On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection Letter" from Darwin to Asa Gray. This was the first announcement of the Darwin – Wallace theory of evolution by natural selection; the papers appeared in print on 20 August 1858. The presentation of the papers spurred Darwin to write a condensed "abstract" of his "big book" on "Natural Selection". This was published in November 1859 as "On the Origin of Species". On the voyage of the "Beagle" the young Charles Darwin took a break between graduating and starting his career as a clergyman to study the natural history of South America, an interest he had developed at the University
Genetics and the Origin of Species variation would allow populations to evolve rapidly as environmental conditions change. This book was a landmark in the evolutionary synthesis, as it presented the union of Mendelian genetics and Darwinian theory. In "Genetics and the Origin of Species", polyploidy is considered as a type of mutation. Polyploid cells have a chromosome number that is more than twice the haploid number. The effects of polyploidy between two different species causes hybridization and even greater evolution. Natural selection in an environment produces reproductive success, which benefits the species. Speciation is a process of evolution through which new biological species are formed. Dobzhansky