is the natural outcome of evolution. [2] Thus, the term "Evolution" is often conflated with a linear progression of life towards ever-increasing mental powers and a "comfortable view of human inevitability and superiority." [2] Gould argues that the definition of Evolution to professional biologists is "adaptation to changing environments", not progress, and that the composition of life on the planet is rather a "copiously branching bush, continually pruned by the grim reaper of extinction, not a ladder of predictable progress." [2] In an error that Gould refers to as "life's little joke", he discusses society's obsession with unsuccessful lineages as "textbook cases" of "evolution". To elaborate, we consistently seek out "a single line of advance from the true topology of copious branching. In this misguided effort, we are inevitably drawn to branches so near the brink of total annihilation that they retain only one surviving twig. We then view this twig as the acme of upward achievement, rather than the probable last grasp of a richer ancestry." [2] Gould uses the evolution of the horse to illustrate this point, as the unbroken connection between Hyracotherium (formerly called Eohippus ) and Equus provides an apparent linear path from simplicity to complexity. The only reason the evolution of horses has become the canonical representation of progressive evolution is because their bush has been extremely unsuccessful. [2] Instead, Gould argues, we should look to bats, antelopes, and rodents as champions of mammalian evolution as they present us with "thousands of twigs on a vigorous bush" and are the true embodiments of evolutionarily successful groups. [2]

The cone vs the pyramid

Gould argues that the conventional view of evolution, as illustrated by the cone of increasing diversity, [3] is flawed. It is typically assumed that early life is restricted in form, and from this restriction of form follows diversification into the variety of animal life that currently exists. [2] This cone can be visualized as an inverted Christmas tree, with a narrow base and numerous branches proliferating outward into the present day. [3] Gould presents an alternative hypothesis, however, which states that the history of life is better described as "decimation followed by diversification within a few remaining stocks", [3] represented as a pyramid with a wide base of anatomical disparity that becomes increasingly constrained by natural selection and extinction level events as time moves forward. [2] This is evidenced by the fact that the fossils excavated from the Burgess Shale in British Columbia represent a paleo-ecosystem with much greater anatomical disparity than currently exists and that fewer phyla exist today compared to the Cambrian seas. Gould offers the view that life during the Cambrian explosion quickly proliferated into the diversity of forms seen today due to the availability of numerous ecological niches and was subsequently decimated by extinction level events throughout geological time. [2] He also notes that the survival of groups following extinction events bears no relationship to traditional notions of Darwinian success in normal times. [2] For example,

"Even if fishes hone their adaptations to peaks of aquatic perfection, they will all die if the pond dries up. But grubby old buster the lungfish, former laughing stock of the piscine priesthood, may pull through - and not because a bunion on his great-grandfather's fin warned his ancestors about an impending comet. Buster and his kin may prevail because a feature evolved long ago for a different use has fortuitously permitted survival during a sudden and unpredictable change in the rules. And if we are Buster's legacy, and the result of a thousand other similarly happy accidents, how can we possibly view our mentality as inevitable, or even probable?" - Stephen Jay Gould

Ultimately, Gould explains, both the false iconography of the march of progress and our allegiance to the cone of increasing diversity have led us astray in our thinking about trends in evolutionary biology.

Replaying the "Tape of Life"

The central question proposed by Wonderful Life is that if life initially proliferated into a greater variety of phyla than currently exist and were subsequently decimated by the stochastic grim reaper of extinction, what then can be said about the inevitability of human intelligence and superiority? Additionally, Gould asks what role historical contingencies play in the evolution of life on Earth. It is these central ideas which prompt Gould to propose a thought experiment called "replaying the tape of life." [2] Its central essence is this: if we rewind the clock and replay the history of life on Earth numerous times, will we consistently see the same outcome that is the reality we experience today? [2] The outcome of this thought experiment has two possible interpretations, elaborated by Gould,

"Suppose that ten of a hundred designs will survive and diversify. If the ten survivors are predictable by superiority of anatomy (Interpretation 1), then they will win each time – and Burgess eliminations do not challenge our comforting view of life. But if the ten survivors are protégés of Lady Luck or fortunate beneficiaries of odd historical contingencies (Interpretation 2), then each replay of the tape will yield a different set of survivors and a radically different history. And if you recall from high-school algebra how to calculate permutations and combinations, you will realize that the total number of combinations for 10 items from a pool of 100 yields more than 17 trillion potential outcomes." - Stephen Jay Gould

Gould's opinion, and the central argument of Wonderful Life, is that "any replay of the tape of life would lead evolution down a pathway radically different from the road actually taken." [2] Additionally, Gould argues, no outcome can be predicated from the start, but the resulting pattern that emerges after replaying the tape of life would be just as interpretable and logical as our current situation. [2]

Related Research Articles

<span class="mw-page-title-main">Burgess Shale</span> Fossil-bearing rock formation in the Canadian Rockies

The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At 508 million years old, it is one of the earliest fossil beds containing soft-part imprints.

