Evolution is change in populations of organisms over generations. Offspring differ from their parents in various ways. When these differences are helpful, the offspring have a greater chance of surviving and reproducing, making the differences more common in the next generation. In this way, differences can accumulate over time, leading to major changes in a population.

The scientific theory of evolution—the explanation for how evolution occurs—states that all living things are descended, at some point in the distant past, from a single common ancestor. This is called common descent. Since the beginning of life, evolution has transformed the first species into more and more different species as life has found a variety of ways to survive and flourish. This has resulted in the many diverse forms of life that exist today.

Sourced

• The antagonism between science and religion, about which we hear so much, appears to me to be purely factitious–fabricated, on the one hand, by short-sighted religious people who confound a certain branch of science, theology, with religion; and, on the other, by equally short-sighted scientific people who forget that science takes for its province only that which is susceptible of clear intellectual comprehension; and that, outside the boundaries of that province, they must be content with imagination, with hope, and with ignorance.
  • Thomas Huxley, The interpreters of Genesis and the interpreters of Nature (1885)

• Anthropological, biological, and genetic evidence all put the origin of modern humans at between 200,000 and 100,000 years ago, probably in Africa. There is also much data that show an outburst of cultural behavior occurring around 50,000-40,000 years ago in Europe. That's when archaeologists date the oldest evidence of burial ceremonies, body ornaments, and cave paintings.
  • William J. Cromie, Facing up to Modern Man; Harvard Gazette

• I find it hard to swallow that I have only ten times more genes than those lowly bacteria in my gut. I had always liked the fact that they have ten thousand times less DNA than I did - that felt about right - but a factor of ten was carrying democracy a bit too far.
  • Gottfried Schatz in "Jeff's view on science and scientists", Amsterdam, Elsevier Butterworth-Heinemann, 2006, ISBN 978-0-444-52133-0, ISBN 0-444-52133-X (pbk.), p. 22, "Me and My Genome"

• Authors of the highest eminence seem to be fully satisfied with the view that each species has been independently created. To my mind it accords better with what we know of the laws impressed on matter by the Creator, that the production and extinction of the past and present inhabitants of the world should have been due to secondary causes, like those determining the birth and death of the individual. When I view all beings not as special creations, but as the lineal descendants of some few beings which lived long before the first bed of the Silurian system was deposited, they seem to me to become ennobled.
  • Charles Darwin, The Origin of Species (1859)

• If I did not think you a good tempered and truth-loving man I should not tell you that ... I have read your book with more pain than pleasure. Parts of it I admired greatly; parts I laughed at till my sides were almost sore; other parts I read with absolute sorrow; because I think them utterly false and grievously mischievous. You have deserted - after a start in that tram-road of all solid physical truth - the true method of induction ...
  • Adam Sedgwick, Letter to Charles Darwin from Adam Sedgwick (his mentor), November 24th, 1859, in The Correspondence of Charles Darwin vol. 7, pg. 396, after reading The Origin of Species.

• The most preposterous notion that H. sapiens has ever dreamed up is that the Lord God of Creation, Shaper and Ruler of all the Universes, wants the saccharine adoration of His creatures, can be swayed by their prayers, and becomes petulant if He does not receive this flattery. Yet this absurd fantasy, without a shred of evidence to bolster it, pays all the expenses of the oldest, largest, and least productive industry in all history.
  • Robert A. Heinlein, Time Enough for Love (1973)

• [A] curious aspect of the theory of evolution is that everybody thinks he understands it.
  • Jacques Monod (1910-1979) On the Molecular Theory of Evolution (1974) (French Biochemist, Nobel Prize Medicine 1965)

• Orgel's Second Rule: Evolution is cleverer than you are.
  • Francis Crick (British molecular biologist, 1916- ) quoted by Daniel C. Dennett in Elbow Room (1984)

• "Evolution is a tinkerer.
  • Francois Jacob (French biochemist 1920- )"Evolution and Tinkering" (1977). See "Bricolage"

• A hen is only an egg's way of making another egg.
  • Samuel Butler Life and Habit (1877)

• [Natural Selection] has not vision, no foresight, no sight at all. If it can be said to be play the role of watchmaker in nature, it is the *blind* watchmaker.
  • Richard Dawkins (English biologist,1941-) in The Blind Watchmaker (1986)

• Evolution is a change from an indefinite, incoherent, homogeneity to a definite, coherent, heterogeneity, through continuous differentiations and integrations.
  • Herbert Spencer, First Principles (1862)

• Evolution is a change from a no-howish untalkaboutable all-alikeness by continous sticktogetheration and somethingelsification.
  • A parody of the above quote, often attributed to William James, 1880 (Lecture Notes 1880-1897), but see http://evolvethought.blogspot.com/2005/01/spencer-and-critics.html.

