Friday 12 February 2016

Charles Darwin

PERHAPS no one has influenced our knowledge of life on Earth as much as the English naturalist Charles Darwin (1809-1882). His theory of evolution by natural selection, now the unifying theory of the life sciences, explained where all of the astonishingly diverse kinds of living things came from and how they became exquisitely adapted to their particular environments. His theory reconciled a host of diverse kinds of evidence such as the progressive fossil record, geographical distribution of species, recapitulative appearances in embryology, homologous structures, vestigial organs and nesting taxonomic relationships. No other explanation before or since has made sense of these facts.
In further works Darwin demonstrated that the difference between humans and other animals is one of degree not kind. In geology, zoology, taxonomy, botany, palaeontology, philosophy, anthropology, psychology, literature and theology Darwin's writings produced profound reactions, many of which are still ongoing. Yet even without his evolutionary works, Darwin's accomplishments would be difficult to match. His brilliantly original work in geology, botany, bio-geography, invertebrate zoology, psychology and scientific travel writing would still make him one of the most original and influential workers in the history of science. Darwin's writings are consequently of interest to an extremely large number and wide variety of readers. This site contains the largest collection of his writings ever published.
Darwin's Theory of Evolution - The Premise
Darwin's Theory of Evolution is the widely held notion that all life is related and has descended from a common ancestor: the birds and the bananas, the fishes and the flowers -- all related. Darwin's general theory presumes the development of life from non-life and stresses a purely naturalistic (undirected) "descent with modification". That is, complex creatures evolve from more simplistic ancestors naturally over time. In a nutshell, as random genetic mutations occur within an organism's genetic code, the beneficial mutations are preserved because they aid survival -- a process known as "natural selection." These beneficial mutations are passed on to the next generation. Over time, beneficial mutations accumulate and the result is an entirely different organism (not just a variation of the original, but an entirely different creature).


Darwin's Theory of Evolution - Natural Selection
While Darwin's Theory of Evolution is a relatively young archetype, the evolutionary worldview itself is as old as antiquity. Ancient Greek philosophers such as Anaximander postulated the development of life from non-life and the evolutionary descent of man from animal. Charles Darwin simply brought something new to the old philosophy -- a plausible mechanism called "natural selection." Natural selection acts to preserve and accumulate minor advantageous genetic mutations. Suppose a member of a species developed a functional advantage (it grew wings and learned to fly). Its offspring would inherit that advantage and pass it on to their offspring. The inferior (disadvantaged) members of the same species would gradually die out, leaving only the superior (advantaged) members of the species. Natural selection is the preservation of a functional advantage that enables a species to compete better in the wild. Natural selection is the naturalistic equivalent to domestic breeding. Over the centuries, human breeders have produced dramatic changes in domestic animal populations by selecting individuals to breed. Breeders eliminate undesirable traits gradually over time. Similarly, natural selection eliminates inferior species gradually over time.


No comments:

Post a Comment