Skip to contentWillowOne's Positions
TagsWhat’s newMediaStatistics
Search
Notes
WillowOne's Positions

Natural Selection

My Positions

  1. Evolution by natural selection is an observable phenomenon. It has been observed directly in the laboratory, in the field, and in the fossil record.
  2. Evolution by natural selection is, by definition, not a random process. Selection is the opposite of randomness.
  3. Natural selection is the only known mechanism that produces adaptive complexity. Other mechanisms of evolution (genetic drift, mutation, gene flow) change gene frequencies but do not, by themselves, produce fit between organisms and their environments.
  4. Darwinism, understood as evolution by natural selection acting on heritable variation, remains the most robust scientific explanation for the complexity and diversity of life; it is incomplete in some respects (it does not, on its own, fully account for phenomena such as epigenetic inheritance or horizontal gene transfer), but it forms the core framework of modern evolutionary biology.
  5. Modern evolutionary theory, often called the Modern Synthesis or, in its recent developments, the Extended Evolutionary Synthesis, has built on Darwin's model by incorporating genetics (Mendelian and molecular), population biology, developmental biology (evo-devo), and epigenetics, among others; these are refinements of Darwin's theory, not departures from it.
  6. The term "Darwinism" is used by creationists as though evolution were an ideology or a personal following; it is not, biologists do not call themselves Darwinists any more than physicists call themselves Newtonists, and I use the term here only to refer to the specific mechanism Darwin proposed.

Notes

  • Evolution is not a random process. While genetic mutations arise randomly with respect to the organism's needs, natural selection, the central mechanism of biological evolution, is non-random: it systematically favours traits that enhance an organism's chances of survival and reproduction in its environment. The common creationist claim that evolution is "like a tornado in a junkyard assembling a Boeing 747" (Fred Hoyle's image, borrowed by Ken Ham and others) describes a single random step, not a cumulative selective process. The correct analogy is a tornado that keeps every piece that happens to fit, and discards the rest, over millions of iterations. See Richard Dawkins, Climbing Mount Improbable (1996).
  • The mechanism requires only three things: variation between individuals, heredity of that variation, and differential reproductive success depending on it. Wherever these three conditions hold, evolution by natural selection follows as a logical consequence. It is not a hypothesis about what might happen; it is a description of what must happen.
  • Direct observations include:
    • Antibiotic resistance in bacteria and pesticide resistance in insects, observed within years.
    • Richard Lenski's long-term E. coli experiment, running since 1988, now past 75,000 generations, in which one population evolved the ability to metabolise citrate.
    • The Grants' decades-long study of Darwin's finches on Daphne Major, documenting changes in beak size in response to drought.
    • Industrial melanism in the peppered moth.
    • The evolution of new species (speciation) observed in plants (polyploid hybrids), fruit flies, and cichlid fish.
  • Natural selection does not aim at anything. It has no foresight, no goal, and no concept of "higher" or "lower". Humans are not the point of evolution; we are one of its current products, as is every bacterium. The notion of a "ladder" of evolution with humans at the top is a pre-Darwinian idea that has survived in popular culture.
  • What natural selection explains that nothing else does is the appearance of design. Before Darwin, the only available explanation for the fit between organisms and their environments was a designer (see Teleological Argument). Darwin showed how a blind, cumulative process of variation and differential survival produces the same result, and does so with the characteristic imperfections (vestigial organs, inefficient routing of nerves and blood vessels, the shared bad design of related species) that a designer would not produce.
  • The history of the idea. Charles Darwin (1809–1882) formulated his theory of natural selection without knowledge of genetics, which had not yet been established as a scientific discipline. Alfred Russel Wallace arrived at the same theory independently, and the two were presented jointly to the Linnean Society in 1858.
  • Gregor Mendel published his foundational work on inheritance in pea plants in 1866, but it was largely ignored until around 1900, well after On the Origin of Species (1859). As a result, Darwin lacked a mechanism to explain how traits were inherited without blending away, which he acknowledged as a weakness in his theory. Had he known of Mendel's work, the problem would have been solved in his lifetime.
  • The Modern Synthesis of the 1930s and 1940s (R. A. Fisher, J. B. S. Haldane, Sewall Wright, Theodosius Dobzhansky, Ernst Mayr, and others) resolved this by combining Darwinian selection with Mendelian genetics and population mathematics, forming the basis of contemporary evolutionary biology. The discovery of DNA's structure (1953) and the subsequent development of molecular biology then supplied the physical basis of heredity; the genetic evidence for common descent that followed is set out under Evolution.
  • Beyond biology. Darwin's theory has since been applied to the evolution of languages, technologies, and ideas (see Richard Dawkins on memes, and Daniel Dennett's Darwin's Dangerous Idea, 1995), with varying success. The core insight, that any system with heredity, variation, and differential replication will evolve, is substrate-independent.

Also see