• Survival of the fittest
  • Herbert Spencer, Principles of Biology 1864

• Nature, red in tooth and claw
  • Alfred Lord Tennyson, in 56th stanza of poem In Memoriam A.H.H. 1849

• Darwinian man though well behaved, is really but a monkey shaved!
  • Arthur Sullivan and libretto by W. S. Gilbert, Princess Ida, 1884.

• "Intelligent Design" is a sham. Promote Darwin's Evolution, the REAL thing!
  • Manfred F. Schieder (1937 - ) From http://rebirthofreason.com/Spirit/Quotes/Author_537.shtml

• We conclude - unexpectedly - that there is little evidence for the neo-Darwinian view: its theoretical foundations and the experimental evidence supporting it are weak, and there is no doubt that mutations of large effect are sometimes important in adaptation.
  • Orr, H. Allen [Center for Population Biology, University of California, Davis], & Coyne, Jerry A. [Department of Ecology and Evolution, University of Chicago], "The Genetics of Adaptation: A Reassessment," The American Naturalist, Vol. 140, No. 5, November 1992, p.726; Sourced at: http://members.iinet.net.au/~sejones/darwin03.html.

• Why don't we see gradual transition in the sequences of fossils? According to Darwin, and the current neo-Darwinists, the fossil record has gaps in it because of the haphazard way in which fossilization occurs-it is bound to be an imperfect record of the history of life. But is it? Is the jerky and abrupt nature of the record really just due to 'gaps', or does it reflect the way evolution actually happened? There is a strong feeling among leading palaeontologists that the punctuated history shown by fossils reflects the way life has evolved-in leaps and bounds rather than in gradual transition. There is also a growing sense that there is much more to understanding 'macroevolution' - the large-scale picture one gets from the fossils - than the simple idea of natural selection can alone explain.
  • Leith, Brian [producer, Natural History Unit, BC, Bristol UK], "The Descent of Darwin: A Handbook of Doubts about Darwinism," Collins: London, 1982, p.23. Sourced at: http://members.iinet.net.au/~sejones/evolut04.html.

• The world has arisen in some way or another. How it originated is the great question, and Darwin's theory, like all other attempts to explain the origin of life, is thus far merely conjectural. I believe he has not even made the best conjecture possible in the present state of our knowledge.
  • Louis Agassiz, Evolution and Permanence of Type (1874)

• Charles Darwin's evolution theory states that the strong eat the weak. According to Darwin's evolution theory we are the worst people. But it is actually not so. It is a natural universal law. If we take Darwin's evolution theory literally then God is the worst kind of being. Because God planned creation in a certain way. When love is involved there is no evil. Even mother birds sacrifice their own lives for the sake of their babies.
  • Sun Myung Moon, TRUE DAY OF ALL THINGS AND THE INITIATOR OF HARMONY, June 5, 1997

• We share most of our DNA with chimpanzees, but nowhere in the genome have we found what it is that makes us so different from chimps.
  • James Le Fanu, medical doctor and journalist, author of Why Us? How Science Rediscovered the Mystery of Ourselves (2009), quoted in Timesonline.co.uk (11 January 2009)

• Life and love by love
  We passed through the cycles strange,
  And breath by breath and death by death
  We followed the chain of change.
  • Langdon Smith, in "Evolution" (1895)

Unsourced

• To surrender to ignorance and call it God has always been premature, and it remains premature today.
  • Isaac Asimov

• When non-biologists talk about biological evolution they often confuse two different aspects of the definition. On the one hand there is the question of whether or not modern organisms have evolved from older ancestral organisms or whether modern species are continuing to change over time. On the other hand there are questions about the mechanism of the observed changes... how did evolution occur? Biologists consider the existence of biological evolution to be a fact. It can be demonstrated today and the historical evidence for its occurrence in the past is overwhelming. However, biologists readily admit that they are less certain of the exact mechanism of evolution; there are several theories of the mechanism of evolution.
  • Laurence Moran

• The 3 1/2" floppy drive came first, and then evolution kicked in, thus creating a chicken who laid an egg.
  • Louise Barros

• Books must follow sciences, and not sciences books.
  • Francis Bacon

• Science has proof without any certainty. Creationists have certainty without any proof.
  • Ashley Montagu

• People are DNA's way of making more DNA.
  • Edward O. Wilson, 1975

• Some creationists suggest that Noah took not dogs, wolves, and foxes on the ark with him, but only one animal which after the flood generated all the species of canines. This is actually stupider than simply saying "God just did it; don't ask questions." It seems to come from a worry that, after all, canines do seem to be genetically related; but then it sweeps away the genetic relationship to felines, primates, birds, chordates, etc.
  • Mark Rosenfelder

See also

The following pages include extensive additional material on this subject:

• Charles Darwin
• Richard Dawkins
• Thomas Henry Huxley
• Stephen Jay Gould
• Intelligent design
• Creationism and evolution