<i>Darwins Dangerous Idea</i> 1995 book by Daniel Dennett

Darwin's Dangerous Idea: Evolution and the Meanings of Life is a 1995 book by the philosopher Daniel Dennett, in which the author looks at some of the repercussions of Darwinian theory. The crux of the argument is that, whether or not Darwin's theories are overturned, there is no going back from the dangerous idea that design might not need a designer. Dennett makes this case on the basis that natural selection is a blind process, which is nevertheless sufficiently powerful to explain the evolution of life. Darwin's discovery was that the generation of life worked algorithmically, that processes behind it work in such a way that given these processes the results that they tend toward must be so.

<span class="mw-page-title-main">Punctuated equilibrium</span> Theory in evolutionary biology

In evolutionary biology, punctuated equilibrium is a theory that proposes that once a species appears in the fossil record, the population will become stable, showing little evolutionary change for most of its geological history. This state of little or no morphological change is called stasis. When significant evolutionary change occurs, the theory proposes that it is generally restricted to rare and geologically rapid events of branching speciation called cladogenesis. Cladogenesis is the process by which a species splits into two distinct species, rather than one species gradually transforming into another.

<span class="mw-page-title-main">Stephen Jay Gould</span> American biologist and historian of science (1941–2002)

Stephen Jay Gould was an American paleontologist, evolutionary biologist, and historian of science. He was one of the most influential and widely read authors of popular science of his generation. Gould spent most of his career teaching at Harvard University and working at the American Museum of Natural History in New York. In 1996, Gould was hired as the Vincent Astor Visiting Research Professor of Biology at New York University, after which he divided his time teaching between there and Harvard.

<i>The Selfish Gene</i> 1976 book by Richard Dawkins

The Selfish Gene is a 1976 book on evolution by ethologist Richard Dawkins, in which the author builds upon the principal theory of George C. Williams's Adaptation and Natural Selection (1966). Dawkins uses the term "selfish gene" as a way of expressing the gene-centred view of evolution, popularising ideas developed during the 1960s by W. D. Hamilton and others. From the gene-centred view, it follows that the more two individuals are genetically related, the more sense it makes for them to behave cooperatively with each other.

<i>Wonderful Life</i> (book) 1989 book by Stephen Jay Gould

Wonderful Life: The Burgess Shale and the Nature of History is a 1989 book on the evolution of Cambrian fauna by Harvard paleontologist Stephen Jay Gould. The volume made The New York Times Best Seller list, was the 1991 winner of the Royal Society's Rhone-Poulenc Prize, the American Historical Association's Forkosch Award, and was a 1991 finalist for the Pulitzer Prize. Gould described his later book Full House (1996) as a companion volume to Wonderful Life.

<i>Pikaia</i> Extinct genus of primitive chordates

Pikaia gracilens is an extinct, primitive chordate animal known from the Middle Cambrian Burgess Shale of British Columbia. Described in 1911 by Charles Doolittle Walcott as an annelid, and in 1979 by Harry B. Whittington and Simon Conway Morris as a chordate, it became "the most famous early chordate fossil", or "famously known as the earliest described Cambrian chordate". It is estimated to have lived during the latter period of the Cambrian explosion. Since its initial discovery, more than a hundred specimens have been recovered.

<span class="mw-page-title-main">Orthogenesis</span> Hypothesis that organisms have an innate tendency to evolve towards some goal

Orthogenesis, also known as orthogenetic evolution, progressive evolution, evolutionary progress, or progressionism, is an obsolete biological hypothesis that organisms have an innate tendency to evolve in a definite direction towards some goal (teleology) due to some internal mechanism or "driving force". According to the theory, the largest-scale trends in evolution have an absolute goal such as increasing biological complexity. Prominent historical figures who have championed some form of evolutionary progress include Jean-Baptiste Lamarck, Pierre Teilhard de Chardin, and Henri Bergson.

In evolutionary biology, megatrajectories are the major evolutionary milestones and directions in the evolution of life.

<i>Nonzero: The Logic of Human Destiny</i> Book by Robert Wright

Nonzero: The Logic of Human Destiny is a 1999 book by Robert Wright, in which the author argues that biological evolution and cultural evolution are shaped and directed first and foremost by "non-zero-sumness" i.e., the prospect of creating new interactions that are not zero-sum.

