Note: Definitions  &  Natural Selection and Adaptation are all functions that operate within the process of micro evolution, utilizing the genetic material inherent to the species. Darwin observed variation (within species), which is accomplished by a loss of genetic information. Micro evolution has never been shown to create a new species by what is termed macro evolution. see chapter: Micro & Macro Evolution
Definitions 1-6 are courtesy of The Free Dictionary by Farlex, 2013
 natural selection The process in nature by which, according to Darwin's theory of evolution, only the organisms best adapted to their environment tend to survive and transmit their genetic characteristics in increasing numbers to succeeding generations while those less adapted tend to be eliminated.
 Adaptation An alteration or adjustment in structure or habits, often hereditary, by which a species or individual improves its condition in relationship to its environment.
Genetic drift Random fluctuations in the frequency of the appearance of a gene in a small isolated population owing to chance rather than natural selection.
Comment: Definitions for Micro and Macro evolution ( &  below) describe the processes from an evolutionary perspective. The topics of micro and macro evolution will be discussed in the chapter of that name. Micro-evolution Evolution resulting from a succession of relatively small genetic changes that often cause the formation of new subspecies.  Macro-evolution Large scale evolution occurring over geologic time that results in the formation of new taxonomic groups.
Return to Darwinism: Natural Selection and Adaptation