Natural selection, where the environment chooses the newly mutated organism to survive while others die out, is the main instrument of evolution.
The Facts Are .....
"But how do you get from nothing to such an elaborate something if evolution must proceed through a long sequence of intermediate stages, each favoured by natural selection? You can't fly with 2% of a wing or gain much protection from an iota's similarity with a potentially concealing piece of vegetation. How, in other words, can natural selection explain these incipient stages of structure that can only be used (as we now observe them) in much more elaborated forms?" Written by evolutionist and palaeontologist Stephen J. Gould in "Not Necessarily a Wing", in Natural History, Vol. 94, No. 10, 1985 p:12
"But natural selection per se does not work to create new species." Written by the well-known naturalist and evolutionist, Niles Eldredge (a curator of the American Museum of Natural History in New York City), in "An Extravagance of Species (The Diversity of Fossil Trilobites Pose a Challenge to Traditional Evolutionary Theory)", in Natural History, Vol. 89, No. 7, July 1980 p:46
"The role assigned to natural selection in establishing adaptation, while speciously probable, is based on not one single sure datum [ie: a fact]." Written by the distinguished evolutionist Pierre Paul Grassé (former President of the French Acadamie des Sciences, and holder of the Chair of Evolution at the Sorbonne in Paris for 20 years), in his book "Evolution of Living Organisms", Academic Press: New York, 1977 p:170
"The hypothesis that natural selection has the degree of creative power required by Darwinist theory remains unsupported by empirical evidence." Written by Professor Phillip Johnson of the University of Californian in his book "Darwin on Trial", Intervarsity Press: Illinois, 1991 p:96
"In other words, natural selection over the long run does not seem to improve a species' chance of survival but simply enables it to 'track', or keep up with, the constantly changing environment." Written by Dr Richard Lewontin (Professor of Zoology, University of Chicago, and co-editor of the journal American Naturalist), in the article "Adaptation", in Scientific American, Vol. 239, No. 3, September 1978 p:215
"In the early part of the present century ..... the prestige of the selection theory declined until many biologists regarded it not only as a relatively unimportant factor in evolution, but in addition as a subject not worthy of study by progressive, serious-minded biologists." Written by G.L. Stebbins in the book
"Variation and Evolution in Plants", Columbia University Press: New York, 1950 p:101; Creation Ex Nihilo, Vol. 9, No. 2, 1987 p:14
"No one has ever produced a species by mechanisms of natural selection. No one has ever gotten near it ....." Spoken by evolutionist, Dr Colin Patterson, in an interview on the subject of Cladistics, BBC TV, March 4, 1982
"The central question of the  Chicago Conference was whether the mechanisms of microevolution (mutations and natural selection) could be extrapolated to explain the phenomenon of macroevolution. At the risk of doing violence to the positions of some people at the meeting, the answer can be given as a clear 'NO'!" Written by science writer and evolutionist, Roger Lewin, in the article "Evolutionary Theory Under Fire", in Science, Vol. 210, No. 4472, November 1980 p:883-887
Darwin, in his original publication, rejected Lamarck's hypothesis of acquired traits in favour of natural selection. Later, subsequent research and debate caused him to return to Lamarck's theory. In the sixth edition of his book Darwin abandoned natural selection as the driving force behind evolution.
This was due to the continuing lack of evidence and of theoretical problems. Charles Darwin, "The Origin of Species", (6th ed.) The Modern Library: New York, 1872 p:66