Genetics and the Origin of Species natural selection, and speciation throughout his book to explain habits of populations and the resulting effects on their genetic behavior. The book explains evolution in depth as a process over time that accounts for the diversity of all life on Earth. The study of evolution was present, but greatly neglected at the time. Dobzhansky illustrates that evolution regarding the origin and nature of species during this time in history was deemed mysterious, but had expanding potential for progress to be made in its field. In Darwin's theory of natural selection, more organisms are produced than can survive. Some have variations
Reactions to On the Origin of Species breeding that would eventually form part of "The Variation of Animals and Plants under Domestication". He wrote to Asa Gray and used the example of fantail pigeons to argue against Gray's belief "that variation has been led along certain beneficial lines", with the implication of Creationism rather than Natural Selection. Over the winter he organised a third edition of the "Origin", adding an introductory historical sketch. Asa Gray had published three supportive articles in the "Atlantic Monthly". Darwin persuaded Gray to publish them as a pamphlet, and was delighted when Gray came up with the title of "Natural Selection Not