Simon Conway Morris is an English palaeontologist, evolutionary biologist, and astrobiologist known for his study of the fossils of the Burgess Shale and the Cambrian explosion. The results of these discoveries were celebrated in Stephen Jay Gould's 1989 book Wonderful Life. Conway Morris's own book on the subject, The Crucible of Creation (1998), however, is critical of Gould's presentation and interpretation.

<span class="mw-page-title-main">Structuralism (biology)</span> Attempt to explain evolution by forces other than natural selection

Biological or process structuralism is a school of biological thought that objects to an exclusively Darwinian or adaptationist explanation of natural selection such as is described in the 20th century's modern synthesis. It proposes instead that evolution is guided differently, basically by more or less physical forces which shape the development of an animal's body, and sometimes implies that these forces supersede selection altogether.

<i>Ontogeny and Phylogeny</i> Book by Stephen Jay Gould

Ontogeny and Phylogeny is a 1977 book on evolution by Stephen Jay Gould, in which the author explores the relationship between embryonic development (ontogeny) and biological evolution (phylogeny). Unlike his many popular books of essays, it was a technical book, and over the following decades it was influential in stimulating research into heterochrony, which had been neglected since Ernst Haeckel's theory that ontogeny recapitulates phylogeny had been largely discredited. This helped to create the field of evolutionary developmental biology.

<span class="mw-page-title-main">History of paleontology</span> History of the effort to understand the history of life on Earth by studying the fossil record

The history of paleontology traces the history of the effort to understand the history of life on Earth by studying the fossil record left behind by living organisms. Since it is concerned with understanding living organisms of the past, paleontology can be considered to be a field of biology, but its historical development has been closely tied to geology and the effort to understand the history of Earth itself.

Many scientists and philosophers of science have described evolution as fact and theory, a phrase which was used as the title of an article by paleontologist Stephen Jay Gould in 1981. He describes fact in science as meaning data, not known with absolute certainty but "confirmed to such a degree that it would be perverse to withhold provisional assent". A scientific theory is a well-substantiated explanation of such facts. The facts of evolution come from observational evidence of current processes, from imperfections in organisms recording historical common descent, and from transitions in the fossil record. Theories of evolution provide a provisional explanation for these facts.

<i>Dawkins vs. Gould</i> Book by Kim Sterelny

Dawkins vs. Gould: Survival of the Fittest is a book about the differing views of biologists Richard Dawkins and Stephen Jay Gould by philosopher of biology Kim Sterelny. When published in 2001 it became an international best-seller. A new edition was published in 2007 to include Gould's The Structure of Evolutionary Theory finished shortly before his death in 2002, and recent works by Dawkins. The synopsis below is from the 2007 publication.

The Cambrian explosion is an interval of time approximately 538.8 million years ago in the Cambrian period of the early Paleozoic when there was a sudden radiation of complex life, and practically all major animal phyla started appearing in the fossil record. It lasted for about 13 to 25 million years and resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversification in other groups of organisms as well.

<i>March of Progress</i> Illustration of human evolution

The March of Progress, originally titled The Road to Homo Sapiens, is an illustration that presents 25 million years of human evolution. It was created for the Early Man volume of the Life Nature Library, published in 1965, and drawn by the artist Rudolph Zallinger.

The fossils of the Burgess Shale, like the Burgess Shale itself, are fossils that formed around 505 million years ago in the mid-Cambrian period. They were discovered in Canada in 1886, and Charles Doolittle Walcott collected over 65,000 specimens in a series of field trips up to the alpine site from 1909 to 1924. After a period of neglect from the 1930s to the early 1960s, new excavations and re-examinations of Walcott's collection continue to reveal new species, and statistical analysis suggests that additional discoveries will continue for the foreseeable future. Stephen Jay Gould's 1989 book Wonderful Life describes the history of discovery up to the early 1980s, although his analysis of the implications for evolution has been contested.

Non-overlapping magisteria (NOMA) is the view, advocated by paleontologist Stephen Jay Gould, that science and religion each represent different areas of inquiry, fact vs. values, so there is a difference between the "nets" over which they have "a legitimate magisterium, or domain of teaching authority", and the two domains do not overlap. He suggests, with examples, that "NOMA enjoys strong and fully explicit support, even from the primary cultural stereotypes of hard-line traditionalism" and that it is "a sound position of general consensus, established by long struggle among people of goodwill in both magisteria." Some have criticized the idea or suggested limitations to it, and there continues to be disagreement over where the boundaries between the two magisteria should be.

References

  1. Bothamley, Jennifer (2002). Dictionary of Theories. Barnes and Noble. p. 557.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Gould, Stephen Jay. (17 September 1990). Wonderful life : the Burgess Shale and the nature of history. ISBN   9780393245202. OCLC   916045701.
  3. 1 2 3 "Models of Evolution". www.as.wvu.edu. Retrieved 2019-09-20.